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Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2018	Feb. 01, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	ARCH COAL INC
Entity Central Index Key	0001037676
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		17,688,875
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 1.5
Entity Small Business Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false

Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 575,688		$ 2,451,787	$ 2,324,623
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)	470,319		1,925,202	1,839,993
Depreciation, depletion and amortization	32,604		119,563	122,464
Accretion on asset retirement obligations	7,634		27,970	30,209
Amortization of sales contracts, net	796		11,107	53,985
Change in fair value of coal derivatives and coal trading activities, net	396		9,118	7,222
Asset impairment and mine closure costs	0		0	0
Selling, general and administrative expenses	23,193		100,300	87,952
Gain on sale of Lone Mountain Processing, Inc.	0		0	(21,297)
Other operating income, net	(5,340)		(20,611)	(30,241)
Costs, expenses and other operating	529,602		2,172,649	2,090,287
Income (loss) from operations	46,086		279,138	234,336
Interest expense, net
Interest expense	(11,241)		(20,471)	(26,905)
Interest and investment income	487		6,782	2,649
Interest expense, net	(10,754)		(13,689)	(24,256)
Income (loss) before nonoperating expenses	35,332		265,449	210,080
Nonoperating income (expense)
Non-service related pension and postretirement benefit costs	32		(3,202)	(1,940)
Net loss resulting from early retirement of debt and debt restructuring	0		(485)	(2,547)
Reorganization income (loss), net	(759)		(1,661)	(2,398)
Nonoperating income (expense)	(727)		(5,348)	(6,885)
Income before income taxes	34,605		260,101	203,195
Provision for (benefit from) income taxes	1,156		(52,476)	(35,255)
Net income	$ 33,449		$ 312,577	$ 238,450
Earnings per common share
Basic earnings per common share (in dollars per share)	$ 1.34		$ 15.90	$ 10.05
Diluted earnings per common share (in dollars per share)	$ 1.31		$ 15.15	$ 9.84
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)	25,002		19,663	23,725
Diluted weighted average shares outstanding (in shares)	25,469		20,629	24,240
Predecessor
Revenues		$ 1,398,709
Costs, expenses and other operating
Cost of sales (exclusive of items shown separately below)		1,262,174
Depreciation, depletion and amortization		191,581
Accretion on asset retirement obligations		24,321
Amortization of sales contracts, net		(728)
Change in fair value of coal derivatives and coal trading activities, net		2,856
Asset impairment and mine closure costs		129,267
Selling, general and administrative expenses		59,918
Gain on sale of Lone Mountain Processing, Inc.		0
Other operating income, net		(15,257)
Costs, expenses and other operating		1,654,132
Income (loss) from operations		(255,423)
Interest expense, net
Interest expense		(135,888)
Interest and investment income		2,653
Interest expense, net		(133,235)
Income (loss) before nonoperating expenses		(388,658)
Nonoperating income (expense)
Non-service related pension and postretirement benefit costs		(1,715)
Net loss resulting from early retirement of debt and debt restructuring		(2,213)
Reorganization income (loss), net		1,630,041
Nonoperating income (expense)		1,626,113
Income before income taxes		1,237,455
Provision for (benefit from) income taxes		(4,626)
Net income		$ 1,242,081
Earnings per common share
Basic earnings per common share (in dollars per share)		$ 58.33
Diluted earnings per common share (in dollars per share)		$ 58.28
Weighted average shares outstanding
Basic weighted average shares outstanding (in shares)		21,293
Diluted weighted average shares outstanding (in shares)		21,313

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 33,449		$ 312,577	$ 238,450
Derivative instruments
Comprehensive income (loss) before tax	0		2,681	647
Income tax benefit (provision)	0		0	0
Derivative instruments, net of tax	0		2,681	647
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax	24,067		20,591	(4,347)
Income tax benefit (provision)	0		0	0
Pension, postretirement and other post-employment benefits, net of tax	24,067		20,591	(4,347)
Available-for-sale securities
Comprehensive income (loss) before tax	387		(343)	(387)
Income tax benefit (provision)	0		0	0
Available-for-sale securities, net of tax	387		(343)	(387)
Total other comprehensive income (loss)	24,454		22,929	(4,087)
Total comprehensive income	$ 57,903		$ 335,506	$ 234,363
Predecessor
Net income		$ 1,242,081
Derivative instruments
Comprehensive income (loss) before tax		(532)
Income tax benefit (provision)		80
Derivative instruments, net of tax		(452)
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax		(1,848)
Income tax benefit (provision)		483
Pension, postretirement and other post-employment benefits, net of tax		(1,365)
Available-for-sale securities
Comprehensive income (loss) before tax		2,968
Income tax benefit (provision)		(1,042)
Available-for-sale securities, net of tax		1,926
Total other comprehensive income (loss)		109
Total comprehensive income		$ 1,242,190

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 264,937	$ 273,387
Short-term investments	162,797	155,846
Trade accounts receivable	200,904	172,604
Other receivables	48,926	29,771
Inventories	125,470	128,960
Other current assets	75,749	70,426
Total current assets	878,783	830,994
Property, plant and equipment
Coal lands and mineral rights	396,125	390,920
Plant and equipment	510,683	445,407
Deferred mine development	194,363	267,063
Property, plant and equipment, gross	1,101,171	1,103,390
Less accumulated depreciation, depletion and amortization	(266,343)	(147,442)
Property, plant and equipment, net	834,828	955,948
Other assets
Prepaid royalties	600	4,280
Deferred income taxes	170	22,520
Equity investments	104,676	106,107
Other noncurrent assets	68,003	59,783
Total other assets	173,449	192,690
Total assets	1,887,060	1,979,632
Current liabilities
Accounts payable	128,024	134,137
Accrued expenses and other current liabilities	183,514	184,161
Current maturities of debt	17,797	15,783
Total current liabilities	329,335	334,081
Long-term debt	300,186	310,134
Asset retirement obligations	230,304	308,855
Accrued pension benefits	16,147	14,036
Accrued postretirement benefits other than pension	83,163	102,369
Accrued workers’ compensation	174,303	184,835
Other noncurrent liabilities	48,801	59,457
Total liabilities	1,182,239	1,313,767
Stockholders' equity
Common stock, $0.01 par value, authorized 300,000 shares, issued 25,047 shares at December 31, 2018 and 2017, respectively	250	250
Paid-in capital	717,492	700,125
Treasury stock, 7,216 and 3,977 shares at December 31, 2018 and 2017, respectively, at cost	(583,883)	(302,109)
Retained earnings	527,666	247,232
Accumulated other comprehensive income	43,296	20,367
Total stockholders’ equity	704,821	665,865
Total liabilities and stockholders’ equity	$ 1,887,060	$ 1,979,632

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	25,047,000	25,047,000
Treasury stock, shares (in shares)	7,216,000	3,977,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income	$ 33,449		$ 312,577	$ 238,450
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation, depletion and amortization	32,604		119,563	122,464
Accretion on asset retirement obligations	7,634		27,970	30,209
Amortization of sales contracts, net	796		11,107	53,985
Prepaid royalties expensed	2,587		134	2,905
Deferred income taxes	3		18,701	(21,965)
Employee stock-based compensation expense	1,032		17,519	10,437
Gains on disposals and divestitures	(485)		(625)	(24,327)
Asset impairment and noncash mine closure costs	0		0	0
Amortization relating to financing activities	467		4,179	3,736
Net loss resulting from early retirement of debt and debt restructuring	0		485	2,547
Non-cash bankruptcy reorganization items	0		0	0
Changes in:
Receivables	(22,196)		(22,903)	8,370
Inventories	24,870		3,490	(19,626)
Coal derivative assets and liabilities	1,662		7,716	6,040
Accounts payable, accrued expenses and other current liabilities	34,129		(14,208)	17,173
Asset retirement obligations	(4,535)		(9,743)	(20,584)
Pension, postretirement and other postemployment benefits	(5,625)		(4,703)	(15,253)
Other	(22,200)		(53,296)	1,913
Cash provided by (used in) operating activities	84,192		417,963	396,474
Investing activities
Capital expenditures	(15,214)		(95,272)	(59,205)
Minimum royalty payments	(63)		(584)	(5,296)
Proceeds from (consideration paid for) disposals and divestiture	572		1,083	12,920
Purchases of short term investments	0		(143,328)	(258,948)
Proceeds from sales of short term investments	23,000		136,630	190,064
Proceeds from sale of investments in equity investments and securities	0		0	0
Investments in and advances to affiliates, net	(823)		(2,481)	(10,173)
Cash provided by (used in) investing activities	7,472		(103,952)	(130,638)
Financing activities
Proceeds from issuance of term loan due 2024	0		0	298,500
Payments to extinguish term loan due 2021	0		0	(325,684)
Payments on term loan	(816)		(3,000)	(2,250)
Net receipts (payments) on other debt	3,374		(6,077)	(694)
Debt financing costs	0		(1,257)	(10,149)
Dividends paid	0		(31,269)	(24,369)
Purchases of treasury stock	0		(280,871)	(301,512)
Expenses related to debt restructuring	0		(50)	(2,360)
Other	151		(152)	(138)
Cash provided by (used in) financing activities	2,709		(322,676)	(368,656)
Increase (decrease) in cash and cash equivalents, including restricted cash	94,373		(8,665)	(102,820)
Cash and cash equivalents, including restricted cash, beginning of period	282,049		273,602	376,422
Cash and cash equivalents, including restricted cash, end of period	376,422	$ 282,049	264,937	273,602
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid during the period for interest	39,620		17,493	34,691
Cash refunded during the period for income taxes, net	287		$ 24,330	$ 7,958
Predecessor
Operating activities
Net income		1,242,081
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation, depletion and amortization		191,581
Accretion on asset retirement obligations		24,321
Amortization of sales contracts, net		(728)
Prepaid royalties expensed		4,791
Deferred income taxes		(419)
Employee stock-based compensation expense		2,096
Gains on disposals and divestitures		(6,628)
Asset impairment and noncash mine closure costs		119,194
Amortization relating to financing activities		12,800
Net loss resulting from early retirement of debt and debt restructuring		2,213
Non-cash bankruptcy reorganization items		(1,775,910)
Changes in:
Receivables		(42,786)
Inventories		34,440
Coal derivative assets and liabilities		5,678
Accounts payable, accrued expenses and other current liabilities		15,316
Asset retirement obligations		(12,041)
Pension, postretirement and other postemployment benefits		(15,692)
Other		(28,525)
Cash provided by (used in) operating activities		(228,218)
Investing activities
Capital expenditures		(82,434)
Minimum royalty payments		(305)
Proceeds from (consideration paid for) disposals and divestiture		(2,921)
Purchases of short term investments		(98,750)
Proceeds from sales of short term investments		185,859
Proceeds from sale of investments in equity investments and securities		1,147
Investments in and advances to affiliates, net		(3,441)
Cash provided by (used in) investing activities		(845)
Financing activities
Proceeds from issuance of term loan due 2024		0
Payments to extinguish term loan due 2021		0
Payments on term loan		0
Net receipts (payments) on other debt		(11,986)
Debt financing costs		(23,011)
Dividends paid		0
Purchases of treasury stock		0
Expenses related to debt restructuring		(2,213)
Other		0
Cash provided by (used in) financing activities		(37,210)
Increase (decrease) in cash and cash equivalents, including restricted cash		(266,273)
Cash and cash equivalents, including restricted cash, beginning of period	$ 282,049	548,322
Cash and cash equivalents, including restricted cash, end of period		282,049
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid during the period for interest		79,979
Cash refunded during the period for income taxes, net		$ 49

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Treasury Stock, at cost	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (Predecessor) at Dec. 31, 2015	$ (1,244,289)	$ 2,145	$ 3,054,211	$ (53,863)	$ (4,244,967)	$ (1,815)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee stock-based compensation expense \| Predecessor	2,099		2,099
Elimination of predecessor equity \| Predecessor	0	(2,145)	(3,056,310)	53,863	3,002,886	1,706
Total comprehensive income \| Predecessor	1,242,190				1,242,081	109
Ending Balance (Predecessor) at Oct. 01, 2016	0	0	0	0	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of successor equity	687,483	250	687,233
Employee stock-based compensation expense	1,032		1,032
Warrants exercised	159		159
Total comprehensive income	57,903				33,449	24,454
Ending Balance at Dec. 31, 2016	746,577	250	688,424		33,449	24,454
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares	(24,667)				(24,667)
Employee stock-based compensation expense	10,437		10,437
Issuance of 17,233 shares of common stock under long-term incentive plan	1,244		1,244
Warrants exercised	20		20
Purchase of common stock under share repurchase program	(302,109)			(302,109)
Total comprehensive income	234,363		0		238,450	(4,087)
Ending Balance at Dec. 31, 2017	665,865	250	700,125	(302,109)	247,232	20,367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common shares	(32,143)		0		(32,143)
Employee stock-based compensation expense	17,519		17,519
Warrants exercised	9		9
Purchase of common stock under share repurchase program	(281,774)			(281,774)
Retirement of 1,968 shares for payment of employee taxes upon vesting	(161)		(161)
Total comprehensive income	335,506				312,577	22,929
Ending Balance at Dec. 31, 2018	$ 704,821	$ 250	$ 717,492	$ (583,883)	$ 527,666	$ 43,296

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Issuance of shares of common stock under long-term incentive plan (in shares)		17,233
Purchase of shares of common stock under share repurchase program (in shares)	3,238,615	3,977,215
Retirement of shares for payment of employee taxes upon vesting (in shares)	1,968

Basis of Presentation	12 Months Ended
Basis of Presentation	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of Arch Coal, Inc. and its subsidiaries and controlled entities (the “Company”). Unless the context indicates otherwise, the terms “Arch” and the “Company” are used interchangeably in this Annual Report on Form 10-K refer to both the Predecessor and Successor Company. The Company’s primary business is the production of thermal and metallurgical coal from surface and underground mines located throughout the United States, for sale to utility, industrial and steel producers both in the United States and around the world. The Company currently operates mining complexes in West Virginia, Illinois, Wyoming and Colorado. All subsidiaries are wholly-owned. Intercompany transactions and accounts have been eliminated in consolidation. Chapter 11 Filing and Emergence from Bankruptcy On January 11, 2016 (the “Petition Date”), Arch and substantially all of its wholly owned domestic subsidiaries (the “Filing Subsidiaries” and, together with Arch, the “Debtors”) filed voluntary petitions for reorganization (collectively, the “Bankruptcy Petitions”) under Chapter 11 of Title 11 of the U.S. Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the Eastern District of Missouri (the “Court”). The Debtor’s Chapter 11 Cases (collectively, the “Chapter 11 Cases”) were jointly administered under the caption In re Arch Coal, Inc., et al. Case No. 16-40120 (lead case). During the bankruptcy proceedings, each Debtor operated its business as a “debtor in possession” under the jurisdiction of the Court and in accordance with the applicable provisions of the Bankruptcy Code and the orders of the Court. For periods subsequent to filing the Bankruptcy Petitions, the Company applied the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 852, “Reorganizations”, in preparing its consolidated financial statements. ASC 852 requires that financial statements distinguish transactions and events that are directly associated with the reorganization from the ongoing operations of the business. Accordingly, certain revenues, expenses, realized gains and losses and provisions for losses that are realized or incurred in the bankruptcy proceedings have been recorded in a reorganization line item on the Consolidated Income Statements. In addition, the pre-petition obligations that may be impacted by the bankruptcy reorganization process were classified on the balance sheet as liabilities subject to compromise. On September 13, 2016, the Bankruptcy Court entered an order, Docket No. 1324, confirming the Debtors’ Fourth Amended Joint Plan of Reorganization under Chapter 11 of the Bankruptcy Code dated as of September 11, 2016 (the “Plan”), which order was amended on September 15, 2016, Docket No. 1334. On October 5, 2016, Arch Coal satisfied the closing conditions contemplated by the Plan, which became effective on that date (the “Effective Date”). On the Plan Effective Date, the Company applied fresh start accounting which required the Company to allocate its reorganization value to the fair value of assets and liabilities in conformity with the guidance for the acquisition method of accounting for business combinations. In addition to fresh start accounting, the Company’s consolidated financial statements reflect all impacts of the transactions contemplated by the Plan. Under the provisions of fresh start accounting, a new entity has been created for financial reporting purposes. The Company selected an accounting convenience date of October 1, 2016 for purposes of applying fresh start accounting as the activity between the convenience date and the Effective Date does not result in a material difference in the results. References to “Successor” in the financial statements and accompanying footnotes are in reference to reporting dates on or after October 2, 2016; references to “Predecessor” in the financial statements and accompanying footnotes are in reference to reporting dates through October 1, 2016 which includes the impact of the Plan provisions and the application of fresh start accounting. As such, the Company’s financial statements for the Successor will not be comparable in many respects to its financial statements for periods prior to the adoption of fresh start accounting and prior to the accounting for the effects of the Plan.

Accounting Policies

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Accounting Policies

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for financial reporting and U.S. Securities and Exchange Commission regulations.

Accounting Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and revenues and expenses in the accompanying consolidated financial statements and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

Cash and Cash Equivalents

Cash and cash equivalents are stated at cost. Cash equivalents consist of highly-liquid investments with an original maturity of three months or less when purchased.

Restricted cash

Restricted cash represents cash collateral supporting letters of credit issued under the Company’s accounts receivable securitization program.

Accounts Receivable

Accounts receivable are recorded at amounts that are expected to be collected, based on past collection history, the economic environment and specified risks identified in the receivables portfolio.

Inventories

Coal and supplies inventories are valued at the lower of average cost or market. Coal inventory costs include labor, supplies, equipment costs, transportation costs incurred prior to the transfer of title to customers and operating overhead. The costs of removing overburden, called stripping costs, incurred during the production phase of the mine are considered variable production costs and are included in the cost of the coal extracted during the period the stripping costs are incurred.

Investments and Membership Interests in Joint Ventures

Investments and membership interests in joint ventures are accounted for under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. The Company’s share of the entity’s income or loss is reflected in “Other operating income, net” in the Consolidated Income Statements. Information about investment activity is provided in Note 9 to the Consolidated Financial Statements, “Equity Method Investments and Membership Interests in Joint Ventures.”

Investments in debt securities and marketable equity securities that do not qualify for equity method accounting are classified as available-for-sale and are recorded at their fair values. Unrealized gains and losses on these investments are recorded in other comprehensive income or loss. A decline in the value of an investment that is considered other-than-temporary would be recognized in operating expenses.

Sales Contracts

Coal supply agreements (sales contracts) valued during fresh start accounting or acquired in a business combination are capitalized at their fair value and amortized over the tons of coal shipped during the term of the contract. The fair value of a sales contract is determined by discounting the cash flows attributable to the difference between the contract price and the prevailing forward prices for the tons under contract at the date of acquisition. See Note 10 to the Consolidated Financial Statements, “Sales Contracts” for further information related to the Company’s sales contracts.

Exploration Costs

Costs to acquire permits for exploration activities are capitalized. Drilling and other costs related to locating coal deposits and evaluating the economic viability of such deposits are expensed as incurred.

Prepaid Royalties

Leased mineral rights are often acquired through royalty payments. When royalty payments represent prepayments recoupable against royalties owed on future revenues from the underlying coal, they are recorded as a prepaid asset, with amounts expected to be recouped within one year classified as current. When coal from these leases is sold, the royalties owed are recouped against the prepayment and charged to cost of sales. An impairment charge is recognized for prepaid royalties that are not expected to be recouped.

Property, Plant and Equipment

Plant and Equipment

Plant and equipment were recorded at fair value at emergence during fresh start accounting; subsequent purchases of property, plant and equipment have been recorded at cost. Interest costs incurred during the construction period for major asset additions are capitalized. The Company capitalized an immaterial amount of interest costs during years ended December 31, 2018 and 2017, respectively. Expenditures that extend the useful lives of existing plant and equipment or increase the productivity of the asset are capitalized. The cost of maintenance and repairs that do not extend the useful life or increase the productivity of the asset is expensed as incurred.

Preparation plants and loadouts are depreciated using the units-of-production method over the estimated recoverable reserves, subject to a minimum level of depreciation. Other plant and equipment are depreciated principally using the straight-line method over the estimated useful lives of the assets, limited by the remaining life of the mine. The useful lives of mining equipment, including longwalls, draglines and shovels, range from 1 to 18 years. The useful lives of buildings and leasehold improvements generally range from 1 to 20 years.

Deferred Mine Development

Costs of developing new mines or significantly expanding the capacity of existing mines are capitalized and amortized using the units-of-production method over the estimated recoverable reserves that are associated with the property being benefited. Costs may include construction permits and licenses; mine design; construction of access roads, shafts, slopes and main entries; and removing overburden to access reserves in a new pit. Additionally, deferred mine development includes the asset cost associated with asset retirement obligations. Coal sales revenue related to incidental production during the development phase will be recorded as coal sales revenue with an offset to cost of coal sales based on the estimated cost per ton sold for the mine when the asset is in place for its intended use.

Coal Lands and Mineral Rights

Rights to coal reserves may be acquired directly through governmental or private entities. A significant portion of the Company’s coal reserves are controlled through leasing arrangements. Lease agreements are generally long-term in nature (original terms range from 10 to 50 years), and substantially all of the leases contain provisions that allow for automatic extension of the lease term providing certain requirements are met.

The net book value of the Company’s coal interests was $338.1 million and $361.2 million at December 31, 2018 and 2017, respectively. Payments to acquire royalty lease agreements and lease bonus payments are capitalized as a cost of the underlying mineral reserves and depleted over the life of proven and probable reserves. Coal lease rights are depleted using the units-of-production method, and the rights are assumed to have no residual value.

The Company currently does not have any future lease bonus payments.

Depreciation, depletion and amortization

The depreciation, depletion and amortization related to long-lived assets is reflected in the income statement as a separate line item. No depreciation, depletion or amortization is included in any other operating cost categories.

Impairment

If facts and circumstances suggest that the carrying value of a long-lived asset or asset group may not be recoverable, the asset or asset group is reviewed for potential impairment. If this review indicates that the carrying amount of the asset will not be recoverable through projected undiscounted cash flows generated by the asset and its related asset group over its remaining life, then an impairment loss is recognized by reducing the carrying value of the asset to its fair value. The Company may, under certain circumstances, idle mining operations in response to market conditions or other factors. Because an idling is not a permanent closure, it is not considered an automatic indicator of impairment. See additional discussion in Note 6 to the Consolidated Financial Statements, “Impairment Charges and Mine Closure Costs.”

Deferred Financing Costs

The Company capitalizes costs incurred in connection with new borrowings, the establishment or enhancement of credit facilities and the issuance of debt securities. These costs are amortized as an adjustment to interest expense over the life of the borrowing or term of the credit facility using the interest method. Debt issuance costs related to a recognized liability are presented in the balance sheet as a direct reduction from the carrying amount of that liability whereas debt issuance costs related to a credit facility with no balance outstanding are shown as an asset. The unamortized balance of deferred financing costs shown as an asset was $4.7 million at December 31, 2018, with $2.2 million classified as current; the unamortized balance of deferred financing costs shown as an asset at December 31, 2017 was $5.7 million with $2.6 million classified as current. The current amounts are classified within “Other current assets” and the noncurrent amounts are classified within “Other noncurrent assets.” For information on the unamortized balance of deferred financing fees related to outstanding debt, see Note 13 to the Consolidated Financial Statements, “Debt and Financing Arrangements.”

Revenue Recognition

Revenues include sales to customers of coal produced at Company operations and coal purchased from third parties. The Company recognizes revenue at the time risk of loss passes to the customer at contracted amounts. Transportation costs are included in cost of sales and amounts billed by the Company to its customers for transportation are included in revenues.

Other Operating Income, net

Other operating income, net in the accompanying Consolidated Income Statements reflects income and expense from sources other than physical coal sales, including: bookouts, or the practice of offsetting purchase and sale contracts for shipping convenience purposes; contract settlements; liquidated damage charges related to unused terminal and port capacity; royalties earned from properties leased to third parties; income from equity investments (Note 9, “Equity Method Investments and Membership Interests in Joint Ventures”); non-material gains and losses from divestitures and dispositions of assets; and realized gains and losses on derivatives that do not qualify for hedge accounting and are not held for trading purposes (Note 11, “Derivatives”); and land management expenses.

Asset Retirement Obligations

The Company’s legal obligations associated with the retirement of long-lived assets are recognized at fair value at the time the obligations are incurred. Accretion expense is recognized through the expected settlement date of the obligation. Obligations are incurred at the time development of a mine commences for underground and surface mines or construction begins for support facilities, refuse areas and slurry ponds. The obligation’s fair value is determined using a discounted cash flow technique and is based upon permit requirements and various estimates and assumptions that would be used by market participants, including estimates of disturbed acreage, reclamation costs and assumptions regarding equipment productivity. Upon initial recognition of a liability, a corresponding amount is capitalized as part of the carrying value of the related long-lived asset.

The Company reviews its asset retirement obligation at least annually and makes necessary adjustments for permit changes as granted by state authorities and for revisions of estimates of the amount and timing of costs. For ongoing operations, adjustments to the liability result in an adjustment to the corresponding asset. For idle operations, adjustments to the liability are recognized as income or expense in the period the adjustment is recorded. Any difference between the recorded obligation and the actual cost of reclamation is recorded in profit or loss in the period the obligation is settled. See additional discussion in Note 15, “Asset Retirement Obligations.”

Loss Contingencies

The Company accrues for cost related to contingencies when a loss is probable and the amount is reasonably determinable. Disclosure of contingencies is included in the financial statements when it is at least reasonably possible that a material loss or an additional material loss in excess of amounts already accrued may be incurred. The amount accrued represents the Company’s best estimate of the loss, or, if no best estimate within a range of outcomes exists, the minimum amount in the range.

Derivative Instruments

The Company generally utilizes derivative instruments to manage exposures to commodity prices and interest rate risk on long-term debt. Additionally, the Company may hold certain coal derivative instruments for trading purposes. Derivative financial instruments are recognized on the balance sheet at fair value. Certain coal contracts may meet the definition of a derivative instrument, but because they provide for the physical purchase or sale of coal in quantities expected to be used or sold by the Company over a reasonable period in the normal course of business, they are not recognized on the balance sheet.

Certain derivative instruments are designated as the hedge instrument in a hedging relationship. In a fair value hedge, the Company hedges the risk of changes in the fair value of a firm commitment, typically a fixed-price coal sales contract. Changes in both the hedged firm commitment and the fair value of a derivative used as a hedge instrument in a fair value hedge are recorded in earnings. In a cash flow hedge, the Company hedges the risk of changes in future cash flows related to the underlying item being hedged. Changes in the fair value of the derivative instrument used as a hedge instrument in a cash flow hedge are recorded in other comprehensive income or loss. Amounts in other comprehensive income or loss are reclassified to earnings when the hedged transaction affects earnings and are classified in a manner consistent with the transaction being hedged. The Company formally documents the relationships between hedging instruments and the respective hedged items, as well as its risk management objectives for hedge transactions.

The Company evaluates the effectiveness of its hedging relationships both at the hedge’s inception and on an ongoing basis. Any ineffective portion of the change in fair value of a derivative instrument used as a hedge instrument in a fair value or cash flow hedge is recognized immediately in earnings. The ineffective portion is based on the extent to which exact offset is not achieved between the change in fair value of the hedge instrument and the cumulative change in expected future cash flows on the hedged transaction from inception of the hedge in a cash flow hedge or the change in the fair value. Ineffectiveness was insignificant for the periods disclosed within.

See Note 11, “Derivatives” for further disclosures related to the Company’s derivative instruments.

Fair Value

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly hypothetical transaction between market participants at a given measurement date. Valuation techniques used must maximize the use of observable inputs and minimize the use of unobservable inputs. See Note 16, “Fair Value Measurements” for further disclosures related to the Company’s recurring fair value estimates.

Income Taxes

Deferred income taxes are provided for temporary differences arising from differences between the financial statement and tax basis of assets and liabilities existing at each balance sheet date using enacted tax rates anticipated to be in effect when the related taxes are expected to be paid or recovered. A valuation allowance is established if it is more likely than not that a deferred tax asset will not be realized. Management reassesses the ability to realize its deferred tax assets annually in the fourth quarter or when circumstances indicate that the ability to realize deferred tax assets has changed. In determining the need for a valuation allowance, the Company considers projected realization of tax benefits based on expected levels of future taxable income, available tax planning strategies and the reversal of temporary differences.

Benefits from tax positions that are uncertain are not recognized unless the Company concludes that it is more likely than not that the position would be sustained in a dispute with taxing authorities, should the dispute be taken to the court of last resort. The Company would measure any such benefit at the largest amount of benefit that is greater than 50 percent likely of being realized upon settlement with taxing authorities.

See Note 14, “Taxes” for further disclosures about income taxes.

Benefit Plans

The Company has non-contributory defined benefit pension plans covering most of its salaried and hourly employees. On January 1, 2015 the Company’s cash balance and excess pension plans were amended to freeze new service credits for any new or active employee. The Company also currently provides certain postretirement medical and life insurance coverage for eligible employees. The cost of providing these benefits is determined on an actuarial basis and accrued over the employee’s period of active service.

The Company recognizes the overfunded or underfunded status of these plans as determined on an actuarial basis on the balance sheet and the changes in the funded status are recognized in other comprehensive income. The Company amortizes actuarial gains and losses over the remaining service attribution periods of the employees using the corridor method. See Note 20, “Employee Benefit Plans” for additional disclosures relating to these obligations.

Stock-Based Compensation

The compensation cost of all stock-based awards is determined based on the grant-date fair value of the award, and is recognized over the requisite service period. The grant-date fair value of option awards and restricted stock awards with a market condition is determined using a Monte Carlo simulation. Compensation cost for an award with performance conditions is accrued if it is probable that the conditions will be met. The Company accounts for forfeitures as they occur. See further discussion in Note 18, “Stock-Based Compensation and Other Incentive Plans.”

Recently Adopted Accounting Guidance

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers.” ASU 2014-09 is a comprehensive revenue recognition standard that has superseded nearly all existing revenue recognition guidance under current U.S GAAP and replaced it with a principle based approach for determining revenue recognition. ASU 2014-09 requires that companies recognize revenue based on the value of transferred goods or services as they occur in the contract. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. ASU 2014-09 is effective for interim and annual periods beginning after December 15, 2017. The Company’s primary source of revenue is from the sale of coal through both short-term and long-term contracts with utilities, industrial customers and steel producers whereby revenue is currently recognized when risk of loss has passed to the customer. During the fourth quarter of 2017, the Company finalized its assessment related to the new standard by analyzing certain contracts representative of the majority of the Company’s coal sales and determined that the timing of revenue recognition related to the Company’s coal sales will remain consistent between the new standard and the previous standard. The Company also reviewed other sources of revenue, and concluded the current basis of accounting for these items is in accordance with the new standard. The Company adopted ASU 2014-09 effective January 1, 2018 using the modified retrospective method, and there was no cumulative adjustment to retained earnings. The Company also reviewed the disclosure requirements under the new standard and has compiled information needed for the expanded disclosures which are included within Note 24, “Revenue Recognition” in the Condensed Consolidated Financial Statements.

In August 2016, the FASB issued ASU 2016-15, “Classification of Certain Cash Receipts and Cash Payments.” The amendment requires the classification of certain cash receipts and cash payments in the statement of cash flows to reduce diversity in practice. The new guidance is effective for fiscal years beginning after December 15, 2017 and the interim periods therein, with early adoption permitted. The amendments in the classification should be applied retrospectively to all periods presented, unless deemed impracticable, in which case, the prospective application is permitted. The Company adopted ASU 2016-15 effective January 1, 2018 with no impact on the Company’s financial statements.

In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash.” The ASU applies to all entities that have restricted cash or restricted cash equivalents and are required to present a statement of cash flows. The ASU requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. As a result, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning of period and end of period total amounts shown on the statement of cash flows. The ASU is effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The ASU should be adopted using a retrospective transition method to each period presented. The Company adopted ASU 2016-18 effective January 1, 2018 and applied the ASU retrospectively to the periods presented in the Company's Consolidated Statements of Cash Flow. As a result, net cash used in investing activities for the periods presented below was adjusted to exclude the change in restricted cash as follows:



	Successor					Predecessor
(in thousands)	Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
Cash provided by (used in) investing activities previously reported	$	(59,802	)	$	17,984	$	15,134
Less: Withdrawals of restricted cash	70,836			10,512		15,979

Cash provided by (used in) investing activities	$	(130,638	)	$	7,472	$	(845	)

In March 2017, the FASB issued ASU 2017-07, “Compensation-Retirement Benefits (Topic 715) Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” ASU 2017-07 changes the income statement presentation of defined benefit plan expense by requiring separation between operating expense (service cost component) and non-operating expense (all other components, including interest cost, amortization of prior service cost, curtailments and settlements, etc.). The operating expense component is reported with similar compensation costs while the non-operating components are reported in Nonoperating expense. In addition, only the service cost component is eligible for capitalization as part of an asset such as inventory or property, plant and equipment. The ASU is effective for public companies for fiscal years beginning after December 15, 2017, and interim periods therein. The ASU should be adopted using a retrospective transition method to each period presented. The Company adopted ASU 2017-07 effective January 1, 2018 and applied the ASU retrospectively to the periods presented in the Company's Consolidated Income Statements. The retrospective application resulted in the following changes detailed in the table below:



	Successor						Predecessor
(in thousands)	Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
Cost of sales previously reported	$	1,843,093		$	470,644		$	1,264,464
Reclassification	(3,100		)	(325		)	(2,290		)

Cost of sales	$	1,839,993		$	470,319		$	1,262,174

Selling, general and administrative expenses previously reported	$	86,821		$	22,836		$	59,343
Reclassification	1,131			357			575

Selling, general and administrative expenses	$	87,952		$	23,193		$	59,918

Other operating income, net previously reported	$	(30,270	)	$	(5,340	)	$	(15,257	)
Reclassification	29			—			—

Other operating income, net	$	(30,241	)	$	(5,340	)	$	(15,257	)

Recent Accounting Guidance Issued Not Yet Effective

In February 2016, the FASB established Topic 842, Leases, by issuing ASU No. 2016-02, “Leases” which requires lessees to recognize leases on-balance sheet and disclose key information about leasing arrangements. The ASU was subsequently amended by ASU 2018-01, “Land Easements Practical Expedient for Transition to Topic 842;” ASU 2018-10, “Codification Improvements to Topic 842, Leases;” and ASU 2018-11, “Targeted Improvements.” The new standard establishes a right-of-use (ROU) model that requires a lessee to recognize an ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. The standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the term of the lease, on a generally straight line basis. Leases of mineral reserves and related land lease have been exempted from the standard. The Company will elect the “package of practical expedients” within the standard which permits the Company not to reassess its prior conclusions about lease identification, lease classification and initial direct costs. Additionally, the Company will make an election to not separate lease and non-lease components for all leases, and will not use hindsight. Finally, the Company will continue its current policy for accounting for land easements as executory contracts. The standard is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years; early adoption is permitted. The Company expects the adoption of this standard to result in the recognition of right-of-use assets and lease liabilities ranging between $15 million to $20 million not currently recorded on the Company’s financial statements.

In June 2016, the FASB issued ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires an entity to assess impairment of its financial instruments based on its estimate of expected credit losses. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years; early adoption is permitted. The Company anticipates adopting the standard in the first quarter of 2020, although it does not expect a significant impact to the Company’s financial results.

In August 2017, the FASB issued ASU No. 2017-12, “Targeted Improvements to Accounting for Hedging Activities.” The new guidance provides targeted improvements to the accounting for hedging activities to better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedging results. ASU 2017-12 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years; early adoption is permitted. The Company anticipates adopting the standard in the first quarter of 2019, although it does not expect a significant impact to the Company’s financial results.

In February 2018, the FASB issued ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220)

Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” ASU 2018-02 provides an option to

reclassify stranded tax effects within accumulated other comprehensive income to retained earnings due to the change in the U.S. federal tax rate in the Tax Cuts and Jobs Act of 2017. The ASU is effective for public companies for fiscal years beginning after December 15, 2018, and interim periods therein with early adoption permitted. The Company is currently in the process of

analyzing the standard, but does not expect a significant impact to the Company’s financial statements.

In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement.” The primary focus of ASU 2018-13 is to improve the effectiveness of the disclosures for fair value measurements by requiring public entities to disclose certain new information while modifying some existing disclosure requirements. The FASB issued this ASU as part of its broader disclosure framework project, which aims to improve the effectiveness of disclosures in the notes to the financial statements by focusing on requirements that clearly communicate the most important information to users of the financial statements. The ASU is effective for public companies for fiscal years beginning after December 15, 2019, and interim periods therein with early adoption permitted. The Company is currently in the process of analyzing the standard, but does not expect a significant impact to the Company’s financial statements.

In August 2018, the FASB issued ASU 2018-14, “Compensation-Retirement Benefits-Defined Benefit Plans-General (Subtopic 715-20), Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans.” ASU 2018-14 makes minor changes to the disclosure requirements for employers that sponsor defined benefit pension and postretirement benefit plants. The new guidance eliminates requirements for certain disclosures that are no longer considered cost beneficial and adds new ones that the FASB considers pertinent. The FASB issued this ASU as part of its broader disclosure framework project, which aims to improve the effectiveness of disclosures in the notes to the financial statements by focusing on requirements that clearly communicate the most important information to users of the financial statements. The ASU is effective for public companies for fiscal years beginning after December 15, 2020, and interim periods therein with early adoption permitted. The Company is currently in the process of analyzing the standard, but does not expect a significant impact to the Company’s financial statements.

Emergence from Bankruptcy and Fresh Start Accounting

12 Months Ended

Dec. 31, 2018

Reorganizations [Abstract]

Emergence from Bankruptcy and Fresh Start Accounting

On January 11, 2016 (the “Petition Date”), Arch and substantially all of its wholly owned domestic subsidiaries (the “Filing Subsidiaries” and, together with Arch, the “Debtors”) filed voluntary petitions for reorganization (collectively, the “Bankruptcy Petitions”) under Chapter 11 of Title 11 of the U.S. Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the Eastern District of Missouri (the “Court”). The Debtor’s Chapter 11 Cases (collectively, the “Chapter 11 Cases”) were jointly administered under the caption In re Arch Coal, Inc., et al. Case No. 16-40120 (lead case). During the bankruptcy proceedings, each Debtor operated its business as a “debtor in possession” under the jurisdiction of the Court and in accordance with the applicable provisions of the Bankruptcy Code and the orders of the Court.

For periods subsequent to filing the Bankruptcy Petitions, the Company applied the FASB Accounting Standards Codification (“ASC”) 852, “Reorganizations”, in preparing its consolidated financial statements. ASC 852 requires that financial statements distinguish transactions and events that are directly associated with the reorganization from the ongoing operations of the business. Accordingly, certain revenues, expenses, realized gains and losses and provisions for losses that are realized or incurred in the bankruptcy proceedings have been recorded in a reorganization line item on the Consolidated Income Statements. In addition, the pre-petition obligations that may be impacted by the bankruptcy reorganization process were classified on the balance sheet as liabilities subject to compromise.

On September 13, 2016, the Bankruptcy Court entered an order, Docket No. 1324, confirming the Debtors’ Fourth Amended Joint Plan of Reorganization under Chapter 11 of the Bankruptcy Code dated as of September 11, 2016 (the “Plan”), which order was amended on September 15, 2016, Docket No. 1334.

On October 5, 2016, Arch Coal satisfied the closing conditions contemplated by the Plan, which became effective on that date (the “Effective Date”).

On the Plan Effective Date, the Company applied fresh start accounting which required the Company to allocate its reorganization value to the fair value of assets and liabilities in conformity with the guidance for the acquisition method of accounting for business combinations. In addition to fresh start accounting, the Company’s consolidated financial statements reflect all impacts of the transactions contemplated by the Plan. Under the provisions of fresh start accounting, a new entity has been created for financial reporting purposes. The Company selected an accounting convenience date of October 1, 2016 for purposes of applying fresh start accounting as the activity between the convenience date and the Effective Date does not result in a material difference in the results. References to “Successor” in the financial statements and accompanying footnotes are in reference to reporting dates on or after October 2, 2016; references to “Predecessor” in the financial statements and accompanying footnotes are in reference to reporting dates through October 1, 2016 which includes the impact of the Plan provisions and the application of fresh start accounting. As such, the Company’s financial statements for the Successor will not be comparable in many respects to its financial statements for periods prior to the adoption of fresh start accounting and prior to the accounting for the effects of the Plan.

Reorganization Items, Net

In accordance with ASC 852, the income statement shall portray the results of operations of the reporting entity while it is in Chapter 11. Revenues, expenses (including professional fees), realized gains and losses, and provisions for losses resulting from reorganization and restructuring of the business shall be reported separately as reorganization items.

The Company’s reorganization items, net for the respective periods are as follows:



	Successor									Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
(In thousands)
Gain on settlement of claims	$	—		$	—		$	—		$	4,142,104
Fresh start adjustments, net	—			—			—			(2,466,010		)
Professional fees	(1,661		)	(2,398		)	(759		)	(46,053		)

	$	(1,661	)	$	(2,398	)	$	(759	)	$	1,630,041

Professional fees directly related to the reorganization include fees associated with advisors to the Company, certain secured creditors and the Creditors’ Committee. During the Successor period ended December 31, 2018, the Company continued to incur costs related to professional fees that are directly attributable to the reorganization.

Contractual Interest Expense During Bankruptcy

Upon the filing of bankruptcy, the Company discontinued recording interest expense on unsecured debt that was classified as a liability subject to compromise. Actual interest expense recorded on the Predecessor debt subsequent to the Petition Date was $135.9 million for the period January 1 through October 1, 2016; contractual interest during this time was $300.9 million.

Accumulated Other Comprehensive Income

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Accumulated Other Comprehensive Income

The following items are included in accumulated other comprehensive income (loss):




				Pension,
				Postretirement						Accumulated
				and Other Post-						Other
	Derivative			Employment			Available-for-			Comprehensive
	Instruments			Benefits			Sale Securities			Income (Loss)
	(In thousands)
January 1, 2017	$	—		$	24,067		$	387		$	24,454
Unrealized gains (losses)	497			(3,589		)	—			(3,092		)
Amounts reclassified from accumulated other comprehensive income (loss)	150			(758		)	(387		)	(995		)
December 31, 2017	$	647		$	19,720		$	—		$	20,367
Unrealized gains (losses)	(4,359		)	22,923			(319		)	18,245
Amounts reclassified from accumulated other comprehensive income (loss)	7,040			(2,332		)	(24		)	4,684
December 31, 2018	$	3,328		$	40,311		$	(343	)	$	43,296

The following amounts were reclassified out of accumulated other comprehensive income during the respective periods:



Details about accumulated other comprehensive income components	Year Ended December 31, 2018			Year Ended December 31, 2017			Line Item in the Consolidated Income Statements
(in thousands)
Derivative instruments
Coal hedges	$	(8,206	)	$	—		Revenues
Interest rate hedges	1,166			(150		)	Interest expense
	—			—			Provision for (benefit from) income taxes
	$	(7,040	)	$	(150	)	Net of tax

Pension, postretirement and other post-employment benefits
Curtailments	$	—		$	(773	)
Settlement gains	2,332			1,531
	$	2,332		$	758		Total before tax
	—			—			Provision for (benefit from) income taxes
	$	2,332		$	758		Net of tax

Available-for-sale securities ²	$	24		$	387		Interest and investment income
	—			—			Provision for (benefit from) income taxes
	$	24		$	387		Net of tax
¹ Production-related benefits and workers’ compensation costs are included in costs to produce coal.
² The gains and losses on sales of available-for-sale-securities are determined on a specific identification basis.

Divestitures	12 Months Ended
Divestitures	Dec. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Divestitures	Divestitures On September 14, 2017, the Company closed on its’ definitive agreement to sell Lone Mountain Processing LLC, an operating mine complex within the Company’s metallurgical coal segment, and two idled mining companies, Cumberland River Coal LLC and Powell Mountain Energy LLC to Revelation Energy LLC. The Company received $8.3 million of proceeds offset by $1.4 million in disbursements related to landholder consent fees and professional fees; and recorded a gain of $21.3 million which is reflected as a separate line, “Gain on sale of Lone Mountain Processing, Inc.,” within the Consolidated Income Statements. The gain included a $4.7 million curtailment gain related to black lung liabilities accrued for active employees at these operations.

Impairment Charges and Mine Closure Costs	12 Months Ended
Impairment Charges and Mine Closure Costs	Dec. 31, 2018
Impairment Charges and Mine Closure Costs [Abstract]
Impairment Charges and Mine Closure Costs	Impairment Charges and Mine Closure Costs During the period January 1 through October 1, 2016, the Company recorded the following to “Asset impairment and mine closure costs” in the Consolidated Income Statements: $74.1 million recorded in the first quarter related to the impairment of coal reserves and surface land in Kentucky that are being leased to a mining company that idled its mining operations; $3.4 million recorded in the first quarter related to the impairment on the portion of an advance royalty balance on a reserve base mined at the Company’s Mountain Laurel operation that will not be recouped; $2.9 million recorded in the first quarter related to an other-than-temporary-impairment charge on an available-for-sale security; a $38.0 million impairment recorded in the second quarter related to the Company’s equity investment in a brownfield bulk commodity terminal on the Columbia River in Longview, Washington as the Company relinquished its ownership rights in exchange for future throughput rights; $7.2 million of severance expense related to headcount reductions during the first half of the year; a $3.6 million curtailment charge related to the Company’s pension, postretirement health and black lung actuarial liabilities due to headcount reductions in the first half of the year.

Inventories

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories consist of the following:



	December 31, 2018		December 31, 2017
(In thousands)
Coal	$	40,982	$	54,692
Repair parts and supplies	84,488		74,268
	$	125,470	$	128,960

The repair parts and supplies are stated net of an allowance for slow-moving and obsolete inventories of $0.6 million at December 31, 2018 and $0.3 million at December 31, 2017.

Investments in Available-for-Sale Securities

12 Months Ended

Dec. 31, 2018

Debt Securities, Available-for-sale [Abstract]

Investments in Available-for-Sale Securities

The Company has invested in marketable debt securities, primarily highly liquid U.S Treasury securities and investment grade corporate bonds. These investments are held in the custody of a major financial institution. These securities are classified as available-for-sale securities and, accordingly, the unrealized gains and losses are recorded through other comprehensive income.

The Company’s investments in available-for-sale marketable securities are as follows:



	December 31, 2018
										Balance Sheet
			Gross		Gross					Classification
			Unrealized		Unrealized			Fair		Short-Term		Other
	Cost Basis		Gains		Losses			Value		Investments		Assets
	(In thousands)
Available-for-sale:
U.S. government and agency securities	$	100,003	$	11	$	(126	)	$	99,888	$	99,888	$	—
Corporate notes and bonds	63,137		4		(232		)	62,909		62,909		—
Total Investments	$	163,140	$	15	$	(358	)	$	162,797	$	162,797	$	—



	December 31, 2017
										Balance Sheet
			Gross		Gross					Classification
			Unrealized		Unrealized			Fair		Short-Term		Other
	Cost Basis		Gains		Losses			Value		Investments		Assets
	(In thousands)
Available-for-sale:
U.S. government and agency securities	$	64,151	$	22	$	(73	)	$	64,100	$	64,100	$	—
Corporate notes and bonds	92,038		—		(292		)	91,746		91,746		—
Total Investments	$	156,189	$	22	$	(365	)	$	155,846	$	155,846	$	—

The aggregate fair value of investments with unrealized losses that had been owned for less than a year was $115.2 million and $132.0 million at December 31, 2018 and 2017, respectively. The aggregate fair value of investments with unrealized losses that have been owned for over a year was $32.4 million and $0.0 million at December 31, 2018 and 2017, respectively.

The debt securities outstanding at December 31, 2018 have maturity dates ranging from the first quarter of 2019 through the second quarter of 2020. The Company classifies its investments as current based on the nature of the investments and their availability to provide cash for use in current operations, if needed.

Equity Method Investments and Membership Interests in Joint Ventures

12 Months Ended

Dec. 31, 2018

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investments and Membership Interests in Joint Ventures

The Company accounts for its investments and membership interests in joint ventures under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. Equity method investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investments may not be recoverable.

Below are the equity method investments reflected in the consolidated balance sheets:



(In thousands)	Knight Hawk			DTA			Millennium			Other			Total
Predecessor Company
January 1, 2016	$	151,592		$	13,239		$	37,589		$	(543	)	$	201,877
Advances to (distributions from) affiliates, net	(8,374		)	1,474			1,966			—			(4,934		)
Equity in comprehensive income (loss)	9,033			(2,095		)	(1,530		)	(94		)	5,314
Impairment of equity investment	—			—			(38,025		)	—			(38,025		)
Fresh start accounting adjustment	(58,251		)	(4,018		)	—			662			(61,607		)
October 1, 2016	$	94,000		$	8,600		$	—		$	25		$	102,625
Successor Company
Advances to (distributions from) affiliates, net	(9,076		)	822			—			—			(8,254		)
Equity in comprehensive income (loss)	2,569			(841		)	—			—			1,728
December 31, 2016	$	87,493		$	8,581		$	—		$	25		$	96,099
Investments in affiliates	—			7,158			—			—			7,158
Advances to (distributions from) affiliates, net	(8,736		)	3,014			—			—			(5,722		)
Equity in comprehensive income (loss)	11,409			(2,812		)	—			(25		)	8,572
December 31, 2017	$	90,166		$	15,941		$	—		$	—		$	106,107
Advances to (distributions from) affiliates, net	(10,534		)	2,481			—			—			(8,053		)
Equity in comprehensive income (loss)	10,389			(3,767		)	—			—			6,622

December 31, 2018	$	90,021		$	14,655		$	—		$	—		$	104,676

The Company holds a 49% equity interest in Knight Hawk Holdings, LLC (“Knight Hawk”), a coal producer in the Illinois Basin.

The Company holds a general partnership interest in Dominion Terminal Associates (“DTA”), which is accounted for under the equity method. In March 2017, the Company paid $7.2 million through an auction process held by one of the existing owners, increasing its ownership in DTA from 21.875% to 35%. DTA operates a ground storage-to-vessel coal transloading facility in Newport News, Virginia for use by the partners. Under the terms of a throughput and handling agreement with DTA, each partner is charged its share of cash operating and debt-service costs in exchange for the right to use the facility’s loading capacity and is required to make periodic cash advances to DTA to fund such costs.

The Company previously held a 38% ownership interest in Millennium Bulk Terminals-Longview, LLC (“Millennium”), the owner of a brownfield bulk commodity terminal on the Columbia River near Longview, Washington. Millennium continues to work on obtaining the required approvals and necessary permits to complete dredging and other upgrades to ship coal, alumina and cementitious material from the terminal. During the second quarter of 2016, the Company recorded an impairment charge of $38.0 million representing the entire value of its equity investment as the Company relinquished its ownership rights in exchange for future throughput rights through the facility when completed.

The Company is not required to make any future contingent payments related to development financing for any of its equity investees.

Sales Contracts

12 Months Ended

Dec. 31, 2018

Acquired Sales Contracts [Abstract]

Sales Contracts

The sales contracts reflected in the consolidated balance sheets are as follows:



	December 31, 2018									December 31, 2017
	Assets			Liabilities			Net Total			Assets			Liabilities			Net Total
	(In thousands)									(In thousands)
Original fair value	$	97,196		$	31,742					$	97,196		$	31,742
Accumulated amortization	(96,812		)	(30,924		)				(84,760		)	(29,979		)
Total	$	384		$	818		$	(434	)	$	12,436		$	1,763		$	10,673
Balance Sheet classification:
Other current	$	384		$	570					$	12,432		$	934
Other noncurrent	$	—		$	248					$	4		$	829

The Company anticipates the majority of the remaining net book value of sales contracts to be amortized in 2019 based upon expected shipments.

Derivatives

12 Months Ended

Dec. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivatives

Interest rate risk management

The Company has entered into interest rate swaps to reduce the variability of cash outflows associated with interest payments on its variable rate term loan. These swaps have been designated as cash flow hedges. For additional information on these arrangements, see Note 13, “Debt and Financing Arrangements” in the Consolidated Financial Statements.

Diesel fuel price risk management

The Company is exposed to price risk with respect to diesel fuel purchased for use in its operations. The Company anticipates purchasing approximately 40 to 46 million gallons of diesel fuel for use in its operations during 2019. To protect the Company’s cash flows from increases in the price of diesel fuel for its operations, the Company uses forward physical diesel purchase contracts and purchased heating oil call options. At December 31, 2018, the Company had heating oil call options for approximately 26.2 million gallons at an average strike price of $2.30. These positions are not designated as hedges for accounting purposes, and therefore, changes in the fair value are recorded immediately to earnings.

Coal risk management positions

The Company may sell or purchase forward contracts, swaps and options in the over-the-counter coal market in order to manage its exposure to coal prices. The Company has exposure to the risk of fluctuating coal prices related to forecasted sales or purchases of coal or to the risk of changes in the fair value of a fixed price physical sales contract. Certain derivative contracts may be designated as hedges of these risks.

At December 31, 2018, the Company held derivatives for risk management purposes that are expected to settle in the following years:



(Tons in thousands)	2019	2020	Total
Coal sales	2,601	93	2,694
Coal purchases	1,368	93	1,461

The Company may also enter into natural gas options to protect the Company from decreases in natural gas prices, which could impact thermal coal demand. These options are not designated as hedges. Additionally, the Company may enter into nominal quantities of foreign currency options protecting for decreases in the Australian to United States dollar exchange rate, which could impact metallurgical coal demand. These options are not designated as hedges.

Coal trading positions

The Company may sell or purchase forward contracts, swaps and options in the over-the-counter coal market for trading purposes. The Company is exposed to the risk of changes in coal prices on the value of its coal trading portfolio. The unrecognized losses of $0.2 million in the trading portfolio are expected to be realized in 2019.

Tabular derivatives disclosures

The Company has master netting agreements with all of its counterparties which allow for the settlement of contracts in an asset position with contracts in a liability position in the event of default or termination. Such netting arrangements reduce the Company’s credit exposure related to these counterparties. For classification purposes, the Company records the net fair value of all the positions with a given counterparty as a net asset or liability in the consolidated balance sheets. The amounts shown in the table below represent the fair value position of individual contracts, and not the net position presented in the accompanying consolidated balance sheets.

The fair value and location of derivatives reflected in the accompanying consolidated balance sheets are as follows:



	December 31, 2018									December 31, 2017
Fair Value of Derivatives	Asset			Liability						Asset			Liability
(In thousands)	Derivative			Derivative						Derivative			Derivative
Derivatives Designated as Hedging Instruments
Coal	$	2,342		$	(805	)				$	942		$	(2,146	)

Derivatives Not Designated as Hedging Instruments
Heating oil -- diesel purchases	532			—						5,354			—
Coal held for trading purposes, exchange traded swaps and futures	10,329			(10,701		)				44,088			(45,221		)
Coal -- risk management	5,672			(19,579		)				5,139			(9,892		)
Natural gas	4			(4		)				27			—
Total	$	16,537		(30,284		)				$	54,608		$	(55,113	)
Total derivatives	$	18,879		$	(31,089	)				$	55,550		$	(57,259	)
Effect of counterparty netting	(17,801		)	17,801						(50,042		)	50,042
Net derivatives as classified in the balance sheets	$	1,078		$	(13,288	)	$	(12,210	)	$	5,508		$	(7,217	)	$	(1,709	)



		December 31, 2018			December 31, 2017
Net derivatives as reflected on the balance sheets
Heating oil	Other current assets	$	532		$	5,354
Coal	Other current assets	546			154
	Accrued expenses and other current liabilities	(13,288		)	(7,217		)
		$	(12,210	)	$	(1,709	)

The Company had a current asset representing cash collateral posted to a margin account for derivative positions primarily related to coal derivatives of $24.7 million and $16.2 million at December 31, 2018 and 2017, respectively. These amounts are not included with the derivatives presented in the table above and are included in “other current assets” in the accompanying Consolidated Balance Sheets.

The effects of derivatives on measures of financial performance are as follows:

Derivatives used in Cash Flow Hedging Relationships (in thousands)

For the noted periods,



		Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)
		Successor								Predecessor
		Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
Coal sales	⁽¹⁾	$	(7,517	)	$	(2,127	)	$	—	(672		)
Coal purchases	⁽²⁾	1,348			942			—		536
		$	(6,169	)	$	(1,185	)	$	—	$	(136	)


		Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)
		Successor								Predecessor
		Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
Coal sales		$	(10,912	)	$	—		$	—	$	1,634
Coal purchases		2,707			—			—		(1,237		)
		$	(8,205	)	$	—		$	—	$	397

No ineffectiveness or amounts excluded from effectiveness testing relating to the Company’s cash flow hedging relationships were recognized in the results of operations in the respective periods.

Derivatives Not Designated as Hedging Instruments (in thousands)

For the noted periods,



		Gain (Loss) Recognized
		Successor									Predecessor
		Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
Coal trading— realized and unrealized	⁽³⁾	$	135		$	(2,047	)	$	(7	)	$	(891	)
Coal risk management— unrealized	⁽³⁾	(9,530		)	(4,648		)	(408		)	(1,662		)
Natural gas trading — realized and unrealized	⁽³⁾	277			(527		)	19			(303		)
Change in fair value of coal derivatives and coal trading activities, net total		$	(9,118	)	$	(7,222	)	$	(396	)	$	(2,856	)

Coal risk management — realized	⁽⁴⁾	$	(8,734	)	$	—		$	116		$	(476	)
Heating oil — diesel purchases	⁽⁴⁾	$	(505	)	$	(1,057	)	$	827		$	826
Foreign currency	⁽⁴⁾	$	—		$	—		$	(9	)	$	(451	)

Location in income statement:

(1) — Revenues

(2) — Cost of sales

(3) — Change in fair value of coal derivatives and coal trading activities, net

(4) — Other operating income, net

Based on fair values at December 31, 2018, amounts on derivative contracts designated as hedge instruments in cash flow hedges expected to be reclassified from other comprehensive income into earnings during the next twelve months are gains of $1.1 million.

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2018

Accrued Expenses and Other Current Liabilities [Abstract]

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following:



	December 31, 2018		December 31, 2017
(In thousands)
Payroll and employee benefits	$	57,166	$	53,149
Taxes other than income taxes	75,017		77,017
Interest	156		246
Sales contracts	570		934
Workers’ compensation	20,044		18,782
Asset retirement obligations	13,113		19,840
Other	17,448		14,193
	$	183,514	$	184,161

Debt and Financing Arrangements

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Debt and Financing Arrangements



	December 31, 2018			December 31, 2017
(In thousands)
Term loan due 2024 ($294.8 and $297.8 million face value, respectively)	$	293,626		$	296,435
Other	30,449			36,514
Debt issuance costs	(6,092		)	(7,032		)
	$	317,983		$	325,917
Less current maturities of debt	17,797			15,783
Long-term debt	$	300,186		$	310,134

Term Loan Facility

On March 7, 2017, the Company entered into a senior secured term loan credit agreement in an aggregate principal amount of $300 million (the “Term Loan Debt Facility”) with Credit Suisse AG, Cayman Islands Branch, as administrative agent and collateral agent (in such capacities, the “Agent”), and the other financial institutions from time to time party thereto (collectively, the “Lenders”). The Term Loan Debt Facility was issued at 99.50% of the face amount and will mature on March 7, 2024. The term loans provided under the Term Loan Debt Facility (the “Term Loans”) are subject to quarterly principal amortization payments in an amount equal to $750,000.

On September 25, 2017, the Company entered into the First Amendment (the “First Amendment”) to its Term Loan Debt Facility. The First Amendment reduced the interest rate on the $300 million term loan facility to, at the option of Arch Coal, either (i) the London interbank offered rate (“LIBOR”) plus an applicable margin of 3.25%, subject to a 1.00% LIBOR floor, or (ii) a base rate plus an applicable margin of 2.25%. The Amendment also reset the 1.00% call premium to apply to repricing events that occur on or prior to March 26, 2018.

On April 3, 2018, the Company entered into the Second Amendment (the “Second Amendment”) to its Term Loan Debt Facility. The Second Amendment further reduced the interest rate on its Term Loan Debt Facility to, at the option of Arch Coal, either (i) the London interbank offered rate (“LIBOR”) plus an applicable margin of 2.75%, subject to a 1.00% LIBOR floor, or (ii) a base rate plus an applicable margin of 1.75%. The Second Amendment also resets the 1.00% call premium to apply to repricing events that occur on or prior to October 3, 2018. The LIBOR floor remains at 1.00%. There is no change to the maturities as a result of the Second Amendment.

The Term Loan Debt Facility is guaranteed by all existing and future wholly owned domestic subsidiaries of the Company (collectively, the “Subsidiary Guarantors” and, together with Arch Coal, the “Loan Parties”), subject to customary exceptions, and is secured by first priority security interests on substantially all assets of the Loan Parties, including 100% of the voting equity interests of directly owned domestic subsidiaries and 65% of the voting equity interests of directly owned foreign subsidiaries, subject to customary exceptions.

The Company has the right to prepay Term Loans at any time and from time to time in whole or in part without premium or penalty, upon written notice, except that any prepayment of Term Loans that bear interest at the LIBOR Rate other than at the end of the applicable interest periods therefor shall be made with reimbursement for any funding losses and redeployment costs of the Lenders resulting therefrom.

The Term Loan Debt Facility is subject to certain usual and customary mandatory prepayment events, including 100% of net cash proceeds of (i) debt issuances (other than debt permitted to be incurred under the terms of the New Term Loan Debt Facility) and (ii) non-ordinary course asset sales or dispositions, subject to customary thresholds, exceptions and reinvestment rights.

The Term Loan Debt Facility contains customary affirmative covenants and representations.

The Term Loan Debt Facility also contains customary negative covenants, which, among other things, and subject to certain exceptions, include restrictions on (i) indebtedness, (ii) liens, (iii) liquidations, mergers, consolidations and acquisitions, (iv) disposition of assets or subsidiaries, (v) affiliate transactions, (vi) creation or ownership of certain subsidiaries, partnerships and joint ventures, (vii) continuation of or change in business, (viii) restricted payments, (ix) prepayment of subordinated and junior lien indebtedness, (x) restrictions in agreements on dividends, intercompany loans and granting liens on the collateral, (xi) loans and investments, (xii) sale and leaseback transactions, (xiii) changes in organizational documents and fiscal year and (xiv) transactions with respect to bonding subsidiaries. The New Term Loan Debt Facility does not contain any financial maintenance covenant.

The Term Loan Debt Facility contains customary events of default, subject to customary thresholds and exceptions, including, among other things, (i) nonpayment of principal and nonpayment of interest and fees, (ii) a material inaccuracy of a representation or warranty at the time made, (iii) a failure to comply with any covenant, subject to customary grace periods in the case of certain affirmative covenants, (iv) cross-events of default to indebtedness of at least $50 million, (v) cross-events of default to surety, reclamation or similar bonds securing obligations with an aggregate face amount of at least $50 million, (vi) uninsured judgments in excess of $50 million, (vii) any loan document shall cease to be a legal, valid and binding agreement, (viii) uninsured losses or proceedings against assets with a value in excess of $50 million, (ix) certain ERISA events, (x) a change of control or (xi) bankruptcy or insolvency proceedings relating to the Company or any material subsidiary of the Company.

Accounts Receivable Securitization Facility

On April 27, 2017, the Company extended and amended its existing trade accounts receivable securitization facility provided to Arch Receivable Company, LLC, a special-purpose entity that is a wholly owned subsidiary of the Company (“Arch Receivable”) (the “Securitization Facility”), which supports the issuance of letters of credit and requests for cash advances. The amendment to the Extended Securitization Facility decreased the borrowing capacity from $200 million to $160 million and extended the maturity date to the date that is three years after the Securitization Facility Closing Date. Pursuant to the Extended Securitization Facility, Arch Receivable also agreed to a revised schedule of fees payable to the administrator and the providers of the Extended Securitization Facility.

On August 27, 2018, the Company extended and amended the Securitization facility. The amendment to the Securitization Facility maintains the $160 million borrowing capacity and extends the maturity date to the date that is three years after the Securitization Facility Closing Date. Additionally, the amendment provided the Company the opportunity to use credit insurance to increase the pool of eligible receivables for borrowing. Pursuant to the Securitization Facility, Arch Receivable also agreed to a revised schedule of fees payable to the administrator and the providers of the Securitization Facility.

The Securitization Facility will terminate at the earliest of (i) three years from the Securitization Facility Closing Date, (ii) if the Liquidity (defined in the Securitization Facility and consistent with the definition in the Inventory Facility) is less than $175 million for a period of 60 consecutive days, the date that is the 364th day after the first day of such 60 consecutive day period and (iii) the occurrence of certain predefined events substantially consistent with the existing transaction documents. Under the Securitization Facility, Arch Receivable, the Company and certain of its subsidiaries party to the Extended Securitization Facility have granted to the administrator of the Securitization Facility a first priority security interest in eligible trade accounts receivable generated by such parties from the sale of coal and all proceeds thereof. As of December 31, 2018, letters of credit totaling $74.8 million were outstanding under the facility with $53.5 million of additional availability for borrowings.

Inventory-Based Revolving Credit Facility

On April 27, 2017, the Company and certain subsidiaries of Arch Coal entered into a senior secured inventory-based revolving credit facility in an aggregate principal amount of $40 million (the “Inventory Facility”) with Regions Bank (“Regions”) as administrative agent and collateral agent (in such capacities, the “Agent”), as lender and swingline lender (in such capacities, the “Lender”) and as letter of credit issuer. Availability under the Inventory Facility is subject to a borrowing base consisting of (i) 85% of the net orderly liquidation value of eligible coal inventory, (ii) the lesser of (x) 85% of the net orderly liquidation value of eligible parts and supplies inventory and (y) 35% of the amount determined pursuant to clause (i), and (iii) 100% of Arch Coal’s Eligible Cash (defined in the Inventory Facility), subject to reduction for reserves imposed by Regions.

On November 19, 2018, the Company and certain subsidiaries of Arch Coal amended and extended the Inventory Facility by increasing the facility size by $10 million bringing the total aggregate principal amount available to $50 million, subject to borrowing base calculations described above.

The commitments under the Inventory Facility will terminate on the date that is the earliest to occur of (i) the date, if any, that is 364 days following the first day that Liquidity (defined in the Inventory Facility and consistent with the definition in the Securitization Facility (as defined below)) is less than $250 million for a period of 60 consecutive days and (ii) the date, if any, that is 60 days following the maturity, termination or repayment in full of the Securitization Facility.

Revolving loan borrowings under the Inventory Facility bear interest at a per annum rate equal to, at the option of the Company, either at the base rate or the London interbank offered rate plus, in each case, a margin ranging from 2.00% to 2.50% (in the case of LIBOR loans) and 1.00% to 1.50% (in the case of base rate loans) determined using a Liquidity-based grid. Letters of credit under the New Inventory Facility are subject to a fee in an amount equal to the applicable margin for LIBOR loans, plus customary fronting and issuance fees.

All existing and future direct and indirect domestic subsidiaries of the Company, subject to customary exceptions, will either constitute co-borrowers under or guarantors of the Inventory Facility (collectively with the Company, the “Loan Parties”). The Inventory Facility is secured by first priority security interests in the ABL Priority Collateral (defined in the Inventory Facility) of the Loan Parties and second priority security interests in substantially all other assets of the Loan Parties, subject to customary exceptions (including an exception for the collateral that secures the Extended Securitization Facility).

The Company has the right to prepay borrowings under the Inventory Facility at any time and from time to time in whole or in part without premium or penalty, upon written notice, except that any prepayment of such borrowings that bear interest at the LIBOR rate other than at the end of the applicable interest periods therefore shall be made with reimbursement for any funding losses and redeployment costs of the Lender resulting therefrom.

The Inventory Facility is subject to certain usual and customary mandatory prepayment events, including non-ordinary course asset sales or dispositions, subject to customary thresholds, exceptions (including exceptions for required prepayments under the Company’s term loan facility) and reinvestment rights.

The Inventory Facility contains certain customary affirmative and negative covenants; events of default, subject to customary thresholds and exceptions; and representations, including certain cash management and reporting requirements that are customary for asset-based credit facilities. The Inventory Facility also includes a requirement to maintain Liquidity equal to or exceeding $175 million at all times. As of December 31, 2018, letters of credit totaling $35.7 million were outstanding under the facility with $11.2 million additional availability for borrowings.

Interest Rate Swaps

During the second quarter of 2017, the Company entered into a series of interest rate swaps to fix a portion of the LIBOR interest payments due under the term loan. The interest rate swaps qualify for cash flow hedge accounting treatment and as such, the change in the fair value of the interest rate swaps are recorded on the Company’s Consolidated Balance Sheet as an asset or liability with the effective portion of the gains or losses reported as a component of accumulated other comprehensive income and the ineffective portion reported in earnings. As interest payments are made on the term loan, amounts in accumulated other comprehensive income will be reclassified into earnings through interest expense to reflect a net interest on the term loan equal to the effective yield of the fixed rate of the swap plus 2.75% which is the spread on the revised LIBOR term loan. In the event that an interest rate swap is terminated prior to maturity, gains or losses in accumulated other comprehensive income will remain deferred and reclassified into earnings in the periods which the hedged forecasted transaction affects earnings.

Below is a summary of the Company’s outstanding interest rate swap agreements designated as hedges as of

December 31, 2018:



Notional Amount (in millions)	Effective Date	Fixed Rate	Receive Rate	Expiration Date

$250.0	June 29, 2018	1.662%	1-month LIBOR	June 28, 2019
$200.0	June 28, 2019	1.952%	1-month LIBOR	June 30, 2020
$150.0	June 30, 2020	2.182%	1-month LIBOR	June 30, 2021

The fair value of the interest rate swaps at December 31, 2018 is an asset of $2.5 million which is recorded within Other noncurrent assets with the offset to accumulated other comprehensive income on the Company’s Consolidated Balance Sheet. The Company realized $1.2 million of gains and $0.1 million of losses during the years ended December 31, 2018 and 2017, respectively, related to settlements of the interest rate swaps which was recorded to interest expense on the Company’s Consolidated Income Statements. The interest rate swaps are classified as level 2 within the fair value hierarchy.

Debt Maturities

The contractual maturities of debt as of December 31, 2018 are as follows:



Year	(In thousands)
2019	$	18,863
2020	11,442
2021	8,853
2022	3,130
2023	3,161
Thereafter	279,750
	$	325,199

Financing Costs

The Company paid financing costs of $1.3 million and $10.1 million during the years ended December 31, 2018 and 2017; zero during the period October 2 through December 31, 2016; and $23.0 million during the period January 1 through October 1, 2016, respectively, in conjunction with its financing activities.

Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Taxes

In 2016, under the Plan of bankruptcy reorganization, the Company’s pre-petition equity, bank related debt and certain other obligations were cancelled and extinguished. Absent an exception, a debtor recognizes cancellation of debt income (“CODI”) upon discharge of its outstanding indebtedness for an amount of consideration that is less than its adjusted issue price. In accordance with Internal Revenue Code (IRC) Section 108, the Company excluded the amount of discharged indebtedness from taxable income since the IRC provides that a debtor in a bankruptcy case may exclude CODI from income but must reduce certain tax attributes by the amount of CODI realized as a result of the consummation of a plan of reorganization. The amount of CODI realized by a taxpayer is the adjusted issue price of any indebtedness discharged less than the sum of (i) the amount of cash paid, (ii) the issue price of any new indebtedness issued, and (iii) the fair market value of any other consideration, including equity, issued.

CODI from the discharge of indebtedness was $4,089 million. As a result of the CODI and in accordance with IRC rules, the Company reduced its gross federal net operating loss (NOL) carryovers $3,436 million and its alternative minimum tax (AMT) credits $3 million and the gross basis in timing deferreds $646.3 million. The Company was able to retain $1,384 million of gross federal NOLs, $73.3 million of AMT credit and $64.5 million of capital loss carryforwards following the bankruptcy.

Due to changes in ownership that occurred in connection with the Company’s emergence from bankruptcy, there was a change in ownership for purposes of IRC Section 382. Section 382 provides a combined annual limitation with respect to the ability of a corporation to use its NOLs, AMT credits and capital loss carryforwards generated before the ownership change against future taxable income. The Company’s annual limit under IRC section 382 is estimated to be $29.8 million. The Company had a net unrealized built-in gain, based on comparing the fair value and carryover tax basis in assets, at the time of the ownership change, therefore, certain built-in gains recognized within five years after the ownership change will increase the annual IRC section 382 limit for the five year recognition period beginning October 1, 2016 through September 30, 2021. There is uncertainty surrounding which assets with built-in gain will be realized within the five year period following the Company’s emergence from bankruptcy and allow the Company to realize the incremental net operating losses and credit in excess of the base 382 limitation. The Company is reflecting a deferred tax asset for the full amount of the net operating losses and credit carryforwards. If at some point in time it becomes evident that some portion of the deferred tax assets will not be realizable, the deferred tax asset, and offsetting valuation allowance will be reduced.

During 2018, the IRS completed an audit of AMT NOL carryback claims the Company filed in prior periods. In addition, the Company filed an amended 2016 tax return which changed the amount of available tax attributes and the mix used to offset its bankruptcy CODI as of January 1, 2017. As a result, the Company increased available AMT credits and reduced other tax attributes as of that date. The AMT credits do not require a valuation allowance to be recorded against them due to the law changes enacted as part of the Tax Cut and Jobs Act of 2017 (“The Act”), while the Company’s other tax attributes are fully offset by a valuation allowance. The associated valuation allowance release related to the shift in attributes reflects what the Company believes will be realized upon audit of the amended tax return filing. The Company anticipates that all AMT credits will be converted to cash in the next four years as provided by The Act. In total, these changes resulted in a recorded benefit from income taxes of $48.8 million, which was net of a $26.6 million uncertain tax position charge.

The Company is subject to U.S. federal income tax as well as income tax in multiple state jurisdictions. The tax years 2002 through 2018 remain open to examination for U.S. federal income tax matters and 2002 through 2018 remain open to examination for various state income tax matters.

Significant components of the provision for (benefit from) income taxes are as follows:



	Successor									Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
(In thousands)
Current:
Federal	$	86		$	835		$	—		$	—
State	136			31			(252		)	7
Total current	$	222		$	866		$	(252	)	$	7
Deferred:
Federal	(52,309		)	(36,162		)	1,352			(4,720		)
State	(389		)	41			56			87
Total deferred	$	(52,698	)	$	(36,121	)	$	1,408		$	(4,633	)
	$	(52,476	)	$	(35,255	)	$	1,156		$	(4,626	)

A reconciliation of the statutory federal income tax provision (benefit) at the statutory rate to the actual provision for (benefit from) income taxes follows:



	Successor									Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
(In thousands)
Income tax provision (benefit) at statutory rate	$	54,621		$	71,118		$	12,112		$	433,109
Percentage depletion allowance	(17,725		)	(31,255		)	(4,292		)	(3,681		)
State taxes, net of effect of federal taxes	4,480			7,002			633			(46,122		)
Reversal of cancellation of indebtedness income	—			—			—			(1,493,162		)
Worthless stock deduction	—			—			—			(80,077		)
Change in valuation allowance	(79,961		)	(410,983		)	(7,655		)	1,185,326
Impact of Tax Cuts and Jobs Act of 2017	(17,645		)	332,345			—			—
Other, net	3,754			(3,482		)	358			(19		)
Provision for (benefit from) income taxes	$	(52,476	)	$	(35,255	)	$	1,156		$	(4,626	)

Significant components of the Company’s deferred tax assets and liabilities that result from carryforwards and temporary differences between the financial statement basis and tax basis of assets and liabilities are summarized as follows:



	December 31, 2018			December 31, 2017
(In thousands)
Deferred tax assets:
Tax loss carryforwards	$	307,615		$	271,405
Tax credit carryforwards	5,394			29,736
Investment in partnerships	193,217			308,653
Other	28,747			28,321
Gross deferred tax assets	$	534,973		$	638,115
Valuation allowance	(530,612		)	(610,571		)
Total deferred tax assets	$	4,361		$	27,544
Deferred tax liabilities:
Plant and equipment	3,037			3,674
Other	1,154			1,351
Total deferred tax liabilities	$	4,191		$	5,025
Net deferred tax asset	$	170		$	22,519

The Company has gross federal NOL carryforwards for regular income tax purposes of $1.3 billion at December 31, 2018 that will expire between 2022 and 2037. The Company has an AMT credit carryforward of $61.1 million net of a $26.6 million uncertain tax position charge at December 31, 2018, which has no expiration date and will be refunded during 2019 through 2022. The future annual usage of NOLs and AMT credit will be limited under IRC section 382.

As part of an effort to maximize efficiency, the Company consolidated its mining operations and land management into a partnership structure to match its legal form with the Company’s streamlined operations during 2016. As such, deferred taxes related to those operations are reported based upon the book and tax outside basis difference in the partnership interests as provided in ASC 740-30-25-7.

On December 22, 2017, The Act was signed into law making significant changes to the Internal Revenue Code. The Company provided its best estimate of the impact of the Act at December 31, 2017 and during 2018 completed its analysis as provided by SAB 118. The Company has recorded the impact of the Act in its year-end income tax provision in accordance with the guidance and interpretations available. The following items have been impacted by the Act:

•

Remeasurement of deferred taxes: Deferred tax assets and liabilities attributable to the U.S. were remeasured from 35% to the reduced tax rate of 21%. The amount related to the remeasurement of certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future was $330.9 million of income tax expense in 2017 and $16.7 million of income tax benefit in 2018, related to the 2016 amended return filing, with offsetting valuation allowance adjustments.

•

One-time transition tax on mandatory deemed repatriation of cumulative foreign earnings: The amount of income tax expense related to the mandatory deemed repatriation of foreign earnings was $1.5 million based on cumulative foreign earnings of $4.2 million. The deemed repatriation tax is completely offset with net operating loss carryforwards, with an offsetting valuation allowance adjustment and will not result in a cash tax liability.

•

Elimination of the corporate AMT regime: Existing AMT credits as of December 31, 2018 will be refunded during 2019 through 2022. The Company has determined that it will receive a refund of existing AMT credits of approximately $45.0 million, net of a $26.6 million uncertain tax position charge. The valuation allowance previously recorded against these credits was released in 2017. The credits were reflected as a deferred tax asset. In 2018, the credits have been reclassified from a deferred tax asset to short term and long term receivables.

•

Elimination of executive compensation exemptions: The Act made changes to the $1 million limit on deductible compensation paid to certain “covered” employees. The Act eliminated exemptions for qualified performance based compensation and compensation paid after termination and expanded the number of employees to which the limit applies. The Company recorded an amount of $0.2 million of tax expense in 2017 and $6.1 million of tax expense in 2018, with an offsetting valuation allowance adjustment.


•	Other provisions in the Act such as global intangible low-taxed income “GILTI” rules covering foreign income earned in low-tax countries, base-erosion and anti-abuse tax “BEAT,” and the foreign derived intangible income “FDII” deduction will have no material impact on the company

At December 31, 2017 additional tax losses were realized primarily as a result of the reversal of deductible temporary differences and percentage depletion. A $35.7 million benefit was recorded from the release of valuation allowance offsetting alternative minimum tax credits that have become refundable by the Act, as well as carryback claims filed in the fourth quarter related to specific liability losses that resulted in claims for refund of previously paid alternative minimum taxes. At December 31, 2017 a $610.6 million valuation allowance fully offsets all net deferred tax assets, other than alternative minimum tax credits.

At December 31, 2018, the valuation allowance related to sequestration on the AMT credits has been released and the credits have been reclassified from deferred tax assets to short and long term receivables, as all AMT credits will be refunded between 2019 through 2022. The impact of the 2016 amended return and finalization of the AMT NOL 10-yr carryback claims also affects NOLs, AMT credits and the investment in partnerships. A $530.6 million valuation allowance fully offsets all net deferred tax assets.

A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits follows:



		(In thousands)
Balance at	January 1, 2016	$	38,877
Additions based on tax positions related to the current year		2,979
Additions for tax positions of prior years		2,709
Reductions as a result of lapses in the statute of limitations		(37,110		)
Balance at	December 31, 2016	7,455
Additions based on tax positions related to the current year		—
Additions for tax positions of prior years		3,928
Reductions as a result of lapses in the statute of limitations		—
Balance at	December 31, 2017	11,383
Additions for tax positions of prior years		28,387
Additions for tax positions related to the current year		3,228
Reductions for tax positions of prior years		(634		)
Reductions as a result of lapses in the statute of limitations		$	(3,271	)
Balance at	December 31, 2018	$	39,093

If recognized, the entire amount of the gross unrecognized tax benefits at December 31, 2018 would affect the effective tax rate.

As a result of the bankruptcy, federal and state governments are precluded from assessing additional tax in audits of tax periods ending prior to bankruptcy. As a result, the Company has released $37.1 million of gross unrecognized tax benefits for years 2015 and prior. These gross unrecognized tax benefits are fully offset by a corresponding release in valuation allowance.

The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense. The Company had accrued interest and penalties of $0.3 million and $0.6 million at December 31, 2018 and 2017, respectively. In the next 12 months, $0.4 million gross unrecognized tax benefits are expected to be reduced due to the expiration of the statute of limitations.

Asset Retirement Obligations

12 Months Ended

Dec. 31, 2018

Asset Retirement Obligation [Abstract]

Asset Retirement Obligations

The Company’s asset retirement obligations arise from the Federal Surface Mining Control and Reclamation Act of 1977 and similar state statutes, which require that mine property be restored in accordance with specified standards and an approved reclamation plan. The required reclamation activities to be performed are outlined in the Company’s mining permits. These activities include reclaiming the pit and support acreage at surface mines, sealing portals at underground mines, reclaiming refuse areas and slurry ponds and water treatment.

The following table describes the changes to the Company’s asset retirement obligation liability:



	Year Ended December 31, 2018			Year Ended December 31, 2017
(In thousands)
Balance at beginning of period (including current portion)	$	328,695		$	356,742
Accretion expense	27,970			30,209
Obligations of divested operations	—			(12,569		)
Adjustments to the liability from changes in estimates	(100,728		)	(23,215		)
Liabilities settled	(12,520		)	(22,472		)
Fresh start accounting adjustment	—			—
Balance at period end	$	243,417		$	328,695
Current portion included in accrued expenses	(13,113		)	(19,840		)
Noncurrent liability	$	230,304		$	308,855

The reduction in the asset retirement obligation during the year ended December 31, 2018 primarily relates to a revised mining and reclamation plan at the Company’s Black Thunder Mine. The revised plan provides for accelerated mine reclamation during the ordinary mining process, which significantly reduces the size of the mine’s open pit at the time of final reclamation. The change reduced the asset retirement obligation, and corresponding deferred mine development asset on the Company’s balance sheet by $95.6 million.

As of December 31, 2018, the Company had $536.2 million in surety bonds outstanding and no letters of credit to secure reclamation bonding obligations. Additionally, the Company has posted $0.6 million in cash as collateral related to reclamation surety bonds; this amount is recorded within “Noncurrent assets” on the Consolidated Balance Sheet.

Fair Value Measurements

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

The hierarchy of fair value measurements assigns a level to fair value measurements based on the inputs used in the respective valuation techniques. The levels of the hierarchy, as defined below, give the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs.

· Level 1 is defined as observable inputs such as quoted prices in active markets for identical assets. Level 1 assets include available-for-sale equity securities, U.S. Treasury securities, and coal swaps and futures that are submitted for clearing on the New York Mercantile Exchange.

· Level 2 is defined as observable inputs other than Level 1 prices. These include quoted prices for similar assets or liabilities in an active market, quoted prices for identical assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. The Company’s level 2 assets and liabilities include U.S. government agency securities, coal commodity contracts and interest rate swaps with fair values derived from quoted prices in over-the-counter markets or from prices received from direct broker quotes.

· Level 3 is defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. These include the Company’s commodity option contracts (coal and heating oil) valued using modeling techniques, such as Black-Scholes, that require the use of inputs, particularly volatility, that are rarely observable. Changes in the unobservable inputs would not have had a significant impact on the reported Level 3 fair values at December 31, 2018 and 2017.

The table below sets forth, by level, the Company’s financial assets and liabilities that are recorded at fair value in the accompanying consolidated balance sheet:



	Fair Value at				December 31, 2018
	Total		Level 1			Level 2		Level 3
	(In thousands)
Assets:
Investments in marketable securities	$	162,797	$	99,888		$	62,909	$	—
Derivatives	3,554		—			3,022		532
Total assets	$	166,351	$	99,888		$	65,931	$	532
Liabilities:
Derivatives	$	13,288	$	13,252		$	36	$	—



	Fair Value at				December 31, 2017
	Total		Level 1			Level 2		Level 3
	(In thousands)
Assets:
Investments in marketable securities	$	155,846	$	64,100		$	91,746	$	—
Derivatives	7,339		—			1,985		5,354
Total assets	$	163,185	$	64,100		$	93,731	$	5,354
Liabilities:
Derivatives	$	7,217	$	7,263		$	26	$	(72	)

The Company’s contracts with its counterparties allow for the settlement of contracts in an asset position with contracts in a liability position in the event of default or termination. For classification purposes, the Company records the net fair value of all the positions with these counterparties as a net asset or liability. Each level in the table above displays the underlying contracts according to their classification in the accompanying consolidated balance sheet, based on this counterparty netting.

The following table summarizes the change in the fair values of financial instruments categorized as level 3.



	Year Ended December 31, 2018			Year Ended December 31, 2017
(In thousands)
Balance, beginning of period	$	5,426		$	4,537
Realized and unrealized (gains) losses recognized in earnings, net	(302		)	(2,305		)
Purchases	3,420			4,910
Issuances	(724		)	(535		)
Settlements	(7,288		)	(1,181		)
Ending balance	$	532		$	5,426

Net unrealized losses of $2.0 million were recognized during the year ended December 31, 2018 related to level 3 financial instruments held on December 31, 2018.

Cash and Cash Equivalents

At December 31, 2018 and 2017, the carrying amounts of cash and cash equivalents approximate their fair value.

Fair Value of Long-Term Debt

At December 31, 2018 and 2017, the fair value of the Company’s debt, including amounts classified as current, was $318.6 million and $336.1 million, respectively. Fair values are based upon observed prices in an active market, when available, or from valuation models using market information, which fall into Level 2 in the fair value hierarchy.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Capital Stock

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Capital Stock

Dividends

The Company declared and paid cash dividends per share during the periods presented below:



2018:	Dividends per share		Amount (in thousands)
1st quarter	$	0.40	$	8,335
2nd quarter	0.40		7,998
3rd quarter	0.40		7,633
4th quarter	0.40		7,303
Total cash dividends declared and paid	$	1.60	$	31,269

2017:	Dividends per share		Amount (in thousands)
1st quarter	$	—	$	—
2nd quarter	0.35		8,563
3rd quarter	0.35		8,200
4th quarter	0.35		7,606
Total cash dividends declared and paid	$	1.05	$	24,369

Future dividend declarations will be subject to ongoing Board review and authorization will be based on a number of factors, including business and market conditions, the Company’s future financial performance and other capital priorities.

Share Repurchase Program

During April 2017, the Board of Directors of Arch Coal, Inc. authorized a new share repurchase program for up to $300 million of its common stock. In October 2017, the Company’s Board of Directors approved an incremental $200 million increase to the share repurchase program, and in July 2018, the Company’s Board of Directors authorized an incremental $250 million increase to the share repurchase program bringing the total authorization to $750 million. Below is a table showing the share repurchase activity during the periods presented below:



2018:	Number of Shares	Average Repurchase Price per Share		Amount (in thousands)
1st quarter	407,091	$	94.79	$	38,588
2nd quarter	960,105	81.54		78,287
3rd quarter	870,538	87.59		76,248
4th quarter	1,000,881	88.57		88,651
Total shares repurchased	3,238,615	$	87.00	$	281,774

2017:	Number of Shares	Average Repurchase Price per Share		Amount (in thousands)
1st quarter	—	$	—	$	—
2nd quarter	710,701	71.82		51,043
3rd quarter	2,208,133	75.49		166,685
4th quarter	1,058,381	79.73		84,381
Total shares repurchased	3,977,215	$	75.96	$	302,109

The timing of any future share repurchases, and the ultimate number of shares purchased, will depend on a number of factors, including business and market conditions, the Company’s future financial performance and other capital priorities. The shares will be acquired in the open market or through private transactions in accordance with the Securities and Exchange Commission requirements. The share repurchase program has no termination date, but may be amended, suspended or discontinued at any time and does not commit the Company to repurchase shares of its common stock. The actual number and value of the shares to be purchased will depend on the performance of the Company’s stock price and other market conditions.

Outstanding Warrants

On the Effective Date, the Company entered into a warrant agreement (the “Warrant Agreement”) with American Stock Transfer & Trust Company, LLC as warrant agent and, pursuant to the terms of the Plan, issued warrants (“Warrants”) to purchase up to an aggregate of 1,914,856 shares of Class A Common Stock, par value $0.01 per share, of Arch Coal (the “Class A Common Stock”) to holders of claims arising under the Cancelled Notes (as defined below). Each Warrant expires on October 5, 2023, and is initially exercisable for one share of Class A Common Stock at an initial exercise price of $57.00 per share. The Warrants are exercisable by a holder paying the exercise price in cash or on a cashless basis, at the election of the holder. The Warrants contain anti-dilution adjustments for stock splits, reverse stock splits, stock dividends, dividends and distributions of cash, other securities or other property, spin-offs and tender and exchange offers by Arch Coal or its subsidiaries to purchase Class A Common Stock at above-market prices.

If, in connection with a merger, recapitalization, business combination, transfer to a third party of substantially all of Arch Coal’s consolidated assets or other transaction that results in a change to the Class A Common Stock (each, a “Transaction”), (i) the Transaction is consummated prior to the fifth anniversary of the Effective Date and the Transaction consideration to holders of Class A Common Stock is 90% or more listed common stock or common stock of a company that provides publicly available financial reporting, and holds management calls regarding the same, no less than quarterly (“Reporting Stock”) or (ii) regardless of the consideration, the Transaction is consummated on or after the fifth anniversary of the Effective Date, the Warrants will be assumed by the surviving company and will become exercisable for the consideration that the holders of Class A Common Stock receive in such Transaction; provided that if the consideration such holders receive consists solely of cash, then upon the consummation of such Transaction, Arch Coal will pay for each Warrant an amount of cash equal to the greater of (i) (x) the amount of cash payable with respect to the number of shares of Class A Common Stock underlying the Warrant minus (y) the exercise price per share then in effect multiplied by the number of shares of Class A Common Stock underlying the Warrant and (ii) $0.

If a Transaction is consummated prior to the fifth anniversary of the Effective Date in which the Transaction consideration is less than 90% Reporting Stock, a portion of the Warrants corresponding to the portion of the Transaction consideration that is Reporting Stock will be assumed by the surviving company and will become exercisable for the Reporting Stock consideration that the holders of Class A Common Stock receive in such Transaction, and the portion of the Warrants corresponding to the portion of the Transaction consideration that is not Reporting Stock will, at the option of each holder, (i) be assumed by the surviving company and will become exercisable for the consideration that the holders of Class A Common Stock receive in such Transaction or (ii) be redeemed by Arch Coal for cash in an amount equal to the Black Scholes Payment (as defined in the Warrant Agreement).

During 2018, holders of warrants had exercised 204 of the warrants, leaving 1,845,954 warrants outstanding at December 31, 2018.

As provided in ASC 825-20, “Financial Instruments,” the warrants are considered equity because they can only be physically settled in Company shares, can be settled in unregistered shares, the Company has adequate authorized shares to settle the outstanding warrants and each warrant is fixed in terms of settlement to one share of Company stock subject only to remote contingency adjustment factors designed to assure the relative value in terms of shares remains fixed.

Stock-Based Compensation and Other Incentive Plans

12 Months Ended

Dec. 31, 2018

Share-based Compensation [Abstract]

Stock-Based Compensation And Other Incentive Plans

Stock-Based Compensation and Other Incentive Plans

Under the Company’s 2016 Omnibus Incentive Plan (the “Incentive Plan”), 3.0 million shares of the Company’s common stock were reserved for awards to officers and other selected key management employees of the Company. The Incentive Plan provides the Board of Directors with the flexibility to grant stock options, stock appreciation rights, restricted stock awards, restricted stock units, performance stock or units, phantom stock awards and rights to acquire stock through purchase under a stock purchase program (“Awards”). Awards the Board of Directors elects to pay out in cash do not impact the shares authorized in the Incentive Plan. Shares available for award under the plan were 2.1 million at December 31, 2018.

Restricted Stock Unit Awards

The Company may issue restricted stock and restricted stock units, which require no payment from the employee. Restricted stock cliff-vests at various dates and restricted stock units either vest ratably over or vest at the end of the award’s stated vesting period. Compensation expense is based on the fair value on the grant date and is recorded ratably over the vesting period utilizing the straight-line recognition method. The employee receives cash compensation equal to the amount of dividends that would have been paid on the underlying shares.

During 2018, the Company granted both time based awards and performance based awards. The time based awards vest over either a one or three year period and the performance based awards vest over a three year period. The time based awards’ grant date fair value was determined based on the stock price at the date of grant. The performance awards grant date fair value was determined using a Black-Scholes Monte Carlo simulation. A historical volatility of 50% and 36% were selected for each of the performance-based awards based on comparator companies, and the three-year risk free rate was derived from yields on U.S. Government bonds. Information regarding the restricted stock units activity and weighted average grant-date fair value follows:



	Time Based Awards				Performance Based Awards
	Restricted Stock Units		Weighted Average Grant-Date Fair Value		Restricted Stock Units		Weighted Average Grant-Date Fair Value
(Shares in thousands)
Outstanding at January 1, 2018	240		$	79.87	311		$	76.75
Granted	150		90.83		105		110.85
Forfeited/Canceled	(2	)	81.28		(1	)	135.34
Vested	—		—		—		—
Unvested outstanding at December 31, 2018	388		$	84.11	415		$	85.30

The Company recognized expense related to restricted stock units of $17.5 million and $10.4 million for the years ended December 31, 2018 and 2017; and $1.0 million for the period October 2, 2016 through December 31, 2016. As of December 31, 2018, there was $40.1 million of unrecognized share-based compensation expense which is expected to be recognized over a weighted-average period of approximately three years.

Long-Term Incentive Compensation

The Company has a long-term incentive program that allows for the award of performance units. The total number of units earned by a participant is based on financial and operational performance measures, and may be paid out in cash or in shares of the Company’s common stock. The Company recognizes compensation expense over the three year term of the grant. The liabilities are remeasured quarterly. The Company recognized expense of $2.7 million and $0.7 million for the years ended December 31, 2018 and 2017; $1.6 million for the period October 2 through December 31, 2016; and $7.2 million for the period January 1 through October 1, 2016 , respectively. The expense is included primarily in “Selling, general and administrative expenses” in the accompanying Consolidated Income Statements.

Amounts accrued and unpaid for all grants under the plan totaled $6.9 million and $8.7 million as of December 31, 2018 and 2017, respectively.

Workers' Compensation Expense

12 Months Ended

Dec. 31, 2018

Workers' Compensation Expense

Workers’ Compensation Expense

The Company is liable under the Federal Mine Safety and Health Act of 1969, as subsequently amended, to provide for pneumoconiosis (occupational disease) benefits to eligible employees, former employees and dependents. The Company currently provides for federal claims principally through a self-insurance program. The Company is also liable under various state workers’ compensation statutes for occupational disease benefits. The occupational disease benefit obligation represents the present value of the actuarially computed present and future liabilities for such benefits over the employees’ applicable years of service.

In addition, the Company is liable for workers’ compensation benefits for traumatic injuries which are calculated using actuarially-based loss rates, loss development factors and discounted based on a risk free rate of 3.08%. Traumatic workers’ compensation claims are insured with varying retentions/deductibles, or through state-sponsored workers’ compensation programs.

Workers’ compensation expense consists of the following components:



	Successor						Predecessor
	Year Ended December 31, 2018		Year Ended December 31, 2017		October 2 through December 31, 2016		January 1 through October 1, 2016
(In thousands)
Self-insured occupational disease benefits:
Service cost	$	7,440	$	6,320	$	1,583	$	3,465
Interest cost⁽¹⁾	4,365		4,651		1,126		3,184
Net amortization⁽¹⁾	—		—		—		4,325
Total occupational disease	$	11,805	$	10,971	$	2,709	$	10,974
Traumatic injury claims and assessments	5,395		3,208		3,162		6,628
Total workers’ compensation expense	$	17,200	$	14,179	$	5,871	$	17,602

⁽¹⁾ In accordance with the adoption of ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” these costs are recorded within Nonoperating expenses in the Consolidated Income Statements on the line item “Non-service related pension and postretirement benefit costs.” For additional information about the adoption of the standard, see Note 2, “Accounting Policies” in the Consolidated Financial Statements.

The table below reconciles changes in the occupational disease liability for the respective period.



(In thousands)	Year Ended December 31, 2018			Year Ended December 31, 2017
Beginning of period	$	122,426		$	111,159
Service cost	7,440			6,320
Interest cost	4,365			4,651
Curtailments	—			(5,433		)
Actuarial (gain) loss	(7,071		)	12,242
Benefit and administrative payments	(8,260		)	(6,513		)
	$	118,900		$	122,426

The following table provides the assumptions used to determine the projected occupational disease obligation:



	Year Ended December 31, 2018	Year Ended December 31, 2017
(Percentages)
Discount rate	4.26	3.66
Cost escalation rate	N/A	N/A

Summarized below is information about the amounts recognized in the accompanying consolidated balance sheets for workers’ compensation benefits:



	Year Ended December 31, 2018		Year Ended December 31, 2017
(In thousands)
Occupational disease costs	$	118,900	$	122,426
Traumatic and other workers’ compensation claims	75,447		81,191
Total obligations	194,347		203,617
Less amount included in accrued expenses	20,044		18,782
Noncurrent obligations	$	174,303	$	184,835

As of December 31, 2018, the Company had $121.7 million in surety bonds and letters of credit outstanding to secure workers’ compensation obligations.

As of December 31, 2018, the Company’s recorded liabilities include $20.3 million of obligations that are reimbursable under various insurance policies purchased by the company. These insurance receivables are recorded in the balance sheet line items “Other receivables” and “Other noncurrent assets” for $3.3 million and $17.0 million, respectively.

Employee Benefit Plans

12 Months Ended

Dec. 31, 2018

Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]

Employee Benefit Plans

Defined Benefit Pension and Other Postretirement Benefit Plans

The Company provides funded and unfunded non-contributory defined benefit pension plans covering certain of its salaried and hourly employees. Benefits are generally based on the employee’s age and compensation. The Company funds the plans in an amount not less than the minimum statutory funding requirements or more than the maximum amount that can be deducted for U.S. federal income tax purposes.

The Company also currently provides certain postretirement medical and life insurance coverage for eligible employees. Generally, covered employees who terminate employment after meeting eligibility requirements are eligible for postretirement coverage for themselves and their dependents. The Company offers a subsidy to eligible retirees based on age and years of service at retirement and contain other cost-sharing features such as deductibles and coinsurance. The Company’s current funding policy is to fund the cost of all postretirement benefits as they are paid.

On January 1, 2015, the Company’s cash balance and excess plans were amended to freeze new service credits for any new or active employee.

Obligations and Funded Status.

Summaries of the changes in the benefit obligations, plan assets and funded status of the plans are as follows:



	Pension Benefits						Other Postretirement Benefits
	Year Ended December 31, 2018			Year Ended December 31, 2017			Year Ended December 31, 2018			Year Ended December 31, 2017
(In thousands)
CHANGE IN BENEFIT OBLIGATIONS
Benefit obligations at beginning of period	$	270,098		$	313,629		$	110,519		$	111,867
Service cost	—			—			558			671
Interest cost	9,269			11,169			3,674			4,150
Divestitures (see Note 5 to the Consolidated Financial Statements)	—			(29,097		)	—			—
Settlement gain	(2,332		)	(1,532		)	—			—
Curtailments	—			—			—			(520		)
Benefits paid	(36,895		)	(38,197		)	(5,388		)	(8,152		)
Other-primarily actuarial (gain) loss	(11,267		)	14,126			(20,800		)	2,503
Benefit obligations at end of period	$	228,873		$	270,098		$	88,563		$	110,519
CHANGE IN PLAN ASSETS
Value of plan assets at beginning of period	$	255,642		$	274,225		$	—		$	—
Actual return on plan assets	(6,463		)	39,689						—
Employer contributions	222			429			5,388			8,152
Benefits paid	(36,895		)	(38,197		)	(5,388		)	(8,152		)
Divestitures	$	—		$	(20,504	)	$	—		$	—
Value of plan assets at end of period	$	212,506		$	255,642		$	—		$	—
Accrued benefit cost	$	(16,367	)	$	(14,456	)	$	(88,563	)	$	(110,519	)
ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST
Accumulated gain	$	8,899		$	16,178		$	25,936		$	5,137
	$	8,899		$	16,178		$	25,936		$	5,137
BALANCE SHEET AMOUNTS
Current liability	$	(220	)	$	(420	)	$	(5,400	)	$	(8,150	)
Noncurrent liability	(16,147		)	(14,036		)	(83,163		)	(102,369		)
	$	(16,367	)	$	(14,456	)	$	(88,563	)	$	(110,519	)

Pension Benefits

The accumulated benefit obligation for all pension plans was $228.9 million and $270.1 million at December 31, 2018 and 2017, respectively.

The Company uses the corridor method of amortizing actuarial gains (losses); it is anticipated there will be no amortization recorded into net periodic benefit cost during 2019.

Other Postretirement Benefits

The Company uses the corridor method of amortizing actuarial gains (losses); it is anticipated there will be $3.0 million of gains amortized from accumulated other comprehensive income into net periodic benefit cost during 2019.

Components of Net Periodic Benefit Cost. The following table details the components of pension and postretirement benefit costs (credits):



	Pension Benefits												Other Postretirement Benefits
	Successor									Predecessor			Successor							Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016			Year Ended December 31, 2018		Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
(In thousands)
Service cost	$	—		$	—		$	—		$	—		$	558	$	671		$	180	$	393
Interest cost⁽¹⁾	9,269			11,169			2,768			9,338			3,674		4,150			978		3,223
Curtailments	—			—			—			454			—		(520		)	—		(970		)
Settlements⁽¹⁾	(2,332		)	(1,532		)	(135		)	—			—		—			—		—
Expected return on plan assets⁽¹⁾	(12,083		)	(16,498		)	(4,770		)	(13,623		)	—		—			—		—
Amortization of prior service credits⁽¹⁾	—			—			—			—			—		—			—		(7,854		)
Amortization of other actuarial losses (gains) ⁽¹⁾	—			—			—			3,973			—		—			—		(849		)
Net benefit cost (credit)	$	(5,146	)	$	(6,861	)	$	(2,137	)	$	142		$	4,232	$	4,301		$	1,158	$	(6,057	)

The differences generated from changes in assumed discount rates and returns on plan assets are amortized into earnings over the remaining service attribution periods of the employees using the corridor method.

Assumptions. The following table provides the weighted average assumptions used to determine the actuarial present value of projected benefit obligations for the respective periods.



	Year Ended December 31, 2018	Year Ended December 31, 2017
(Percentages)
Pension Benefits
Discount rate	4.11/3.94	3.49/3.27

Other Postretirement Benefits
Discount rate	4.12	3.49

The following table provides the weighted average assumptions used to determine net periodic benefit cost for the respective periods.



	Successor			Predecessor
	Year Ended December 31, 2018	Year Ended December 31, 2017	October 2 through December 31, 2016	January 1 through October 1, 2016
(Percentages)
Pension Benefits
Discount rate	3.82	3.77	3.39/3.95	4.59/3.80
Expected return on plan assets	5.3	6.2	6.85	6.85

Other Postretirement Benefits
Discount rate	3.49	3.85	3.37	4.57/3.80

The discount rates used in 2018, 2017 and 2016 were reevaluated during the year for settlements and curtailments. The obligations are remeasured at an updated discount rate that impacts the benefit cost recognized subsequent to the remeasurement.

The Company establishes the expected long-term rate of return at the beginning of each fiscal year based upon historical returns and projected returns on the underlying mix of invested assets. The Company utilizes modern portfolio theory modeling techniques in the development of its return assumptions. This technique projects rates of return that can be generated through various asset allocations that lie within the risk tolerance set forth by members of the Company’s pension committee (the “Pension Committee”). The risk assessment provides a link between a pension plan’s risk capacity, management’s willingness to accept investment risk and the asset allocation process, which ultimately leads to the return generated by the invested assets.

The health care cost trend rate assumed for 2019 is 5.9% and is expected to reach an ultimate trend rate of 4.5% by 2038. A one-percentage-point increase in the health care cost trend rate would increase the postretirement benefit obligation at December 31, 2018 by $8.5 million and the net periodic postretirement benefit cost for the year ended December 31, 2018 by $0.4 million.

Plan Assets

The Pension Committee is responsible for overseeing the investment of pension plan assets. The Pension Committee is responsible for determining and monitoring appropriate asset allocations and for selecting or replacing investment managers, trustees and custodians. The pension plan’s current investment targets are 35% equity and 65% fixed income securities. The Pension Committee reviews the actual asset allocation in light of these targets on a periodic basis and rebalances among investments as necessary. The Pension Committee evaluates the performance of investment managers as compared to the performance of specified benchmarks and peers and monitors the investment managers to ensure adherence to their stated investment style and to the plan’s investment guidelines.

The Company’s pension plan assets at December 31, 2018 and 2017, respectively, are categorized below according to the fair value hierarchy as defined in Note 16, “Fair Value Measurements”:



	Total						Level 1				Level 2				Level 3
	2018			2017			2018		2017		2018		2017		2018		2017
	(In thousands)
Equity Securities:^(A)
U.S. small-cap	$	2,751		$	4,692		$	2,751	$	4,692	$	—	$	—	$	—	$	—
U.S. mid-cap	1,182			6,017			1,182		6,017		—		—		—		—
U.S. large-cap	—			21,416			—		21,416		—		—		—		—
Non-U.S.	—			—			—		—		—		—		—		—
Fixed income securities:																	—
U.S. government securities^(B)	43,829			66,922			38,436		60,286		5,393		6,636		—		—
Non-U.S. government securities^(C)	2,092			4,050			—		—		2,092		4,050		—		—
U.S. government asset and mortgage backed securities^(D)	7,667			2,440			—		—		7,667		2,440		—		—
Corporate fixed income^(E)	68,762			54,679			—		—		68,762		54,679		—		—
State and local government securities^(F)	3,480			3,829			—		—		3,480		3,829		—		—
Other investments^(I)	5,223			8,457			—		—		5,223		8,457		—		—
Total	$	134,986		$	172,502		$	42,369	$	92,411	$	92,617	$	80,091	$	—	$	—
Assets at net asset value^(G)	82,765			84,172
Short-term investments^(H)	7,003			8,573
Other liabilities^(J)	(12,248		)	(9,605		)
	$	212,506		$	255,642

^(A) Equity securities includes investments in 1) common stock, 2) preferred stock and 3) mutual funds. Investments in common and preferred stocks are valued using quoted market prices multiplied by the number of shares owned. Investments in mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date and are traded on listed exchanges.

^(B)U.S. government securities includes agency and treasury debt. These investments are valued using dealer quotes in an active market.

^(C) Non-U.S. government securities includes debt securities issued by foreign governments and are valued utilizing a price spread basis valuation technique with observable sources from investment dealers and research vendors.

^(D) U.S. government asset and mortgage backed securities includes government-backed mortgage funds which are valued utilizing an income approach that includes various valuation techniques and sources such as discounted cash flows models, benchmark yields and securities, reported trades, issuer trades and/or other applicable data.

^(E) Corporate fixed income is primarily comprised of corporate bonds and certain corporate asset-backed securities that are denominated in the U.S. dollar and are investment-grade securities. These investments are valued using dealer quotes.

^(F) State and local government securities include different U.S. state and local municipal bonds and asset backed securities, these investments are valued utilizing a market approach that includes various valuation techniques and sources such as value generation models, broker quotes, benchmark yields and securities, reported trades, issuer trades and/or other applicable data.

^(G) Investments that are measured at fair value using the net asset value per share practical expedient have not been classified in the fair value hierarchy in accordance with Accounting Standards Update 2015-07. These investments are primarily mutual funds that are highly liquid with no restrictions on ability to redeem the funds into cash.

^(H) Short-term investments include governmental agency funds, government repurchase agreements, commingled funds, and pooled funds and mutual funds. Governmental agency funds are valued utilizing an option adjusted spread valuation technique and sources such as interest rate generation processes, benchmark yields and broker quotes. Investments in governmental repurchase agreements, commingled funds and pooled funds and mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date.

^(I)Other investments include cash, forward contracts, derivative instruments, credit default swaps, interest rate swaps and mutual funds. Investments in interest rate swaps are valued utilizing a market approach that includes various valuation techniques and sources such as value generation models, broker quotes in active and non-active markets, benchmark yields and securities, reported trades, issuer trades and/or other applicable data. Forward contracts and derivative instruments are valued at their exchange listed price or broker quote in an active market. The mutual funds are valued at the net asset value per share multiplied by the number of shares held as of the measurement date and are traded on listed exchanges.

^(J)Net payable amount due for pending securities purchased and sold due to broker/dealer.

Cash Flows. The Company expects to make contributions of $0.4 million to the pension plans in 2019, which is impacted by the Moving Ahead for Progress in the 21st Century Act (MAP-21). MAP-21 does not reduce the Company’s obligations under the plan, but redistributes the timing of required payments by providing near term funding relief for sponsors under the Pension Protection Act.

The following represents expected future benefit payments from the plan:



			Other
	Pension		Postretirement
	Benefits		Benefits
	(In thousands)
2019	$	16,400	$	11,993
2020	17,363		12,125
2021	18,173		12,058
2022	18,532		12,253
2023	16,904		12,072
Next 5 years	73,508		57,896
	$	160,880	$	118,397

Other Plans

The Company sponsors savings plans which were established to assist eligible employees in providing for their future retirement needs. The Company’s expense, representing its contributions to the plans, was $17.9 million and $18.0 million for the years ended December 31, 2018 and 2017, respectively; $3.5 million for the period October 2 through December 31, 2016; and $13.8 million for the period January 1 through October 1, 2016, respectively.

Earnings Per Common Share

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Earnings Per Common Share

The Company computes basic net income per share using the weighted average number of common shares outstanding during the period. Diluted net income per share is computed using the weighted average number of common shares and the effect of potentially dilutive securities outstanding during the period. Potentially dilutive securities may consist of warrants, restricted stock units or other contingently issuable shares. The dilutive effect of outstanding warrants, restricted stock units and other contingently issuable shares is reflected in diluted earnings per share by application of the treasury stock method.

The following table provides the basis for basic and diluted EPS by reconciling the numerators and denominators of the computations:



	Successor			Predecessor
	Year Ended December 31, 2018	Year Ended December 31, 2017	October 2 through December 31, 2016	January 1 through October 1, 2016
(In Thousands)
Weighted average shares outstanding:
Basic weighted average shares outstanding	19,663	23,725	25,002	21,293
Effect of dilutive securities	966	515	467	20

Diluted weighted average shares outstanding	20,629	24,240	25,469	21,313

Leases

12 Months Ended

Dec. 31, 2018

Leases [Abstract]

Leases

The Company leases equipment, land and various other properties under non-cancelable long-term leases, expiring at various dates. Certain leases contain options that would allow the Company to extend the lease or purchase the leased asset at the end of the base lease term.

In addition, the Company enters into various non-cancelable royalty lease agreements under which future minimum payments are due.

Minimum payments due in future years under these agreements in effect at December 31, 2018 are as follows:



	Operating
	Leases		Royalties
	(In thousands)
2019	$	3,681	$	3,669
2020	2,260		8,096
2021	1,985		8,296
2022	2,024		8,086
2023	2,044		7,749
Thereafter	6,248		84,913
	$	18,242	$	120,809

The Company has no obligations for future minimum payments under capital leases for equipment at December 31, 2018 and 2017.

Rental expense, including amounts related to these operating leases and other shorter-term arrangements, amounted to $12.4 million in 2018, $19.2 million in 2017, $5.0 million for the period October 2 through December 31, 2016 and $19.4 million for the period January 1 through October 1, 2016.

Royalties are paid to lessors either as a fixed price per ton or as a percentage of the gross selling price of the mined coal. Royalties under the majority of the Company’s significant leases are paid on the percentage of gross selling price basis. Royalty expense, including production royalties, was $166.1 million in 2018, $167.4 million in 2017, $45.3 million for the period October 2 through December 31, 2016 and $116.4 million for the period January 1 through October 1, 2016.

As of December 31, 2018, certain of the Company’s lease obligations were secured by outstanding surety bonds totaling $30.4 million.

Risk Concentrations

12 Months Ended

Dec. 31, 2018

Risks and Uncertainties [Abstract]

Risk Concentrations

Credit Risk and Major Customers

The Company has a formal written credit policy that establishes procedures to determine creditworthiness and credit limits for trade customers and counterparties in the over-the-counter coal market. Generally, credit is extended based on an evaluation of the customer’s financial condition. Collateral is not generally required, unless credit cannot be established. Credit losses are provided for in the financial statements and historically have been minimal.

The Company markets its steam coal principally to domestic and foreign electric utilities and its metallurgical coal to domestic and foreign steel producers. As of December 31, 2018 and 2017, accounts receivable from electric utilities of $73.9 million and $72.9 million, respectively, represented 37% and 42% of total trade receivables at each date. As of December 31, 2018 and 2017, accounts receivable from sales of metallurgical-quality coal of $126.5 million and $99.4 million, respectively, represented 63% and 58% of total trade receivables at each date.

The Company uses shipping destination as the basis for attributing revenue to individual countries. Because title may transfer on brokered transactions at a point that does not reflect the end usage point, they are reflected as exports, and attributed to an end delivery point if that knowledge is known to the Company. The Company’s foreign revenues by geographical location are as follows:



	Successor						Predecessor
	Year Ended December 31, 2018		Year Ended December 31, 2017		October 2 through December 31, 2016		January 1 through October 1, 2016
(In thousands)
Europe	$	559,165	$	388,926	$	61,169	$	112,986
Asia	452,711		264,503		55,634		68,536
Central and South America	79,085		30,982		13,224		41,861
Africa	17,567		14,901		—		—
Brokered Sales	2,372		3,150		—		—
Total	$	1,110,900	$	702,462	$	130,027	$	223,383

The Company is committed under long-term contracts to supply steam coal that meets certain quality requirements at specified prices. These prices are generally adjusted based on market indices. Quantities sold under some of these contracts may vary from year to year within certain limits at the option of the customer based on their requirements. The Company sold approximately 96.6 million tons of coal in 2018. Approximately 60% of this tonnage (representing approximately 47% of the Company’s revenues) was sold under long-term contracts (contracts having a term of greater than one year). Long-term contracts range in remaining life from one to four years.

Third-party sources of coal

The Company purchases coal from third parties that it sells to customers. Factors beyond the Company’s control could affect the availability of coal purchased by the Company. Disruptions in the quantities of coal purchased by the Company could impair its ability to fill customer orders or require it to purchase coal from other sources at prevailing market prices in order to satisfy those orders.

Transportation

The Company depends upon barge, rail, truck and belt transportation systems to deliver coal to its customers. Disruption of these transportation services due to weather-related problems, mechanical difficulties, strikes, lockouts, bottlenecks, and other events could temporarily impair the Company’s ability to supply coal to its customers. In the past, disruptions in rail service have resulted in missed shipments and production interruptions.

Revenue Recognition

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Revenue Recognition

ASC 606-10-50-5 requires that entities disclose disaggregated revenue information in categories (such as type of good or service, geography, market, type of contract, etc.) that depict how the nature, amount, timing, and uncertainty of revenue and cash flow are affected by economic factors. ASC 606-10-55-89 explains that the extent to which an entity’s revenue is disaggregated depends on the facts and circumstances that pertain to the entity’s contracts with customers and that some entities may need to use more than one type of category to meet the objective for disaggregating revenue.

In general, the Company’s business segmentation is aligned according to the nature and economic characteristics of its coal and customer relationships and provides meaningful disaggregation of each segment’s results. The company has further disaggregated revenue between North America and Seaborne revenues which depicts the pricing and contract differences between the two. North America revenue is characterized by contracts with a term of one year or longer and typically the pricing is fixed; whereas Seaborne revenue generally is derived by spot or short term contracts with an indexed based pricing mechanism.



	PRB		MET		Other Thermal		Corporate, Other and Eliminations		Consolidated
	(in thousands)
Year Ended December 31, 2018
North America revenues	$	971,337	$	160,969	$	195,547	$	13,034	$	1,340,887
Seaborne revenues	1,911		875,652		233,337		—		1,110,900

Total revenues	$	973,248	$	1,036,621	$	428,884	$	13,034	$	2,451,787

Year Ended December 31, 2017
North America revenues	$	1,024,197	$	312,874	$	269,007	$	16,083	$	1,622,161
Seaborne revenues	—		574,965		127,497		—		702,462

Total revenues	$	1,024,197	$	887,839	$	396,504	$	16,083	$	2,324,623

October 2 through December 31, 2016
North America revenues	$	275,703	$	91,086	$	76,646	$	2,226	$	445,661
Seaborne revenues	—		109,291		20,736		—		130,027

Total revenues	$	275,703	$	200,377	$	97,382	$	2,226	$	575,688

January 1 through October 1, 2016
North America revenues	$	726,747	$	215,585	$	211,153	$	21,841	$	1,175,326
Seaborne revenues	—		221,484		1,899		—		223,383

Total revenues	$	726,747	$	437,069	$	213,052	$	21,841	$	1,398,709

As of December 31, 2018, the Company has outstanding performance obligations for approximately 73.0 million tons of coal for 2019 representing 63.0 million tons of fixed price contracts and 10.0 million tons of variable price contracts.

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company accrues for cost related to contingencies when a loss is probable and the amount is reasonably determinable. Disclosure of contingencies is included in the financial statements when it is at least reasonably possible that a material loss or an additional material loss in excess of amounts already accrued may be incurred. The Company is a party to numerous claims and lawsuits with respect to various matters. As of December 31, 2018 and 2017, the Company had accrued $0.2 million and $0.2 million, respectively, for all legal matters, all classified as current. The ultimate resolution of any such legal matter could result in outcomes which may be materially different from amounts the Company has accrued for such matters. The Company has unconditional purchase obligations relating to purchases of coal, materials and supplies and capital commitments, other than reserve acquisitions, and is also a party to transportation capacity commitments. The future commitments under these agreements total $70.0 million in 2019, and is immaterial thereafter.

Segment Information

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Segment Information

The Company’s reportable business segments are based on two distinct lines of business, metallurgical coal and thermal coal, and may include a number of mine complexes. The Company manages its coal sales by market, not by individual mining complex. Geology, coal transportation routes to customers, and regulatory environments also have a significant impact on the Company’s marketing and operations management. Mining operations are evaluated based on Adjusted EBITDAR, per-ton cash operating costs (defined as including all mining costs except depreciation, depletion, amortization, accretion on asset retirement obligations, and pass-through transportation expenses), and on other non-financial measures, such as safety and environmental performance. Adjusted EBITDAR is not a measure of financial performance in accordance with generally accepted accounting principles, and items excluded from Adjusted EBITDAR are significant in understanding and assessing our financial condition. Therefore, Adjusted EBITDAR should not be considered in isolation, nor as an alternative to net income, income from operations, cash flows from operations or as a measure of our profitability, liquidity or performance under generally accepted accounting principles. The Company uses Adjusted EBITDAR to measure the operating performance of its segments and allocate resources to the segments. Furthermore, analogous measures are used by industry analysts and investors to evaluate the Company’s operating performance. Investors should be aware that the Company’s presentation of Adjusted EBITDAR may not be comparable to similarly titled measures used by other companies. The Company reports its results of operations primarily through the following reportable segments: Powder River Basin (PRB) segment containing the Company’s primary thermal operations in Wyoming; the Metallurgical (MET) segment, containing the Company’s metallurgical operations in West Virginia, Kentucky, and Virginia, and the Other Thermal segment containing the Company’s supplementary thermal operations in Colorado, Illinois, and West Virginia. Periods presented in this note have been recast for comparability.

On September 14, 2017, the Company closed on its’ definitive agreement to sell Lone Mountain Processing LLC, an operating mine complex within the Company’s metallurgical coal segment. Through this transaction the Company divested all active operations in the states of Kentucky and Virginia. Lone Mountain is included in the MET segment results below up to the date of divestiture. For further information on the divestiture, please see Note 5 to the Consolidated Financial Statements, “Divestitures.”

Operating segment results for the year ended December 31, 2018, the year ended December 31, 2017, the Successor period October 2 through December 31, 2016, and the Predecessor period January 1 through October 1, 2016 are presented below. The Company measures its segments based on “adjusted earnings before interest, taxes, depreciation, depletion, amortization, accretion on asset retirements obligations, and reorganization items, net (Adjusted EBITDAR).” Adjusted EBITDAR does not reflect mine closure or impairment costs, since those are not reflected in the operating income reviewed by management. See Note 6, “Impairment Charges and Mine Closure Costs” for discussion of these costs. The Corporate, Other and Eliminations grouping includes these charges, as well as the change in fair value of coal derivatives and coal trading activities, net; corporate overhead; land management activities; other support functions; and the elimination of intercompany transactions.



(In thousands)		PRB		MET		Other Thermal		Corporate, Other and Eliminations			Consolidated
Successor Year Ended	December 31, 2018
Revenues		$	973,248	$	1,036,621	$	428,884	$	13,034		$	2,451,787
Adjusted EBITDAR		126,525		349,524		68,620		(106,891		)	437,778
Depreciation, depletion and amortization		33,120		69,560		14,699		2,184			119,563
Accretion on asset retirement obligation		19,541		1,874		2,261		4,294			27,970
Total Assets		278,314		545,061		125,333		938,352			1,887,060
Capital expenditures		12,140		64,307		11,999		6,826			95,272
Successor Year Ended	December 31, 2017
Revenues		$	1,024,197	$	887,839	$	396,504	$	16,083		$	2,324,623
Adjusted EBITDAR		158,882		243,616		102,006		(84,807		)	419,697
Depreciation, depletion and amortization		36,349		70,896		13,588		1,631			122,464
Accretion on asset retirement obligation		20,160		2,000		2,161		5,888			30,209
Total assets		390,665		548,476		134,397		906,094			1,979,632
Capital expenditures		6,212		32,678		11,901		8,414			59,205
Successor Period	October 2 through December 31, 2016
Revenues		$	275,703	$	200,377	$	97,382	$	2,226		$	575,688
Adjusted EBITDAR		55,765		30,819		31,159		(23,278		)	94,465
Depreciation, depletion and amortization		9,949		18,287		3,911		457			32,604
Accretion on asset retirement obligation		5,049		528		540		1,517			7,634
Total assets		446,775		576,793		129,602		983,427			2,136,597
Capital expenditures		934		13,329		684		267			15,214
Predecessor Period	January 1 through October 1, 2016
Revenues		$	726,747	$	437,069	$	213,052	$	21,841		$	1,398,709
Adjusted EBITDAR		113,185		11,851		31,448		(67,466		)	89,018
Depreciation, depletion and amortization		100,151		55,311		32,310		3,809			191,581
Accretion on asset retirement obligation		16,940		1,765		1,988		3,628			24,321
Total assets		456,711		619,154		131,173		916,791			2,123,829
Capital expenditures		612		17,296		3,895		60,631			82,434

A reconciliation of segment Adjusted EBITDAR to consolidated income (loss) from continuing operations before income taxes follows:



	Successor								Predecessor
(In thousands)	Year Ended December 31, 2018		Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016

Income before income taxes	$	260,101	$	203,195		$	34,605		$	1,237,455
Interest expense, net	13,689		24,256			10,754			133,235
Depreciation, depletion and amortization	119,563		122,464			32,604			191,581
Accretion on asset retirement obligations	27,970		30,209			7,634			24,321
Amortization of sales contracts, net	11,107		53,985			796			(728		)
Asset impairment and mine closure costs	—		—			—			129,267
Gain on sale of Lone Mountain Processing, Inc.	—		(21,297		)	—			—
Net loss resulting from early retirement of debt and debt restructuring	485		2,547			—			2,213
Non-service related postretirement benefit costs	3,202		1,940			(32		)	1,715
Reorganization items, net	1,661		2,398			759			(1,630,041		)
Fresh start coal inventory fair value adjustment	—		—			7,345			—
Adjusted EBITDAR	$	437,778	$	419,697		$	94,465		$	89,018

Quarterly Selected Financial Data (unaudited)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Selected Financial Data (unaudited)



	Three Months Ended
Year Ended December 31, 2018	March 31			June 30			September 30			December 31

(In thousands, except per share data)

Revenues	$	575,295		$	592,349		$	633,180		$	650,963
Gross profit	$	81,198		$	77,663		$	109,740		$	101,396
Income from operations	$	65,167		$	44,595		$	82,886		$	86,490
Reorganization items, net	$	(301	)	$	(740	)	$	(560	)	$	(60	)
Net income	$	59,985		$	43,306		$	123,192		$	86,094
Diluted income per common share	$	2.74		$	2.06		$	6.10		$	4.44



	Three Months Ended
Year Ended December 31, 2017	March 31			June 30			September 30			December 31

(In thousands, except per share data)

Revenues	$	600,975		$	549,866		$	613,538		$	560,244
Gross profit	$	86,707		$	63,150		$	66,145		$	63,460
Income from operations	$	66,985		$	42,924		$	73,310		$	51,117
Reorganization items, net	$	(2,828	)	$	(21	)	$	(43	)	$	494
Net income	$	51,668		$	37,160		$	68,351		$	81,271
Diluted income per common share	$	2.03		$	1.48		$	2.83		$	3.64

Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2018

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

Valuation and Qualifying Accounts



			Additions
			(Reductions)
	Balance at		Charged to			Charged to						Balance at
	Beginning of		Costs and			Other						End of
	Year		Expenses			Accounts				Deductions ^(a)		Year
	(In thousands)

Year Ended December 31, 2018
Reserves deducted from asset accounts:
Accounts receivable and other receivables	$	—	—			—				—		$	—
Current assets — supplies and inventory	261		1,247			—				860		648
Deferred income taxes	610,571		(79,959		)							530,612
Year Ended December 31, 2017
Reserves deducted from asset accounts:
Accounts receivable and other receivables	$	—	$	—		$	—			$	—	$	—
Current assets — supplies and inventory	—		365			(17		)	^(b)	87		261
Deferred income taxes	1,021,553		(410,982		)	—				—		610,571
October 2 through December 31, 2016
Reserves deducted from asset accounts:
Accounts receivable and other receivables	$	—	$	—		$	—			$	—	$	—
Current assets — supplies and inventory	—		—			—				—		—
Deferred income taxes	1,033,982		(12,429		)					—		1,021,553
Predecessor
January 1 through October 1, 2016
Reserves deducted from asset accounts:
Accounts receivable and other receivables	$	7,842	$	—		$	—			$	7,842	$	—
Current assets — supplies and inventory	5,991		844			(5,060		)	^(c)	1,775		—
Deferred income taxes	1,135,399		(101,417		)	—				—		1,033,982

(a) Reserves utilized, unless otherwise indicated.

(b) Disposition of subsidiaries

Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Consolidation Policy

The accompanying consolidated financial statements include the accounts of Arch Coal, Inc. and its subsidiaries and controlled entities (the “Company”). Unless the context indicates otherwise, the terms “Arch” and the “Company” are used interchangeably in this Annual Report on Form 10-K refer to both the Predecessor and Successor Company. The Company’s primary business is the production of thermal and metallurgical coal from surface and underground mines located throughout the United States, for sale to utility, industrial and steel producers both in the United States and around the world. The Company currently operates mining complexes in West Virginia, Illinois, Wyoming and Colorado. All subsidiaries are wholly-owned. Intercompany transactions and accounts have been eliminated in consolidation.

Accounting Estimates

Cash and Cash Equivalents

Cash and cash equivalents are stated at cost. Cash equivalents consist of highly-liquid investments with an original maturity of three months or less when purchased.

Restricted cash

Restricted cash represents cash collateral supporting letters of credit issued under the Company’s accounts receivable securitization program.

Accounts Receivable

Accounts receivable are recorded at amounts that are expected to be collected, based on past collection history, the economic environment and specified risks identified in the receivables portfolio.

Inventories

Investments and Membership Interests in Joint Ventures

Sales Contracts

Exploration Costs

Prepaid Royalties

Property, Plant and Equipment

Plant and Equipment

Deferred Mine Development

Coal Lands and Mineral Rights

The Company currently does not have any future lease bonus payments.

Depreciation, depletion and amortization

Impairment

Deferred Financing Costs

Revenue Recognition

Other Operating Income, net

Asset Retirement Obligations

Loss Contingencies

Derivative Instruments

Fair Value

Income Taxes

Benefit Plans

Stock-Based Compensation

Recently Adopted Accounting Guidance and Recent Accounting Guidance Issued Not Yet Effective

Recently Adopted Accounting Guidance



	Successor					Predecessor
(in thousands)	Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
Cash provided by (used in) investing activities previously reported	$	(59,802	)	$	17,984	$	15,134
Less: Withdrawals of restricted cash	70,836			10,512		15,979

Cash provided by (used in) investing activities	$	(130,638	)	$	7,472	$	(845	)



	Successor						Predecessor
(in thousands)	Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
Cost of sales previously reported	$	1,843,093		$	470,644		$	1,264,464
Reclassification	(3,100		)	(325		)	(2,290		)

Cost of sales	$	1,839,993		$	470,319		$	1,262,174

Selling, general and administrative expenses previously reported	$	86,821		$	22,836		$	59,343
Reclassification	1,131			357			575

Selling, general and administrative expenses	$	87,952		$	23,193		$	59,918

Other operating income, net previously reported	$	(30,270	)	$	(5,340	)	$	(15,257	)
Reclassification	29			—			—

Other operating income, net	$	(30,241	)	$	(5,340	)	$	(15,257	)

Recent Accounting Guidance Issued Not Yet Effective

In February 2018, the FASB issued ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220)

Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” ASU 2018-02 provides an option to

analyzing the standard, but does not expect a significant impact to the Company’s financial statements.

Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Schedule of New Accounting Pronouncements and Changes in Accounting Principles

As a result, net cash used in investing activities for the periods presented below was adjusted to exclude the change in restricted cash as follows:



	Successor					Predecessor
(in thousands)	Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
Cash provided by (used in) investing activities previously reported	$	(59,802	)	$	17,984	$	15,134
Less: Withdrawals of restricted cash	70,836			10,512		15,979

Cash provided by (used in) investing activities	$	(130,638	)	$	7,472	$	(845	)

The retrospective application resulted in the following changes detailed in the table below:



	Successor						Predecessor
(in thousands)	Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
Cost of sales previously reported	$	1,843,093		$	470,644		$	1,264,464
Reclassification	(3,100		)	(325		)	(2,290		)

Cost of sales	$	1,839,993		$	470,319		$	1,262,174

Selling, general and administrative expenses previously reported	$	86,821		$	22,836		$	59,343
Reclassification	1,131			357			575

Selling, general and administrative expenses	$	87,952		$	23,193		$	59,918

Other operating income, net previously reported	$	(30,270	)	$	(5,340	)	$	(15,257	)
Reclassification	29			—			—

Other operating income, net	$	(30,241	)	$	(5,340	)	$	(15,257	)

Emergence from Bankruptcy and Fresh Start Accounting (Tables)

12 Months Ended

Dec. 31, 2018

Reorganizations [Abstract]

Schedule of Reorganization Items, Net

The Company’s reorganization items, net for the respective periods are as follows:



	Successor									Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
(In thousands)
Gain on settlement of claims	$	—		$	—		$	—		$	4,142,104
Fresh start adjustments, net	—			—			—			(2,466,010		)
Professional fees	(1,661		)	(2,398		)	(759		)	(46,053		)

	$	(1,661	)	$	(2,398	)	$	(759	)	$	1,630,041

Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Schedule of Accumulated Other Comprehensive Income (Loss)

The following items are included in accumulated other comprehensive income (loss):




				Pension,
				Postretirement						Accumulated
				and Other Post-						Other
	Derivative			Employment			Available-for-			Comprehensive
	Instruments			Benefits			Sale Securities			Income (Loss)
	(In thousands)
January 1, 2017	$	—		$	24,067		$	387		$	24,454
Unrealized gains (losses)	497			(3,589		)	—			(3,092		)
Amounts reclassified from accumulated other comprehensive income (loss)	150			(758		)	(387		)	(995		)
December 31, 2017	$	647		$	19,720		$	—		$	20,367
Unrealized gains (losses)	(4,359		)	22,923			(319		)	18,245
Amounts reclassified from accumulated other comprehensive income (loss)	7,040			(2,332		)	(24		)	4,684
December 31, 2018	$	3,328		$	40,311		$	(343	)	$	43,296

Schedule of Comprehensive Income Reclassifications

The following amounts were reclassified out of accumulated other comprehensive income during the respective periods:



Details about accumulated other comprehensive income components	Year Ended December 31, 2018			Year Ended December 31, 2017			Line Item in the Consolidated Income Statements
(in thousands)
Derivative instruments
Coal hedges	$	(8,206	)	$	—		Revenues
Interest rate hedges	1,166			(150		)	Interest expense
	—			—			Provision for (benefit from) income taxes
	$	(7,040	)	$	(150	)	Net of tax

Pension, postretirement and other post-employment benefits
Curtailments	$	—		$	(773	)
Settlement gains	2,332			1,531
	$	2,332		$	758		Total before tax
	—			—			Provision for (benefit from) income taxes
	$	2,332		$	758		Net of tax

Available-for-sale securities ²	$	24		$	387		Interest and investment income
	—			—			Provision for (benefit from) income taxes
	$	24		$	387		Net of tax
¹ Production-related benefits and workers’ compensation costs are included in costs to produce coal.
² The gains and losses on sales of available-for-sale-securities are determined on a specific identification basis.

Inventories (Tables)

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories consist of the following:



	December 31, 2018		December 31, 2017
(In thousands)
Coal	$	40,982	$	54,692
Repair parts and supplies	84,488		74,268
	$	125,470	$	128,960

Investments in Available-for-Sale Securities (Tables)

12 Months Ended

Dec. 31, 2018

Debt Securities, Available-for-sale [Abstract]

Available-for-sale Securities

The Company’s investments in available-for-sale marketable securities are as follows:



	December 31, 2018
										Balance Sheet
			Gross		Gross					Classification
			Unrealized		Unrealized			Fair		Short-Term		Other
	Cost Basis		Gains		Losses			Value		Investments		Assets
	(In thousands)
Available-for-sale:
U.S. government and agency securities	$	100,003	$	11	$	(126	)	$	99,888	$	99,888	$	—
Corporate notes and bonds	63,137		4		(232		)	62,909		62,909		—
Total Investments	$	163,140	$	15	$	(358	)	$	162,797	$	162,797	$	—



	December 31, 2017
										Balance Sheet
			Gross		Gross					Classification
			Unrealized		Unrealized			Fair		Short-Term		Other
	Cost Basis		Gains		Losses			Value		Investments		Assets
	(In thousands)
Available-for-sale:
U.S. government and agency securities	$	64,151	$	22	$	(73	)	$	64,100	$	64,100	$	—
Corporate notes and bonds	92,038		—		(292		)	91,746		91,746		—
Total Investments	$	156,189	$	22	$	(365	)	$	155,846	$	155,846	$	—

Equity Method Investments and Membership Interests in Joint Ventures (Tables)

12 Months Ended

Dec. 31, 2018

Equity Method Investments and Joint Ventures [Abstract]

Schedule Of Equity Method Investments

Below are the equity method investments reflected in the consolidated balance sheets:



(In thousands)	Knight Hawk			DTA			Millennium			Other			Total
Predecessor Company
January 1, 2016	$	151,592		$	13,239		$	37,589		$	(543	)	$	201,877
Advances to (distributions from) affiliates, net	(8,374		)	1,474			1,966			—			(4,934		)
Equity in comprehensive income (loss)	9,033			(2,095		)	(1,530		)	(94		)	5,314
Impairment of equity investment	—			—			(38,025		)	—			(38,025		)
Fresh start accounting adjustment	(58,251		)	(4,018		)	—			662			(61,607		)
October 1, 2016	$	94,000		$	8,600		$	—		$	25		$	102,625
Successor Company
Advances to (distributions from) affiliates, net	(9,076		)	822			—			—			(8,254		)
Equity in comprehensive income (loss)	2,569			(841		)	—			—			1,728
December 31, 2016	$	87,493		$	8,581		$	—		$	25		$	96,099
Investments in affiliates	—			7,158			—			—			7,158
Advances to (distributions from) affiliates, net	(8,736		)	3,014			—			—			(5,722		)
Equity in comprehensive income (loss)	11,409			(2,812		)	—			(25		)	8,572
December 31, 2017	$	90,166		$	15,941		$	—		$	—		$	106,107
Advances to (distributions from) affiliates, net	(10,534		)	2,481			—			—			(8,053		)
Equity in comprehensive income (loss)	10,389			(3,767		)	—			—			6,622

December 31, 2018	$	90,021		$	14,655		$	—		$	—		$	104,676

Sales Contracts (Tables)

12 Months Ended

Dec. 31, 2018

Acquired Sales Contracts [Abstract]

Schedule of Sales Contracts

The sales contracts reflected in the consolidated balance sheets are as follows:



	December 31, 2018									December 31, 2017
	Assets			Liabilities			Net Total			Assets			Liabilities			Net Total
	(In thousands)									(In thousands)
Original fair value	$	97,196		$	31,742					$	97,196		$	31,742
Accumulated amortization	(96,812		)	(30,924		)				(84,760		)	(29,979		)
Total	$	384		$	818		$	(434	)	$	12,436		$	1,763		$	10,673
Balance Sheet classification:
Other current	$	384		$	570					$	12,432		$	934
Other noncurrent	$	—		$	248					$	4		$	829

Derivatives (Tables)

12 Months Ended

Dec. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Price Risk Derivatives

At December 31, 2018, the Company held derivatives for risk management purposes that are expected to settle in the following years:



(Tons in thousands)	2019	2020	Total
Coal sales	2,601	93	2,694
Coal purchases	1,368	93	1,461

Disclosure Of Fair Value Of Derivatives

The fair value and location of derivatives reflected in the accompanying consolidated balance sheets are as follows:



	December 31, 2018									December 31, 2017
Fair Value of Derivatives	Asset			Liability						Asset			Liability
(In thousands)	Derivative			Derivative						Derivative			Derivative
Derivatives Designated as Hedging Instruments
Coal	$	2,342		$	(805	)				$	942		$	(2,146	)

Derivatives Not Designated as Hedging Instruments
Heating oil -- diesel purchases	532			—						5,354			—
Coal held for trading purposes, exchange traded swaps and futures	10,329			(10,701		)				44,088			(45,221		)
Coal -- risk management	5,672			(19,579		)				5,139			(9,892		)
Natural gas	4			(4		)				27			—
Total	$	16,537		(30,284		)				$	54,608		$	(55,113	)
Total derivatives	$	18,879		$	(31,089	)				$	55,550		$	(57,259	)
Effect of counterparty netting	(17,801		)	17,801						(50,042		)	50,042
Net derivatives as classified in the balance sheets	$	1,078		$	(13,288	)	$	(12,210	)	$	5,508		$	(7,217	)	$	(1,709	)



		December 31, 2018			December 31, 2017
Net derivatives as reflected on the balance sheets
Heating oil	Other current assets	$	532		$	5,354
Coal	Other current assets	546			154
	Accrued expenses and other current liabilities	(13,288		)	(7,217		)
		$	(12,210	)	$	(1,709	)

Effects Of Derivatives On Measures Of Financial Performance

The effects of derivatives on measures of financial performance are as follows:

Derivatives used in Cash Flow Hedging Relationships (in thousands)

For the noted periods,



		Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)
		Successor								Predecessor
		Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
Coal sales	⁽¹⁾	$	(7,517	)	$	(2,127	)	$	—	(672		)
Coal purchases	⁽²⁾	1,348			942			—		536
		$	(6,169	)	$	(1,185	)	$	—	$	(136	)


		Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)
		Successor								Predecessor
		Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
Coal sales		$	(10,912	)	$	—		$	—	$	1,634
Coal purchases		2,707			—			—		(1,237		)
		$	(8,205	)	$	—		$	—	$	397

No ineffectiveness or amounts excluded from effectiveness testing relating to the Company’s cash flow hedging relationships were recognized in the results of operations in the respective periods.

Derivatives Not Designated as Hedging Instruments (in thousands)

For the noted periods,



		Gain (Loss) Recognized
		Successor									Predecessor
		Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
Coal trading— realized and unrealized	⁽³⁾	$	135		$	(2,047	)	$	(7	)	$	(891	)
Coal risk management— unrealized	⁽³⁾	(9,530		)	(4,648		)	(408		)	(1,662		)
Natural gas trading — realized and unrealized	⁽³⁾	277			(527		)	19			(303		)
Change in fair value of coal derivatives and coal trading activities, net total		$	(9,118	)	$	(7,222	)	$	(396	)	$	(2,856	)

Coal risk management — realized	⁽⁴⁾	$	(8,734	)	$	—		$	116		$	(476	)
Heating oil — diesel purchases	⁽⁴⁾	$	(505	)	$	(1,057	)	$	827		$	826
Foreign currency	⁽⁴⁾	$	—		$	—		$	(9	)	$	(451	)

Location in income statement:

(1) — Revenues

(2) — Cost of sales

(3) — Change in fair value of coal derivatives and coal trading activities, net

(4) — Other operating income, net

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2018

Accrued Expenses and Other Current Liabilities [Abstract]

Schedule of Accrued Liabilities

Accrued expenses and other current liabilities consist of the following:



	December 31, 2018		December 31, 2017
(In thousands)
Payroll and employee benefits	$	57,166	$	53,149
Taxes other than income taxes	75,017		77,017
Interest	156		246
Sales contracts	570		934
Workers’ compensation	20,044		18,782
Asset retirement obligations	13,113		19,840
Other	17,448		14,193
	$	183,514	$	184,161

Debt and Financing Arrangements (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Debt



	December 31, 2018			December 31, 2017
(In thousands)
Term loan due 2024 ($294.8 and $297.8 million face value, respectively)	$	293,626		$	296,435
Other	30,449			36,514
Debt issuance costs	(6,092		)	(7,032		)
	$	317,983		$	325,917
Less current maturities of debt	17,797			15,783
Long-term debt	$	300,186		$	310,134

Schedule of Interest Rate Swap Agreements

Below is a summary of the Company’s outstanding interest rate swap agreements designated as hedges as of

December 31, 2018:



Notional Amount (in millions)	Effective Date	Fixed Rate	Receive Rate	Expiration Date

$250.0	June 29, 2018	1.662%	1-month LIBOR	June 28, 2019
$200.0	June 28, 2019	1.952%	1-month LIBOR	June 30, 2020
$150.0	June 30, 2020	2.182%	1-month LIBOR	June 30, 2021

Schedule of Maturities of Long-term Debt

The contractual maturities of debt as of December 31, 2018 are as follows:



Year	(In thousands)
2019	$	18,863
2020	11,442
2021	8,853
2022	3,130
2023	3,161
Thereafter	279,750
	$	325,199

Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit)

Significant components of the provision for (benefit from) income taxes are as follows:



	Successor									Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
(In thousands)
Current:
Federal	$	86		$	835		$	—		$	—
State	136			31			(252		)	7
Total current	$	222		$	866		$	(252	)	$	7
Deferred:
Federal	(52,309		)	(36,162		)	1,352			(4,720		)
State	(389		)	41			56			87
Total deferred	$	(52,698	)	$	(36,121	)	$	1,408		$	(4,633	)
	$	(52,476	)	$	(35,255	)	$	1,156		$	(4,626	)

Schedule of Effective Income Tax Rate Reconciliation

A reconciliation of the statutory federal income tax provision (benefit) at the statutory rate to the actual provision for (benefit from) income taxes follows:



	Successor									Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016
(In thousands)
Income tax provision (benefit) at statutory rate	$	54,621		$	71,118		$	12,112		$	433,109
Percentage depletion allowance	(17,725		)	(31,255		)	(4,292		)	(3,681		)
State taxes, net of effect of federal taxes	4,480			7,002			633			(46,122		)
Reversal of cancellation of indebtedness income	—			—			—			(1,493,162		)
Worthless stock deduction	—			—			—			(80,077		)
Change in valuation allowance	(79,961		)	(410,983		)	(7,655		)	1,185,326
Impact of Tax Cuts and Jobs Act of 2017	(17,645		)	332,345			—			—
Other, net	3,754			(3,482		)	358			(19		)
Provision for (benefit from) income taxes	$	(52,476	)	$	(35,255	)	$	1,156		$	(4,626	)

Schedule of Deferred Tax Assets and Liabilities



	December 31, 2018			December 31, 2017
(In thousands)
Deferred tax assets:
Tax loss carryforwards	$	307,615		$	271,405
Tax credit carryforwards	5,394			29,736
Investment in partnerships	193,217			308,653
Other	28,747			28,321
Gross deferred tax assets	$	534,973		$	638,115
Valuation allowance	(530,612		)	(610,571		)
Total deferred tax assets	$	4,361		$	27,544
Deferred tax liabilities:
Plant and equipment	3,037			3,674
Other	1,154			1,351
Total deferred tax liabilities	$	4,191		$	5,025
Net deferred tax asset	$	170		$	22,519

Summary of Income Tax Contingencies

A reconciliation of the beginning and ending amounts of gross unrecognized tax benefits follows:



		(In thousands)
Balance at	January 1, 2016	$	38,877
Additions based on tax positions related to the current year		2,979
Additions for tax positions of prior years		2,709
Reductions as a result of lapses in the statute of limitations		(37,110		)
Balance at	December 31, 2016	7,455
Additions based on tax positions related to the current year		—
Additions for tax positions of prior years		3,928
Reductions as a result of lapses in the statute of limitations		—
Balance at	December 31, 2017	11,383
Additions for tax positions of prior years		28,387
Additions for tax positions related to the current year		3,228
Reductions for tax positions of prior years		(634		)
Reductions as a result of lapses in the statute of limitations		$	(3,271	)
Balance at	December 31, 2018	$	39,093

Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2018

Asset Retirement Obligation [Abstract]

Schedule of Change in Asset Retirement Obligation

The following table describes the changes to the Company’s asset retirement obligation liability:



	Year Ended December 31, 2018			Year Ended December 31, 2017
(In thousands)
Balance at beginning of period (including current portion)	$	328,695		$	356,742
Accretion expense	27,970			30,209
Obligations of divested operations	—			(12,569		)
Adjustments to the liability from changes in estimates	(100,728		)	(23,215		)
Liabilities settled	(12,520		)	(22,472		)
Fresh start accounting adjustment	—			—
Balance at period end	$	243,417		$	328,695
Current portion included in accrued expenses	(13,113		)	(19,840		)
Noncurrent liability	$	230,304		$	308,855

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Summary Of Financial Assets And Liabilities Accounted For At Fair Value

The table below sets forth, by level, the Company’s financial assets and liabilities that are recorded at fair value in the accompanying consolidated balance sheet:



	Fair Value at				December 31, 2018
	Total		Level 1			Level 2		Level 3
	(In thousands)
Assets:
Investments in marketable securities	$	162,797	$	99,888		$	62,909	$	—
Derivatives	3,554		—			3,022		532
Total assets	$	166,351	$	99,888		$	65,931	$	532
Liabilities:
Derivatives	$	13,288	$	13,252		$	36	$	—



	Fair Value at				December 31, 2017
	Total		Level 1			Level 2		Level 3
	(In thousands)
Assets:
Investments in marketable securities	$	155,846	$	64,100		$	91,746	$	—
Derivatives	7,339		—			1,985		5,354
Total assets	$	163,185	$	64,100		$	93,731	$	5,354
Liabilities:
Derivatives	$	7,217	$	7,263		$	26	$	(72	)

Summary Of Change In The Fair Values Of Financial Instruments Categorized As Level 3

The following table summarizes the change in the fair values of financial instruments categorized as level 3.



	Year Ended December 31, 2018			Year Ended December 31, 2017
(In thousands)
Balance, beginning of period	$	5,426		$	4,537
Realized and unrealized (gains) losses recognized in earnings, net	(302		)	(2,305		)
Purchases	3,420			4,910
Issuances	(724		)	(535		)
Settlements	(7,288		)	(1,181		)
Ending balance	$	532		$	5,426

Capital Stock (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Dividends declared and paid

The Company declared and paid cash dividends per share during the periods presented below:



2018:	Dividends per share		Amount (in thousands)
1st quarter	$	0.40	$	8,335
2nd quarter	0.40		7,998
3rd quarter	0.40		7,633
4th quarter	0.40		7,303
Total cash dividends declared and paid	$	1.60	$	31,269

2017:	Dividends per share		Amount (in thousands)
1st quarter	$	—	$	—
2nd quarter	0.35		8,563
3rd quarter	0.35		8,200
4th quarter	0.35		7,606
Total cash dividends declared and paid	$	1.05	$	24,369

Share repurchase activity

Below is a table showing the share repurchase activity during the periods presented below:



2018:	Number of Shares	Average Repurchase Price per Share		Amount (in thousands)
1st quarter	407,091	$	94.79	$	38,588
2nd quarter	960,105	81.54		78,287
3rd quarter	870,538	87.59		76,248
4th quarter	1,000,881	88.57		88,651
Total shares repurchased	3,238,615	$	87.00	$	281,774

2017:	Number of Shares	Average Repurchase Price per Share		Amount (in thousands)
1st quarter	—	$	—	$	—
2nd quarter	710,701	71.82		51,043
3rd quarter	2,208,133	75.49		166,685
4th quarter	1,058,381	79.73		84,381
Total shares repurchased	3,977,215	$	75.96	$	302,109

Stock-Based Compensation and Other Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2018

Share-based Compensation [Abstract]

Schedule of Restricted Stock Units Activity

Information regarding the restricted stock units activity and weighted average grant-date fair value follows:



	Time Based Awards				Performance Based Awards
	Restricted Stock Units		Weighted Average Grant-Date Fair Value		Restricted Stock Units		Weighted Average Grant-Date Fair Value
(Shares in thousands)
Outstanding at January 1, 2018	240		$	79.87	311		$	76.75
Granted	150		90.83		105		110.85
Forfeited/Canceled	(2	)	81.28		(1	)	135.34
Vested	—		—		—		—
Unvested outstanding at December 31, 2018	388		$	84.11	415		$	85.30

Workers' Compensation Expense (Tables)

12 Months Ended

Dec. 31, 2018

Workers' compensation expense

Workers’ compensation expense consists of the following components:



	Successor						Predecessor
	Year Ended December 31, 2018		Year Ended December 31, 2017		October 2 through December 31, 2016		January 1 through October 1, 2016
(In thousands)
Self-insured occupational disease benefits:
Service cost	$	7,440	$	6,320	$	1,583	$	3,465
Interest cost⁽¹⁾	4,365		4,651		1,126		3,184
Net amortization⁽¹⁾	—		—		—		4,325
Total occupational disease	$	11,805	$	10,971	$	2,709	$	10,974
Traumatic injury claims and assessments	5,395		3,208		3,162		6,628
Total workers’ compensation expense	$	17,200	$	14,179	$	5,871	$	17,602

Schedule of Changes in Occupational Disease Obligations

The table below reconciles changes in the occupational disease liability for the respective period.



(In thousands)	Year Ended December 31, 2018			Year Ended December 31, 2017
Beginning of period	$	122,426		$	111,159
Service cost	7,440			6,320
Interest cost	4,365			4,651
Curtailments	—			(5,433		)
Actuarial (gain) loss	(7,071		)	12,242
Benefit and administrative payments	(8,260		)	(6,513		)
	$	118,900		$	122,426

Schedule of Occupational Disease Obligation Assumptions Used

The following table provides the assumptions used to determine the projected occupational disease obligation:



	Year Ended December 31, 2018	Year Ended December 31, 2017
(Percentages)
Discount rate	4.26	3.66
Cost escalation rate	N/A	N/A

Workers' compensation liabilities

Summarized below is information about the amounts recognized in the accompanying consolidated balance sheets for workers’ compensation benefits:



	Year Ended December 31, 2018		Year Ended December 31, 2017
(In thousands)
Occupational disease costs	$	118,900	$	122,426
Traumatic and other workers’ compensation claims	75,447		81,191
Total obligations	194,347		203,617
Less amount included in accrued expenses	20,044		18,782
Noncurrent obligations	$	174,303	$	184,835

Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2018

Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]

Pension Benefit Costs

Summaries of the changes in the benefit obligations, plan assets and funded status of the plans are as follows:



	Pension Benefits						Other Postretirement Benefits
	Year Ended December 31, 2018			Year Ended December 31, 2017			Year Ended December 31, 2018			Year Ended December 31, 2017
(In thousands)
CHANGE IN BENEFIT OBLIGATIONS
Benefit obligations at beginning of period	$	270,098		$	313,629		$	110,519		$	111,867
Service cost	—			—			558			671
Interest cost	9,269			11,169			3,674			4,150
Divestitures (see Note 5 to the Consolidated Financial Statements)	—			(29,097		)	—			—
Settlement gain	(2,332		)	(1,532		)	—			—
Curtailments	—			—			—			(520		)
Benefits paid	(36,895		)	(38,197		)	(5,388		)	(8,152		)
Other-primarily actuarial (gain) loss	(11,267		)	14,126			(20,800		)	2,503
Benefit obligations at end of period	$	228,873		$	270,098		$	88,563		$	110,519
CHANGE IN PLAN ASSETS
Value of plan assets at beginning of period	$	255,642		$	274,225		$	—		$	—
Actual return on plan assets	(6,463		)	39,689						—
Employer contributions	222			429			5,388			8,152
Benefits paid	(36,895		)	(38,197		)	(5,388		)	(8,152		)
Divestitures	$	—		$	(20,504	)	$	—		$	—
Value of plan assets at end of period	$	212,506		$	255,642		$	—		$	—
Accrued benefit cost	$	(16,367	)	$	(14,456	)	$	(88,563	)	$	(110,519	)
ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST
Accumulated gain	$	8,899		$	16,178		$	25,936		$	5,137
	$	8,899		$	16,178		$	25,936		$	5,137
BALANCE SHEET AMOUNTS
Current liability	$	(220	)	$	(420	)	$	(5,400	)	$	(8,150	)
Noncurrent liability	(16,147		)	(14,036		)	(83,163		)	(102,369		)
	$	(16,367	)	$	(14,456	)	$	(88,563	)	$	(110,519	)

Other Postretirement Benefit Costs

The following table details the components of pension and postretirement benefit costs (credits):



	Pension Benefits												Other Postretirement Benefits
	Successor									Predecessor			Successor							Predecessor
	Year Ended December 31, 2018			Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016			Year Ended December 31, 2018		Year Ended December 31, 2017			October 2 through December 31, 2016		January 1 through October 1, 2016
(In thousands)
Service cost	$	—		$	—		$	—		$	—		$	558	$	671		$	180	$	393
Interest cost⁽¹⁾	9,269			11,169			2,768			9,338			3,674		4,150			978		3,223
Curtailments	—			—			—			454			—		(520		)	—		(970		)
Settlements⁽¹⁾	(2,332		)	(1,532		)	(135		)	—			—		—			—		—
Expected return on plan assets⁽¹⁾	(12,083		)	(16,498		)	(4,770		)	(13,623		)	—		—			—		—
Amortization of prior service credits⁽¹⁾	—			—			—			—			—		—			—		(7,854		)
Amortization of other actuarial losses (gains) ⁽¹⁾	—			—			—			3,973			—		—			—		(849		)
Net benefit cost (credit)	$	(5,146	)	$	(6,861	)	$	(2,137	)	$	142		$	4,232	$	4,301		$	1,158	$	(6,057	)

Schedule of Assumptions Used

The following table provides the weighted average assumptions used to determine the actuarial present value of projected benefit obligations for the respective periods.



	Year Ended December 31, 2018	Year Ended December 31, 2017
(Percentages)
Pension Benefits
Discount rate	4.11/3.94	3.49/3.27

Other Postretirement Benefits
Discount rate	4.12	3.49

The following table provides the weighted average assumptions used to determine net periodic benefit cost for the respective periods.



	Successor			Predecessor
	Year Ended December 31, 2018	Year Ended December 31, 2017	October 2 through December 31, 2016	January 1 through October 1, 2016
(Percentages)
Pension Benefits
Discount rate	3.82	3.77	3.39/3.95	4.59/3.80
Expected return on plan assets	5.3	6.2	6.85	6.85

Other Postretirement Benefits
Discount rate	3.49	3.85	3.37	4.57/3.80

Schedule of Allocation of Plan Assets

The Company’s pension plan assets at December 31, 2018 and 2017, respectively, are categorized below according to the fair value hierarchy as defined in Note 16, “Fair Value Measurements”:



	Total						Level 1				Level 2				Level 3
	2018			2017			2018		2017		2018		2017		2018		2017
	(In thousands)
Equity Securities:^(A)
U.S. small-cap	$	2,751		$	4,692		$	2,751	$	4,692	$	—	$	—	$	—	$	—
U.S. mid-cap	1,182			6,017			1,182		6,017		—		—		—		—
U.S. large-cap	—			21,416			—		21,416		—		—		—		—
Non-U.S.	—			—			—		—		—		—		—		—
Fixed income securities:																	—
U.S. government securities^(B)	43,829			66,922			38,436		60,286		5,393		6,636		—		—
Non-U.S. government securities^(C)	2,092			4,050			—		—		2,092		4,050		—		—
U.S. government asset and mortgage backed securities^(D)	7,667			2,440			—		—		7,667		2,440		—		—
Corporate fixed income^(E)	68,762			54,679			—		—		68,762		54,679		—		—
State and local government securities^(F)	3,480			3,829			—		—		3,480		3,829		—		—
Other investments^(I)	5,223			8,457			—		—		5,223		8,457		—		—
Total	$	134,986		$	172,502		$	42,369	$	92,411	$	92,617	$	80,091	$	—	$	—
Assets at net asset value^(G)	82,765			84,172
Short-term investments^(H)	7,003			8,573
Other liabilities^(J)	(12,248		)	(9,605		)
	$	212,506		$	255,642

^(B)U.S. government securities includes agency and treasury debt. These investments are valued using dealer quotes in an active market.

^(J)Net payable amount due for pending securities purchased and sold due to broker/dealer.

Schedule of Expected Benefit Payments

The following represents expected future benefit payments from the plan:



			Other
	Pension		Postretirement
	Benefits		Benefits
	(In thousands)
2019	$	16,400	$	11,993
2020	17,363		12,125
2021	18,173		12,058
2022	18,532		12,253
2023	16,904		12,072
Next 5 years	73,508		57,896
	$	160,880	$	118,397

Earnings Per Common Share (Tables)

12 Months Ended

Dec. 31, 2018

Earnings Per Share [Abstract]

Schedule of Weighted Average Number of Shares

The following table provides the basis for basic and diluted EPS by reconciling the numerators and denominators of the computations:



	Successor			Predecessor
	Year Ended December 31, 2018	Year Ended December 31, 2017	October 2 through December 31, 2016	January 1 through October 1, 2016
(In Thousands)
Weighted average shares outstanding:
Basic weighted average shares outstanding	19,663	23,725	25,002	21,293
Effect of dilutive securities	966	515	467	20

Diluted weighted average shares outstanding	20,629	24,240	25,469	21,313

Leases (Tables)

12 Months Ended

Dec. 31, 2018

Leases [Abstract]

Operating Leases of Lessee Disclosure

Minimum payments due in future years under these agreements in effect at December 31, 2018 are as follows:



	Operating
	Leases		Royalties
	(In thousands)
2019	$	3,681	$	3,669
2020	2,260		8,096
2021	1,985		8,296
2022	2,024		8,086
2023	2,044		7,749
Thereafter	6,248		84,913
	$	18,242	$	120,809

Risk Concentrations (Tables)

12 Months Ended

Dec. 31, 2018

Risks and Uncertainties [Abstract]

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas

The Company’s foreign revenues by geographical location are as follows:



	Successor						Predecessor
	Year Ended December 31, 2018		Year Ended December 31, 2017		October 2 through December 31, 2016		January 1 through October 1, 2016
(In thousands)
Europe	$	559,165	$	388,926	$	61,169	$	112,986
Asia	452,711		264,503		55,634		68,536
Central and South America	79,085		30,982		13,224		41,861
Africa	17,567		14,901		—		—
Brokered Sales	2,372		3,150		—		—
Total	$	1,110,900	$	702,462	$	130,027	$	223,383

Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Schedule of effects of revenue recognition



	PRB		MET		Other Thermal		Corporate, Other and Eliminations		Consolidated
	(in thousands)
Year Ended December 31, 2018
North America revenues	$	971,337	$	160,969	$	195,547	$	13,034	$	1,340,887
Seaborne revenues	1,911		875,652		233,337		—		1,110,900

Total revenues	$	973,248	$	1,036,621	$	428,884	$	13,034	$	2,451,787

Year Ended December 31, 2017
North America revenues	$	1,024,197	$	312,874	$	269,007	$	16,083	$	1,622,161
Seaborne revenues	—		574,965		127,497		—		702,462

Total revenues	$	1,024,197	$	887,839	$	396,504	$	16,083	$	2,324,623

October 2 through December 31, 2016
North America revenues	$	275,703	$	91,086	$	76,646	$	2,226	$	445,661
Seaborne revenues	—		109,291		20,736		—		130,027

Total revenues	$	275,703	$	200,377	$	97,382	$	2,226	$	575,688

January 1 through October 1, 2016
North America revenues	$	726,747	$	215,585	$	211,153	$	21,841	$	1,175,326
Seaborne revenues	—		221,484		1,899		—		223,383

Total revenues	$	726,747	$	437,069	$	213,052	$	21,841	$	1,398,709

Segment Information (Tables)

12 Months Ended

Dec. 31, 2018

Segment Reporting [Abstract]

Schedule Of Operating Segment Results



(In thousands)		PRB		MET		Other Thermal		Corporate, Other and Eliminations			Consolidated
Successor Year Ended	December 31, 2018
Revenues		$	973,248	$	1,036,621	$	428,884	$	13,034		$	2,451,787
Adjusted EBITDAR		126,525		349,524		68,620		(106,891		)	437,778
Depreciation, depletion and amortization		33,120		69,560		14,699		2,184			119,563
Accretion on asset retirement obligation		19,541		1,874		2,261		4,294			27,970
Total Assets		278,314		545,061		125,333		938,352			1,887,060
Capital expenditures		12,140		64,307		11,999		6,826			95,272
Successor Year Ended	December 31, 2017
Revenues		$	1,024,197	$	887,839	$	396,504	$	16,083		$	2,324,623
Adjusted EBITDAR		158,882		243,616		102,006		(84,807		)	419,697
Depreciation, depletion and amortization		36,349		70,896		13,588		1,631			122,464
Accretion on asset retirement obligation		20,160		2,000		2,161		5,888			30,209
Total assets		390,665		548,476		134,397		906,094			1,979,632
Capital expenditures		6,212		32,678		11,901		8,414			59,205
Successor Period	October 2 through December 31, 2016
Revenues		$	275,703	$	200,377	$	97,382	$	2,226		$	575,688
Adjusted EBITDAR		55,765		30,819		31,159		(23,278		)	94,465
Depreciation, depletion and amortization		9,949		18,287		3,911		457			32,604
Accretion on asset retirement obligation		5,049		528		540		1,517			7,634
Total assets		446,775		576,793		129,602		983,427			2,136,597
Capital expenditures		934		13,329		684		267			15,214
Predecessor Period	January 1 through October 1, 2016
Revenues		$	726,747	$	437,069	$	213,052	$	21,841		$	1,398,709
Adjusted EBITDAR		113,185		11,851		31,448		(67,466		)	89,018
Depreciation, depletion and amortization		100,151		55,311		32,310		3,809			191,581
Accretion on asset retirement obligation		16,940		1,765		1,988		3,628			24,321
Total assets		456,711		619,154		131,173		916,791			2,123,829
Capital expenditures		612		17,296		3,895		60,631			82,434

Reconciliation Statement Of Segment Income From Operations To Consolidated Income Before Income Taxes

A reconciliation of segment Adjusted EBITDAR to consolidated income (loss) from continuing operations before income taxes follows:



	Successor								Predecessor
(In thousands)	Year Ended December 31, 2018		Year Ended December 31, 2017			October 2 through December 31, 2016			January 1 through October 1, 2016

Income before income taxes	$	260,101	$	203,195		$	34,605		$	1,237,455
Interest expense, net	13,689		24,256			10,754			133,235
Depreciation, depletion and amortization	119,563		122,464			32,604			191,581
Accretion on asset retirement obligations	27,970		30,209			7,634			24,321
Amortization of sales contracts, net	11,107		53,985			796			(728		)
Asset impairment and mine closure costs	—		—			—			129,267
Gain on sale of Lone Mountain Processing, Inc.	—		(21,297		)	—			—
Net loss resulting from early retirement of debt and debt restructuring	485		2,547			—			2,213
Non-service related postretirement benefit costs	3,202		1,940			(32		)	1,715
Reorganization items, net	1,661		2,398			759			(1,630,041		)
Fresh start coal inventory fair value adjustment	—		—			7,345			—
Adjusted EBITDAR	$	437,778	$	419,697		$	94,465		$	89,018

Quarterly Selected Financial Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information



	Three Months Ended
Year Ended December 31, 2018	March 31			June 30			September 30			December 31

(In thousands, except per share data)

Revenues	$	575,295		$	592,349		$	633,180		$	650,963
Gross profit	$	81,198		$	77,663		$	109,740		$	101,396
Income from operations	$	65,167		$	44,595		$	82,886		$	86,490
Reorganization items, net	$	(301	)	$	(740	)	$	(560	)	$	(60	)
Net income	$	59,985		$	43,306		$	123,192		$	86,094
Diluted income per common share	$	2.74		$	2.06		$	6.10		$	4.44



	Three Months Ended
Year Ended December 31, 2017	March 31			June 30			September 30			December 31

(In thousands, except per share data)

Revenues	$	600,975		$	549,866		$	613,538		$	560,244
Gross profit	$	86,707		$	63,150		$	66,145		$	63,460
Income from operations	$	66,985		$	42,924		$	73,310		$	51,117
Reorganization items, net	$	(2,828	)	$	(21	)	$	(43	)	$	494
Net income	$	51,668		$	37,160		$	68,351		$	81,271
Diluted income per common share	$	2.03		$	1.48		$	2.83		$	3.64

Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statutory Accounting Practices
Mineral rights	$ 338.1	$ 361.2
Deferred finance costs, net	4.7	5.7
Deferred finance costs, current	$ 2.2	$ 2.6
Exploration and production equipment \| Minimum
Statutory Accounting Practices
Estimated useful life	1 year
Exploration and production equipment \| Maximum
Statutory Accounting Practices
Estimated useful life	18 years
Building and building improvements \| Minimum
Statutory Accounting Practices
Estimated useful life	1 year
Building and building improvements \| Maximum
Statutory Accounting Practices
Estimated useful life	20 years
Mining properties and mineral rights \| Minimum
Statutory Accounting Practices
Term of contract	10 years
Mining properties and mineral rights \| Maximum
Statutory Accounting Practices
Term of contract	50 years
Accounting Standards Update 2016-02 \| Minimum
Statutory Accounting Practices
RIght-of-use assets and lease liabilities	$ 15.0
Lease liability	15.0
Accounting Standards Update 2016-02 \| Maximum
Statutory Accounting Practices
RIght-of-use assets and lease liabilities	20.0
Lease liability	$ 20.0

Accounting Policies (Impacts of ASUs) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash used in investing activities	$ 7,472		$ (103,952)	$ (130,638)
Cost of sales	470,319		1,925,202	1,839,993
Selling, general and administrative expenses	23,193		100,300	87,952
Other operating income, net	(5,340)		$ (20,611)	(30,241)
Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash used in investing activities	17,984			(59,802)
Cost of sales	470,644			1,843,093
Selling, general and administrative expenses	22,836			86,821
Other operating income, net	(5,340)			(30,270)
Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash used in investing activities	10,512			70,836
Cost of sales	(325)			(3,100)
Selling, general and administrative expenses	357			1,131
Other operating income, net	$ 0			$ 29
Predecessor
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash used in investing activities		$ (845)
Cost of sales		1,262,174
Selling, general and administrative expenses		59,918
Other operating income, net		(15,257)
Predecessor \| Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash used in investing activities		15,134
Cost of sales		1,264,464
Selling, general and administrative expenses		59,343
Other operating income, net		(15,257)
Predecessor \| Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash used in investing activities		15,979
Cost of sales		(2,290)
Selling, general and administrative expenses		575
Other operating income, net		$ 0

Emergence from Bankruptcy and Fresh Start Accounting (Details) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Fresh-Start Adjustment [Line Items]
Gain on settlement of claims									$ 0		$ 0	$ 0
Fresh start adjustments, net									0		0	0
Professional fees									(759)		(1,661)	(2,398)
Reorganization Items	$ (60)	$ (560)	$ (740)	$ (301)	$ 494	$ (43)	$ (21)	$ (2,828)	$ (759)		$ (1,661)	$ (2,398)
Predecessor
Fresh-Start Adjustment [Line Items]
Gain on settlement of claims										$ 4,142,104
Fresh start adjustments, net										(2,466,010)
Professional fees										(46,053)
Reorganization Items										1,630,041
Interest expense										135,900
Contractual interest expense										$ 300,900

Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Unrealized gains (losses)	$ 18,245	$ (3,092)
Amounts reclassified from accumulated other comprehensive income (loss)	4,684	(995)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	20,367	24,454
Ending balance	43,296	20,367
Derivative Instruments
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	647	0
Unrealized gains (losses)	(4,359)	497
Amounts reclassified from accumulated other comprehensive income (loss)	7,040	150
Ending balance	3,328	647
Pension, Postretirement and Other Post-Employment Benefits
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	19,720	24,067
Unrealized gains (losses)	22,923	(3,589)
Amounts reclassified from accumulated other comprehensive income (loss)	(2,332)	(758)
Ending balance	40,311	19,720
Available-for-Sale Securities
Accumulated Other Comprenhensive Income (Loss) [Roll Forward]
Beginning balance	0	387
Unrealized gains (losses)	(319)	0
Amounts reclassified from accumulated other comprehensive income (loss)	(24)	(387)
Ending balance	$ (343)	$ 0

Accumulated Other Comprehensive Income (Schedule of Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 560,244	$ 613,538	$ 549,866	$ 600,975	$ 575,688	$ 2,451,787	$ 2,324,623
Interest expense									(11,241)	(20,471)	(26,905)
Provision for (benefit from) income taxes									(1,156)	52,476	35,255
Total before tax									34,605	260,101	203,195
Interest and investment income									487	6,782	2,649
Net of tax	$ 86,094	$ 123,192	$ 43,306	$ 59,985	$ 81,271	$ 68,351	$ 37,160	$ 51,668	$ 33,449	312,577	238,450
Reclassification out of accumulated other comprehensive income \| Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues										(8,206)	0
Interest expense										1,166	(150)
Provision for (benefit from) income taxes										0	0
Net of tax										(7,040)	(150)
Reclassification out of accumulated other comprehensive income \| Pension, Postretirement and Other Post-Employment Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision for (benefit from) income taxes										0	0
Curtailments										0	(773)
Settlement gains										2,332	1,531
Total before tax										2,332	758
Net of tax										2,332	758
Reclassification out of accumulated other comprehensive income \| Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision for (benefit from) income taxes										0	0
Interest and investment income										24	387
Net of tax										$ 24	$ 387

Divestitures (Details) $ in Thousands		3 Months Ended	12 Months Ended
Divestitures (Details) $ in Thousands	Sep. 14, 2017 USD ($) company	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of Lone Mountain Processing, Inc.		$ 0	$ 0	$ 21,297
Lone Mountain Processing LLC \| Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of mining companies \| company	2
Proceeds from sale	$ 8,300
Disbursements related to landholder consent fees and professional fees	1,400
Gain on sale of Lone Mountain Processing, Inc.	21,300
Pension Benefits
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Curtailment gains		$ 0	$ 0	$ 0
Pension Benefits \| Lone Mountain Processing LLC \| Discontinued operations, disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Curtailment gains	$ 4,700

Impairment Charges and Mine Closure Costs (Details) - Predecessor - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2016
Impaired Long-Lived Assets Held and Used [Line Items]
Other-than-temporary impairment loss on available-for-sale securities		$ 2.9
Severance costs			$ 7.2
Curtailments			$ 3.6
Royalty Agreements
Impaired Long-Lived Assets Held and Used [Line Items]
Prepaid royalties		3.4
Kentucky
Impaired Long-Lived Assets Held and Used [Line Items]
Net book value of idled facility		$ 74.1
Longview, Washington
Impaired Long-Lived Assets Held and Used [Line Items]
Other-than-temporary impairment loss on available-for-sale securities	$ 38.0

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Coal	$ 40,982	$ 54,692
Repair parts and supplies	84,488	74,268
Inventories	125,470	128,960
Allowance for slow-moving and obsolete inventories	$ 600	$ 300

Investments in Available-for-Sale Securities (Cost Basis to Fair Value Reconciliation) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Cost Basis	$ 163,140	$ 156,189
Gross Unrealized Gains	15	22
Gross Unrealized Losses	(358)	(365)
Fair Value	162,797	155,846
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Cost Basis	100,003	64,151
Gross Unrealized Gains	11	22
Gross Unrealized Losses	(126)	(73)
Fair Value	99,888	64,100
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Cost Basis	63,137	92,038
Gross Unrealized Gains	4	0
Gross Unrealized Losses	(232)	(292)
Fair Value	62,909	91,746
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Fair Value	162,797	155,846
Short-term investments \| U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	99,888	64,100
Short-term investments \| Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value	62,909	91,746
Other assets
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 0	0
Other assets \| U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Fair Value		0
Other assets \| Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value		$ 0

Investments in Available-for-Sale Securities (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Abstract]
Continuous unrealized loss position for less than a year	$ 115.2	$ 132.0
Continuous unrealized loss position for over a year	$ 32.4	$ 0.0

Equity Method Investments and Membership Interests in Joint Ventures (Schedule of Equity Method Investments) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2016
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	$ 96,099		$ 106,107
Advances to (distributions from) affiliates, net	(5,722)	$ (8,254)	(8,053)
Equity in comprehensive income (loss)	8,572	1,728	6,622
Investments in affiliates	7,158
Ending Balance		96,099	104,676
Knight Hawk
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	87,493		90,166
Advances to (distributions from) affiliates, net	(8,736)	(9,076)	(10,534)
Equity in comprehensive income (loss)	11,409	2,569	10,389
Investments in affiliates	0
Ending Balance		87,493	90,021
DTA
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	8,581		15,941
Advances to (distributions from) affiliates, net	3,014	822	2,481
Equity in comprehensive income (loss)	(2,812)	(841)	(3,767)
Investments in affiliates	7,158
Ending Balance		8,581	14,655
Millennium
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	0		0
Advances to (distributions from) affiliates, net	0	0	0
Equity in comprehensive income (loss)	0	0	0
Investments in affiliates	0
Ending Balance		0	0
Other
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance	25		0
Advances to (distributions from) affiliates, net	0	0	0
Equity in comprehensive income (loss)	(25)	0	0
Investments in affiliates	0
Ending Balance		25	$ 0
Predecessor
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance		201,877		$ 201,877
Advances to (distributions from) affiliates, net				(4,934)
Equity in comprehensive income (loss)				5,314
Impairment of equity investment				(38,025)
Fresh start accounting adjustment				(61,607)
Ending Balance	102,625			102,625
Predecessor \| Knight Hawk
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance		151,592		151,592
Advances to (distributions from) affiliates, net				(8,374)
Equity in comprehensive income (loss)				9,033
Impairment of equity investment				0
Fresh start accounting adjustment				(58,251)
Ending Balance	94,000			94,000
Predecessor \| DTA
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance		13,239		13,239
Advances to (distributions from) affiliates, net				1,474
Equity in comprehensive income (loss)				(2,095)
Impairment of equity investment				0
Fresh start accounting adjustment				(4,018)
Ending Balance	8,600			8,600
Predecessor \| Millennium
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance		37,589		37,589
Advances to (distributions from) affiliates, net				1,966
Equity in comprehensive income (loss)				(1,530)
Impairment of equity investment				(38,025)
Fresh start accounting adjustment				0
Ending Balance	0			0
Predecessor \| Other
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Beginning Balance		$ (543)		(543)
Advances to (distributions from) affiliates, net				0
Equity in comprehensive income (loss)				(94)
Impairment of equity investment				0
Fresh start accounting adjustment				662
Ending Balance	$ 25			$ 25

Equity Method Investments and Membership Interests in Joint Ventures (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Mar. 01, 2017
Predecessor
Schedule of Equity Method Investments [Line Items]
Impairment of equity investment			$ 38,025
Knight Hawk
Schedule of Equity Method Investments [Line Items]
Ownership interest (percent)				49.00%
DTA
Schedule of Equity Method Investments [Line Items]
Ownership interest (percent)	35.00%					21.875%
Payments to auction house to increase ownership	$ 7,200
Millennium
Schedule of Equity Method Investments [Line Items]
Ownership interest (percent)					38.00%
Millennium \| Predecessor
Schedule of Equity Method Investments [Line Items]
Impairment of equity investment		$ 38,000

Sales Contracts (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Original fair value, Assets	$ 97,196	$ 97,196
Original fair value, Liabilities	31,742	31,742
Accumulated amortization, Asset	(96,812)	(84,760)
Accumulated amortization, Liabilities	(30,924)	(29,979)
Total, Assets	384	12,436
Total, Liabilities	818	1,763
Net total, Liabilities	(434)	10,673
Coal Supply agreement, Liabilities	570	934
Other current assets
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal supply agreement, Assets	384	12,432
Other current liabilities
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal Supply agreement, Liabilities	570	934
Other noncurrent assets
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal supply agreement, Assets	0	4
Other noncurrent liabilities
Acquired Finite-Lived Intangible Assets And Liabilities By Major Class [Line Items]
Coal Supply agreement, Liabilities	$ 248	$ 829

Derivatives (Narrative) (Details) $ in Thousands, gal in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) $ / option gal	Dec. 31, 2017 USD ($)
Derivative [Line Items]
Right to reclaim cash collateral, asset	$ 17,801	$ 50,042
Derivative contracts expected to be reclassified from OCI into earnings	1,100
2019
Derivative [Line Items]
Value of trading portfolio realized	$ (200)
Diesel purchases \| Heating oil
Derivative [Line Items]
Quantities under derivative contracts \| gal	26.2
Average strike price (in dollars per option) \| $ / option	2.30
Diesel purchases \| Minimum
Derivative [Line Items]
Gallons of diesel fuel purchased annually \| gal	40.0
Diesel purchases \| Maximum
Derivative [Line Items]
Gallons of diesel fuel purchased annually \| gal	46.0
Other current assets
Derivative [Line Items]
Right to reclaim cash collateral, asset	$ 24,700	$ 16,200

Derivatives (Schedule of Price Risk Derivatives) (Details) T in Thousands	12 Months Ended
	Dec. 31, 2018 T
Coal sales
Derivative [Line Items]
Derivatives Held	2,694
Coal purchases
Derivative [Line Items]
Derivatives Held	1,461
2019 \| Coal sales
Derivative [Line Items]
Derivatives Held	2,601
2019 \| Coal purchases
Derivative [Line Items]
Derivatives Held	1,368
2020 \| Coal sales
Derivative [Line Items]
Derivatives Held	93
2020 \| Coal purchases
Derivative [Line Items]
Derivatives Held	93

Derivatives (Disclosure of Fair Value of Derivatives) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative Assets	$ 18,879	$ 55,550
Derivative Liabilities	(31,089)	(57,259)
Effect of counterparty netting in derivative assets	(17,801)	(50,042)
Effect of counterparty netting in derivative liabilities	17,801	50,042
Net derivative assets as classified in the balance sheet	1,078	5,508
Net derivative liabilities as classified in the balance sheet	(13,288)	(7,217)
Net derivatives as classified in the balance sheet	(12,210)	(1,709)
Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	16,537	54,608
Derivative Liabilities	(30,284)	(55,113)
Derivatives Not Designated as Hedging Instruments \| Coal held for trading purposes, exchange traded swaps and futures
Derivative [Line Items]
Derivative Assets	10,329	44,088
Derivative Liabilities	(10,701)	(45,221)
Coal \| Derivatives Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	2,342	942
Derivative Liabilities	(805)	(2,146)
Coal \| Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	5,672	5,139
Derivative Liabilities	(19,579)	(9,892)
Heating oil -- diesel purchases \| Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	532	5,354
Derivative Liabilities	0	0
Natural gas \| Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Derivative Assets	4	27
Derivative Liabilities	$ (4)	$ 0

Derivatives (Net Derivatives as Reflected on the Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ (12,210)	$ (1,709)
Other current assets \| Heating oil
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	532	5,354
Other current assets \| Coal
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	546	154
Accrued expenses and other current liabilities \| Coal
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ (13,288)	$ (7,217)

Derivatives (Effects of Derivatives on Measures of Financial Performance) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Change In Fair Value Of Coal Derivatives And Coal Trading Activities, Net	$ (396)		$ (9,118)	$ (7,222)
Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Change In Fair Value Of Coal Derivatives And Coal Trading Activities, Net	(396)		(9,118)	(7,222)
Coal contract \| Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	0		(6,169)	(1,185)
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)	0		(8,205)	0
Coal contract \| Derivatives Not Designated as Hedging Instruments \| Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net
Derivative Instruments, Gain (Loss) [Line Items]
Trading - realized and unrealized	(7)		135	(2,047)
Coal risk management— unrealized	(408)		(9,530)	(4,648)
Coal risk management — realized	116		(8,734)	0
Natural gas \| Derivatives Not Designated as Hedging Instruments \| Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net
Derivative Instruments, Gain (Loss) [Line Items]
Trading - realized and unrealized	19		277	(527)
Heating oil -- diesel purchases \| Derivatives Not Designated as Hedging Instruments \| Other Operating Income (Expense)
Derivative Instruments, Gain (Loss) [Line Items]
Heating oil — diesel purchases	827		(505)	(1,057)
Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency	(9)			0
Foreign currency \| Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency			0
Predecessor
Derivative Instruments, Gain (Loss) [Line Items]
Change In Fair Value Of Coal Derivatives And Coal Trading Activities, Net		$ (2,856)
Predecessor \| Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Change In Fair Value Of Coal Derivatives And Coal Trading Activities, Net		(2,856)
Predecessor \| Coal contract \| Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)		(136)
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)		397
Predecessor \| Coal contract \| Derivatives Not Designated as Hedging Instruments \| Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net
Derivative Instruments, Gain (Loss) [Line Items]
Trading - realized and unrealized		(891)
Coal risk management— unrealized		(1,662)
Coal risk management — realized		(476)
Predecessor \| Natural gas \| Derivatives Not Designated as Hedging Instruments \| Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net
Derivative Instruments, Gain (Loss) [Line Items]
Trading - realized and unrealized		(303)
Predecessor \| Heating oil -- diesel purchases \| Derivatives Not Designated as Hedging Instruments \| Other Operating Income (Expense)
Derivative Instruments, Gain (Loss) [Line Items]
Heating oil — diesel purchases		826
Predecessor \| Foreign currency
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency		(451)
Short \| Coal contract \| Derivatives Designated as Hedging Instruments \| Sales Revenue, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	0		(7,517)	(2,127)
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)	0		(10,912)	0
Short \| Predecessor \| Coal contract \| Derivatives Designated as Hedging Instruments \| Sales Revenue, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)		(672)
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)		1,634
Long \| Coal contract \| Derivatives Designated as Hedging Instruments \| Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)	0		1,348	942
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)	$ 0		$ 2,707	$ 0
Long \| Predecessor \| Coal contract \| Derivatives Designated as Hedging Instruments \| Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion)		536
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion)		$ (1,237)

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Expenses and Other Current Liabilities [Abstract]
Payroll and employee benefits	$ 57,166	$ 53,149
Taxes other than income taxes	75,017	77,017
Interest	156	246
Sales contracts	570	934
Workers’ compensation	20,044	18,782
Asset retirement obligations	13,113	19,840
Other	17,448	14,193
Accrued Liabilities, Current	$ 183,514	$ 184,161

Debt and Financing Arrangements (Debt Outstanding) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Term loan	$ 293,626	$ 296,435
Other	30,449	36,514
Debt issuance costs	(6,092)	(7,032)
Total	317,983	325,917
Less current maturities of debt	17,797	15,783
Long-term debt	300,186	310,134
Term loan due 2024 ($294.8 and $297.8 million face value, respectively)
Debt Instrument [Line Items]
Term loan, face value	$ 294,800	$ 297,800

Debt and Financing Arrangements (Company Debt Narrative) (Details) - USD ($)							3 Months Ended		9 Months Ended	12 Months Ended
	Nov. 19, 2018	Apr. 27, 2018	Apr. 03, 2018	Sep. 25, 2017	Apr. 27, 2017	Mar. 07, 2017	Sep. 30, 2017	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Letters of credit outstanding										$ 0
Additional availability for borrowings										11,200,000
Derivative assets										18,879,000	$ 55,550,000
Debt financing costs								$ 0		1,257,000	10,149,000
Predecessor
Debt Instrument [Line Items]
Debt financing costs									$ 23,011,000
Senior notes \| Term loan debt facility
Debt Instrument [Line Items]
Amount of debt instrument				$ 300,000,000
Call premium				1.00%
Mandatory prepayment amount						100.00%
Default to indebtedness amount						$ 50,000,000
Default to surety, reclamation, or similar bonds securing obligations						50,000,000
Default to uninsured judgements						50,000,000
Uninsured losses or proceedings against minimum amount						50,000,000
Senior notes \| Term loan debt facility \| LIBOR
Debt Instrument [Line Items]
Applicable margin on interest rate				3.25%
Line of credit \| Secured debt
Debt Instrument [Line Items]
Letters of credit outstanding										74,800,000
Term loan debt facility \| Senior notes
Debt Instrument [Line Items]
Amount of debt instrument						$ 300,000,000
Percent of face amount of debt issued						99.50%
Quarterly principal amortization payments						$ 750,000
Voting interests of directly owned subsidiaries						100.00%
Voting equity interests of directly owned foreign subsidiaries						65.00%
Term loan debt facility \| Senior notes \| LIBOR
Debt Instrument [Line Items]
Applicable margin on interest rate							2.75%
Term loan debt facility \| Senior notes \| LIBOR \| Minimum
Debt Instrument [Line Items]
Applicable margin on interest rate				1.00%
Term loan debt facility \| Senior notes \| Base rate
Debt Instrument [Line Items]
Applicable margin on interest rate				2.25%
Term loan debt facility \| Line of credit
Debt Instrument [Line Items]
Call premium			1.00%
Term loan debt facility \| Line of credit \| LIBOR
Debt Instrument [Line Items]
Applicable margin on interest rate			2.75%
Term loan debt facility \| Line of credit \| LIBOR \| Minimum
Debt Instrument [Line Items]
Applicable margin on interest rate			1.00%
Term loan debt facility \| Line of credit \| Base rate
Debt Instrument [Line Items]
Applicable margin on interest rate			1.75%
Regions Bank \| Line of credit \| Secured debt
Debt Instrument [Line Items]
Amount of debt instrument					$ 40,000,000
Maximum borrowing capacity	$ 50,000,000									200,000,000
Current borrowing capacity					160,000,000
Liquidity amount minimum					$ 175,000,000
Letters of credit outstanding										35,700,000
Borrowing base percentage, coal inventory					85.00%
Borrowing base percentage, parts and supplies inventory					85.00%
Borrowing base, percentage of clause					35.00%
Percent of eligible cash					100.00%
Increase to line of credit facility	$ 10,000,000
Covenant amount					$ 250,000,000
Regions Bank \| Line of credit \| Secured debt \| LIBOR \| Minimum
Debt Instrument [Line Items]
Applicable margin on interest rate					2.00%
Regions Bank \| Line of credit \| Secured debt \| LIBOR \| Maximum
Debt Instrument [Line Items]
Borrowing base, percentage of clause					2.50%
Regions Bank \| Line of credit \| Secured debt \| Base rate \| Minimum
Debt Instrument [Line Items]
Applicable margin on interest rate					1.00%
Regions Bank \| Line of credit \| Secured debt \| Base rate \| Maximum
Debt Instrument [Line Items]
Applicable margin on interest rate					1.50%
Arch Receivable Company, LLC \| Line of credit \| Secured debt \| Accounts Receivable Securitization Facility
Debt Instrument [Line Items]
Current borrowing capacity										53,500,000
Maturity date		3 years
Liquidity threshold, consecutive days		60 days
Liquidity threshold		364 days
Liquidity threshold, expiration period		60 days
Interest rate swap
Debt Instrument [Line Items]
Gain (loss) on interest rate swap										1,200,000	$ (100,000)
Interest rate swap \| Other noncurrent assets
Debt Instrument [Line Items]
Derivative assets										$ 2,500,000

Debt and Financing Arrangements (Interest Rate Derivatives) (Details)	Dec. 31, 2018 USD ($)
June 29, 2018
Derivative [Line Items]
Notional Amount (in millions)	$ 250,000,000
Fixed Rate	1.662%
June 28, 2019
Derivative [Line Items]
Notional Amount (in millions)	$ 200,000,000
Fixed Rate	1.952%
June 30, 2020
Derivative [Line Items]
Notional Amount (in millions)	$ 150,000,000
Fixed Rate	2.182%

Debt and Financing Arrangements (Debt Maturities) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Debt Disclosure [Abstract]
2019	$ 18,863
2020	11,442
2021	8,853
2022	3,130
2023	3,161
Thereafter	279,750
Total	$ 325,199

Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Taxes (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2019	Oct. 02, 2016	Oct. 01, 2016
Operating Loss Carryforwards [Line Items]
Cancellation of debt income								$ 4,089,000
Decrease in operating loss carryforwards								3,436,000
Gross timing of deferrals								646,300
Operating loss carryforwards	$ 1,300,000	$ 1,300,000
Annual limitation on operating loss use	29,800	29,800
Income tax benefit from cumulative adjustments		48,800
Tax credit carryforwards	61,100	61,100
Change in uncertain tax positions		26,600
Increase (decrease) in valuation allowance			$ 35,700
Tax loss carryforwards	307,615	307,615	271,405
Tax Cuts and Jobs Act of 2017, Income tax expense (benefit)		16,700	(330,900)
Repatriation of foreign earnings		1,500
Cumulative foreign earnings		4,200
Tax Cuts and Jobs Act of 2017, Income tax expense (benefit) related to valuation allowance	(45,000)
Tax Cuts and Jobs Act of 2017, Provisional income tax expense (benefit) related to change in limit on deductible for covered employees		6,100	200
Valuation allowance	530,612	530,612	610,571
Reductions as a result of lapses in the statute of limitations		3,271	0	$ 37,110	$ 37,100
Interest and penalties accrued related to unrecognized tax benefits	300	300	600
Gross unrecognized tax benefits	$ 39,093	$ 39,093	$ 11,383	$ 7,455	$ 38,877
Scenario, forecast
Operating Loss Carryforwards [Line Items]
Gross unrecognized tax benefits						$ 400
Alternative minimum tax credits
Operating Loss Carryforwards [Line Items]
Decrease in tax credit carryforwards								$ 3,000
Tax credit carryforwards							$ 73,300
Capital loss carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards							64,500
Domestic tax authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards							$ 1,384,000

Taxes (Schedule of Components of Income Tax) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 0		$ 86	$ 835
State	(252)		136	31
Total current	(252)		222	866
Deferred:
Federal	1,352		(52,309)	(36,162)
State	56		(389)	41
Total deferred	1,408		(52,698)	(36,121)
Provision for (benefit from) income taxes	$ 1,156		$ (52,476)	$ (35,255)
Predecessor
Current:
Federal		$ 0
State		7
Total current		7
Deferred:
Federal		(4,720)
State		87
Total deferred		(4,633)
Provision for (benefit from) income taxes		$ (4,626)

Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Income Tax Examination [Line Items]
Income tax provision (benefit) at statutory rate	$ 12,112		$ 54,621	$ 71,118
Percentage depletion allowance	(4,292)		(17,725)	(31,255)
State taxes, net of effect of federal taxes	633		4,480	7,002
Reversal of cancellation of indebtedness income	0		0	0
Worthless stock deduction	0		0	0
Change in valuation allowance	(7,655)		(79,961)	(410,983)
Impact of Tax Cuts and Jobs Act of 2017	0		(17,645)	332,345
Other, net	358		3,754	(3,482)
Provision for (benefit from) income taxes	$ 1,156		$ (52,476)	$ (35,255)
Predecessor
Income Tax Examination [Line Items]
Income tax provision (benefit) at statutory rate		$ 433,109
Percentage depletion allowance		(3,681)
State taxes, net of effect of federal taxes		(46,122)
Reversal of cancellation of indebtedness income		(1,493,162)
Worthless stock deduction		(80,077)
Change in valuation allowance		1,185,326
Impact of Tax Cuts and Jobs Act of 2017		0
Other, net		(19)
Provision for (benefit from) income taxes		$ (4,626)

Taxes (Schedule of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Tax loss carryforwards	$ 307,615	$ 271,405
Tax credit carryforwards	5,394	29,736
Investment in partnerships	193,217	308,653
Other	28,747	28,321
Gross deferred tax assets	534,973	638,115
Valuation allowance	(530,612)	(610,571)
Total deferred tax assets	4,361	27,544
Deferred tax liabilities:
Plant and equipment	3,037	3,674
Other	1,154	1,351
Total deferred tax liabilities	4,191	5,025
Net deferred tax asset	$ 170	$ 22,519

Taxes (Schedule of Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 11,383	$ 7,455	$ 38,877
Additions based on tax positions related to the current year	3,228	0	2,979
Additions for tax positions of prior years	28,387	3,928	2,709
Reductions for tax positions of prior years	(634)
Reductions as a result of lapses in the statute of limitations	(3,271)	0	(37,110)	$ (37,100)
Ending Balance	$ 39,093	$ 11,383	$ 7,455	$ 38,877

Asset Retirement Obligations (Rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning Balance		$ 328,695	$ 356,742
Accretion expense	$ 7,634	27,970	30,209
Obligations of divested operations		0	(12,569)
Adjustments to the liability from changes in estimates		(100,728)	(23,215)
Liabilities settled		(12,520)	(22,472)
Fresh start accounting adjustment		0	0
Ending Balance	$ 356,742	243,417	328,695
Current portion included in accrued expenses		(13,113)	(19,840)
Noncurrent liability		$ 230,304	$ 308,855

Asset Retirement Obligations (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
asset retirement obligations [Line Items]
Adjustments to the liability from changes in estimates	$ 100,728,000	$ 23,215,000
Surety bonds outstanding	30,400,000
Letters of credit outstanding	0
Cash collateral for surety bond	600,000
Asset retirement obligations
asset retirement obligations [Line Items]
Surety bonds outstanding	536,200,000
Black Thunder Mine
asset retirement obligations [Line Items]
Adjustments to the liability from changes in estimates	$ 95,600,000

Fair Value Measurements (Financial Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets:
Investments in marketable securities	$ 162,797	$ 155,846
Derivatives	3,554	7,339
Total assets	166,351	163,185
Liabilities:
Derivatives	13,288	7,217
Level 1
Assets:
Investments in marketable securities	99,888	64,100
Derivatives	0	0
Total assets	99,888	64,100
Liabilities:
Derivatives	13,252	7,263
Level 2
Assets:
Investments in marketable securities	62,909	91,746
Derivatives	3,022	1,985
Total assets	65,931	93,731
Liabilities:
Derivatives	36	26
Level 3
Assets:
Investments in marketable securities	0	0
Derivatives	532	5,354
Total assets	532	5,354
Liabilities:
Derivatives	$ 0	$ (72)

Fair Value Measurements (Change in Instruments Categorized as Level 3) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 5,426	$ 4,537
Realized and unrealized (gains) losses recognized in earnings, net	(302)	(2,305)
Purchases	3,420	4,910
Issuances	(724)	(535)
Settlements	(7,288)	(1,181)
Ending balance	$ 532	$ 5,426

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Net unrealized (losses) related to level 3 instruments	$ (2.0)
Fair value of senior notes and other long-term debt, including amounts classified as current	$ 318.6	$ 336.1

Capital Stock (Dividends) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Dividends (in dollars per share)	$ 0.4	$ 0.4	$ 0.4	$ 0.4	$ 0.35	$ 0.35	$ 0.35	$ 0	$ 1.6	$ 1.05
Amount (in thousands)	$ 7,303	$ 7,633	$ 7,998	$ 8,335	$ 7,606	$ 8,200	$ 8,563	$ 0	$ 31,269	$ 24,369

Capital Stock (Narrative) (Details) - USD ($)		12 Months Ended
Capital Stock (Narrative) (Details) - USD ($)	Oct. 05, 2016	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2017	Oct. 31, 2017	Apr. 30, 2017
Class of Stock [Line Items]
Authorized amount of share repurchase program		$ 750,000,000				$ 300,000,000
Common Stock, Par or Stated Value Per Share		$ 0.01		$ 0.01
Incremental increase to authorized amount of share repurchase program			$ 250,000,000		$ 200,000,000
Warrants exercised (in shares)		204
Warrants issued (in shares)		1,845,954
Common Class A [Member]
Class of Stock [Line Items]
Common Stock, Par or Stated Value Per Share	$ 0.01
Investment Warrants, Exercise Price	$ 57.00
Warrants issued (in shares)	1,914,856

Capital Stock (Share repurchase activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Number of Shares (in shares)	1,000,881	870,538	960,105	407,091	1,058,381	2,208,133	710,701	0	3,238,615	3,977,215
Average Repurchase Price per Share (in dollars per share)	$ 88.57	$ 87.59	$ 81.54	$ 94.79	$ 79.73	$ 75.49	$ 71.82	$ 0.00	$ 87.00	$ 75.96
Amount (in thousands)	$ 88,651	$ 76,248	$ 78,287	$ 38,588	$ 84,381	$ 166,685	$ 51,043	$ 0	$ 281,774	$ 302,109

Stock-Based Compensation and Other Incentive Plans (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1.0		$ 17.5	$ 10.4
Unrecognized share-based compensation expense			$ 40.1
Weighted-average period for recognition of unrecognized share-based compensation expense			3 years
Time Based Restricted Stock Units (RSUs) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			1 year
Time Based Restricted Stock Units (RSUs) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Performance Based Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Performance Based Restricted Stock Units (RSUs) \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility rate (percent)			50.00%
Performance Based Restricted Stock Units (RSUs) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility rate (percent)			36.00%
2016 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for incentive plan (in shares)			3.0
Number of shares available for grant (in shares)			2.1
Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requisite service period			3 years
Compensation expense	$ 1.6		$ 2.7	0.7
Amounts unpaid under long term incentive plan			$ 6.9	$ 8.7
Predecessor \| Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense		$ 7.2

Stock-Based Compensation and Other Incentive Plans (Restricted Stock Unit Activity) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Time Based Awards
Restricted Stock Common Shares
Outstanding at beginning of period (in shares) \| shares	240
Granted (in shares) \| shares	150
Forfeited/Canceled (in shares) \| shares	(2)
Vested (in shares) \| shares	0
Outstanding at end of period (in shares) \| shares	388
Weighted Average Grant Date Fair Value
Outstanding weighted average grant date fair value at beginning of period (in dollars per share) \| $ / shares	$ 79.87
Granted (in dollars per share) \| $ / shares	$ 90.83
Forfeited/Canceled (in dollars per share) \| $ / shares	81.28
Vested (in dollars per share) \| $ / shares	$ 0.00
Outstanding weighted average grant date fair value at end of period (in dollars per share) \| $ / shares	$ 84.11
Performance Based Awards
Restricted Stock Common Shares
Outstanding at beginning of period (in shares) \| shares	311
Granted (in shares) \| shares	105
Forfeited/Canceled (in shares) \| shares	(1)
Vested (in shares) \| shares	0
Outstanding at end of period (in shares) \| shares	415
Weighted Average Grant Date Fair Value
Outstanding weighted average grant date fair value at beginning of period (in dollars per share) \| $ / shares	$ 76.75
Granted (in dollars per share) \| $ / shares	$ 110.85
Forfeited/Canceled (in dollars per share) \| $ / shares	135.34
Vested (in dollars per share) \| $ / shares	$ 0.00
Outstanding weighted average grant date fair value at end of period (in dollars per share) \| $ / shares	$ 85.30

Workers' Compensation Expense (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Reimbursable liabilities	$ 20.3
Insurance receivable, current	3.3
Insurance receivable, noncurrent	17.0
Traumatic and other workers’ compensation claims
Defined Benefit Plan Disclosure [Line Items]
Surety bonds and letters of credit outstanding	$ 121.7
Risk Free Interest Rate \| Traumatic and other workers’ compensation claims
Defined Benefit Plan Disclosure [Line Items]
Discount rate	0.0308

Workers' Compensation Expense (Worker's Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Accrued Workers' Compensation [Line Items]
Service cost	$ 1,583		$ 7,440	$ 6,320
Interest cost	1,126		4,365	4,651
Net amortization	0		0	0
Traumatic and other workers’ compensation claims
Accrued Workers' Compensation [Line Items]
Total workers’ compensation expense	5,871		17,200	14,179
Total occupational disease
Accrued Workers' Compensation [Line Items]
Service cost			7,440	6,320
Interest cost			4,365	4,651
Total occupational disease	2,709		11,805	10,971
Traumatic injury claims and assessments
Accrued Workers' Compensation [Line Items]
Traumatic injury claims and assessments	$ 3,162		$ 5,395	$ 3,208
Predecessor
Accrued Workers' Compensation [Line Items]
Service cost		$ 3,465
Interest cost		3,184
Net amortization		4,325
Predecessor \| Traumatic and other workers’ compensation claims
Accrued Workers' Compensation [Line Items]
Total workers’ compensation expense		17,602
Predecessor \| Total occupational disease
Accrued Workers' Compensation [Line Items]
Total occupational disease		10,974
Predecessor \| Traumatic injury claims and assessments
Accrued Workers' Compensation [Line Items]
Traumatic injury claims and assessments		$ 6,628

Workers' Compensation Expense (Occupational Disease Costs Activity and Assumptions) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Self Insurance Reserve [Roll Forward]
Service cost	$ 1,583	$ 7,440	$ 6,320
Interest cost	1,126	$ 4,365	$ 4,651
Discount Rate
Self Insurance Reserve [Roll Forward]
Discount rate		0.0426	0.0366
Occupational disease costs
Self Insurance Reserve [Roll Forward]
Beginning of period		$ 122,426	$ 111,159
Service cost		7,440	6,320
Interest cost		4,365	4,651
Curtailments		0	(5,433)
Actuarial (gain) loss		(7,071)	12,242
Benefit and administrative payments		(8,260)	(6,513)
End of period	$ 111,159	$ 118,900	$ 122,426

Workers' Compensation Expense (Schedule of Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accrued Workers' Compensation [Line Items]
Total obligations	$ 194,347	$ 203,617
Less amount included in accrued expenses	20,044	18,782
Noncurrent obligations	174,303	184,835
Occupational disease costs
Accrued Workers' Compensation [Line Items]
Occupational disease costs	118,900	122,426	$ 111,159
Traumatic and other workers’ compensation claims
Accrued Workers' Compensation [Line Items]
Occupational disease costs	$ 75,447	$ 81,191

Employee Benefit Plans (Schedule of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	$ 1,583	$ 7,440	$ 6,320
Interest cost	1,126	4,365	4,651
CHANGE IN PLAN ASSETS
Value of Plan Assets at beginning of year		172,502
Value of Plan Assets at end of year		134,986	172,502
Pension Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year		270,098	313,629
Service cost	0	0	0
Interest cost	2,768	9,269	11,169
Divestitures (see Note 5 to the Consolidated Financial Statements)		0	(29,097)
Settlement gain		(2,332)	(1,532)
Curtailments		0	0
Benefits paid		(36,895)	(38,197)
Other-primarily actuarial (gain) loss		(11,267)	14,126
Benefit Obligations at end of year	313,629	228,873	270,098
CHANGE IN PLAN ASSETS
Value of Plan Assets at beginning of year		255,642	274,225
Actual return on plan assets		(6,463)	39,689
Employer contributions		222	429
Benefits paid		(36,895)	(38,197)
Divestitures		0	(20,504)
Value of Plan Assets at end of year	274,225	212,506	255,642
Accrued benefit cost		(16,367)	(14,456)
ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST
Accumulated gain		8,899	16,178
Total not yet recognized as a component of net periodic benefit cost		8,899	16,178
BALANCE SHEET AMOUNTS
Current liability		(220)	(420)
Noncurrent liability		(16,147)	(14,036)
Liability, Defined Benefit Plan		(16,367)	(14,456)
Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligations at beginning of year		110,519	111,867
Service cost	180	558	671
Interest cost	978	3,674	4,150
Divestitures (see Note 5 to the Consolidated Financial Statements)		0	0
Settlement gain		0	0
Curtailments		0	(520)
Benefits paid		(5,388)	(8,152)
Other-primarily actuarial (gain) loss		(20,800)	2,503
Benefit Obligations at end of year	111,867	88,563	110,519
CHANGE IN PLAN ASSETS
Value of Plan Assets at beginning of year		0	0
Actual return on plan assets			0
Employer contributions		5,388	8,152
Benefits paid		(5,388)	(8,152)
Divestitures		0	0
Value of Plan Assets at end of year	$ 0	0	0
Accrued benefit cost		(88,563)	(110,519)
ITEMS NOT YET RECOGNIZED AS A COMPONENT OF NET PERIODIC BENEFIT COST
Accumulated gain		25,936	5,137
Total not yet recognized as a component of net periodic benefit cost		25,936	5,137
BALANCE SHEET AMOUNTS
Current liability		(5,400)	(8,150)
Noncurrent liability		(83,163)	(102,369)
Liability, Defined Benefit Plan		$ (88,563)	$ (110,519)

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed			5.90%
Ultimate trend rate			4.50%
Effect of one percentage point increase on postretirement benefit obligation			$ 8.5
Effect of one percentage point increase on postretirement benefit cost			$ 0.4
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (percent)			35.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (percent)			65.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation of pension plans			$ 228.9	$ 270.1
Pension contributions planned for next fiscal year			0.4
Other postretirement benefits payments	$ 3.5		17.9	$ 18.0
Pension Benefits \| Predecessor
Defined Benefit Plan Disclosure [Line Items]
Other postretirement benefits payments		$ 13.8
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Gains amortized from accumulated other comprhensive income into net periodic benefit cost, next fiscal year			$ 3.0

Employee Benefit Plans (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,583		$ 7,440	$ 6,320
Interest cost	1,126		4,365	4,651
Amortization of other actuarial losses (gains)	0		0	0
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0		0	0
Interest cost	2,768		9,269	11,169
Curtailments	0		0	0
Settlements	(135)		(2,332)	(1,532)
Expected return on plan assets	(4,770)		(12,083)	(16,498)
Amortization of prior service credits	0		0	0
Amortization of other actuarial losses (gains)	0		0	0
Total occupational disease	(2,137)		(5,146)	(6,861)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	180		558	671
Interest cost	978		3,674	4,150
Curtailments	0		0	(520)
Settlements	0		0	0
Expected return on plan assets	0		0	0
Amortization of prior service credits	0		0	0
Amortization of other actuarial losses (gains)	0		0	0
Total occupational disease	$ 1,158		$ 4,232	$ 4,301
Predecessor
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 3,465
Interest cost		3,184
Amortization of other actuarial losses (gains)		(4,325)
Predecessor \| Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		0
Interest cost		9,338
Curtailments		454
Settlements		0
Expected return on plan assets		(13,623)
Amortization of prior service credits		0
Amortization of other actuarial losses (gains)		3,973
Total occupational disease		142
Predecessor \| Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		393
Interest cost		3,223
Curtailments		(970)
Settlements		0
Expected return on plan assets		0
Amortization of prior service credits		(7,854)
Amortization of other actuarial losses (gains)		(849)
Total occupational disease		$ (6,057)

Employee Benefit Plans (Schedule of Assumptions Used to Calculate Benefit Obligations) (Details)	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits \| Cash Balance
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.11%	3.49%
Pension Benefits \| Excess Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.94%	3.27%
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	412.00%	349.00%

Employee Benefit Plans (Schedule of Assumptions Used) (Details)	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate			3.82%	3.77%
Expected return on plan assets	685.00%		530.00%	620.00%
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate			3.49%	3.85%
Predecessor \| Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets		685.00%
Cash Balance \| Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.39%
Cash Balance \| Predecessor \| Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		4.59%
Cash Balance \| Predecessor \| Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		4.57%
Excess Plan \| Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.95%
Excess Plan \| Predecessor \| Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		3.80%
Excess Plan \| Predecessor \| Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate		3.80%

Employee Benefit Plans (Schedule of Allocation of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	$ 134,986	$ 172,502
Other liabilities	(12,248)	(9,605)
Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	42,369	92,411
Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	92,617	80,091
Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. small-cap
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,751	4,692
U.S. small-cap \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,751	4,692
U.S. small-cap \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. small-cap \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. mid-cap
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,182	6,017
U.S. mid-cap \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,182	6,017
U.S. mid-cap \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. mid-cap \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. large-cap
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	21,416
U.S. large-cap \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	21,416
U.S. large-cap \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. large-cap \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. government securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	43,829	66,922
U.S. government securities \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	38,436	60,286
U.S. government securities \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	5,393	6,636
U.S. government securities \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. government securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,092	4,050
Non-U.S. government securities \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Non-U.S. government securities \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2,092	4,050
Non-U.S. government securities \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. governement asset and mortgage backed securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	7,667	2,440
U.S. governement asset and mortgage backed securities \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
U.S. governement asset and mortgage backed securities \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	7,667	2,440
U.S. governement asset and mortgage backed securities \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Corporate notes and bonds
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	68,762	54,679
Corporate notes and bonds \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Corporate notes and bonds \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	68,762	54,679
Corporate notes and bonds \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
State and local government securities
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	3,480	3,829
State and local government securities \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
State and local government securities \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	3,480	3,829
State and local government securities \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Other investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	5,223	8,457
Other investments \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Other investments \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	5,223	8,457
Other investments \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	0	0
Other fixed income
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	82,765	84,172
Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	7,003	8,573
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	$ 212,506	$ 255,642	$ 274,225

Employee Benefit Plans (Summary of Estimated Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
2019	$ 16,400
2020	17,363
2021	18,173
2022	18,532
2023	16,904
Next 5 years	73,508
Total	160,880
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
2019	11,993
2020	12,125
2021	12,058
2022	12,253
2023	12,072
Next 5 years	57,896
Total	$ 118,397

Earnings Per Common Share (Details) - shares shares in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic weighted average shares outstanding (in shares)	25,002		19,663	23,725
Effect of dilutive securities (in shares)	467		966	515
Diluted weighted average shares outstanding (in shares)	25,469		20,629	24,240
Predecessor
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic weighted average shares outstanding (in shares)		21,293
Effect of dilutive securities (in shares)		20
Diluted weighted average shares outstanding (in shares)		21,313

Leases (Schedule of Lease Minimum Payments) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Operating leases
lease payments [Line Items]
2019	$ 3,681
2020	2,260
2021	1,985
2022	2,024
2023	2,044
Thereafter	6,248
Total	18,242
Royalties
lease payments [Line Items]
2019	3,669
2020	8,096
2021	8,296
2022	8,086
2023	7,749
Thereafter	84,913
Total	$ 120,809

Leases (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Leases (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Operating Leased Assets [Line Items]
Rental expense	$ 5.0		$ 12.4	$ 19.2
Royalty expense	$ 45.3		166.1	$ 167.4
Surety bonds outstanding			$ 30.4
Predecessor
Operating Leased Assets [Line Items]
Rental expense		$ 19.4
Royalty expense		$ 116.4

Risk Concentrations (Narrative) (Details) $ in Thousands, T in Millions	3 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 01, 2016 USD ($)	Dec. 31, 2018 USD ($) T	Dec. 31, 2017 USD ($)
Concentration Risk [Line Items]
Trade accounts receivable	$ 200,904				$ 172,604						$ 200,904	$ 172,604
Tons of coal sold \| T											96.6
Percentage of tons sold under long term contract											60.00%
Long term contracts percentage of company revenue											47.00%
Long-term contracts, life term, minimum											1 year
Long-term contracts, life term, maximum											4 years
Revenues	650,963	$ 633,180	$ 592,349	$ 575,295	560,244	$ 613,538	$ 549,866	$ 600,975	$ 575,688		$ 2,451,787	2,324,623
Europe
Concentration Risk [Line Items]
Revenues									61,169		559,165	388,926
Asia
Concentration Risk [Line Items]
Revenues									55,634		452,711	264,503
Central and South America
Concentration Risk [Line Items]
Revenues									13,224		79,085	30,982
Africa
Concentration Risk [Line Items]
Revenues									0		17,567	14,901
Brokered Sales
Concentration Risk [Line Items]
Revenues									$ 0		2,372	3,150
Predecessor
Concentration Risk [Line Items]
Revenues										$ 1,398,709
Predecessor \| Europe
Concentration Risk [Line Items]
Revenues										112,986
Predecessor \| Asia
Concentration Risk [Line Items]
Revenues										68,536
Predecessor \| Central and South America
Concentration Risk [Line Items]
Revenues										41,861
Predecessor \| Africa
Concentration Risk [Line Items]
Revenues										0
Predecessor \| Brokered Sales
Concentration Risk [Line Items]
Revenues										$ 0
Electric utilities
Concentration Risk [Line Items]
Receivables	73,900				72,900						$ 73,900	$ 72,900
Percentage of total trade accounts receivable											37.00%	42.00%
Domestic and foreign steel producers
Concentration Risk [Line Items]
Trade accounts receivable	$ 126,500				$ 99,400						$ 126,500	$ 99,400
Trade receivables, percentage	63.00%				58.00%						63.00%	58.00%

Risk Concentrations (Schedule of Foreign Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Revenues	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 560,244	$ 613,538	$ 549,866	$ 600,975	$ 575,688		$ 2,451,787	$ 2,324,623
Europe
Concentration Risk [Line Items]
Revenues									61,169		559,165	388,926
Asia
Concentration Risk [Line Items]
Revenues									55,634		452,711	264,503
Central and South America
Concentration Risk [Line Items]
Revenues									13,224		79,085	30,982
Africa
Concentration Risk [Line Items]
Revenues									0		17,567	14,901
Brokered Sales
Concentration Risk [Line Items]
Revenues									0		2,372	3,150
Foreign Countries
Concentration Risk [Line Items]
Revenues									$ 130,027		$ 1,110,900	$ 702,462
Predecessor
Concentration Risk [Line Items]
Revenues										$ 1,398,709
Predecessor \| Europe
Concentration Risk [Line Items]
Revenues										112,986
Predecessor \| Asia
Concentration Risk [Line Items]
Revenues										68,536
Predecessor \| Central and South America
Concentration Risk [Line Items]
Revenues										41,861
Predecessor \| Africa
Concentration Risk [Line Items]
Revenues										0
Predecessor \| Brokered Sales
Concentration Risk [Line Items]
Revenues										0
Predecessor \| Foreign Countries
Concentration Risk [Line Items]
Revenues										$ 223,383

Revenue Recognition (Schedule of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 560,244	$ 613,538	$ 549,866	$ 600,975	$ 575,688		$ 2,451,787	$ 2,324,623
North America revenues
Disaggregation of Revenue [Line Items]
Revenues									445,661		1,340,887	1,622,161
Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									130,027		1,110,900	702,462
Operating segments \| PRB
Disaggregation of Revenue [Line Items]
Revenues									275,703		973,248	1,024,197
Operating segments \| PRB \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues									275,703		971,337	1,024,197
Operating segments \| PRB \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									0		1,911	0
Operating segments \| MET
Disaggregation of Revenue [Line Items]
Revenues									200,377		1,036,621	887,839
Operating segments \| MET \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues									91,086		160,969	312,874
Operating segments \| MET \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									109,291		875,652	574,965
Operating segments \| Other Thermal
Disaggregation of Revenue [Line Items]
Revenues									97,382		428,884	396,504
Operating segments \| Other Thermal \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues									76,646		195,547	269,007
Operating segments \| Other Thermal \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									20,736		233,337	127,497
Corporate, Other and Eliminations
Disaggregation of Revenue [Line Items]
Revenues									2,226		13,034	16,083
Corporate, Other and Eliminations \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues									2,226		13,034	16,083
Corporate, Other and Eliminations \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues									$ 0		$ 0	$ 0
Predecessor
Disaggregation of Revenue [Line Items]
Revenues										$ 1,398,709
Predecessor \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues										1,175,326
Predecessor \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues										223,383
Predecessor \| Operating segments \| PRB
Disaggregation of Revenue [Line Items]
Revenues										726,747
Predecessor \| Operating segments \| PRB \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues										726,747
Predecessor \| Operating segments \| PRB \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues										0
Predecessor \| Operating segments \| MET
Disaggregation of Revenue [Line Items]
Revenues										437,069
Predecessor \| Operating segments \| MET \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues										215,585
Predecessor \| Operating segments \| MET \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues										221,484
Predecessor \| Operating segments \| Other Thermal
Disaggregation of Revenue [Line Items]
Revenues										213,052
Predecessor \| Operating segments \| Other Thermal \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues										211,153
Predecessor \| Operating segments \| Other Thermal \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues										1,899
Predecessor \| Corporate, Other and Eliminations
Disaggregation of Revenue [Line Items]
Revenues										21,841
Predecessor \| Corporate, Other and Eliminations \| North America revenues
Disaggregation of Revenue [Line Items]
Revenues										21,841
Predecessor \| Corporate, Other and Eliminations \| Seaborne revenues
Disaggregation of Revenue [Line Items]
Revenues										$ 0

Revenue Recognition (Narrative) (Details) - Coal - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 T in Millions	Dec. 31, 2018 T
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation (in tons)	73.0
Remaining performance obligations, fixed price contracts (in tons)	63.0
Remaining performance obligation, variable price contracts (in tons)	10.0

Commitments and Contingencies (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Amount accrued	$ 0.2	$ 0.2
Future commitments	$ 70.0

Segment Information (Narrative) (Details)	12 Months Ended
Segment Information (Narrative) (Details)	Dec. 31, 2018 Segment
Segment Reporting [Abstract]
Distinct lines of business	2

Segment Information (Schedule of Operating Segment Results) (Details) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017	Oct. 02, 2016
Segment Reporting Information [Line Items]
Revenues	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 560,244	$ 613,538	$ 549,866	$ 600,975	$ 575,688		$ 2,451,787	$ 2,324,623
Adjusted EBITDAR									94,465		437,778	419,697
Depreciation, depletion and amortization									32,604		119,563	122,464
Accretion on asset retirement obligations									7,634		27,970	30,209
Total Assets	1,887,060				1,979,632						1,887,060	1,979,632	$ 2,136,597
Capital expenditures									15,214		95,272	59,205
Operating segments \| PRB
Segment Reporting Information [Line Items]
Revenues									275,703		973,248	1,024,197
Adjusted EBITDAR									55,765		126,525	158,882
Depreciation, depletion and amortization									9,949		33,120	36,349
Accretion on asset retirement obligations									5,049		19,541	20,160
Total Assets	278,314				390,665						278,314	390,665	446,775
Capital expenditures									934		12,140	6,212
Operating segments \| MET
Segment Reporting Information [Line Items]
Revenues									200,377		1,036,621	887,839
Adjusted EBITDAR									30,819		349,524	243,616
Depreciation, depletion and amortization									18,287		69,560	70,896
Accretion on asset retirement obligations									528		1,874	2,000
Total Assets	545,061				548,476						545,061	548,476	576,793
Capital expenditures									13,329		64,307	32,678
Operating segments \| Other Thermal
Segment Reporting Information [Line Items]
Revenues									97,382		428,884	396,504
Adjusted EBITDAR									31,159		68,620	102,006
Depreciation, depletion and amortization									3,911		14,699	13,588
Accretion on asset retirement obligations									540		2,261	2,161
Total Assets	125,333				134,397						125,333	134,397	129,602
Capital expenditures									684		11,999	11,901
Corporate, Other and Eliminations
Segment Reporting Information [Line Items]
Revenues									2,226		13,034	16,083
Adjusted EBITDAR									(23,278)		(106,891)	(84,807)
Depreciation, depletion and amortization									457		2,184	1,631
Accretion on asset retirement obligations									1,517		4,294	5,888
Total Assets	$ 938,352				$ 906,094						938,352	906,094	$ 983,427
Capital expenditures									$ 267		$ 6,826	$ 8,414
Predecessor
Segment Reporting Information [Line Items]
Revenues										$ 1,398,709
Adjusted EBITDAR										89,018
Depreciation, depletion and amortization										191,581
Accretion on asset retirement obligations										24,321
Total Assets										2,123,829
Capital expenditures										82,434
Predecessor \| Operating segments \| PRB
Segment Reporting Information [Line Items]
Revenues										726,747
Adjusted EBITDAR										113,185
Depreciation, depletion and amortization										100,151
Accretion on asset retirement obligations										16,940
Total Assets										456,711
Capital expenditures										612
Predecessor \| Operating segments \| MET
Segment Reporting Information [Line Items]
Revenues										437,069
Adjusted EBITDAR										11,851
Depreciation, depletion and amortization										55,311
Accretion on asset retirement obligations										1,765
Total Assets										619,154
Capital expenditures										17,296
Predecessor \| Operating segments \| Other Thermal
Segment Reporting Information [Line Items]
Revenues										213,052
Adjusted EBITDAR										31,448
Depreciation, depletion and amortization										32,310
Accretion on asset retirement obligations										1,988
Total Assets										131,173
Capital expenditures										3,895
Predecessor \| Corporate, Other and Eliminations
Segment Reporting Information [Line Items]
Revenues										21,841
Adjusted EBITDAR										(67,466)
Depreciation, depletion and amortization										3,809
Accretion on asset retirement obligations										3,628
Total Assets										916,791
Capital expenditures										$ 60,631

Segment Information (Reconciliation of Segment Income from Operations to Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Income before income taxes									$ 34,605		$ 260,101	$ 203,195
Interest expense, net									10,754		13,689	24,256
Depreciation, depletion and amortization									32,604		119,563	122,464
Accretion on asset retirement obligations									7,634		27,970	30,209
Amortization of sales contracts, net									796		11,107	53,985
Asset impairment and mine closure costs									0		0	0
Gain on sale of Lone Mountain Processing, Inc.									0		0	(21,297)
Net loss resulting from early retirement of debt and debt restructuring									0		485	2,547
Non-service related postretirement benefit costs									(32)		3,202	1,940
Reorganization items, net	$ 60	$ 560	$ 740	$ 301	$ (494)	$ 43	$ 21	$ 2,828	759		1,661	2,398
Fresh start coal inventory fair value adjustment									7,345		0	0
Adjusted EBITDAR									$ 94,465		$ 437,778	$ 419,697
Predecessor
Segment Reporting Information [Line Items]
Income before income taxes										$ 1,237,455
Interest expense, net										133,235
Depreciation, depletion and amortization										191,581
Accretion on asset retirement obligations										24,321
Amortization of sales contracts, net										(728)
Asset impairment and mine closure costs										129,267
Gain on sale of Lone Mountain Processing, Inc.										0
Net loss resulting from early retirement of debt and debt restructuring										2,213
Non-service related postretirement benefit costs										1,715
Reorganization items, net										(1,630,041)
Fresh start coal inventory fair value adjustment										0
Adjusted EBITDAR										$ 89,018

Quarterly Selected Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 650,963	$ 633,180	$ 592,349	$ 575,295	$ 560,244	$ 613,538	$ 549,866	$ 600,975	$ 575,688	$ 2,451,787	$ 2,324,623
Gross profit	101,396	109,740	77,663	81,198	63,460	66,145	63,150	86,707
Asset impairment and mine closure costs									0	0	0
Income from operations	86,490	82,886	44,595	65,167	51,117	73,310	42,924	66,985	46,086	279,138	234,336
Reorganization items, net	(60)	(560)	(740)	(301)	494	(43)	(21)	(2,828)	(759)	(1,661)	(2,398)
Net income	$ 86,094	$ 123,192	$ 43,306	$ 59,985	$ 81,271	$ 68,351	$ 37,160	$ 51,668	$ 33,449	$ 312,577	$ 238,450
Diluted earnings per common share (in dollars per share)	$ 4.44	$ 6.10	$ 2.06	$ 2.74	$ 3.64	$ 2.83	$ 1.48	$ 2.03	$ 1.31	$ 15.15	$ 9.84

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=109256448&loc=d3e4984-109258

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109260490&loc=d3e1252-109256

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(23))
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109260490&loc=d3e1337-109256

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(21))
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109260490&loc=SL5780133-109256

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(19))
-URI http://asc.fasb.org/extlink&oid=114873790&loc=SL114874131-224263

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Oct. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Accounts receivable and other receivables
Reserves deducted from asset accounts:
Balance at Beginning of Year	$ 0		$ 0	$ 0
Additions (Reductions) Charged to Costs and Expenses	0			0
Charged to Other Accounts	0			0
Deductions	0			0
Balance at End of Year	0	$ 0	0	0
Current assets — supplies and inventory
Reserves deducted from asset accounts:
Balance at Beginning of Year	0		261	0
Additions (Reductions) Charged to Costs and Expenses	0		1,247	365
Charged to Other Accounts	0		0	(17)
Deductions	0		860	87
Balance at End of Year	0	0	648	261
Deferred income taxes
Reserves deducted from asset accounts:
Balance at Beginning of Year	1,033,982		610,571	1,021,553
Additions (Reductions) Charged to Costs and Expenses	(12,429)		(79,959)	(410,982)
Charged to Other Accounts				0
Deductions	0			0
Balance at End of Year	1,021,553	1,033,982	$ 530,612	$ 610,571
Predecessor \| Accounts receivable and other receivables
Reserves deducted from asset accounts:
Balance at Beginning of Year	0	7,842
Additions (Reductions) Charged to Costs and Expenses		0
Charged to Other Accounts		0
Deductions		7,842
Balance at End of Year		0
Predecessor \| Current assets — supplies and inventory
Reserves deducted from asset accounts:
Balance at Beginning of Year	0	5,991
Additions (Reductions) Charged to Costs and Expenses		844
Charged to Other Accounts		(5,060)
Deductions		1,775
Balance at End of Year		0
Predecessor \| Deferred income taxes
Reserves deducted from asset accounts:
Balance at Beginning of Year	$ 1,033,982	1,135,399
Additions (Reductions) Charged to Costs and Expenses		(101,417)
Charged to Other Accounts		0
Deductions		0
Balance at End of Year		$ 1,033,982