Alpha Metallurgical Resources (AMR) 10-K 18 Mar 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Feb. 29, 2020	Jun. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	Contura Energy, Inc.
Entity Central Index Key	0001704715
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Well-Known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		18,259,421
Entity Public Float			$ 600

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Revenue from contract with customer	$ 2,282,007	$ 2,020,889	$ 1,639,883
Other revenues	8,253	10,316	10,086
Total revenues	2,290,260	2,031,205	1,649,969
Costs and expenses:
Cost of coal sales (exclusive of items shown separately below)	1,924,709	1,661,118	1,327,297
Depreciation, depletion and amortization	228,792	77,549	34,910
Accretion on asset retirement obligations	27,798	9,966	9,934
Amortization of acquired intangibles, net	(88)	(5,392)	59,007
Selling, general and administrative expenses (exclusive of depreciation, depletion and amortization shown separately above)	78,953	59,271	67,459
Merger-related costs	1,090	51,800	0
Secondary offering costs	0	0	4,491
Asset impairment	66,324	0	0
Goodwill impairment	124,353	0	0
Total other operating (income) loss:
Mark-to-market adjustment for acquisition-related obligations	(3,564)	24	3,221
Gain on settlement of acquisition-related obligations	0	(580)	(38,886)
Other (income) expense	(575)	(16,311)	178
Total costs and expenses	2,447,792	1,837,445	1,467,611
(Loss) income from operations	(157,532)	193,760	182,358
Other income (expense):
Interest expense	(66,798)	(38,810)	(35,977)
Interest income	7,296	1,949	210
Loss on modification and extinguishment of debt	(26,459)	(12,042)	(38,701)
Equity loss in affiliates	(6,874)	(6,112)	(3,339)
Bargain purchase gain	0	0	1,011
Miscellaneous (loss) income, net	(10,332)	(1,254)	194
Total other expense, net	(103,167)	(56,269)	(76,602)
(Loss) income from continuing operations before income taxes	(260,699)	137,491	105,756
Income tax benefit	57,557	165,363	67,979
Net income (loss) from continuing operations	(203,142)	302,854	173,735
Discontinued operations:
Loss from discontinued operations before income taxes	(117,391)	(4,994)	(36,894)
Income tax benefit from discontinued operations	4,214	1,305	17,681
Loss from discontinued operations	(113,177)	(3,689)	(19,213)
Net (loss) income	$ (316,319)	$ 299,165	$ 154,522
Basic (loss) income per common share:
(Loss) Income from continuing operations (in dollars per share)	$ (10.80)	$ 27.61	$ 17.01
Loss from discontinued operations (in dollars per share)	(6.02)	(0.33)	(1.89)
Net (loss) income (in dollars per share)	(16.82)	27.28	15.12
Diluted (loss) income per common share:
(Loss) income from continuing operations (in dollars per share)	(10.80)	25.86	16.13
Loss from discontinuing operations (in dollars per share)	(6.02)	(0.32)	(1.78)
Net (loss) income (in dollars per share)	$ (16.82)	$ 25.54	$ 14.35
Weighted average shares - basic (in shares)	18,808,460	10,967,014	10,216,464
Weighted average shares - diluted (in shares)	18,808,460	11,712,653	10,770,005
Coal revenues
Revenues:
Revenue from contract with customer	$ 2,282,007	$ 2,020,889	$ 1,392,481
Freight and handling revenues
Revenues:
Revenue from contract with customer	$ 0	0	$ 247,402
Total other operating (income) loss:
Total costs and expenses		$ 363,128

Consolidated Statements of Comp

Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Other Comprehensive Income [Abstract]
Net (loss) income	$ (316,319)	$ 299,165	$ 154,522
Employee benefit plans:
Current period actuarial loss	(42,891)	(22,895)	(3,832)
Income tax	0	1,572	0
Current period actuarial (loss) gain, net of income tax	(42,891)	(21,323)	(3,832)
Less: reclassification adjustments for amounts reclassified to earnings due to amortization of net actuarial loss (gain) and settlements	7,405	155	(203)
Income tax	0	(14)	0
Less: reclamation adjustments for amounts reclassified to earnings due to amortization of net actuarial (gain) loss and settlements, net of income tax	7,405	141	(203)
Total other comprehensive loss, net of tax	(35,486)	(21,182)	(4,035)
Total comprehensive (loss) income	$ (351,805)	$ 277,983	$ 150,487

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 212,793	$ 233,599
Trade accounts receivable, net of allowance for doubtful accounts of $0 as of December 31, 2019 and 2018	244,666	292,617
Inventories, net	162,659	121,965
Prepaid expenses and other current assets	91,361	158,945
Current assets - discontinued operations	0	22,475
Total current assets	711,479	829,601
Property, plant, and equipment, net of accumulated depreciation and amortization of $314,276 and $106,766 as of December 31, 2019 and 2018	583,262
Property, plant, and equipment, net of accumulated depreciation and amortization of $314,276 and $106,766 as of December 31, 2019 and 2018		699,990
Owned and leased mineral rights, net of accumulated depletion and amortization of $27,877 and $11,390 as of December 31, 2019 and 2018	523,141	528,232
Goodwill	0	95,624
Other acquired intangibles, net of accumulated amortization of $32,686 and $20,267 as of December 31, 2019 and 2018	125,145	154,584
Long-term restricted cash	122,524	227,173
Deferred income taxes	33,065	27,179
Other non-current assets	204,207	183,675
Total assets	2,302,823	2,746,058
Current liabilities:
Current portion of long-term debt	28,485	42,743
Trade accounts payable	98,746	114,568
Acquisition-related obligations - current	33,639	27,334
Accrued expenses and other current liabilities	154,282	148,699
Current liabilities - discontinued operations	0	21,892
Total current liabilities	315,152	355,236
Long-term debt	564,481	545,269
Acquisition-related obligations - long-term	46,259	72,996
Workers’ compensation and black lung obligations	260,778	249,294
Pension obligations	204,086	180,802
Asset retirement obligations	184,130	203,694
Deferred income taxes	422	15,118
Other non-current liabilities	31,393	52,415
Non-current liabilities - discontinued operations	0	94
Total liabilities	1,606,701	1,674,918
Commitments and Contingencies (Note 23)
Stockholders’ Equity
Preferred stock - par value $0.01, 5.0 million shares authorized at December 31, 2019 and 2018, none issued	0	0
Common stock - par value $0.01, 50.0 million shares authorized, 20.5 million issued and 18.2 million outstanding at December 31, 2019 and 20.2 million issued and 19.1 million outstanding at December 31, 2018	205	202
Additional paid-in capital	775,707	761,301
Accumulated other comprehensive loss	(58,616)	(23,130)
Treasury stock, at cost: 2.3 million shares at December 31, 2019 and 1.1 million shares at December 31, 2018	(107,984)	(70,362)
Retained earnings	86,810	403,129
Total stockholders’ equity	696,122	1,071,140
Total liabilities and stockholders’ equity	$ 2,302,823	$ 2,746,058

Consolidated Balance Sheets - P

Consolidated Balance Sheets - Parenthetical - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 0	$ 0
Other acquired intangibles, accumulated amortization	32,686	20,267
Less accumulated depreciation, depletion and amortization	314,276
Less accumulated depreciation, depletion and amortization		106,766
Owned and leased mineral rights, accumulated depletion and amortization	$ 27,877	$ 11,390
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	20,500,000	20,200,000
Common stock, shares outstanding (in shares)	18,200,000	19,100,000
Treasury stock, shares at cost (in shares)	2,300,000	1,100,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net (loss) income	$ (316,319)	$ 299,165	$ 154,522
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation, depletion and amortization	315,162	77,549	65,000
Amortization of acquired intangibles, net	(88)	(5,392)	59,007
Accretion of acquisition-related obligations discount	5,522	5,627	7,531
Amortization of debt issuance costs and accretion of debt discount	14,070	4,483	2,884
Mark-to-market adjustment for acquisition-related obligations	(3,564)	24	3,221
Gain on settlement of acquisition-related obligations	0	(580)	(38,886)
Loss (gain) on disposal of assets	8,142	(16,852)	(570)
Gain on assets acquired in an exchange transaction	(9,083)	0	0
Bargain purchase gain	0	0	(1,011)
Accretion on asset retirement obligations	33,759	9,966	21,275
Employee benefit plans, net	20,846	9,231	11,739
Deferred income taxes	(12,098)	(66,682)	(78,744)
Loss on sale of Powder River Basin	0	0	36,086
Goodwill impairment	124,353	0	0
Asset impairment	83,485	0	0
Loss on modification and extinguishment of debt	26,459	12,042	38,701
Stock-based compensation	12,397	13,354	20,372
Equity in loss of affiliates	6,874	6,112	3,325
Other, net	(5,204)	1,643	0
Changes in operating assets and liabilities
Trade accounts receivable, net	47,424	(84,139)	34,840
Inventories, net	(40,694)	33,232	441
Prepaid expenses and other current assets	56,671	(44,266)	(40,425)
Deposits	15,170	(7,493)	38,447
Other non-current assets	(24,460)	(36,655)	24,498
Trade accounts payable	(28,148)	(7,075)	6,102
Accrued expenses and other current liabilities	(25,495)	(7,345)	(12,207)
Acquisition-related obligations	(28,128)	(14,500)	(22,800)
Asset retirement obligations	(111,616)	(3,175)	(2,567)
Other non-current liabilities	(33,557)	(19,893)	(16,521)
Net cash provided by operating activities	131,880	158,381	314,260
Investing activities:
Capital expenditures	(192,411)	(81,881)	(83,121)
Payments on disposal of assets	0	(10,250)	0
Proceeds on disposal of assets	2,780	997	2,579
Capital contributions to equity affiliates	(10,051)	(5,253)	(5,691)
Cash, cash equivalents and restricted cash acquired in acquisition, net of amounts paid	0	198,506	0
Purchase of additional ownership interest in equity affiliate	0	0	(13,293)
Cash paid on sale of Powder River Basin	0	0	(21,375)
Purchase of investment securities	(92,855)	(3,280)	(406)
Maturity of investment securities	100,250	3,360	0
Other, net	535	(3)	0
Net cash (used in) provided by investing activities	(191,752)	102,196	(121,307)
Financing activities:
Proceeds from borrowings on debt	544,946	537,750	396,000
Principal repayments of debt	(552,809)	(471,704)	(369,500)
Principal repayments of financing lease obligations	(3,654)
Principal repayments of financing lease obligations		(533)	(1,009)
Form S-4 costs	0	(3,918)	0
Debt issuance costs	(6,689)	(14,931)	(14,385)
Debt extinguishment costs	0	0	(25,036)
Debt amendment costs	0	0	(4,520)
Common stock repurchases and related expenses	(37,622)	(20,270)	(49,932)
Special dividend paid	0	0	(100,735)
Principal repayments of notes payable	(14,818)	(3,844)	(1,517)
Other, net	952	159	352
Net cash (used in) provided by financing activities	(69,694)	22,709	(170,282)
Net (decrease) increase in cash and cash equivalents and restricted cash	(129,566)	283,286	22,671
Cash and cash equivalents and restricted cash at beginning of period	477,246	193,960	171,289
Cash and cash equivalents and restricted cash at end of period	347,680	477,246	193,960
Supplemental cash flow information:
Cash paid for interest	51,877	27,340	40,635
Cash paid for income taxes	3,039	37	13,328
Cash received for income tax refunds	72,236	14,157	0
Supplemental disclosure of noncash investing and financing activities:
Financing leases and capital financing - equipment	5,324	6,513	1,574
Accrued capital expenditures	4,110	6,879	9,408
Issuance of equity in connection with acquisition	0	664,460	0
Net balance due to Alpha deemed effectively settled	0	47,048	0
Reconciliation of Cash and Cash Equivalents and Restricted Cash
Total cash and cash equivalents and restricted cash	$ 347,680	$ 477,246	$ 193,960

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Treasury Stock at Cost	(Accumulated Deficit) Retained Earnings
Beginning balance at Dec. 31, 2016	$ 37,224	$ 103	$ 45,964	$ 2,087	$ 0	$ (10,930)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	154,522					154,522
Other comprehensive loss, net	(4,035)			(4,035)
Stock-based compensation and net issuance of common stock for share vesting	20,209	4	20,205
Special dividend	(100,735)		(27,132)			(73,603)
Common stock repurchase and related expenses	(50,040)				(50,040)
Warrant exercises	362	1	413		(52)
Ending balance at Dec. 31, 2017	92,648	108	40,616	(1,948)	(50,092)	103,964
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Retrospective warrants adjustment	35,141		1,166			33,975
Net (loss) income	299,165					299,165
Other comprehensive loss, net	(21,182)			(21,182)
Stock-based compensation and net issuance of common stock for share vesting	13,031		13,031
Exercise of stock options	146		146
Common stock repurchase and related expenses	(20,266)				(20,266)
Warrant exercises	8		12		(4)
Form S-4 costs	(3,918)		(3,918)
Equity consideration for the Alpha Merger	664,460	94	664,366
Net balances due to Alpha deemed effectively settled	47,048		47,048
Ending balance at Dec. 31, 2018	1,071,140	202	761,301	(23,130)	(70,362)	403,129
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(316,319)					(316,319)
Other comprehensive loss, net	(35,486)			(35,486)
Stock-based compensation and net issuance of common stock for share vesting	13,456	1	13,455
Exercise of stock options	934	2	932
Common stock repurchase and related expenses	(37,622)				(37,622)
Warrant exercises	19		19
Ending balance at Dec. 31, 2019	$ 696,122	$ 205	$ 775,707	$ (58,616)	$ (107,984)	$ 86,810

Business and Basis of Presentat

Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Business Contura Energy, Inc. (“Contura” or the “Company”) is a Tennessee-based coal supplier with affiliate mining operations across major coal basins in Pennsylvania, Virginia and West Virginia. With customers across the globe, high-quality reserves and significant port capacity, Contura reliably supplies both metallurgical coal to produce steel and thermal coal to generate power. Contura was formed to acquire and operate certain of Alpha Natural Resources, Inc.’s (“Alpha”) core coal operations, as part of the Alpha Restructuring. Contura began operations on July 26, 2016 and currently operates mines in the Northern Appalachia and Central Appalachia regions. A Merger with ANR, Inc. (“ANR”) and Alpha Natural Resources Holdings, Inc. (“Holdings,” and, together with ANR, the "Alpha Companies”) was completed on November 9, 2018 (the “Merger” or the “Alpha Merger”). Refer to Note 3 for information on terms of the definitive merger agreement (the “Merger Agreement”). Upon the consummation of the transactions contemplated by the Merger Agreement, Contura began trading on the New York Stock Exchange under the ticker “CTRA.” Basis of Presentation Together, the consolidated balance sheet and consolidated statements of operations, comprehensive (loss) income, cash flows and stockholders’ equity for the Company are referred to as the “Financial Statements.” The Financial Statements are also referred to as “Consolidated” and references across periods are generally labeled “Balance Sheets,” “Statements of Operations,” and “Statements of Cash Flows.” The Consolidated Financial Statements include all wholly owned subsidiaries’ results of operations for the years ended December 31, 2019 , 2018 and 2017 . All significant intercompany transactions have been eliminated in consolidation. For the year ended December 31, 2018, the Alpha Companies’ financial results are included in the Financial Statements for the period from November 9, 2018 through December 31, 2018. The Alpha Companies’ financial results are not included in the Financial Statements in periods prior to November 9, 2018. Refer to Note 3 for information on Alpha Merger. On December 8, 2017, the Company closed a transaction with Blackjewel L.L.C. (“Buyer”) to sell the Eagle Butte and Belle Ayr mines located in the Powder River Basin (“PRB”), Wyoming, along with related coal reserves, equipment, infrastructure and other real properties. The PRB results of operations and financial position are reported as discontinued operations in the Consolidated Financial Statements. The historical information in the accompanying Notes to the Consolidated Financial Statements has been restated to reflect the effects of the PRB operations being reported as discontinued operations in the Consolidated Financial Statements. Refer to Note 4 for further information on discontinued operations. The accompanying Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). Liquidity Risks and Uncertainties Weak market conditions and depressed coal prices have resulted in operating losses. If market conditions do not improve, the Company may experience continued operating losses and cash outflows in the coming quarters, which would adversely affect its liquidity. The Company may need to raise additional funds more quickly if market conditions deteriorate, and may not be able to do so in a timely fashion, or at all. The Company has cash on hand which will be sufficient to meet its working capital requirements, anticipated capital expenditures, debt service requirements, acquisition-related obligations, and reclamation obligations for the 12 months subsequent to the issuance of these financial statements. The Company relies on a number of assumptions in budgeting for future activities. These include the costs for mine development to sustain capacity of its operating mines, cash flows from operations, effects of regulation and taxes by governmental agencies, mining technology improvements and reclamation costs. These assumptions are inherently subject to significant business, political, economic, regulatory, environmental and competitive uncertainties, contingencies and risks, all of which are difficult to predict and many of which are beyond the Company’s control. Therefore, the cash on hand and from future operations will be subject to any significant changes in these assumptions. Reclassifications Freight and handling costs has been reclassified in the prior year periods from a separate line item into cost of coal sales in the Consolidated Statements of Operations to conform to the current year presentation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of the Company’s Consolidated Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include inventories; mineral reserves; asset impairments; goodwill impairment; reclamation obligations; post-employment and other employee benefit obligations; useful lives, depletion and amortization; reserves for workers’ compensation and black lung claims; deferred income taxes; income taxes refundable and receivable; reserves for contingencies and litigation; fair value of financial instruments; and fair value adjustments for acquisition accounting. Estimates are based on facts and circumstances believed to be reasonable at the time; however, actual results could differ from those estimates. Cash and Cash Equivalents Cash and cash equivalents consist of cash held with reputable depository institutions and highly liquid, short-term investments with original maturities of three months or less. Cash and cash equivalents are stated at cost, which approximates fair value. As of December 31, 2019 and December 31, 2018 , the Company’s cash equivalents of $212,793 and $233,599 , respectively, consisted of highly-rated money market funds. Restricted Cash Amounts included in restricted cash represent cash deposits that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $38,944 , $12,706 , $67,868 , and $3,006 as of December 31, 2019 for securing the Company’s obligations under certain workers’ compensation, black lung, reclamation-related obligations, and financial guarantees and other, respectively, which have been written on the Company’s behalf. Additionally, the Company had $12,363 of short-term restricted cash held in escrow related to the Company’s contingent revenue payment obligation as of December 31, 2019. As of December 31, 2018 , collateral was provided in the amounts of $90,759 , $29,611 , $86,217 , $27,386 , and $2,833 for securing the Company’s obligations under certain workers’ compensation, black lung, reclamation-related obligations, general liabilities, and financial guarantees, respectively, which have been written on the Company’s behalf. Additionally, the Company had $6,841 of short-term restricted cash held in escrow related to the Company’s contingent revenue payment obligation as of December 31, 2018. Refer to Note 16 for further information regarding the contingent payment revenue obligation. The Company’s restricted cash is primarily invested in interest-bearing accounts. This restricted cash is classified as both short-term and long-term on the Company’s Consolidated Balance Sheets. Restricted Investments Amounts included in restricted investments consist of certificates of deposit, mutual funds, and U.S. treasury bills classified as either trading securities or held-to-maturity securities. The trading securities are recorded initially at cost and adjusted to fair value at each reporting period. The trading securities’ unrealized gains and losses resulting from fair value adjustments are recorded in current period earnings or loss. The held-to-maturity securities are recorded at amortized cost with interest income recorded in current period earnings. These restricted investments are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $3,100 and $18,786 as of December 31, 2019 for securing the Company’s obligations under certain workers’ compensation and reclamation-related obligations, respectively, which have been written on the Company’s behalf, of which $13,508 are classified as trading securities and $8,378 are classified as held-to-maturity securities. As of December 31, 2018, collateral was provided in the amounts of $1,888 , $27,049 , and $200 for securing the Company’s obligations under certain workers’ compensation, reclamation-related obligations, and general liabilities, respectively, which have been written on the Company’s behalf, of which all were classified as held-to-maturity securities. These restricted investments are classified as long-term on the Company’s Consolidated Balance Sheets. Deposits Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral. The Company had cash collateral in the form of deposits in the amounts of $8,887 and $1,836 as of December 31, 2019 and $24,002 and $1,390 as of December 31, 2018 to secure the Company’s obligations under reclamation-related obligations and various other operating agreements, respectively. These deposits are classified as both short-term and long-term on the Company’s Consolidated Balance Sheets. Trade Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The Company records an allowance for doubtful accounts at the estimate of the amount of probable credit losses in the Company’s existing accounts receivable. The Company establishes provisions for losses on accounts receivable when it is probable that all or part of the outstanding balance will not be collected. The Company regularly reviews its accounts receivable balances and establishes or adjusts the allowance as necessary primarily using the specific identification method. The allowance for doubtful accounts was $0 at both December 31, 2019 and 2018 . Account balances are written off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. Inventories Coal is reported as inventory at the point in time the coal is extracted from the mine. Raw coal represents coal stockpiles that may be sold in current condition or may be further processed prior to shipment to a customer. Saleable coal represents coal stockpiles that require no further processing prior to shipment to a customer. Coal inventories are valued at the lower of average cost or net realizable value. The cost of coal inventories is determined based on the average cost of production, which includes labor, supplies, equipment costs, operating overhead, depreciation, and other related costs. Net realizable value considers the projected future sales price of the product, less estimated preparation and selling costs. Material and supplies inventories are valued at average cost, less an allowance for obsolete and surplus items. Discontinued Operations In accordance with Accounting Standards Codification (“ASC”) 205-20-45, the Company treats a disposal transaction as a discontinued operation when the disposal of a component or group of components represents a strategic shift that will have a major effect on the Company’s operations and financial results. In the period in which the discontinued operations criteria are met, the assets and liabilities of the discontinued operations are separately presented on the Company's Consolidated Balance Sheets and the results of operations, including any gain or loss recognized, is reclassified to discontinued operations on the Company’s Consolidated Statement of Operations. Refer to Note 4 for further information on discontinued operations. Deferred Longwall Move Expenses The Company defers the direct costs, including labor and supplies, associated with moving longwall equipment, the related equipment refurbishment costs, costs to drill vent holes and plug existing gas wells in advance of the longwall panel. These deferred costs are amortized on a units-of-production basis into cost of coal sales over the life of the related panel of coal mined by the longwall equipment. The amount of deferred longwall move expenses was $11,852 and $9,822 as of December 31, 2019 and 2018 , respectively, included within prepaid expenses and other current assets and other non-current assets in the Company’s Consolidated Balance Sheets. Advanced Mining Royalties Lease rights to coal reserves are often acquired in exchange for royalty payments. Advance mining royalties are advance payments made to lessors under terms of mineral lease agreements that are recoupable against future production royalties. These advance payments are deferred and charged to operations as the coal reserves are mined. The Company regularly reviews recoverability of advance mining royalties and establishes or adjusts the allowance for advance mining royalties as necessary using the specific identification method. Advance royalty balances are generally charged off against the allowance when they are no longer recoupable. Property, Plant, and Equipment, Net Costs for mine development incurred to expand capacity of operating mines or to develop new mines are capitalized and charged to operations on the units-of-production method over the estimated proven and probable reserve tons directly benefiting from the capital expenditures. Mine development costs include costs incurred for site preparation and development of the mines during the development stage less any incidental revenue generated during the development stage. Mining equipment, buildings and other fixed assets are stated at cost and depreciated on a straight-line basis over estimated useful lives ranging from one to 47 years. Leasehold improvements are amortized using the straight-line method, over the shorter of the estimated useful lives or term of the lease. Major repairs and betterments that significantly extend original useful lives or improve productivity are capitalized and depreciated over the period benefited. Maintenance and repairs are expensed as incurred. When equipment is retired or disposed, the related cost and accumulated depreciation are removed from the respective accounts and any profit or loss on disposal is recognized in other (income) expense in the Company’s Consolidated Statements of Operations. Costs to obtain owned and leased mineral rights are capitalized and amortized to operations as depletion expense using the units-of-production method. Only proven and probable reserves are included in the depletion base. Refer to Note 10 for further detail on property, plant and equipment, net. Owned and Leased Mineral Rights Owned and leased mineral rights, net of accumulated depletion, for the years ended December 31, 2019 and 2018 were $523,141 and $528,232 , respectively, and are reported in assets in the Company’s Consolidated Balance Sheets. These amounts include $36,772 and $47,276 of asset retirement obligation assets, net of accumulated depletion, associated with active mining operations for the years ended December 31, 2019 and 2018 , respectively. Refer to Note 3 for information on owned and leased mineral rights assumed with the Merger. During the year ended December 31, 2019, the Company recorded a long-lived asset impairment which reduced the carrying value of owned and leased mineral rights, net, by $35,445 . Refer to the asset impairment disclosure included in Note 2 . Costs to obtain owned and leased mineral rights are capitalized and amortized to operations as depletion expense using the units-of-production method. Only proven and probable reserves are included in the depletion base. Depletion expense is included in depreciation, depletion and amortization on the accompanying Consolidated Statements of Operations and was $2,140 , $6,804 , and $2,954 for the years ended December 31, 2019 , 2018, and 2017, respectively. Depletion expense for the years ended December 31, 2019 , 2018, and 2017 includes a credit of ( $19,973 ), an expense of $1,907 , and a credit of ($821) , respectively, related to revisions to asset retirement obligations. Refer to Note 17 for further disclosures related to asset retirement obligations. Acquired Intangibles The Company has recognized assets for acquired above market-priced coal supply agreements and acquired mine permits and liabilities for acquired below market-priced coal supply agreements. The coal supply agreements were valued based on the present value of the difference between the expected net contractual cash flows based on the stated contract terms, and the estimated net contractual cash flows derived from applying forward market prices at the Merger or acquisition date for new contracts of similar terms and conditions. The acquired mine permits were valued based on the replacement cost and lost profits method as of the Merger date. The balances and respective balance sheet classifications of such assets and liabilities as of December 31, 2019 and 2018 , net of accumulated amortization, are set forth in the following tables: December 31, 2019 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 917 $ (6,018 ) $ (5,101 ) Acquired mine permits, net 124,228 — 124,228 Total $ 125,145 $ (6,018 ) $ 119,127 December 31, 2018 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 4,687 $ (33,912 ) $ (29,225 ) Acquired mine permits, net 149,897 — 149,897 Total $ 154,584 $ (33,912 ) $ 120,672 (1) Included within other acquired intangibles, net of accumulated amortization, on the Company’s Consolidated Balance Sheets. (2) Included within other non-current liabilities on the Company’s Consolidated Balance Sheets. During the year ended December 31, 2019, the Company recorded a long-lived asset impairment which reduced the carrying value of acquired mine permits, net, by $5,997 . Refer to the asset impairment disclosure included in Note 2 . The acquired mine permits are amortized over the estimated life of the associated mine. The coal supply agreement assets and liabilities are amortized over the actual number of tons shipped over the life of each contract. Amortization of mine permits acquired as a result of the Merger was $23,921 and $3,409 for the years ended December 31, 2019 and 2018, respectively, which is reported within amortization of acquired intangibles, net, in the Consolidated Statements of Operations. Amortization of above-market coal supply agreements was $3,884 , $14,506 , and $59,007 , and amortization of below-market coal supply agreements was ($27,893) , ($23,307) , and $0 , resulting in a net (income) expense of ($24,009) , ($8,801) , and $59,007 for the years ended December 31, 2019 , 2018 , and 2017, respectively, which is reported within amortization of acquired intangibles, net, in the Consolidated Statements of Operations. Future net amortization expense related to acquired intangibles is expected to be as follows: 2020 $ 15,204 2021 12,556 2022 12,584 2023 10,709 2024 8,657 Thereafter 59,417 Total net future amortization expense $ 119,127 Goodwill Goodwill represents the excess of the purchase price over the fair value of the net identifiable tangible and intangible assets of acquired companies. In connection with the Merger, the Company recorded goodwill of $124,353 and allocated it to the CAPP - Met reportable segment. Refer to Note 3 for further information. Goodwill is not amortized; instead, it is tested for impairment annually as of October 31 of each year or more frequently if indicators of impairment exist. The Company performed an interim goodwill impairment test as of August 31, 2019 due to a decline in the Company’s market capitalization to amounts below book value combined with a decline in global metallurgical coal pricing which indicated that the fair value of the CAPP - Met segment reporting unit may have been below its carrying value. Following the quantitative testing, the Company concluded that the fair value of the reporting unit exceeded its carrying value and no amounts of goodwill were impaired. As of October 31, 2019, the Company performed its annual goodwill impairment test and concluded that more likely than not the fair value of its CAPP - Met reporting unit to which the Company’s goodwill is allocated exceeded its carrying value. As a result, no amounts of goodwill were considered impaired as a result of impairment testing at October 31, 2019. However, due to the continued weakening in coal market pricing combined with a significant market price decline for the Company’s stock late in the fourth quarter of 2019, the Company performed an interim goodwill impairment test as of December 31, 2019. Following the quantitative testing, the Company concluded that the carrying value of the CAPP - Met reporting unit exceeded its fair value and recorded a goodwill impairment of $124,353 to write down the full carrying amount of goodwill. The Company early adopted Accounting Standards Update (“ASU”) 2017-04 for the period ended December 31, 2017, which eliminated Step 2 of the quantitative goodwill impairment test. The Company first assesses goodwill for impairment on a qualitative basis. If the Company determines that more likely than not the fair value of a reporting unit containing goodwill exceeds its carrying amount, no further impairment testing is required. If the qualitative assessment indicates that an impairment potentially exists, then the Company quantitatively tests goodwill for impairment by comparing the fair value of the reporting unit to its carrying amount. If the fair value of the reporting unit is lower than its carrying amount, its goodwill is written down by the lesser of the amount by which the reporting units carrying amount exceeded its fair value or its carrying amount of goodwill. The valuation methodology utilized to estimate the fair value of the reporting units is based on both a market and income approach and is within the range of fair values yielded under each approach. The income approach is based on a discounted cash flow methodology in which expected future net cash flows are discounted to present value, using an appropriate after-tax weighted average cost of capital (discount rate). The market approach is based on a guideline company and similar transaction methodology. Under the guideline company approach, certain metrics from a selected group of publicly traded guideline companies that have similar operations to the Company’s reporting units are used to estimate the fair value of the reporting units. Under the similar transactions approach, recent merger and acquisition transactions for companies that have similar operations to the Company’s reporting units are used to estimate the fair value of the Company’s reporting units. Asset Impairment Long-lived assets, such as property, plant, and equipment, and acquired intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset groups may not be recoverable. Recoverability of assets or asset groups to be held and used is measured by a comparison of the carrying amount of an asset or asset group to the estimated undiscounted future cash flows expected to be generated by the asset or asset group. Long-lived assets located in a close geographic area are grouped together for purposes of impairment testing when, after considering revenue and cost interdependencies, circumstances indicate the assets are used together to produce future cash flows. The Company’s asset groups generally consist of the assets and applicable liabilities of one or more mines and preparation plants and associated coal reserves for which cash flows are largely independent of cash flows of other mines, preparation plants, and associated coal reserves. If the carrying amount of an asset or asset group exceeds its estimated future cash flows, the potential impairment is equal to the amount by which the carrying amount of the asset or asset group exceeds the fair value of the asset or asset group. The Company estimates the fair value of an asset group using discounted cash flow analyses utilizing marketplace participant assumptions. The amount of impairment, if any, is allocated to the long-lived assets on a pro-rata basis, except that the carrying value of the individual long-lived assets are not reduced below their estimated fair value. During the year ended December 31, 2019, the Company determined that indicators of impairment were present for three long-lived asset groups within each of its CAPP - Met and CAPP - Thermal reporting segments and performed impairment testing as of December 31, 2019. At December 31, 2019, the Company determined that the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. As a result, after allocating the potential impairment to individual assets, the Company recorded a long-lived asset impairment of $60,169 , of which $9,176 was recorded within CAPP - Met and $50,993 was recorded within CAPP - Thermal. The long-lived asset impairment reduced the carrying values of mineral rights by $35,445 , property, plant, and equipment, net, by $17,056 , acquired mine permits, net, by $5,997 , and long-lived assets related to asset retirement obligations by $1,671 . There were no asset impairments during the years ended December 31, 2018 and 2017. Additionally, during the year ended December 31, 2019, the Company recorded an asset impairment of $6,155 primarily related to the write-off of prepaid purchased coal as a result of Blackjewel’s Chapter 11 bankruptcy filing on July 1, 2019. Refer to Note 4 for further information. Asset Retirement Obligations Minimum standards for mine reclamation have been established by various regulatory agencies and dictate the reclamation requirements at the Company’s operations. The Company’s asset retirement obligations consist principally of costs to reclaim acreage disturbed at surface operations and estimated costs to reclaim support acreage, treat mine water discharge, and perform other related functions at underground mines. The Company records these reclamation obligations at fair value in the period in which the legal obligation associated with the retirement of the long-lived asset is incurred. Changes to the liability at operations that are not currently being reclaimed are offset by increasing or decreasing the carrying amount of the related long-lived asset. Changes to the liability at operations that are currently being reclaimed are recorded to depreciation, depletion, and amortization. Over time, the liability is accreted and any capitalized cost is depreciated or depleted over the useful life of the related asset. To settle the liability, the obligation is paid, and to the extent there is a difference between the liability and the amount of cash paid, a gain or loss upon settlement is recorded. The Company annually reviews its estimated future cash flows for its asset retirement obligations. Refer to Note 17 for further disclosures related to asset retirement obligations. During the year ended December 31, 2019, the Company recorded a long-lived asset impairment which reduced the carrying value of long-lived assets related to asset retirement obligations by $1,671 . Refer to the asset impairment disclosure included in Note 2 . Income Taxes The Company recognizes deferred tax assets and liabilities using enacted tax rates for the effect of temporary differences between the book and tax basis of recorded assets and liabilities. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized. In evaluating its ability to recover deferred tax assets within the jurisdiction in which they arise, the Company considers all available positive and negative evidence, including the expected reversals of taxable temporary differences, projected future taxable income, taxable income available via carryback to prior years, tax planning strategies, and results of recent operations. The Company assesses the realizability of its deferred tax assets, including scheduling the reversal of its deferred tax assets and liabilities, to determine the amount of valuation allowance needed. Scheduling the reversal of deferred tax asset and liability balances requires judgment and estimation. The Company believes that the deferred tax liabilities relied upon as future taxable income in its assessment will reverse in the same period and jurisdiction and are of the same character as the temporary differences giving rise to the deferred tax assets that will be realized. Refer to Note 19 for further disclosures related to income taxes. Revenue Recognition The Company adopted ASC 606 Revenue from Contracts with Customers (“ASC 606”), with a date of initial application of January 1, 2018, using the modified retrospective method. The Company applied the guidance only to contracts that were not completed as of the date of adoption, with no cumulative adjustment to retained earnings as a result of the adoption of this guidance. As a result, the Company made changes to its accounting policy for revenue recognition as outlined below. Subsequent to the adoption of ASC 606, the Company measures revenue based on the consideration specified in a contract with a customer and recognizes revenue as a result of satisfying its promise to transfer goods or services in a contract with a customer using the following general revenue recognition five-step model: (1) identify the contract; (2) identify performance obligations; (3) determine transaction price; (4) allocate transaction price; and (5) recognize revenue. Freight and handling costs paid to third-party carriers and invoiced to coal customers are recorded as freight and handling costs and freight and handling fulfillment revenues within cost of coal sales and coal revenues, respectively. Prior to the adoption of ASC 606, the Company earned revenues primarily through the sale of coal produced at Company operations and coal purchased from third parties. The Company recognized revenue using the following general revenue recognition criteria: (i) persuasive evidence of an arrangement exists; (ii) delivery had occurred or services have been rendered; (iii) the price to the buyer was fixed or determinable; and (iv) collectability was reasonably assured. Delivery on the Company’s coal sales was determined to be complete for revenue recognition purposes when title and risk of loss had passed to the customer in accordance with stated contractual terms and there are no other future obligations related to the shipment. For domestic shipments, title and risk of loss generally passed as the coal is loaded into transport carriers for delivery to the customer. For international shipments, title generally passed at the time coal is loaded onto the shipping vessel. Freight and handling costs paid to third-party carriers and invoiced to coal customers were recorded as freight and handling costs and freight and handling revenues, respectively. Adoption of ASC 606 Subsequent to adoption of ASC 606, freight and handling revenues are now classified within coal revenues. Under ASC 606, the Company has elected to treat all shipping and handling costs as fulfillment costs and to recognize these amounts within coal revenues upon control transfer. Prior to the adoption of ASC 606, all freight and handling activities occurring subsequent to control transfer were accounted for as deferred revenue and recognized within freight and handling revenues as the Company fulfilled the related shipping activity. Refer to Note 5 for further disclosure requirements under the new standard. The following table summarizes the impact of the adoption of ASC 606 to the Company’s Consolidated Statements of Operations: Year Ended December 31, 2018 As reported Adjustments (1) Balances prior to adoption of ASC 606 Revenues: Coal revenues $ 2,020,889 $ (363,128 ) $ 1,657,761 Freight and handling revenues — 362,346 362,346 Other revenues 10,316 — 10,316 Total revenues $ 2,031,205 $ (782 ) $ 2,030,423 Freight and handling costs $ 363,128 $ (782 ) $ 362,346 (1) Adjustments primarily represent freight and handling revenues being treated as fulfillments costs and included within coal revenues under ASC 606. The remainder of these adjustments represent freight and handling activity occurring subsequent to control transfer also impacting freight and handling costs and prepaid expenses. Deferred Financing Costs The costs to obtain new debt financing or amend existing financing agreements are generally deferred and amortized to interest expense over the life of the related indebtedness or credit facility using the effective interest method. Unamortized deferred financing costs are presented in the Consolidated Balance Sheet as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts or premiums. Unamortized deferred financing costs associated with undrawn credit facilities are included in the Consolidated Balance Sheets within other non-current assets. Workers’ Compensation and Pneumoconiosis (Black Lung) Benefits Workers’ Compensation As of December 31, 2019 , the Company’s subsidiaries generally utilize high-deductible insurance programs for workers’ compensation claims at its operations with the exception of certain subsidiaries in which the Company is a qualified self-insurer for workers’ compensation related obligations. The liabilities for workers’ compensation claims are estimates of the ultimate losses incurred based on the Company’s experience, and include a provision for incurred but not reported losses. Adjustments to the probable ultimate liabilities are made annually based on an actuarial study and adjustments to the liability are recorded based on the results of this study. These short-term and long-term obligations are included in the Consolidated Balance Sheets within accrued expenses and other current liabilities and workers’ compensation and black lung obligations, respectively, with an offsetting insurance receivable within prepaid expenses and other current assets and other non-current assets. As of December 31, 2019 and 2018, the workers’ compensation liability was net of a discount of $24,458 and $24,655 , respectively, related to fair value adjustments associated with acquisition accounting. Refer to Note 20 for further disclosures related to workers’ compensation. Black Lung Benefits The Company is required by federal and state statutes to provide benefits to employees for awards related to black lung. As of December 31, 2019 , certain of the Company’s subsidiaries are insured for black lung obligations by a third-party insurance provider and certain subsidiaries are self-insured for state black lung obligations. Certain other subsidiaries are self-insured for federal black lung benefits and may fund benefit payments through Section 501(c)(21) tax-exempt trust fund. Charges are made to operations for black lung claims, as determined by an independent actuary at the present value of the actuarially computed liability for such benefits over the employee’s applicable term of service. The Company recognizes in its balance sheet the amount of the Company’s unfunded Accumulated Benefit Obligation (“ABO”) at the end of the year. Amounts recognized in accumulated other comprehensive income (loss) are adjusted out of accumulated other comprehensive income (loss) when they are subsequently recognized as components of net periodic benefit cost. These short-term and long-term obligations are included in the Consolidated Balance Sheets within accrued expenses and other current liabilities and workers’ compensation and black lung obligations, respectively. Refer to Note 20 for further disclosures related to black lung benefits. Pension The Company is required to recognize the overfunded or underfunded status of a defined benefit pension plan as an asset or liability in its Consolidated Balance Sheets and to recognize changes in that funded status in the year in which the changes occur through other comprehensive (loss) income. The Company is required to measure plan assets and benefit obligations as of the date of the Company’s fiscal year-end Consolidated Balance Sheet and provide the required disclosures as of the end of each fiscal year. Refer to Note 20 for further disclosures related to pension. Life Insurance Benefits As part of the Alpha Restructuring and the Retiree Committee Settlement Agreement, the Company assumed the liability for life insurance benefits for certain disabled and non-union retired employees. Provisions are made for estimated benefits based on annual evaluations prepared by independent actuaries. A

Mergers and Acquisitions

Mergers and Acquisitions	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Mergers and Acquisitions	Mergers and Acquisitions On November 9, 2018, Contura, along with the Alpha Companies, completed the Merger in which the Company acquired 100% of the outstanding Class C-1 shares of ANR and the 100% of the outstanding shares of Holdings. Under the terms of the Merger Agreement, the Alpha Companies stockholders received 0.4417 Contura common shares for each ANR Class C-1 share and each share of common stock of Holdings they owned, representing approximately 48.5% ownership in the merged entity, or an aggregate 9,378,199 shares of Contura common stock. Prior to the closing of the transaction, the Alpha Companies stockholders also received a special cash dividend (the “Dividend”) in an amount equal to $ 2.725 for each Class C-1 share and each share of common stock of Holdings they owned. Each outstanding share of Class C-2 common stock of ANR (held exclusively by Holdings) was canceled. The fair value of the issued Contura common stock was equal to the $75.00 closing price of Contura’s common stock on the day of acquisition. The transaction was entered into to enhance the Company’s competitive position in both domestic and international coal markets. The Company possesses diverse high-quality, metallurgical and thermal coal mines, allowing for near-term organic growth opportunities. The transaction was entered into to generate costs synergies, including those resulting from coal blending and marketing optimization and purchasing, operating, and administrative efficiencies. During 2018, the Company recorded $3,918 as a reduction to equity for costs incurred in connection with the Merger. Purchase Price The following table presents the details of the finalized purchase price of $688,534 : Final Fair value of common stock issued $ 703,365 Issued and redeemed equity awards (1) 32,217 Net balances due to Alpha deemed effectively settled (47,048 ) Purchase Price (2) $ 688,534 (1) Amount includes $20,681 of tax withholdings related to share settlements of option exercises, $1,905 paid to certain former ANR employees pursuant to change in control provisions, $6,570 of shares repurchased from certain former ANR directors pursuant to the Merger Agreement, $3,056 of pre-Merger service period value of restricted stock unit ANR employee awards, and $5 in cash paid in lieu of fractional shares of Contura common stock issued pursuant to the Merger Agreement. Of these amounts, $24,074 were obligations assumed and paid by Contura. (2) Purchase price of $688,534 is composed of equity consideration of $664,460 and cash consideration of $24,074 . Allocation of Purchase Price The finalized purchase price of $688,534 has been allocated to the net tangible and intangible assets of Alpha Companies as follows: Provisional as of December 31, 2018 Adjustments Final Cash and cash equivalents $ 29,939 $ — $ 29,939 Trade and other receivables 60,714 — 60,714 Inventories 85,635 — 85,635 Short-term restricted cash 10,592 — 10,592 Other current assets 38,495 10,087 48,582 Property, plant, and equipment 504,852 (33,930 ) 470,922 Owned and leased mineral rights 516,201 23,571 539,772 Other intangible assets 154,041 4,363 158,404 Long-term restricted cash 182,049 — 182,049 Long-term restricted investments 28,809 — 28,809 Other non-current assets 68,022 (3,353 ) 64,669 Total assets $ 1,679,349 $ 738 $ 1,680,087 Accounts payable 69,049 (2,504 ) 66,545 Accrued expenses and other current liabilities 76,774 2,491 79,265 Long-term debt, including current portion 144,832 3,626 148,458 Acquisition-related obligations 74,346 5,738 80,084 Pension obligations 158,005 3,596 161,601 Asset retirement obligation, including current portion 163,636 12,718 176,354 Deferred income taxes, including current portion 134,924 (8,484 ) 126,440 Other intangible liabilities 57,219 — 57,219 Other non-current liabilities 207,654 12,286 219,940 Total liabilities $ 1,086,439 $ 29,467 $ 1,115,906 Goodwill $ 95,624 $ 28,729 $ 124,353 Allocation of purchase price $ 688,534 $ — $ 688,534 Prior to the finalization of the purchase price allocation, the Company recorded measurement-period adjustments to the provisional opening balance sheet as shown in the table above. Adjustments were made primarily to property, plant, and equipment, owned and leased mineral rights, asset retirement obligations, and certain actuarial liabilities. There were no material measurement-period adjustments impacting current-period earnings that would have been recorded in the previous reporting period if the adjustments to the provisional amounts had been recognized as of the acquisition date. In connection with the Merger, the Company originally recorded provisional goodwill of $95,624 , which represented the excess of the purchase price over the estimated fair value of tangible and intangible assets acquired, net of liabilities assumed. As a result of measurement-period adjustments recorded during the period, the provisional amount of goodwill increased by $28,729 resulting in final goodwill of $124,353 , which was allocated to the Company’s CAPP-Met reportable segment. The goodwill was attributed primarily to the following factors: (i) anticipated operating and administrative synergies, and (ii) deferred income taxes arising from the differences between the preliminary purchase price allocated to the assets and liabilities acquired based on fair value and the tax basis of these assets and liabilities. The goodwill was not deductible for tax purposes. Refer to Note 2 for disclosures related to the goodwill impairment recorded during the quarter ended December 31, 2019. The following table represents the intangible assets and the weighted-average amortization periods as of the acquisition date: Final Weighted-Average Amortization Period Mining permits $ 157,555 12.30 Above-market coal supply agreements 849 1.03 Below-market coal supply agreements (57,219 ) 2.10 Total acquired intangibles: $ 101,185 10.16 The Consolidated Statements of Operations include acquisition related expenses (on a pre-tax basis) of $1,090 and $20,571 in merger-related costs for the years ended December 31, 2019 and 2018 , respectively. Acquisition-related expenses include professional fees related to legal, tax, advisory integration services, and contract-related matters. Total revenues reported in the Consolidated Statements of Operations for the year ending December 31, 2018 included revenues of $149,161 from operations acquired from the Alpha Companies. The amount of earnings from continuing operations acquired from the Alpha Companies included in the consolidated results of operations for the year ending December 31, 2018 is not readily determinable due to various intercompany transactions and allocations that have occurred in connection with the integration of the operations of the newly combined company. The following unaudited pro forma information has been prepared for illustrative purposes only and assumes the Merger occurred on January 1, 2017. The unaudited pro forma results have been prepared based on estimates and assumptions, which the Company believes are reasonable; however, they are not necessarily indicative of the consolidated results of operations had the Merger occurred on January 1, 2017, or of future results of operations. Year Ended December 31, 2018 Year Ended December 31, 2017 Total revenues As reported $ 2,031,205 $ 1,649,969 Pro forma $ 2,630,824 $ 2,309,503 Income from continuing operations As reported $ 302,854 $ 173,735 Pro forma $ 314,735 $ 231,504 These amounts have been calculated after applying the Company's accounting policies and adjusting the results of ANR to reflect the additional depreciation, amortization, depletion, and cost of coal sales that would have been charged assuming the fair value adjustments to property, plant, and equipment, as well as intangibles, asset retirement obligations, and inventory, had been applied at January 1, 2017, together with the consequential tax effects. The pro forma results for the year ended December 31, 2018 include $51,800 of merger-related costs, which includes $20,571 of acquisition-related expenses and $31,229 of expenses related primarily to severance payments and one-time bonus payments, $17,064 of incremental cost of coal sales related to the inventory step-up included in the purchase price allocation, and a tax benefit of $126,440 related to the reduction of the Company's deferred tax asset valuation allowance.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations Discontinued operations consist of ongoing activity related to the Company’s former PRB operations. On December 8, 2017, the Company closed a transaction (“PRB Transaction”) with Blackjewel L.L.C. (“Blackjewel” or the “Buyer”) to sell its Eagle Butte and Belle Ayr mines located in Wyoming (the “Western Mines” or “Western Assets”). The Company was in a post closing mine permit transfer period, when on July 1, 2019, prior to the transfer of the permits, Blackjewel announced that it and certain affiliated entities had filed voluntary petitions for relief under Chapter 11 of the Bankruptcy Code in the United States Bankruptcy Court for the Southern District of West Virginia (the “Bankruptcy Court”). As the mine permit transfer process relating to the Company’s sale of the Western Assets to Blackjewel had not been completed prior to Blackjewel’s filing for Chapter 11 bankruptcy protection, the Company remained the permit holder in good standing for both mines and maintained surety bonding to cover related reclamation and other obligations. On October 4, 2019, the Bankruptcy Court entered an order approving the sale by Blackjewel of the Western Assets to Eagle Specialty Materials (“ESM”), an affiliate of FM Coal, LLC (“FM Coal”). The closing of the ESM acquisition occurred on October 18, 2019 (the “ESM Transaction”). In connection with the ESM Transaction, Contura and ESM finalized an agreement which provided, among other items, for the transfer of the Western Asset permits from Contura to ESM once certain approvals for their transfer have been obtained and for the assumption by ESM of the related reclamation obligations. Additionally, the surety bonding previously maintained by the Company for the benefit of the Wyoming Department of Environmental Quality (“DEQ”) was released and replaced with substitute surety bonds arranged for by ESM. Lastly, ESM agreed to indemnify the Company and its affiliates against all reclamation liabilities related to the Western Assets and against claims by the federal government, the State of Wyoming, or Campbell County, Wyoming for royalties, ad valorem taxes, and other amounts relating to the Western Assets for the period beginning on December 8, 2017. The following table presents the details of the ESM transaction: Year Ended December 31, 2019 Cash $ 90,000 DIP obligation (1) 3,008 Other 331 Total consideration $ 93,339 ARO liabilities transferred (152,882 ) Gain on sale (2) $ (59,543 ) (1) The Company paid certain Blackjewel debtor-in-possession lenders $3,008 of principal and interest pursuant to an existing agreement between the Company and those lenders. Refer to Note 22 . (2) The Company recorded a $59,543 gain within the depreciation, depletion, and amortization within discontinued operations in the Consolidated Statements of Operations during the year ended December 31, 2019 as a result of the reduction of the reclamation obligation partially offset by the consideration paid. Additionally, in connection with the closing of the ESM Transaction, the Company paid $13,500 to Campbell County, Wyoming for accrued ad valorem back taxes for 2018 and was released from all claims related thereto. Pursuant to an agreement with ESM, the State of Wyoming Department of Revenue, and Blackjewel, the State of Wyoming Department of Revenue released the Company from any outstanding claims related to state tax obligations arising from or related to the Western Mines for any period through and including the closing date of the transaction. The major components of net income (loss) from discontinued operations in the Consolidated Statements of Operations are as follows: Year Ended December 31, 2019 2018 2017 Revenues: Total revenues (1) $ 227 $ 1,296 $ 346,621 Costs and expenses: Cost of coal sales (exclusive of items shown separately below) $ — $ — $ 299,005 Depreciation, depletion and amortization (2) $ 86,370 $ — $ 30,090 Accretion on asset retirement obligations (3) $ 5,961 $ — $ 11,341 Asset impairment (4) $ 17,161 $ — $ — Selling, general and administrative expenses (5) $ 3,744 $ 43 $ 773 Other expenses $ 4,742 $ 4,107 $ — Other non-major (income) expense items, net $ (360 ) $ 2,140 $ 5,475 Loss on sale $ — $ — $ 36,831 (1) Total revenues for the years ended December 31, 2019 and 2018 consisted entirely of other revenues. (2) During the year ended December 31, 2019 , $145,913 of the depreciation, depletion and amortization was related to an increase in the Company’s estimate of its asset retirement obligations which was partially offset by ($59,543) as a result of the ESM transaction. Refer to the disclosures above for details. (3) The accretion on asset retirement obligations for the year ended December 31, 2019 was related to the asset retirement obligation as a result of Blackjewel’s bankruptcy filing. Refer to the above disclosures for further details. (4) The asset impairment for the year ended December 31, 2019 is primarily related to the write-off of tax related indemnification receivables from Blackjewel. Refer to the disclosures below for further details. (5) Represents professional and legal fees. Refer to Note 7 for net loss per share information related to discontinued operations. The major components of assets and liabilities that are classified as discontinued operations in the Consolidated Balance Sheets are as follows: December 31, 2019 2018 Assets: Prepaid expenses and other current assets $ — $ 22,475 Liabilities: Trade accounts payable, accrued expenses and other current liabilities $ — $ 21,892 Other non-current liabilities $ — $ 94 As of December 31, 2018 , the residual assets and liabilities related to the discontinued operations were primarily composed of taxes for which Contura was considered to be the primary obligor, but which the Buyer was contractually obligated to pay. The Company had recorded the taxes as a liability with an offsetting receivable from the Buyer. The major components of cash flows related to discontinued operations were as follows: Year Ended December 31, 2019 2018 2017 Depreciation, depletion and amortization $ 86,370 $ — $ 30,090 Capital expenditures $ — $ — $ (10,420 ) Other significant operating non-cash items related to discontinued operations: Accretion on asset retirement obligations $ 5,961 $ — $ 11,341 Asset impairment $ 17,161 $ — $ —

Revenue

Revenue	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Disaggregation of Revenue from Contracts with Customers ASC 606 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 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. The Company earns revenues primarily through the sale of coal produced at Company operations and coal purchased from third parties. The Company extracts, processes and markets met and thermal coal from surface and deep mines for sale to electric utilities, steel and coke producers, and industrial customers. The Company conducts mining operations only in the United States with mines in Northern and Central Appalachia. The Company has three reportable segments: CAPP - Met, CAPP - Thermal, and NAPP. In addition to the three reportable segments, the All Other category includes general corporate overhead and corporate assets and liabilities, the elimination of certain intercompany activity, and the Company’s discontinued operations. Refer to Note 25 for further segment information. The following tables disaggregate the Company’s coal revenues by product category and by market to depict how the nature, amount, timing, and uncertainty of the Company’s coal revenues and cash flows are affected by economic factors: Year Ended December 31, 2019 Met Thermal Total Export coal revenues $ 1,196,816 $ 50,798 $ 1,247,614 Domestic coal revenues 551,806 482,587 1,034,393 Total coal revenues $ 1,748,622 $ 533,385 $ 2,282,007 Year Ended December 31, 2018 Met Thermal Total Export coal revenues $ 1,620,277 $ 51,369 $ 1,671,646 Domestic coal revenues 105,587 — 243,656 349,243 Total coal revenues $ 1,725,864 $ 295,025 $ 2,020,889 Year Ended December 31, 2017 (1) Met Thermal Total Export coal revenues $ 1,253,834 $ 11,486 $ 1,265,320 Domestic coal revenues 91,170 283,393 374,563 Total coal revenues $ 1,345,004 $ 294,879 $ 1,639,883 (1) Includes freight and handling revenues. Performance Obligations The Company considers each individual transfer of coal on a per shipment basis to the customer a performance obligation. The pricing terms of the Company’s contracts with customers include fixed pricing, variable pricing, or a combination of both fixed and variable pricing. All the Company’s revenue derived from contracts with customers is recognized at a point in time. The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied as of December 31, 2019 . 2020 2021 2022 2023 2024 Total Estimated coal revenues (1) $ 391,469 $ 264,690 $ 190,644 $ 130,268 $ 46,000 $ 1,023,071 (1) Amounts only include estimated coal revenues associated with contracts with customers with fixed pricing with original expected duration of more than one year. The Company has elected not to disclose the aggregate amount of the transaction price allocated to the performance obligations that are unsatisfied (or partially unsatisfied) as of the end of the reporting period for performance obligations with either of the following conditions: 1) the remaining performance obligation is part of a contract that has an original expected duration of one year or less; or 2) the remaining performance obligation has variable consideration that is allocated entirely to a wholly unsatisfied performance obligation.

Accumulated Other Comprehensive

Accumulated Other Comprehensive (Loss) Income	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income The following tables summarize the changes to accumulated other comprehensive (loss) income during the years ended December 31, 2019 , 2018 and 2017 : Balance Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance Employee benefit costs $ (23,130 ) $ (42,891 ) $ 7,405 $ (58,616 ) Balance Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance December 31, 2018 Employee benefit costs $ (1,948 ) $ (21,323 ) $ 141 $ (23,130 ) Balance January 1, 2017 Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance December 31, 2017 Employee benefit costs $ 2,087 $ (3,832 ) $ (203 ) $ (1,948 ) The following table summarizes the amounts reclassified from accumulated other comprehensive (loss) income and the Statements of Operations line items affected by the reclassification during the years ended December 31, 2019 , 2018 and 2017 : Details about accumulated other comprehensive (loss) income components Amounts reclassified from accumulated other comprehensive (loss) income Affected line item in the Statements of Operations Year Ended December 31, 2019 2018 2017 Employee benefit costs: Amortization of actuarial (gain) loss $ 959 $ 155 $ (203 ) (1) Miscellaneous (loss) income, net Settlement 6,446 — — (1) Miscellaneous (loss) income, net Total before income tax $ 7,405 $ 155 $ (203 ) Income tax expense — (14 ) — Income tax benefit Total, net of income tax $ 7,405 $ 141 $ (203 ) (1) These accumulated other comprehensive (loss) income components are included in the computation of net periodic benefit costs for certain employee benefit plans. Refer to Note 20 .

Net (Loss) Income per Share

Net (Loss) Income per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Net (Loss) Income per Share	Net (Loss) Income per Share The number of shares used to calculate basic net (loss) income per common share is based on the weighted average number of the Company’s outstanding common shares during the respective period. The number of shares used to calculate diluted net (loss) income per common share is based on the number of common shares used to calculate basic net (loss) income per share plus the dilutive effect of stock options and other stock-based instruments held by the Company’s employees and directors during the period, and the Company’s outstanding Series A warrants. The warrants become dilutive for net (loss) income per common share calculations when the market price of the Company’s common stock exceeds the exercise price. For the year ended December 31, 2018 , 129,520 stock options were excluded from the computation of dilutive (loss) earnings per share because they would have been anti-dilutive. For the year ended December 31, 2017 , 129,520 stock options and 108,657 other stock-based instruments were excluded from the computation of dilutive earnings (loss) per share because they would have been anti-dilutive. These potential shares could dilute net (loss) income per share in the future. In periods of net loss, the number of shares used to calculate diluted earnings per share is the same as basic earnings per share. The following table presents the net (loss) income per common share for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Net (loss) income (Loss) income from continuing operations $ (203,142 ) $ 302,854 $ 173,735 Loss from discontinued operations (113,177 ) (3,689 ) (19,213 ) Net (loss) income $ (316,319 ) $ 299,165 $ 154,522 Basic Weighted average common shares outstanding - basic 18,808,460 10,967,014 10,216,464 Basic (loss) income per common share: (Loss) income from continuing operations $ (10.80 ) $ 27.61 $ 17.01 Loss from discontinued operations (6.02 ) (0.33 ) (1.89 ) Net (loss) income $ (16.82 ) $ 27.28 $ 15.12 Diluted Weighted average common shares outstanding - basic 18,808,460 10,967,014 10,216,464 Diluted effect of warrants — 280,969 170,178 Diluted effect of stock options — 262,714 274,456 Diluted effect of restricted stock units and restricted stock — 201,956 108,907 Weighted average common shares outstanding - diluted 18,808,460 11,712,653 10,770,005 Diluted (loss) income per common share: (Loss) income from continuing operations $ (10.80 ) $ 25.86 $ 16.13 Loss from discontinued operations (6.02 ) (0.32 ) (1.78 ) Net (loss) income $ (16.82 ) $ 25.54 $ 14.35

Inventories, net

Inventories, net	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories, net	Inventories, net Inventories, net consisted of the following: December 31, 2019 2018 Raw coal $ 30,274 $ 33,607 Saleable coal 105,092 63,767 Materials, supplies and other, net 27,293 24,591 Total inventories, net $ 162,659 $ 121,965

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expense and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following: December 31, 2019 2018 Prepaid freight $ 8,268 $ 9,839 Deferred longwall move expenses 7,624 9,308 Notes and other receivables 8,931 16,116 Short-term restricted cash 12,363 16,474 Short-term deposits 689 16,181 Prepaid insurance 9,591 8,162 Refundable income taxes 33,915 74,536 Prepaid bond premium 5,471 2,849 Other prepaid expenses 4,509 5,480 Total prepaid expenses and other current assets $ 91,361 $ 158,945

Property, Plant, and Equipment,

Property, Plant, and Equipment, Net	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment, Net	Property, Plant, and Equipment, net Property, plant, and equipment, net, consisted of the following: December 31, 2019 2018 Plant and mining equipment $ 740,009 $ 695,756 Mine development 84,332 47,550 Land 39,925 38,810 Office equipment, software and other 1,582 1,169 Construction in progress 31,690 23,471 Total property, equipment and mine development costs 897,538 806,756 Less accumulated depreciation, depletion and amortization 314,276 106,766 Total property, plant, and equipment, net $ 583,262 $ 699,990 Included in plant and mining equipment are assets under financing leases totaling $14,368 and $20,888 with accumulated depreciation of $4,650 and $1,162 as of December 31, 2019 and December 31, 2018 , respectively. Depreciation and amortization expense associated with property, plant, equipment, and non-mineral asset retirement obligation assets, net, was $226,652 , $70,745 , and $31,956 for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Depreciation expense for the years ended December 31, 2019 , 2018 , and 2017 includes a credit of $(1,522) , an expense of $233 and a credit of ($898) , respectively, related to revisions to asset retirement obligations. Refer to Note 17 for further disclosures related to asset retirement obligations. During the year ended December 31, 2019, the Company recorded a long-lived asset impairment which reduced the carrying value of property, plant, and equipment, net, by $17,056 . Refer to the asset impairment disclosure included in Note 2 for further information. As of December 31, 2019 , the Company had commitments to purchase approximately $19,283 and $279 of new equipment, expected to be acquired at various dates in 2020 and 2022, respectively.

Other Non-Current Assets

Other Non-Current Assets	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Non-Current Assets	Other Non-Current Assets Other non-current assets consisted of the following: December 31, 2019 2018 Operating lease right-of-use assets $ 8,678 $ — Long-term deposits 10,034 9,211 Long-term restricted investments 21,886 29,137 Equity method investments 18,413 15,236 Federal income tax receivable 64,160 43,770 Workers' compensation receivables 58,498 67,776 Other 22,538 18,545 Total other non-current assets $ 204,207 $ 183,675

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases Subsequent to the adoption of ASC 842, the Company recognizes right of use assets and lease liabilities on the balance sheet for all leases with a term longer than 12 months. The discount rates used to determine the present value of the lease assets and liabilities are based on the Company’s incremental borrowing rate at the lease commencement date and commensurate with the remaining lease term. As the rates implicit in most of the Company’s leases are not readily determinable, the Company uses a collateralized incremental borrowing rate based on the information available at the lease commencement date in determining the present value of future payments. The Company uses the portfolio approach and group leases by short-term and long-term categories, applying the corresponding incremental borrowing rates to these categories of leases. For leases with a term of 12 months or less, no right of use assets or liabilities are recognized on the balance sheet and the Company recognizes the lease expense on a straight-line basis over the lease term. Additionally, the Company recognizes variable lease payments as an expense in the period incurred. The Company’s lease population consists primarily of vehicle and heavy equipment leases and leases for office equipment. The Company’s building and land leases relate to corporate office space and certain site offices. The Company determines whether a contract contains a lease based on whether the Company obtains the right to control the use of specifically identifiable property, plant, and equipment for a period of time in exchange for consideration. For the year ended December 31, 2019 , the Company identified no instances requiring significant judgment in determining whether any contracts entered into during the period were or were not leases. Additionally, the Company had no material sublease agreements within the scope of ASC 842 or lease agreements for which the Company was the lessor for the year ended December 31, 2019 . Renewal options in the Company’s lease population primarily relate to month-to-month extensions on vehicle leases and are immaterial both individually and in the aggregate. The Company includes renewal options that are reasonably certain to be exercised in the measurement of lease liabilities. As of December 31, 2019 , the Company does not intend to exercise any termination options on existing leases. As of December 31, 2019 , the Company had the following right-of-use assets and lease liabilities within the Company’s Consolidated Balance Sheets: December 31, 2019 Assets Balance Sheet Classification Financing lease assets Property, plant, and equipment, net $ 9,718 Operating lease right-of-use assets Other non-current assets 8,678 Total lease assets $ 18,396 Liabilities Balance Sheet Classification Financing lease liabilities - current Current portion of long-term debt $ 3,275 Operating lease liabilities - current Accrued expenses and other current liabilities 1,813 Financing lease liabilities - long-term Long-term debt 4,674 Operating lease liabilities - long-term Other non-current liabilities 6,866 Total lease liabilities $ 16,628 Total lease costs and other lease information for the year ended December 31, 2019 included the following: Year Ended December 31, 2019 Lease cost (1) Financing lease cost: Amortization of leased assets $ 3,747 Interest on lease liabilities 480 Operating lease cost 2,771 Short-term lease cost 2,300 Total lease cost $ 9,298 (1) The Company had no variable lease costs or sublease income for the year ended December 31, 2019 . Year Ended December 31, 2019 Other information Cash paid for amounts included in the measurement of lease liabilities $ 9,191 Operating cash flows from financing leases 466 Operating cash flows from operating leases 5,071 Financing cash flows from financing leases 3,654 Right-of-use assets obtained in exchange for new financing lease liabilities 1,459 Lease Term and Discount Rate Weighted-average remaining lease term in months - financing leases 33.7 Weighted-average remaining lease term in months - operating leases 96.3 Weighted-average discount rate - financing leases 5.4 % Weighted-average discount rate - operating leases 11.2 % The Company has elected to show net instead of gross amounts for right-of-use assets and liabilities within its Consolidated Statements of Cash Flows. The following table summarizes the maturity of the Company’s lease liabilities on an undiscounted cash flow basis and a reconciliation to the lease liabilities recognized in the Company’s Consolidated Balance Sheet as of December 31, 2019 : Financing Leases Operating Leases Lease cost 2020 $ 3,729 $ 2,378 2021 2,985 1,957 2022 1,729 1,665 2023 184 1,193 2024 — 1,079 Thereafter — 5,203 Total future minimum lease payments $ 8,627 $ 13,475 Imputed interest (678 ) (4,796 ) Present value of future minimum lease payments $ 7,949 $ 8,679 As of December 31, 2019 , the Company had no leases with future commencement dates that will create significant rights or obligations for the Company.
Leases	Leases Subsequent to the adoption of ASC 842, the Company recognizes right of use assets and lease liabilities on the balance sheet for all leases with a term longer than 12 months. The discount rates used to determine the present value of the lease assets and liabilities are based on the Company’s incremental borrowing rate at the lease commencement date and commensurate with the remaining lease term. As the rates implicit in most of the Company’s leases are not readily determinable, the Company uses a collateralized incremental borrowing rate based on the information available at the lease commencement date in determining the present value of future payments. The Company uses the portfolio approach and group leases by short-term and long-term categories, applying the corresponding incremental borrowing rates to these categories of leases. For leases with a term of 12 months or less, no right of use assets or liabilities are recognized on the balance sheet and the Company recognizes the lease expense on a straight-line basis over the lease term. Additionally, the Company recognizes variable lease payments as an expense in the period incurred. The Company’s lease population consists primarily of vehicle and heavy equipment leases and leases for office equipment. The Company’s building and land leases relate to corporate office space and certain site offices. The Company determines whether a contract contains a lease based on whether the Company obtains the right to control the use of specifically identifiable property, plant, and equipment for a period of time in exchange for consideration. For the year ended December 31, 2019 , the Company identified no instances requiring significant judgment in determining whether any contracts entered into during the period were or were not leases. Additionally, the Company had no material sublease agreements within the scope of ASC 842 or lease agreements for which the Company was the lessor for the year ended December 31, 2019 . Renewal options in the Company’s lease population primarily relate to month-to-month extensions on vehicle leases and are immaterial both individually and in the aggregate. The Company includes renewal options that are reasonably certain to be exercised in the measurement of lease liabilities. As of December 31, 2019 , the Company does not intend to exercise any termination options on existing leases. As of December 31, 2019 , the Company had the following right-of-use assets and lease liabilities within the Company’s Consolidated Balance Sheets: December 31, 2019 Assets Balance Sheet Classification Financing lease assets Property, plant, and equipment, net $ 9,718 Operating lease right-of-use assets Other non-current assets 8,678 Total lease assets $ 18,396 Liabilities Balance Sheet Classification Financing lease liabilities - current Current portion of long-term debt $ 3,275 Operating lease liabilities - current Accrued expenses and other current liabilities 1,813 Financing lease liabilities - long-term Long-term debt 4,674 Operating lease liabilities - long-term Other non-current liabilities 6,866 Total lease liabilities $ 16,628 Total lease costs and other lease information for the year ended December 31, 2019 included the following: Year Ended December 31, 2019 Lease cost (1) Financing lease cost: Amortization of leased assets $ 3,747 Interest on lease liabilities 480 Operating lease cost 2,771 Short-term lease cost 2,300 Total lease cost $ 9,298 (1) The Company had no variable lease costs or sublease income for the year ended December 31, 2019 . Year Ended December 31, 2019 Other information Cash paid for amounts included in the measurement of lease liabilities $ 9,191 Operating cash flows from financing leases 466 Operating cash flows from operating leases 5,071 Financing cash flows from financing leases 3,654 Right-of-use assets obtained in exchange for new financing lease liabilities 1,459 Lease Term and Discount Rate Weighted-average remaining lease term in months - financing leases 33.7 Weighted-average remaining lease term in months - operating leases 96.3 Weighted-average discount rate - financing leases 5.4 % Weighted-average discount rate - operating leases 11.2 % The Company has elected to show net instead of gross amounts for right-of-use assets and liabilities within its Consolidated Statements of Cash Flows. The following table summarizes the maturity of the Company’s lease liabilities on an undiscounted cash flow basis and a reconciliation to the lease liabilities recognized in the Company’s Consolidated Balance Sheet as of December 31, 2019 : Financing Leases Operating Leases Lease cost 2020 $ 3,729 $ 2,378 2021 2,985 1,957 2022 1,729 1,665 2023 184 1,193 2024 — 1,079 Thereafter — 5,203 Total future minimum lease payments $ 8,627 $ 13,475 Imputed interest (678 ) (4,796 ) Present value of future minimum lease payments $ 7,949 $ 8,679 As of December 31, 2019 , the Company had no leases with future commencement dates that will create significant rights or obligations for the Company.

Stock Repurchases and Dividend

Stock Repurchases and Dividend	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stock Repurchase and Dividend	Stock Repurchases and Dividend 2019 Capital Return Program In May 2019, the Company’s Board of Directors adopted a capital return program that permits the Company to return to stockholders up to an aggregate amount of $250,000 of capital. The capital return program does not have a fixed expiration date, and returns of capital may take the form of share repurchases, dividends or a combination thereof. Any share repurchases may be made from time to time through open market transactions, block trades, privately negotiated transactions, tender offers, or otherwise. Any returns of capital under the program will be at the discretion of the Company’s Board of Directors and are subject to market and business conditions, levels of available liquidity, the Company’s cash needs, restrictions under agreements or obligations, legal or regulatory requirements or restrictions, and other relevant factors. On August 29, 2019, the Company announced that its Board of Directors had approved a stock repurchase plan (the “Company Repurchase Plan”) to acquire up to $100,000 in the aggregate of the Company’s common stock at prices as set forth in such plan over a specified period. Through September 30, 2019, the Company had repurchased an aggregate of 529,303 shares of common stock under the Company Repurchase Plan for an aggregate purchase price of $15,969 (comprised of $15,953 of share repurchases and $16 of related fees) for an average price paid for share of $30.17 . On October 1, 2019, the Company suspended the Company Repurchase Plan. Additionally, on September 12, 2019, the Company entered into a common stock repurchase agreement with Whitebox Multi-Strategy Partners, L.P., Whitebox Asymmetric Partners, L.P., Whitebox Credit Partners, L.P. and Whitebox Institutional Partners, L.P. (“Whitebox”). Pursuant to terms of the common stock repurchase agreement, the Company repurchased an aggregate of 500,000 shares of common stock from Whitebox at $32.99 per share for an aggregate purchase price of $16,495 . 2018 Stock Repurchase Plan The Company entered into the Amended and Restated Credit Agreement and the Amended and Restated Asset-Based Revolving Credit Agreement on November 9, 2018. These agreements, among other things, permitted an aggregate amount of $15,000 of cash to be used for the repurchase of its common stock in any twelve-month period after the closing date of the agreement, subject to certain terms and conditions. On December 6, 2018, the Company announced that its Board of Directors had approved a stock repurchase plan (the “Company Repurchase Plan”) to acquire up to $15,000 in the aggregate of the company’s common stock. As of December 31, 2018, the Company had repurchased an aggregate of 223,218 shares under the plan for an aggregate purchase price of approximately $15,007 (comprised of $15,000 of share repurchases and $7 of related fees). 2017 Dividend and Tender Offer The Company entered into the First Amendment to the Asset-Based Revolving Credit Agreement on June 9, 2017 and the First Amendment to the Term Loan Credit Agreement on June 13, 2017. The amendments, among other things, permitted an aggregate amount of $150,000 of cash to be used for the (i) payment of a one-time cash dividend on its common stock no later than July 28, 2017, and (ii) repurchase of its common stock at any time no later than December 31, 2017, subject to certain terms and conditions. On June 16, 2017, the Company declared a special cash distribution of approximately $92,786 in the aggregate (the “Special Dividend”), payable to eligible holders of record of its common stock as of the close of business on July 5, 2017. In addition, pursuant to the terms of the Company’s management incentive plan, dividend equivalent payments of approximately $7,949 in the aggregate (including the amounts payable with respect to each share underlying outstanding stock option awards and restricted stock unit awards and outstanding restricted stock awards under the Management Incentive Plan (the “MIP”)) were paid to plan participants. The dividend equivalent payments were made on July 11, 2017, and the Special Dividend was paid on July 12, 2017. Pursuant to terms of the debt amendments, the Company made an offer to all Term Loan Credit Facility lenders under the Credit Agreement dated March 17, 2017, as amended, to repay the loans at par concurrently with the payment of the Special Dividend, in an aggregate principal amount equal to $10,000 . All the Term Loan Facility lenders under the Credit Agreement dated March 17, 2017, as amended, accepted the offer, and the Company repaid $10,000 on July 13, 2017. On September 15, 2017, the Company repurchased 309,310 shares of its common stock issued pursuant to awards under the MIP for a total purchase amount of $17,445 , or $56.40 per share. On September 26, 2017, the Company announced that it had commenced a modified “Dutch Auction” tender offer to repurchase up to $31,800 of common stock. On December 21, 2017, Contura repurchased an aggregate of 530,000 shares of common stock at a purchase price of $60.00 per share. The total repurchase price of $32,595 (comprised of $31,800 of share repurchases and $795 of related fees) was recorded in the fourth quarter of 2017 as treasury stock in the Consolidated Balance Sheet. Upon completion of the tender offer, provisions within the Company’s Term Loan Credit Facility under the Credit Agreement dated March 17, 2017, as amended, and the Asset-Based Revolving Credit Agreement dated April 3, 2017, as amended, limited the ability of the Company to make future repurchases of its common stock.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: December 31, 2019 2018 Operating lease liabilities $ 1,813 $ — Wages and benefits 45,577 51,026 Workers’ compensation 15,695 16,676 Black lung 7,472 8,133 Taxes other than income taxes 24,946 24,140 Current portion of asset retirement obligations 40,574 24,754 Freight accrual 5,851 10,785 Other 12,354 13,185 Total accrued expenses and other current liabilities $ 154,282 $ 148,699

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: December 31, 2019 2018 Term Loan Credit Facility - due November 2025 $ — $ 550,000 Term Loan Credit Facility - due June 2024 558,991 — LCC Note Payable 45,000 62,500 LCC Water Treatment Obligation 9,375 11,875 Other 9,295 8,395 Debt discount and issuance costs (29,695 ) (44,758 ) Total long-term debt 592,966 588,012 Less current portion (28,485 ) (42,743 ) Long-term debt, net of current portion $ 564,481 $ 545,269 Term Loan Credit Facility - due June 2024 On June 14, 2019, the Company entered into a Credit Agreement with Cantor Fitzgerald Securities, as administrative agent and collateral agent, and the other lenders party thereto (as defined therein) that provides for a senior secured term loan facility in the aggregate principal amount of $561,800 with a maturity date of June 14, 2024 (the “Term Loan Credit Facility”). Principal repayments equal to approximately $1,405 are due each March, June, September and December (commencing with September 30, 2019) with the final principal repayment installment repaid on the maturity date and in an amount equal to the aggregate principal amount outstanding on such date. The Term Loan Credit Facility bears an interest rate per annum based on the character of the loan (defined as either “Base Rate Loan” or “Eurocurrency Rate Loan”) plus an applicable rate of 6.00% for Base Rate Loans and 7.00% for Eurocurrency Rate Loans on or prior to the second anniversary of the Closing Date and 7.00% or 8.00% thereafter (the “Applicable Rate”). Interest accrued on each Base Rate Loan is payable in arrears on the last business day of each March, June, September and December and the maturity date. Interest accrued on each Eurocurrency Rate Loan is payable in arrears on the last day of each interest period as defined therein. As of December 31, 2019 , the interest rate on borrowings made under the Term Loan Credit Facility was 9.00% , calculated as the eurocurrency rate during the period plus 7.00% . As of December 31, 2019 , the carrying value of the Term Loan Credit Facility was $538,765 with $5,618 classified as current within the Consolidated Balance Sheets. The Term Loan Credit Facility was provided primarily by certain of the Company’s existing shareholders (related parties) as of the agreement date. As such, the Company analyzed various factors of the transaction and concluded the Term Loan Credit Facility was issued at a reasonable market rate and therefore considered to be an arm’s length transaction. The Company used the proceeds from the Term Loan Credit Facility to repay the outstanding principal balance of $543,125 under the Amended and Restated Credit Agreement dated November 9, 2018 and fees related to such refinancing. The Company recorded a loss on modification of debt of $255 , primarily related to modification fees paid under the refinance, and a loss on extinguishment of debt of $26,204 , primarily related to the write-off of outstanding debt discounts and unamortized debt issuance costs under the Amended and Restated Credit Agreement dated November 9, 2018, which are recorded in loss on modification and extinguishment of debt within the Consolidated Statements of Operations. All obligations under the Term Loan Credit Facility are substantially guaranteed by the Company’s existing wholly owned domestic subsidiaries, and are required to be guaranteed by the Company’s future wholly-owned domestic subsidiaries. Certain obligations under the Term Loan Facility are secured by a senior lien, subject to certain exceptions (including the ABL Priority Collateral described below), by substantially all of the Company’s assets and the assets of the Company’s subsidiary guarantors (“Term Loan Priority Collateral”), in each case subject to exceptions. The obligations under the Term Loan Credit Facility are also secured by a junior lien, again subject to certain exceptions, against the ABL Priority Collateral. The Term Loan Facility contains negative and affirmative covenants including certain financial covenants that are more flexible than the covenants on the Amended and Restated Credit Agreement dated November 9, 2018. The Company was in compliance with all covenants under this agreement as of December 31, 2019 . Term Loan Credit Facility - due November 2025 On November 9, 2018, the Company entered into an Amended and Restated Credit Agreement with Jefferies Finance LLC, as administrative agent and collateral agent, and the other lenders party thereto (as defined therein) (the “Amended and Restated Credit Agreement”) that provided for a senior secured term loan facility in the aggregate amount of $550,000 with a maturity date of November 9, 2025 (the “Old Term Loan Credit Facility”). Principal repayments equal to $6,875 were due each March, June, September and December (commencing with March 31, 2019) with the final principal repayment installment repaid on the maturity date and in any event would be in an amount equal to the aggregate principal amount outstanding as of such date. The Old Term Loan Credit Facility incurred an interest rate per annum based on the character of the loan (defined as either “Base Rate Loan” or “Eurocurrency Rate Loan”) plus an applicable rate of 4.00% to 5.00% depending on loan type (the “Applicable Rate”), payable bi-monthly in arrears. As of December 31, 2018, the Old Term Loan Credit Facility was classified as a Eurocurrency Rate Loan with an interest rate of 7.39% , calculated as the eurocurrency rate during the period plus an applicable rate of 5.00% . As of December 31, 2018, the carrying value of the Old Term Loan Credit Facility was $521,667 , with $20,625 classified as current, within the Consolidated Balance Sheet. On June 14, 2019, the Company used the proceeds from the Term Loan Credit Facility to repay the outstanding principal of the Old Term Loan Credit Facility. In connection with entering into the Amended and Restated Credit Agreement, the Company repaid the outstanding principal balance of $380,667 under the credit agreement dated March 17, 2017 and the outstanding principal balance of $82,811 under the term loan agreement dated October 23, 2017 between ANR and Cantor Fitzgerald Securities (the “Alpha Term Loan”). In connection with the Amended and Restated Credit Agreement, the Company recorded a loss on modification of debt of $9,370 , primarily related to modification fees paid under the refinance, and a loss on extinguishment of debt of $2,591 , primarily related to a prepayment premium on the Alpha Term Loan and the write-off of outstanding debt discounts under the Credit Agreement dated March 17, 2017, which are recorded in loss on modification and extinguishment of debt within the Consolidated Statements of Operations. In connection with entering into the Credit Agreement dated March 17, 2017, the Company paid all of its $300,000 outstanding 10.00% Senior Secured First Lien Notes due 2021, the $42,500 outstanding Term Facility due 2020, the $8,500 outstanding Closing Tranche Term Loan due 2018, and the $5,500 outstanding GUC Distribution Note due 2018. For the year ended December 31, 2017, the Company recorded a loss on early extinguishment of debt of $38,701 , primarily related to a prepayment premium on the 10.00% Senior Secured First Lien Notes and the write-off of outstanding debt discounts on the 10.00% Senior Secured First Lien Notes and GUC Distribution Note. Amended and Restated Asset-Based Revolving Credit Agreement On November 9, 2018, the Company entered into the Amended and Restated Asset-Based Revolving Credit Agreement with Citibank N.A. as administrative agent, collateral agent, and swingline lender and the other lenders party thereto (the “Lenders”), and Citibank N.A., Barclays Bank PLC, BMO Harris Bank N.A. and Credit Suisse AG as letter of credit issuers (“LC Lenders”). The Amended and Restated Asset-Based Revolving Credit Agreement amended and restated the Asset-Based Revolving Credit Agreement dated April 3, 2017, in its entirety, and includes a senior secured asset-based revolving credit facility (the “ABL Facility”). Under the ABL Facility, the Company may borrow cash from the Lender or cause the LC Lenders to issue letters of credit, on a revolving basis, in an aggregate amount of up to $225,000 , of which no more than $200,000 may be drawn through letters of credit. Any borrowings under the ABL Facility will have a maturity date of April 3, 2022 and will bear interest based on the character of the loan (defined as either “Base Rate Loan” or “Eurocurrency Rate Loan”) plus an applicable rate ranging from 1.00% to 1.50% for Base Rate Loans and 2.00% to 2.50% for Eurocurrency Rate Loans, depending on the amount of credit available. Any letters of credit issued under the ABL Facility will bear a commitment fee rate ranging from 0.25% to 0.375% depending on the amount of availability per terms of the agreement, and a 0.25% fronting fee payable to the ABL Facility’s administrative agent. The Amended and Restated Asset-Based Revolving Credit Agreement provides that a specified percentage of billed, unbilled and approved foreign receivables and raw and clean inventory meeting certain criteria are eligible to be counted for purposes of collateralizing the amount of financing available, subject to certain terms and conditions. The Company recorded a loss on early extinguishment of debt of $81 related to the write-off of unamortized issuance costs on the Old ABL Facility, which is recorded in loss on modification and extinguishment of debt within the Consolidated Statements of Operations. As of December 31, 2019 and 2018 , the Company had no borrowings and $99,876 and $28,700 letters of credit outstanding under the ABL Facility, respectively. The Amended and Restated Asset-Based Revolving Credit Agreement, as amended, and related documents contain negative and affirmative covenants including certain financial covenants. The Company was in compliance with all covenants under these agreements as of December 31, 2019 . The ABL Credit Facility is guaranteed by substantially all of Contura’s direct and indirect subsidiaries (together with Contura, the “Loan Parties”) and secured by all or substantially all assets of the Loan Parties, including equity in its direct domestic subsidiaries and first-tier foreign subsidiaries, as collateral for the obligations under the New ABL Credit Facility. The New ABL Credit Facility has a first lien on ABL priority collateral and a second lien on term loan priority collateral. The Company entered into the First Amendment to the Asset-Based Revolving Credit Agreement on June 9, 2017. The amendment, among other things, permitted an aggregate amount of $150,000 of cash to be used for the (i) payment of a one-time cash dividend on its common stock no later than July 28, 2017, and (ii) repurchase of its common stock at any time no later than December 31, 2017, subject to certain terms and conditions. On April 3, 2017, the Company entered into an Asset-Based Revolving Credit Agreement with Citibank N.A. as administrative agent, collateral agent, and swingline lender and the other lenders party thereto (the “Old Lenders”), and Citibank N.A., BMO Harris Bank N.A. and Credit Suisse AG as letter of credit issuers (“Old LC Lenders”). The Asset-Based Revolving Credit Agreement included a senior secured asset-based revolving credit facility (the “Old ABL Facility”). Under the Old ABL Facility, the Company could borrow cash from the Old Lender or cause the Old LC Lenders to issue letters of credit, on a revolving basis, in an aggregate amount of up to $125,000 , of which no more than $80,000 could be drawn through letters of credit. Any borrowings under the Old ABL Facility had a maturity date of April 4, 2022 and incurred interest based on the character of the loan (defined as either “Base Rate Loan” or “Eurocurrency Rate Loan”) plus an applicable rate ranging from 1.00% to 1.50% for Base Rate Loans and 2.00% to 2.50% for Eurocurrency Rate Loans, depending on the amount of credit that was available. Any letters of credit issued under the Old ABL Facility incurred a commitment fee rate ranging from 0.25% to 0.375% depending on the amount of availability per terms of the agreement, and a 0.25% fronting fee that was payable to the Old ABL Facility’s administrative agent. The Asset-Based Revolving Credit Agreement provided that a specified percentage of billed, unbilled and approved foreign receivables and raw and clean inventory meeting certain criteria were eligible to be counted for purposes of collateralizing the amount of financing available, subject to certain terms and conditions. As of December 31, 2017, the Company had no borrowings and $11,300 in letters of credit outstanding under the Old ABL Facility. LCC Note Payable As a result of the Merger, the Company assumed a note payable to Lexington Coal Company (“LCC”) in the aggregate amount of $62,500 (the “LCC Note Payable”) and with a maturity date of July 26, 2022. The LCC Note Payable has no stated interest rate and an imputed interest rate of 12.45% . Principal repayments equal to $17,500 are due each July during 2019, 2020 and 2021, with the final principal payment of $10,000 due on the maturity date. The carrying value of the LCC Note Payable was $37,695 and $49,361 , with $17,500 and $17,500 reported within the current portion of long-term debt as of December 31, 2019 and 2018 , respectively. LCC Water Treatment Stipulation As a result of the Merger, the Company assumed an obligation to contribute $12,500 into Lexington Coal Company’s water treatment restricted cash accounts (the “LCC Water Treatment Stipulation”). Contributions equal to $625 are due each January, April, July and October from 2019 through 2023. The LCC Water Treatment Stipulation has no stated interest rate and an imputed interest rate of 13.12% . The carrying value of the LCC Water Treatment Stipulation was $7,211 and $8,589 , with $1,875 and $1,875 reported within the current portion of long-term debt as of December 31, 2019 and 2018 , respectively. Financing Leases The Company entered into financing leases for certain property and other equipment during 2019 and 2018 . The Company’s liability for financing leases was $7,949 and $6,423 , with $3,275 and $2,110 reported within the current portion of long-term debt as of December 31, 2019 and 2018 , respectively. Financing leases are included in the other line item in the table above. Refer to Note 12 for additional information on leases. Future Maturities Future maturities of long-term debt as of December 31, 2019 are as follows: 2020 $ 28,485 2021 29,036 2022 20,324 2023 8,297 2024 536,519 Total long-term debt $ 622,661

Acquisition-Related Obligations

Acquisition-Related Obligations	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Acquisition-Related Obligations	Acquisition-Related Obligations Acquisition-related obligations consisted of the following: December 31, 2019 2018 Contingent Revenue Obligation $ 52,427 $ 59,880 Environmental Settlement Obligations 16,305 19,306 Reclamation Funding Liability 12,000 22,000 Retiree Committee VEBA Funding Settlement Liability — 3,500 UMWA Funds Settlement Liability 4,000 6,000 Discount (4,834 ) (10,356 ) Total acquisition-related obligations 79,898 100,330 Less current portion (33,639 ) (27,334 ) Acquisition-related obligations, net of current portion $ 46,259 $ 72,996 The Company entered into various settlement agreements with Alpha and/or the Alpha bankruptcy successor ANR and third parties as part of the Alpha bankruptcy reorganization process. The Company assumed acquisition-related obligations through those settlement agreements which became effective on July 26, 2016, the effective date of Alpha’s plan of reorganization. Additionally, as a result of the Merger, the Company assumed certain acquisition-related obligations pursuant to the terms stipulated within the bankruptcy settlement previously entered into by the Alpha Companies. Contingent Revenue Obligation As a result of the Merger, the Company assumed a contingent revenue payment obligation (the “Contingent Revenue Obligation”) to certain of the Alpha Companies’ creditors pursuant to the terms stipulated within the bankruptcy settlement previously entered into by the Alpha Companies. Pursuant to terms of the obligation, the annual obligation will be limited to revenues derived from legacy operations for the Alpha Companies and will not include revenues related to legacy Contura operations. The Contingent Revenue Obligation consists of a contingent revenue payment of 1.5% of annual gross revenues of the legacy operations for the Alpha Companies up to $500,000 and 1.0% of annual gross revenue of the legacy operations for the Alpha Companies in excess of $500,000 through the period ended December 31, 2022. As of December 31, 2019 and 2018 , the carrying value of the Contingent Revenue Obligation was $52,427 and $59,880 , with $14,646 and $9,459 classified as current, respectively, and classified as an acquisition-related obligation in the Consolidated Balance Sheets. Refer to Note 18 for further disclosures related to the fair value assignment and methods used. During the second quarter of 2019, the Company paid $9,627 pursuant to terms of the Contingent Revenue Obligation. Environmental Settlement Obligations As a result of the Merger, the Company assumed certain environmental settlement obligations (the “Environmental Settlement Obligations”) pursuant to the terms stipulated within the bankruptcy settlement previously entered into by the Alpha Companies. These obligations include payments to a third-party environmental agency and the funding of certain reclamation related projects through 2022. As of December 31, 2019 and 2018 , the carrying value of the Environmental Settlement Obligations was $13,594 and $14,768 , net of discounts of $2,711 and $4,538 , with $6,185 and $3,375 classified as current, respectively, all of which was classified as an acquisition-related obligation in the Consolidated Balance Sheets. Reclamation Funding Agreement Pursuant to the Reclamation Funding Agreement dated July 12, 2016, the Company must pay the aggregate amount of $50,000 into the various Restricted Cash Reclamation Accounts as follows: $8,000 immediately upon the effective date of the agreement; $10,000 on the anniversary of the effective date in each of 2017, 2018, and 2019; and $12,000 on the anniversary of the effective date in 2020. As of December 31, 2019 and 2018 , the carrying value of the Funding of Restricted Cash Reclamation liability was $10,808 and $18,106 , net of discounts of $1,192 and $3,894 , with $10,808 and $10,000 classified as current, respectively, all of which was classified as an acquisition-related obligation in the Consolidated Balance Sheets.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The following table summarizes the changes in asset retirement obligations for the years ended December 31, 2019 and 2018 : Total asset retirement obligations at December 31, 2017 $ 59,205 Accretion for the period 8,961 Sites added during the period (1) 163,636 Revisions in estimated cash flows (2) 1,100 Expenditures for the period (3,175 ) Reclassification to liabilities held for sale (1,279 ) Total asset retirement obligations at December 31, 2018 $ 228,448 Measurement-period adjustments (3) 12,718 Accretion for the period (4) 27,785 Sites added during the period 5,113 Revisions in estimated cash flows (2) (25,244 ) Expenditures for the period (24,116 ) Total asset retirement obligations at December 31, 2019 $ 224,704 Less current portion (40,574 ) Long-term portion $ 184,130 (1) Represents amounts assumed in connection with the Merger. (2) The revisions in estimated cash flows resulted primarily from discount rate adjustments and changes in mine plans. (3) Refer to Note 3 for additional information on the Merger and related measurement-period adjustments recorded during the year ended December 31, 2019 . (4) Amount does not include the accretion related to asset retirement obligations classified as liabilities held for sale.

Fair Value of Financial Instrum

Fair Value of Financial Instruments and Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments and Fair Value Measurements	Fair Value of Financial Instruments and Fair Value Measurements The estimated fair values of financial instruments are determined based on relevant market information. These estimates involve uncertainty and cannot be determined with precision. The carrying amounts for cash and cash equivalents, trade accounts receivable, net, prepaid expenses and other current assets, short-term and long-term restricted cash, short-term and long-term deposits, trade accounts payable, and accrued expenses and other current liabilities approximate fair value as of December 31, 2019 and 2018 due to the short maturity of these instruments. The following tables set forth by level, within the fair value hierarchy, the Company’s long-term debt at fair value as of December 31, 2019 and 2018 : December 31, 2019 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Term Loan Credit Facility - due June 2024 $ 538,765 $ 461,402 $ 461,402 $ — $ — LCC Note Payable 37,695 33,884 — — 33,884 LCC Water Treatment Obligation 7,211 6,280 — — 6,280 Total long term debt $ 583,671 $ 501,566 $ 461,402 $ — $ 40,164 December 31, 2018 Carrying (1) Total Fair Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Term Loan Credit Facility - due November 2025 $ 521,667 $ 540,375 $ 540,375 $ — $ — LCC Note Payable 49,361 50,606 — — 50,606 LCC Water Treatment Obligation 8,589 8,827 — — 8,827 Total long term debt $ 579,617 $ 599,808 $ 540,375 $ — $ 59,433 (1) Net of debt discounts and debt issuance costs. The following tables set forth by level, within the fair value hierarchy, the Company’s acquisition-related obligations at fair value as of December 31, 2019 and 2018 : December 31, 2019 Carrying (1) Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) UMWA Funds Settlement Liability $ 3,069 $ 2,929 $ — $ — $ 2,929 Reclamation Funding Liability 10,808 10,658 — — 10,658 Environmental Settlement Obligations 13,594 12,197 — — 12,197 Total acquisition-related obligations $ 27,471 $ 25,784 $ — $ — $ 25,784 December 31, 2018 Carrying (1) Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Retiree Committee VEBA Funding Settlement Liability $ 3,337 $ 3,391 $ — $ — $ 3,391 UMWA Funds Settlement Liability 4,239 4,729 — — 4,729 Reclamation Funding Liability 18,106 19,362 — — 19,362 Environmental Settlement Obligations 14,768 14,936 — — 14,936 Total acquisition-related obligations $ 40,450 $ 42,418 $ — $ — $ 42,418 (1) Net of discounts. The following table sets forth by level, within the fair value hierarchy, the Company’s financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis as of December 31, 2019 and 2018 . Financial and non-financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the determination of fair value for assets and liabilities and their placement within the fair value hierarchy levels. December 31, 2019 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 52,427 $ — $ — $ 52,427 Trading securities $ 13,508 $ 5,506 $ 8,002 $ — December 31, 2018 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 59,880 $ — $ — $ 59,880 The following table is a reconciliation of the financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis and that were categorized within Level 3 of the fair value hierarchy: December 31, 2018 Payments Measurement Period Adjustments (1) Loss Recognized in Earnings Transfer In (Out) of Level 3 Fair Value Hierarchy December 31, 2019 Contingent Revenue Obligation $ 59,880 $ (9,627 ) 5,738 $ (3,564 ) $ — $ 52,427 (1) Refer to Note 3 for additional information on the Merger and related measurement-period adjustments recorded during the year ended December 31, 2019 . December 31, 2017 Acquisitions Loss (Gain) Recognized in Earnings Transfer In (Out) of Level 3 Fair Value Hierarchy December 31, 2018 Contingent Revenue Obligation — 59,856 24 — 59,880 The following methods and assumptions were used to estimate the fair values of the assets and liabilities in the tables above: Level 1 Fair Value Measurements Term Loan Credit Facility - due June 2024 and Term Loan Credit Facility - due November 2025 - The fair value is based on observable market data. Trading Securities - Includes money market funds and other cash equivalents. The fair value is based on observable market data. Level 2 Fair Value Measurements Trading Securities - Includes certificates of deposit, mutual funds, corporate debt securities and U.S. treasury and agency securities. The fair values of the Company’s trading securities are obtained from a third-party pricing service provider. The fair values provided by the pricing service provider are based on observable market inputs including credit spreads and broker-dealer quotes, among other inputs. The Company classifies the prices obtained from the pricing services within Level 2 of the fair value hierarchy because the underlying inputs are directly observable from active markets. However, the pricing models used entail a certain amount of subjectivity and therefore differing judgments in how the underlying inputs are modeled could result in different estimates of fair value. Level 3 Fair Value Measurements LCC Note Payable, LCC Water Treatment Obligation, Retiree Committee VEBA Funding Settlement Liability, UMWA Funds Settlement Liability, Environmental Settlement Obligations and Reclamation Funding Liability - Observable transactions are not available to aid in determining the fair value of these items. Therefore, the fair value was derived by using the expected present value approach in which estimated cash flows are discounted using a risk-free interest rate adjusted for market risk. Contingent Revenue Obligation - The fair value of the contingent revenue obligation was estimated using a Black-Scholes pricing model and is marked to market at each reporting period with changes in value reflected in earnings. The inputs included in the Black-Scholes pricing model are the Company's forecasted future revenue, the stated royalty rate, the remaining periods in the obligation; annual risk-free interest rate based on the US Constant Maturity Treasury Curve and annualized volatility. The annualized volatility was calculated by observing volatilities for comparable companies with adjustments for the Company's size and leverage. Acquisition accounting - The Company accounts for business combinations under the acquisition method of accounting. The total cost of acquisitions is allocated to the underlying identifiable net tangible and intangible assets based on their respective estimated fair values. Determining the fair value of assets acquired and liabilities assumed requires management’s judgment, the utilization of independent valuation experts and often involves the use of significant estimates and assumptions with respect to the timing and amounts of future cash inflows and outflows, discount rates, market prices and asset lives, among other items. A combination of income, market and cost approaches are used for the valuation where appropriate, depending on the assets or liabilities being valued. The valuation inputs in these models and analyses give consideration to market participant assumptions.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Total income tax benefit provided on income (loss) before income taxes was allocated as follows: Year Ended December 31, 2019 2018 2017 Continuing operations $ (57,557 ) $ (165,363 ) $ (67,979 ) Discontinued operations (4,214 ) (1,305 ) (17,681 ) Total $ (61,771 ) $ (166,668 ) $ (85,660 ) Significant components of income tax expense (benefit) from continuing operations were as follows: Year Ended December 31, 2019 2018 2017 Current tax (benefit) expense: Federal $ (49,943 ) $ (99,965 ) $ 10,078 State 824 (21 ) 687 Total current $ (49,119 ) $ (99,986 ) $ 10,765 Deferred tax (benefit) expense: Federal $ 704 $ (49,322 ) $ (78,744 ) State (9,142 ) (16,055 ) — Total deferred $ (8,438 ) $ (65,377 ) $ (78,744 ) Total income tax (benefit) expense: Federal $ (49,239 ) $ (149,287 ) $ (68,666 ) State (8,318 ) (16,076 ) 687 Total $ (57,557 ) $ (165,363 ) $ (67,979 ) A reconciliation of statutory federal income tax expense (benefit) on income from continuing operations to the actual income tax expense (benefit) is as follows: Year Ended December 31, 2019 2018 2017 Federal statutory income tax expense (benefit) $ (54,747 ) $ 28,873 $ 37,015 Increase (reductions) in taxes due to: Percentage depletion allowance (6,270 ) (3,770 ) (5,164 ) Federal tax rate change — — 179,825 SAB 118 finalization — (6,735 ) — Estimated sequestration impact — (7,139 ) 5,640 State taxes, net of federal tax impact (10,498 ) 6,569 1,059 State tax rate and NOL change, net of federal tax impact (4,172 ) (4,779 ) (4,705 ) Change in valuation allowances 4,329 (208,474 ) (280,094 ) Net operating loss carryback (14,234 ) (59,404 ) — Amended return - capital loss impact 919 69,430 — Non-taxable bargain purchase gain — — (354 ) Non-deductible goodwill impairment 26,114 — — Non-deductible transaction costs — 1,706 — Stock-based compensation (1,085 ) (687 ) (1,144 ) Charitable contribution carryforward expiration 486 9,634 — Provision to return adjustment (869 ) 5,022 — Other, net 2,470 4,391 (57 ) Income tax benefit $ (57,557 ) $ (165,363 ) $ (67,979 ) Deferred income taxes result from temporary differences between the reporting of amounts for financial statement purposes and income tax purposes. The net deferred tax assets and liabilities included in the Consolidated Balance Sheets include the following amounts: Year Ended December 31, 2019 2018 Deferred tax assets: Asset retirement obligations $ 51,114 $ 59,973 Reserves and accruals not currently deductible 8,265 9,163 Workers’ compensation benefit obligations 54,128 56,859 Pension obligations 44,413 47,256 Equity method investments 2,509 3,506 Charitable contribution carryforwards 306 724 Alternative minimum tax credit carryforwards 33,065 68,774 Loss carryforwards, net of Section 382 limitation 142,510 109,850 Acquisition-related obligations 17,902 25,590 Other 11,993 11,909 Gross deferred tax assets 366,205 393,604 Less valuation allowance (133,020 ) (94,802 ) Deferred tax assets $ 233,185 $ 298,802 Deferred tax liabilities: Property, plant and mineral reserves $ (145,487 ) $ (189,232 ) Acquired intangibles, net (27,140 ) (31,540 ) Prepaid expenses (6,780 ) (6,882 ) Restricted cash (20,313 ) (55,112 ) Other (822 ) (3,975 ) Total deferred tax liabilities (200,542 ) (286,741 ) Net deferred tax assets $ 32,643 $ 12,061 Changes in the valuation allowance were as follows: Year Ended December 31, 2019 2018 2017 Valuation allowance beginning of period $ 94,802 $ 298,892 $ 531,054 Increase (decrease) in valuation allowance recorded to income tax expense (benefit) 29,950 (208,474 ) (288,177 ) Increase in valuation allowance not affecting income tax expense 8,268 4,384 56,015 Valuation allowance end of period $ 133,020 $ 94,802 $ 298,892 On December 22, 2017, President Trump signed into law legislation commonly referred to as the “Tax Cuts and Jobs Act” (“TCJA”). Effective for tax years beginning after December 31, 2017, the TCJA reduced the corporate income tax rate from 35% to 21%. As a result of the reduction in the corporate income tax rate, the Company recorded a reduction to the value of its net deferred tax assets before the valuation allowance of $179,825 , resulting in an offsetting release in the valuation allowance of $179,825 , during the year ended December 31, 2017. The TCJA also repealed the corporate alternative minimum tax (“AMT”), provided a mechanism for corporations to monetize alternative minimum tax credits (“AMT Credits”) during the 2018 to 2021 tax years, limited the tax deduction for interest expense to 30% of adjusted earnings, and made changes to net operating loss provisions (“NOL”) to repeal NOL carrybacks, allow NOLs to be carried forward indefinitely, and limit the utilization of an NOL carryforward to 80% of taxable income generated. The changes to the NOL provisions apply to NOLs generated in 2018 and future tax years. During the one-year measurement period ended December 22, 2018, the Company finalized its accounting for the AMT Credits under SAB 118, resulting in the recording of an income tax benefit of $6,735 during the year ended December 31, 2018. Based on the accounting policy election made, the Company classifies the AMT Credits as a deferred tax asset until the taxable year in which the credit can be claimed on the tax return. In that year, the Company reclassifies the amount from a deferred tax asset to an income tax receivable. As of December 31, 2019, the Company recorded a current income tax receivable of $33,065 for AMT Credits expected to be refunded on the 2019 tax return. The remaining $33,065 of AMT Credits, the balance of which are expected to be refunded on the 2020 and 2021 tax returns, are recorded as a deferred tax asset. The Internal Revenue Service (“IRS”) may issue additional guidance in the form of regulations or notices regarding certain technical issues related to the monetization of the AMT Credits. The Company acquired the core assets of Alpha as part of the Alpha Restructuring in transactions intended to be treated as a tax-free reorganization for U.S. federal income tax purposes. As a result of these transactions, the Company inherited the tax basis of the core assets and the net operating loss and other carryforwards of Alpha. On December 31, 2016, the net operating loss carryforwards and other carryforwards were reduced under Internal Revenue Code Section 108 due to the cancellation of indebtedness resulting from the Alpha Restructuring. Due to the change in ownership, the net operating loss and other carryforwards inherited in the Alpha Restructuring are subjected to significant limitations on their use in future years. Due to the Company’s formation through acquisition of certain core coal assets as part of the Alpha Restructuring, the Company does not have a long history of operating results. Additionally, significant ownership change limitations limit the ability of the Company to utilize its net operating loss and other carryforwards in future years. The Company currently is relying primarily on the reversal of taxable temporary differences, along with consideration of taxable income via carryback to prior years and tax planning strategies, to support the realization of deferred tax assets. The Company assesses the realizability of its deferred tax assets, including scheduling the reversal of its deferred tax liabilities, to determine the amount of valuation allowance needed. Scheduling the reversal of deferred tax asset and liability balances requires judgment and estimation. The Company believes the deferred tax liabilities relied upon as future taxable income in its assessment will reverse in the same period and jurisdiction and are of the same character as temporary differences giving rise to the deferred tax assets that will be realized. The valuation allowance recorded represents the portion of deferred tax assets for which the Company is unable to support realization through the methods described above. The Company has concluded that it is more likely than not that the remaining deferred tax assets, net of valuation allowances, are realizable. At December 31, 2019 , the Company has regular tax net operating loss carryforwards for federal income tax purposes of approximately $1,427,000 . This includes $1,011,000 that are available to offset regular federal taxable income subject to an annual Internal Revenue Code Section 382 limitation of approximately $1,000 , $56,000 that are subject to an annual Section 382 limitation of approximately $18,300 , and $299,000 that are subject to an annual Section 382 limitation of approximately $17,500 . These federal net operating loss carryforwards were generated before 2018 and will expire between years 2030 and 2037. The Company also has $61,000 of federal net operating loss carryforwards with an indefinite carryforward period that can be used to offset up to 80% of taxable income. The Company has capital loss carryforwards of approximately $117,000 , of which $66,000 are subject to an annual Section 382 limitation of approximately $1,000 and $51,000 are subject to an annual Section 382 limitation of approximately $17,500 . The capital loss carryforwards will expire between years 2021 and 2024. A full valuation allowance is recorded against the capital loss carryforwards. The Company also has disallowed interest deduction carryforwards of $102,394 , which can be carried forward indefinitely and used to reduce taxable income subject to a 30% of adjusted earnings limitation. No amount of unrecognized tax benefits would affect the Company’s effective tax rate if recognized as of December 31, 2019. The Company believes that it is reasonably possible that a decrease in unrecognized tax benefits of $20,788 may be necessary during the next twelve months, as a result of the issuance of final regulatory guidance from the IRS. The Company’s policy is to classify interest and penalties related to uncertain tax positions as part of income tax expense. As of December 31, 2019 and 2018 , the Company had no accrued interest and penalties. The following reconciliation illustrates the Company’s liability for uncertain tax positions: Year Ended December 31, 2019 2018 2017 Unrecognized tax benefits - beginning of period $ — $ — $ — Additions for tax positions of prior years 5,740 — — Additions for tax positions of current year 15,048 — — Unrecognized tax benefits - end of period $ 20,788 $ — $ — As of December 31, 2019 , tax years 2016 - 2019, which include the impact of net operating loss and other carryforwards and tax basis acquired from Alpha, remain open to federal and state examination.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Compensation Related Costs [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company provides several types of benefits for its employees, including defined benefit and defined contribution pension plans, workers’ compensation and black lung benefits, and postemployment life insurance. The Company does not participate in any multi-employer plans. Company Administered Defined Benefit Pension Plans In connection with the Merger, the Company assumed three qualified non-contributory defined benefit pension plans, which cover certain salaried and non-union hourly employees. Participants accrued benefits either based on certain formulas, the participant’s compensation prior to retirement or plan specified amounts for each year of service with the Company. Benefits are frozen under these plans. The qualified non-contributory defined benefit pension plans are collectively referred to as the “Pension Plans.” Effective October 1, 2019, two of the qualified non-contributory defined benefit pension plans were amended to offer certain eligible participants the option to elect to receive lump sum benefits as of December 1, 2019, which resulted in a partial plan settlement and the accelerated recognition of a portion of the accumulated other comprehensive loss during the three months ended December 31, 2019. Refer to the disclosures below for further information on the partial plan settlement. Annual funding contributions to the Pension Plans are made as recommended by consulting actuaries based upon the ERISA funding standards. Plan assets consist of equity and fixed income funds, private equity funds and a guaranteed insurance contract. The following tables set forth the plans’ accumulated benefit obligations, fair value of plan assets and funded status for the years ended December 31, 2019 and 2018 . For the year ended December 31, 2018, the change in benefit obligations and change in fair value of plan assets only represents activity related to the post-Merger period. Year Ended December 31, 2019 2018 Change in benefit obligations: Accumulated benefit obligation at beginning of period: $ 675,482 $ — Interest cost (1) 26,564 4,500 Actuarial loss 91,287 22,410 Benefits paid (31,371 ) (5,295 ) Acquisition (1) 1,910 653,867 Settlement (89,433 ) — Accumulated benefit obligation at end of period $ 674,439 $ 675,482 Change in fair value of plan assets: Fair value of plan assets at beginning of period $ 494,680 $ — Actual return on plan assets 87,129 4,112 Employer contributions 9,348 — Benefits paid (31,371 ) (5,295 ) Acquisition — 495,863 Settlement (89,433 ) — Fair value of plan assets at end of period $ 470,353 $ 494,680 Funded status $ (204,086 ) $ (180,802 ) Accrued benefit cost at end of period (2) $ (204,086 ) $ (180,802 ) (1) For the year ended December 31, 2019, interest cost includes $22 of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. (2) Amounts are classified as long-term on the Consolidated Balance Sheets as there are sufficient plan assets to make expected benefit payments to plan participants in the succeeding twelve months. Gross amounts related to pension obligations recognized in accumulated other comprehensive loss consisted of the following as of December 31, 2019 and 2018 : December 31, 2019 2018 Net actuarial loss $ 46,568 $ 23,075 The following table details the components of net periodic benefit cost (credit): Year Ended December 31, 2019 2018 Interest cost (1) $ 26,564 $ 4,500 Expected return on plan assets (28,042 ) (4,777 ) Amortization of net losses 797 — Settlement (2) 6,224 — Net periodic benefit cost (credit) $ 5,543 $ (277 ) (1) For the year ended December 31, 2019, interest cost includes $22 of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. (2) For the year ended December 31, 2019, the settlement is recorded within miscellaneous (loss) income, net, within the Consolidated Statements of Operations. Other changes in plan assets and benefit obligations recognized in other comprehensive loss are as follows: Year Ended December 31, 2019 2018 Actuarial loss (1) $ 30,514 $ 23,075 Amortization of net actuarial loss (797 ) — Settlement (6,224 ) — Total recognized in other comprehensive loss $ 23,493 $ 23,075 (1) For the year ended December 31, 2019, the balance includes ($1,686) of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. The following table presents information applicable to plans with accumulated benefit obligations in excess of plan assets: Year Ended December 31, 2019 2018 Projected benefit obligation $ 674,439 $ 675,482 Accumulated benefit obligation $ 674,439 $ 675,482 Fair value of plan assets $ 470,353 $ 494,680 The weighted-average actuarial assumption used in determining the benefit obligations as of December 31, 2019 and 2018 was as follows: December 31, 2019 2018 Discount rate 3.36 % 4.33 % The weighted-average actuarial assumptions used to determine net periodic benefit cost for the years ended December 31, 2019 and 2018 were as follows: Year Ended December 31, 2019 2018 Discount rate for benefit obligation 4.33 % 4.50 % Discount rate for interest cost 4.01 % 4.23 % Expected return on plan assets 5.80 % 5.80 % The discount rate assumptions were determined from a high-quality corporate bond yield-curve timing of the Company’s projected cash out flows. The expected long-term return on assets of the Pension Plans is established each year by the Company’s Benefits Committee in consultation with the plans’ actuaries and outside investment advisors. This rate is determined by taking into consideration the Pension Plans’ target asset allocation, expected long-term rates of return on each major asset class by reference to long-term historic ranges, inflation assumptions and the expected additional value from active management of the Pension Plans’ assets. For the determination of net periodic benefit cost in 2020 , the Company will utilize an expected long-term return on plan assets of 5.90% . Assets of the Pension Plans are held in trusts and are invested in accordance with investment guidelines that have been established by the Company’s Benefits Committee in consultation with outside investment advisors. The target allocation for 2020 and the actual asset allocation as reported at December 31, 2019 are as follows: Target Allocation Percentages 2020 Percentage of Plan Assets 2019 Equity securities 40.0 % 39.3 % Fixed income funds 60.0 % 58.0 % Other — % 2.7 % Total 100.0 % 100.0 % The asset allocation targets have been set with the expectation that the Pension Plans’ assets will fund the expected liabilities within an appropriate level of risk. In determining the appropriate target asset allocations, the Benefits Committee considers the demographics of the Pension Plans’ participants, the funding status of each plan, the Company’s contribution philosophy, the Company’s business and financial profile, and other associated risk factors. The Pension Plans’ assets are periodically rebalanced among the major asset categories to maintain the asset allocation within a specified range of the target allocation percentage. The Company expects to contribute $23,174 to the Pension Plans in 2020 . The following represents expected future pension benefit payments for the next ten years: 2020 $ 30,992 2021 31,148 2022 31,691 2023 32,414 2024 32,901 2025-2029 166,350 $ 325,496 The fair values of the Company’s Pension Plans’ assets as of December 31, 2019 , by asset category are as follows: Asset Category Total Quoted Market Prices in Active Market for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Equity securities: Multi-asset fund (1) $ 182,782 $ — $ 182,782 $ — Fixed income funds: Bond fund (2) 272,239 — 272,239 — Commingled short-term fund (3) 1,572 — 1,572 — Other types of investments: Guaranteed insurance contract 11,155 — — 11,155 Total $ 467,748 $ — $ 456,593 $ 11,155 Receivable (4) 1,061 Total assets at fair value 468,809 Private equity funds measured at net asset value practical expedient (5) 1,544 Total plan assets $ 470,353 (1) This fund contains equities (domestic and international), real estate and bonds. (2) This fund contains bonds representing a diversity of sectors and maturities. This fund also includes mortgage-backed securities and U.S. Treasuries. (3) This fund contains cash and highly liquid short-term investments in a collective investment fund. (4) Receivable for investments sold at December 31, 2019 , which approximates fair value. (5) In accordance with Accounting Standards Update 2015-07, 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. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the total value of assets of the plans. Changes in Level 3 plan assets for the period ended December 31, 2019 were as follows: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Guaranteed Insurance Contract Beginning balance, December 31, 2018 $ 10,886 Actual return on plan assets: Relating to assets still held at the reporting date 644 Purchases, sales and settlements (375 ) Ending balance, December 31, 2019 $ 11,155 The fair values of the Company’s Pension Plans’ assets as of December 31, 2018 , by asset category are as follows: Asset Category Total Quoted Market Prices in Active Market for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Equity securities: Multi-asset fund (1) $ 195,278 $ — $ 195,278 $ — Fixed income funds: Bond fund (2) 283,517 — 283,517 — Commingled short-term fund (3) 1,654 — 1,654 — Other types of investments: Guaranteed insurance contract 10,886 — — 10,886 Total $ 491,335 $ — $ 480,449 $ 10,886 Receivable (4) 921 Total assets at fair value 492,256 Private equity funds measured at net asset value practical expedient (5) 2,424 Total plan assets $ 494,680 (1) This fund contains equities (domestic and international), real estate and bonds. (2) This fund contains bonds representing a diversity of sectors and maturities. This fund also includes mortgage-backed securities and U.S. Treasuries. (3) This fund contains cash and highly liquid short-term investments in a collective investment fund. (4) Receivable for investments sold at December 31, 2018 , which approximates fair value. (5) In accordance with Accounting Standards Update 2015-07, 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. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the total value of assets of the plans. Changes in Level 3 plan assets for the period ended December 31, 2018 were as follows: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Guaranteed Insurance Contract Beginning balance, December 31, 2017 $ — Acquisition 11,266 Actual return on plan assets: Relating to assets still held at the reporting date 11 Purchases, sales and settlements (391 ) Ending balance, December 31, 2018 $ 10,886 The following is a description of the valuation methodologies used for assets measured at fair value: Level 1 Plan Assets: Assets consist of individual security positions that are easily traded on recognized market exchanges. These securities are priced and traded daily, and therefore the fund is valued daily. Level 2 Plan Assets: Funds consist of individual security positions that are mostly securities easily traded on recognized market exchanges. These securities are priced and traded daily, and therefore the fund is valued daily. Level 3 Plan Assets: Assets are valued monthly or quarterly based on the Market Value provided by managers of the underlying fund investments. The Market Value provided typically reflects the fair value of each underlying fund investment, including unrealized gains and losses. Workers’ Compensation and Pneumoconiosis (Black Lung) The Company is required by federal and state statutes to provide benefits to employees for awards related to workers’ compensation and black lung. The Company’s subsidiaries utilize high-deductible third-party insurance for worker’s compensation and black lung obligations with the exception of certain subsidiaries in which the Company is a qualified self-insurer for workers’ compensation and/or black lung related obligations. The Company’s subsidiaries that are self-insured for black lung benefits may fund benefit payments through a Section 501(c) (21) tax-exempt trust fund. Pursuant to the Merger Agreement, the Company assumed a reinsurance contract with a third party. In 2017, the Alpha Companies made a lump sum payment in exchange for a reinsurance company’s agreement to administer and pay certain future workers’ compensation and state black lung obligations in the state of Kentucky. Pursuant to the Merger Agreement, the Company assumed the estimated liability for these future claims. As the liabilities are paid by the insurance company, the prepaid insurance amounts will be reduced by a corresponding amount. The Company accrues for workers’ compensation liability by recognizing costs when it is probable that a covered liability has been incurred and the cost can be reasonably estimated. The Company’s estimates of these costs are adjusted based upon actuarial studies and include a provision for incurred but not reported losses. Actual losses may differ from these estimates, which could increase or decrease the Company’s costs. Additionally, the liability for black lung benefits is estimated by an independent actuary by prorating the accrual of actuarially projected benefits over the employee’s applicable term of service. Adjustments to the probable ultimate liability for workers’ compensation and black lung are made annually based on actuarial valuations. At December 31, 2019 , the Company had $163,818 of workers’ compensation liability, including a current portion of $15,695 recorded in accrued expenses and other current liabilities, offset by $2,375 and $58,498 of expected insurance receivable recorded in prepaid expenses and other current assets and other non-current assets, respectively in the Consolidated Balance Sheets. At December 31, 2018, the Company had $181,989 of workers’ compensation liability, including a current portion of $16,676 recorded in accrued expenses and other current liabilities, offset by $2,661 and $67,776 of expected insurance receivable recorded in prepaid expenses and other current assets and other non-current assets, respectively, in the Consolidated Balance Sheets. For the Company’s subsidiaries that are insured with a high-deductible insurance plan for workers’ compensation and black lung claims, the insurance premium expense for the years ended December 31, 2019 , 2018 , and 2017 was $13,851 , $5,868 , and $4,948 , respectively. Workers’ compensation expense for high-deductible insurance plans for the years ended December 31, 2019 , 2018 , and 2017 was $6,665 , $7,953 , and $9,366 , respectively. The following tables set forth the accumulated black lung benefit obligations, fair value of plan assets and funded status for the years ended December 31, 2019 and 2018 : Year Ended December 31, 2019 2018 Change in benefit obligation: Accumulated benefit obligation at beginning of period $ 94,805 $ 18,370 Service cost (1) 2,057 930 Interest cost (1) 4,474 1,185 Actuarial loss 11,166 272 Benefits paid (6,543 ) (1,462 ) Acquisition (1) 16,829 75,510 Accumulated benefit obligation at end of period $ 122,788 $ 94,805 Change in fair value of plan assets: Fair value of plan assets at beginning of period $ 2,597 $ — Actual return on plan assets 63 28 Benefits paid (6,543 ) (1,462 ) Employer contributions 6,543 1,462 Acquisition — 2,569 Fair value of plan assets at end of period (2) 2,660 2,597 Funded status $ (120,128 ) $ (92,208 ) Accrued benefit cost at end of period $ (120,128 ) $ (92,208 ) Summary of accrued benefit cost at end of period: Continuing operations (120,128 ) (92,114 ) Discontinued operations — (94 ) Total accrued benefit cost at end of period $ (120,128 ) $ (92,208 ) (1) For the year ended December 31, 2019, service cost and interest cost include $61 and $120 , respectively, of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. (2) Assets of the plan are held in a Section 501(c)(21) tax-exempt trust fund and consist primarily of government debt securities. All assets are classified as Level 1 and valued based on quoted market prices. The table below presents amounts recognized in the Balance Sheets: December 31, 2019 2018 Current liabilities $ 7,472 $ 8,133 Long-term liabilities 112,656 83,981 Long-term liabilities - discontinued operations — 94 $ 120,128 $ 92,208 Gross amounts related to the black lung obligations recognized in accumulated other comprehensive loss consisted of the following as of December 31, 2019 and 2018 : December 31, 2019 2018 Net actuarial loss $ 12,980 $ 1,684 The following table details the components of the net periodic benefit cost for black lung obligations: Year Ended December 31, 2019 2018 2017 Service cost (1) $ 2,057 $ 930 $ 651 Interest cost (1) 4,474 1,185 633 Expected return on plan assets (65 ) (11 ) — Amortization of net actuarial loss (gain) 216 199 (149 ) Net periodic benefit cost $ 6,682 $ 2,303 $ 1,135 Summary net periodic benefit cost: Continuing operations $ 6,682 $ 2,304 $ 1,125 Discontinued operations — (1 ) 10 Total net periodic benefit cost $ 6,682 $ 2,303 $ 1,135 (1) For the year ended December 31, 2019, service cost and interest cost include $61 and $120 , respectively, of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. Other changes in the black lung plan assets and benefit obligations recognized in other comprehensive loss are as follows: Year Ended December 31, 2019 2018 2017 Actuarial loss (1) $ 11,512 $ 255 $ 3,661 Amortization of net actuarial (loss) gain (216 ) (199 ) 149 Total recognized in other comprehensive loss $ 11,296 $ 56 $ 3,810 (1) For the year ended December 31, 2019, the balance includes $344 of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. The weighted-average assumptions related to black lung obligations used to determine the benefit obligation as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 Discount rate 3.47 % 4.36 % Federal black lung benefit trend rate 2.00 % 2.50 % Black lung medical benefit trend rate 5.00 % 5.00 % Black lung benefit expense inflation rate 2.00 % 2.50 % The weighted-average assumptions related to black lung obligations used to determine net periodic benefit cost were as follows: Year Ended December 31, 2019 2018 2017 Discount rate for benefit obligation 4.36 % 4.37 % 4.29 % Discount rate for service cost 4.54 % 3.90 % 4.32 % Discount rate for interest cost 3.99 % 3.83 % 4.20 % Federal black lung benefit trend rate 2.50 % 2.50 % 2.50 % Black lung medical benefit trend rate 5.00 % 5.00 % 5.00 % Black lung benefit expense inflation rate 2.50 % 2.50 % 2.50 % Expected return on plan assets 2.50 % 2.50 % N/A Estimated future cash payments related to black lung obligations for the next 10 years ending after December 31, 2019 are as follows: Year ending December 31: 2020 $ 7,472 2021 6,457 2022 6,751 2023 6,894 2024 6,981 2025-2029 19,900 $ 54,455 Life Insurance Benefits As part of the Alpha Restructuring and the Retiree Committee Settlement Agreement, the Company assumed the liability for life insurance benefits for certain disabled and non-union retired employees. Provisions are made for estimated benefits and adjustments to the probable ultimate liabilities are made annually based on an actuarial study prepared by independent actuaries. These obligations are included in the Consolidated Balance Sheet as accrued expenses and other current liabilities and other non-current liabilities. The following tables set forth the accumulated life insurance benefit obligations, fair value of plan assets and funded status for the years ended December 31, 2019 and 2018 : December 31, 2019 2018 Change in benefit obligation: Accumulated benefit obligation at beginning of period $ 11,368 $ 12,640 Interest cost 426 388 Actuarial loss (gain) 1,002 (1,164 ) Benefits paid (455 ) (496 ) Accumulated benefit obligation at end of period $ 12,341 $ 11,368 Change in fair value of plan assets: Benefits paid (1) (455 ) (496 ) Employer contributions (1) 455 496 Fair value of plan assets at end of period $ — $ — Funded status (12,341 ) (11,368 ) Accrued benefit cost at end of year $ (12,341 ) $ (11,368 ) Amounts recognized in the consolidated balance sheets: Current liabilities $ 719 $ 787 Long-term liabilities 11,622 10,581 $ 12,341 $ 11,368 (1) Amount is comprised of premium payments to commercial life insurance provider. Gross amounts related to the life insurance benefit obligations recognized in accumulated other comprehensive income consisted of the following as of December 31, 2019 and 2018 : December 31, 2019 2018 Net actuarial gain $ (872 ) $ (1,979 ) Accumulated other comprehensive income $ (872 ) $ (1,979 ) The following table details the components of the net periodic benefit cost for life insurance benefit obligations: December 31, 2019 2018 Interest cost $ 426 $ 388 Amortization of net actuarial gain (105 ) (46 ) Net periodic benefit cost $ 321 $ 342 Other changes in the life insurance plan assets and benefit obligations recognized in other comprehensive income (loss) are as follows: December 31, 2019 2018 Actuarial loss (gain) $ 1,002 $ (1,164 ) Amortization of net actuarial gain 105 46 Total recognized in other comprehensive income (loss) $ 1,107 $ (1,118 ) The weighted-average assumptions related to life insurance benefit obligations used to determine the benefit obligation as of December 31, 2019 and 2018 was as follows: December 31, 2019 2018 Discount rate 3.22 % 4.21 % The weighted-average assumptions related to life insurance benefit obligations used to determine net periodic benefit cost were as follows: Year Ended December 31, 2019 2018 Discount rate for benefit obligations 4.21 % 3.56 % Discount rate for interest cost 3.90 % 3.18 % Estimated future cash payments related to life insurance benefit obligations for the next 10 years ending after December 31, 2019 are as follows: Year ending December 31: 2020 $ 719 2021 667 2022 658 2023 650 2024 645 2025-2029 3,179 $ 6,518 Defined Contribution and Profit Sharing Plans The Company sponsors defined contribution plans to assist its eligible employees in providing for retirement. Generally, under the terms of these plans, employees make voluntary contributions through payroll deductions and the Company makes matching and/or discretionary contributions, as defined by each plan. The Company’s total contributions to these plans for the years ended December 31, 2019 , 2018 , and 2017 were $27,231 , $10,242 , and $8,823 , respectively. Self-insured Medical Plan The Company is self-insured for health benefit coverage for all of its active employees. Estimated liabilities for health and medical claims are recorded based on the Company’s historical experience and include a component for incurred but not paid claims. During the years ended December 31, 2019 , 2018 , and 2017 , the Company incurred total expenses of $79,896 , $37,958 , and $31,318 , respectively, which primarily include claims processed and an estimate for claims incurred but not paid.

Stock-Based Compensation Awards

Stock-Based Compensation Awards	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation Awards	Stock-Based Compensation Awards The MIP is currently authorized for the issuance of awards of up to 1,201,202 shares of common stock, and as of December 31, 2019 , there were 277,266 shares of common stock available for grant under the MIP. The Long-Term Incentive Plan (the “LTIP”) is currently authorized for the issuance of awards of up to 1,000,000 shares of common stock, and as of December 31, 2019 , there were 756,507 shares of common stock available for grant under the LTIP. Pursuant to the Merger Agreement, the Company assumed the ANR Inc. 2017 Equity Incentive Plan (the “ANR EIP”), which had underlying ANR shares that were converted to 89,766 Contura shares. The ANR EIP is no t authorized for additional issuance of awards of shares of common stock, and as of December 31, 2019 , there were no shares of common stock available for grant under the ANR EIP. As of December 31, 2019, the Company had four types of stock-based awards outstanding: time-based restricted stock, time-based restricted stock units, performance-based restricted stock units, and stock options. Stock-based compensation expense totaled $12,397 , $13,354 , and $20,372 for the years ended December 31, 2019, 2018, and 2017, respectively. For the years ended December 31, 2019, 2018, and 2017, approximately 76% , 90% , and 94% , respectively, of stock-based compensation expense was reported as selling, general and administrative expenses, and the remainder was recorded as cost of coal sales. The Company is authorized to repurchase common shares from employees (upon the election by the employee) to satisfy the employees’ statutory tax withholdings upon the vesting of stock grants. Shares that are repurchased to satisfy the employees’ statutory tax withholdings are recorded in treasury stock at cost. During the year ended December 31, 2019, the Company repurchased 118,935 shares of its common stock issued pursuant to awards under the MIP, LTIP and ANR EIP for a total purchase amount of $5,159 , or $43.37 average price paid per share. During the year ended December 31, 2018, the Company repurchased 76,648 shares of its common stock issued pursuant to awards under the MIP, LTIP and ANR EIP for a total purchase amount of $5,240 , or $68.36 average price paid per share. The Company did not repurchase any common shares from employees to satisfy the employees’ statutory tax withholdings upon vesting of stock grants during the year ended December 31, 2017. On September 15, 2017, the Company repurchased 309,310 shares of its common stock issued pursuant to awards under the MIP for a total purchase amount of $17,445 , or $56.40 per share. 2019 Awards Granted During the year ended December 31, 2019 , the Company granted certain key employees and non-employee directors 79,474 time-based restricted stock units under the LTIP with a weighted average grant date fair value of $49.47 based on the Company’s closing stock price at the trading day before the date of the grant. The awards granted to key employees will either vest ratably over a three-year period or cliff vest in one year from date of grant in accordance with the vesting schedule, subject to the participant’s continuous service with the Company through each applicable vesting date. The awards granted to non-employee directors will vest on the first to occur of (i) April 30, 2020, (ii) the director’s separation from service due to the director’s death or physical or mental incapacity to perform his or her usual duties, such condition likely to remain continuously and permanently, as determined by the Company, and (iii) a change in control. Upon vesting and settlement of time-based restricted stock units, the Company issues authorized and unissued shares of the Company’s common stock to the recipient. Additionally, during the year ended December 31, 2019 , the Company granted certain key employees 81,065 relative total shareholder return performance-based restricted stock units under the LTIP that are valued relative to the median stock price performance of a comparator group and had a weighted average grant date fair value of $65.70 based on a Monte Carlo simulation, and 27,042 absolute total shareholder return performance-based restricted stock units under the LTIP that are valued based on the Company’s stock price performance with a weighted average grant date fair value of $50.60 based on a Monte Carlo simulation. These awards cliff vest on the third anniversary of the date of the grant, subject to continued employment and the satisfaction of the performance criteria. These awards have the potential to be distributed from 0% to 400% of target for the relative total shareholder return units, and 0% to 200% of target for the absolute total shareholder return units depending on actual results versus the pre-established performance criteria over the three-year period. The Monte Carlo simulations incorporate the assumptions as presented in the following tables: Relative performance-based restricted stock units Start price (1) $ 66.06 Dividend adjusted stock price (2) $ 61.27 Expected volatility (3) 29.98 % Risk-free interest rate (4) 2.42 % Expected dividend yield (5) — % (1) The start price for the Company represents the average closing stock price over the ten trading days ending on December 31, 2018, assuming dividends distributed during this period were reinvested in additional shares of the Company’s stock on the ex-dividend date. (2) The dividend adjusted stock price represents the closing price on the grant date assuming dividends distributed during the period since December 17, 2018, were reinvested in additional shares of the Company’s stock on the ex-dividend date. (3) The expected volatility assumption is based on the historical volatility of the price of the Company’s stock. (4) The annual risk-free interest rate equals the yield on zero coupon U.S. Treasury Separate Trading of Registered Interest and Principal of Securities (“STRIPS”) that have a term equal to the length of the remaining performance measurement period as of the valuation date. (5) The expected dividend yield represents the investments return to a share of the Company’s stock that is not available to the holder of an absolute performance-based restricted stock unit. Absolute performance-based restricted stock units Valuation date stock price $ 61.27 Expected volatility (1) 29.98 % Risk-free interest rate (2) 2.42 % Expected dividend yield (3) — % (1) The expected volatility assumption is based on the historical volatility of the price of the Company’s stock. (2) The annual risk-free interest rate equals the yield on zero coupon U.S. Treasury STRIPS that have a term equal to the length of the remaining performance measurement period as of the valuation date. (3) The expected dividend yield represents the investments return to a share of the Company’s stock that is not available to the holder of an absolute performance-based restricted stock unit. 2018 Awards Granted During the year ended December 31, 2018, the Company granted certain key employees 18,063 time-based cash restricted stock units under the MIP with a weighted average grant date fair value of $65.00 based on the Company’s closing stock price at the date of grant. These awards vested on the first anniversary of the date of the grant. As of the grant date of the awards, the Company did not have sufficient authorized and unissued common shares to settle these awards and the awards were expected to be settled with cash, unless shares became available for issuance under the MIP on the applicable vesting date. Therefore, these awards were classified as a liability. On the applicable vesting date, shares were available for issuance and the awards vested as equity awards. The Company’s liability for all outstanding liability awards totaled $0 and $1,058 as of December 31, 2019 and December 31, 2018 , respectively. Additionally, during the year ended December 31, 2018, the Company granted certain key employees and non-employee directors 180,156 time-based restricted stock units under the MIP and LTIP based on the Company’s closing stock price at the trading day before the date of the grant for the key employee awards and the Company’s closing stock price at the date of grant for the non-employee director awards. Additionally, during the year ended December 31, 2018, the Company assumed ANR EIP awards of 89,766 time-based restricted stock units granted to certain key employees based on the Company’s stock price at the Merger date. These awards have a weighted average grant date fair value of $74.73 . The awards granted to key employees will vest ratably over a two-year period or a four-year period from date of grant in accordance with the vesting schedule, subject to the participant’s continuous service with the Company through each applicable vesting date. The awards granted to non-employee directors will vest on the first to occur of (i) the day before the one-year anniversary of the date of grant, (ii) the director’s separation from service (as defined in Section 409A) due to the directors’ death or disability, (iii) a change in control, and (iv) the date immediately prior to an Initial Public Offering (“IPO”), contingent upon the consummation of the IPO, subject in each case to the director’s continuous service with the Company through such date. Upon vesting and settlement of time-based restricted stock units, the Company issues authorized and unissued shares of the Company’s common stock to the recipient. 2017 Awards Granted During the year ended December 31, 2017, the Company granted 437,450 shares of restricted stock under the MIP with a weighted average grant date fair value of $65.55 based on the Company’s closing stock price at the date of grant. Additionally, during the year ended December 31, 2017, the Company granted 129,520 non-qualified stock options under the MIP to certain of its officers and key employees with a weighted average grant date fair value of $37.44 with a 10 -year expiration from the date of grant. These awards vest ratably over a three-year period or, in the event of a change in control, will fully vest, subject in each case to the recipient’s continued employment through such date. The non-qualified stock options have a grant date fair value based on a Black-Scholes pricing model. The Black-Scholes pricing model incorporates the assumptions as presented in the following table: Stock price $ 65.50 Exercise price $ 66.13 Expected term (1) 6.00 Annual risk-free interest rate (2) 2.18 % Annualized volatility (3) 60.9 % (1) The expected term represents the period of time that awards granted are expected to be outstanding. (2) The annual risk-free interest rate is based on the U.S. Constant Maturity Curve with a term equal to the award’s expected term on date of grant. (3) The annualized volatility is calculated by observing volatilities for comparable companies with adjustments for the Company’s size and leverage. Additionally, during the year ended December 31, 2017, the Company granted 5,504 time-based restricted stock units under the MIP to its non-employee directors with weighted average grant date fair value of $73.37 . Additionally, during the year ended December 31, 2017, the Company awarded certain of its non-employee directors 6,700 time-based cash restricted stock units under the MIP with a weighted grant date fair value of $62.55 . As of the grant date of the time-based cash restricted stock units, the Company did not have sufficient authorized and unissued common shares to settle these awards and the awards were expected to be settled with cash, unless shares became available for issuance under the MIP. Therefore, these awards were classified as a liability. On the applicable vesting date, shares were available for issuance and the awards vested as equity awards. The grant date fair value of both of these awards were based on the Company’s closing stock price at the date of grant and will vest on the first to occur of (i) the stated anniversary of the date of grant, (ii) the director’s separation from service (as defined in Section 409A of the Internal Revenue Code) due to the directors’ death or disability, and (iii) a change in control, subject in each case to the director’s continuous service with the Company through such date. Upon settlement of time-based restricted stock units, the Company issues authorized and unissued shares of the Company’s common stock to the recipient. In connection with the Company’s declaration and payment of the Special Dividend and pursuant to the terms of the MIP, dividend equivalent payments of approximately $7,949 in the aggregate (including the amounts payable with respect to each share underlying outstanding stock option awards and restricted stock unit awards and outstanding restricted stock awards under the MIP) were paid to plan participants. The dividend equivalent payments were made on July 11, 2017, which accelerated stock-based compensation expense by $5,113 and reduced the Company’s additional paid-in capital by $7,949 . Restricted Stock Restricted stock activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares outstanding at December 31, 2018 264,799 $ 65.55 Granted — $ — Vested (161,468 ) $ 65.55 Forfeited or Expired (79,733 ) $ 65.55 Non-vested shares outstanding at December 31, 2019 23,598 $ 65.55 As of December 31, 2019 , there was $81 of unrecognized compensation cost related to non-vested time-based restricted stock units which is expected to be recognized as expense during the first quarter of 2020. Restricted Stock Units Time-Based Restricted Stock Units Time-based restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares outstanding at December 31, 2018 251,875 $ 74.71 Granted 79,474 $ 49.47 Vested (1) (121,251 ) $ 72.59 Forfeited or Expired (52,016 ) $ 71.09 Non-vested shares outstanding at December 31, 2019 158,082 $ 64.84 (1) Includes 3,274 shares with deferred settlement pursuant to the award agreement. As of December 31, 2019 , there was $3,687 of unrecognized compensation cost related to non-vested time-based restricted stock units which is expected to be recognized as expense over a weighted-average period of 1.27 years. Time-based cash restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Fair Value (1) Non-vested shares outstanding at December 31, 2018 18,063 $ 65.74 Granted — $ — Vested (1) (18,063 ) $ 61.27 Forfeited or Expired — $ — Non-vested shares outstanding at December 31, 2019 — $ — (1) Pursuant to the award agreement, shares were available for issuance on the applicable vesting date and these shares were ultimately settled in equity. As of December 31, 2019 , there was $0 of unrecognized compensation cost related to non-vested time-based cash restricted stock units. Performance-Based Restricted Stock Units Relative performance-based restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Fair Value Non-vested shares outstanding at December 31, 2018 — $ — Granted 81,065 $ 65.70 Vested (1) (22,322 ) $ 65.70 Forfeited or Expired (27,144 ) $ 65.70 Non-vested shares outstanding at December 31, 2019 (1) 31,599 $ 65.70 (1) Includes 22,322 of vested shares due to the employment criteria being satisfied during the period. Until the performance criteria is satisfied, these shares will remain unsettled. As of December 31, 2019 , there was $1,459 of unrecognized compensation cost related to non-vested performance-based restricted stock units which is expected to be recognized as expense over a weighted-average period of 2.11 years. Absolute performance-based restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Fair Value Non-vested shares outstanding at December 31, 2018 — $ — Granted 27,042 $ 50.60 Vested (1) (7,443 ) $ 50.60 Forfeited or Expired (9,050 ) $ 50.60 Non-vested shares outstanding at December 31, 2019 (1) 10,549 $ 50.60 (1) Includes 7,443 of vested shares due to the employment criteria being satisfied during the period. Until the performance criteria is satisfied, these shares will remain unsettled. As of December 31, 2019 , there was $375 of unrecognized compensation cost related to non-vested performance-based restricted stock units which is expected to be recognized as expense over a weighted-average period of 2.11 years. Stock Options Fixed Price Stock Options Fixed price option activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (1) Outstanding at December 31, 2018 126,128 $ 2.50 7.57 $ 7,976 Exercisable at December 31, 2018 126,128 $ 2.50 7.57 $ 7,976 Granted — $ — Exercised (126,128 ) $ 2.50 $ 6,879 Forfeited or Expired — $ — Outstanding at December 31, 2019 — $ — — $ — Exercisable at December 31, 2019 — $ — — $ — (1) The aggregate intrinsic value of outstanding and exercisable options is calculated as the difference between the exercise price and the Company’s stock price at each reporting period end. The aggregate intrinsic value of exercised options is calculated as the difference between the exercise price and the Company’s stock price on the exercise date. During the year ended December 31, 2018, the aggregate intrinsic value of options exercised was $1,214 . No options were exercised during the year ended December 31, 2017. As of December 31, 2019 , there was no unrecognized compensation cost related to the fixed price stock options. 30-Day Volume-Weighted Average Price (“VWAP”) Stock Options 30-day VWAP stock option activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (1) Outstanding at December 31, 2018 255,648 $ 35.97 7.88 $ 7,611 Exercisable at December 31, 2018 177,152 $ 22.61 7.74 $ 7,641 Granted — $ — Exercised (123,876 ) $ 5.00 $ 6,305 Forfeited or Expired (80,413 ) $ 66.13 Outstanding at December 31, 2019 51,359 $ 63.45 7.15 $ (2,794 ) Exercisable at December 31, 2019 44,356 $ 63.03 7.15 $ (2,394 ) (1) The aggregate intrinsic value of outstanding and exercisable options is calculated as the difference between the exercise price and the Company’s stock price at each reporting period end. The aggregate intrinsic value of exercised options is calculated as the difference between the exercise price and the Company’s stock price on the exercise date. During the year ended December 31, 2018, the aggregate intrinsic value of options exercised was $1,169 . No options were exercised during the year ended December 31, 2017. As of December 31, 2019 , there was $12 of unrecognized compensation cost related to the 30-day VWAP stock options which is expected to be recognized as expense during the first quarter of 2020.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions On June 14, 2019, the Company entered into a Credit Agreement which provides for the Term Loan Credit Facility as provided by a group of existing shareholders as of the agreement date. Refer to Note 15 for additional disclosures. On July 19, 2019, in connection with Blackjewel’s bankruptcy filing, the U.S. Bankruptcy Court approved debtor-in-possession (“DIP”) financing of $2,900 with DIP lenders, Highbridge Capital Management, LLC and Whitebox Advisors LLC, which are existing shareholders of the Company. The Company entered into an arrangement on July 19, 2019 to purchase the obligations under the DIP financing at the request of the lenders thereunder pursuant to certain terms and conditions. Refer to Note 4 for further developments. On September 12, 2019, the Company entered into a common stock repurchase agreement with Whitebox Multi-Strategy Partners, L.P., Whitebox Asymmetric Partners, L.P., Whitebox Credit Partners, L.P. and Whitebox Institutional Partners, L.P., which are existing shareholders of the Company. Refer to Note 13 for additional disclosures. There were no other material related party transactions for the years ended December 31, 2019 , 2018 or 2017.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies (a) General Estimated losses from loss contingencies are accrued by a charge to income when information available indicates that it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. If a loss contingency is not probable or reasonably estimable, disclosure of the loss contingency is made in the Consolidated Financial Statements when it is at least reasonably possible that a loss may be incurred and that the loss could be material. (b) Commitments and Contingencies Commitments The Company leases coal mining and other equipment under long-term financing and operating leases with varying terms. Refer to Note 12 for further information on leases. In addition, the Company leases mineral interests and surface rights from land-owners under various terms and royalty rates. Coal royalty expense was $91,994 , $34,485 , and $21,707 for the years ended December 31, 2019 , 2018 , and 2017 , respectively. Minimum royalty obligations under coal leases total $14,692 , $13,762 , $11,866 , $10,846 , $8,692 , and $34,274 for 2020 , 2021 , 2022 , 2023 , 2024 , and after 2024 , respectively. Other Commitments The Company has obligations under certain coal purchase agreements that contain minimum quantities to be purchased in 2020 totaling an estimated $47,865 , which includes an estimated $3,677 related to contractually committed variable priced tons from vendors with historical performance resulting in less than 20% of the committed tonnage being delivered. The Company has obligations under certain coal transportation agreements that contain minimum quantities to be shipped in 2020 totaling $6,582 . The Company also has obligations under certain equipment purchase agreements that contain minimum quantities to be purchased in 2020 and 2022 totaling $19,283 and $279 , respectively. Contingencies Extensive regulation of the impacts of mining on the environment and of maintaining workplace safety has had and is expected to continue to have a significant effect on the Company’s costs of production and results of operations. Further regulations, legislation or litigation in these areas may also cause the Company’s sales or profitability to decline by increasing costs or by hindering the Company’s ability to continue mining at existing operations or to permit new operations. During the normal course of business, contract-related matters arise between the Company and its customers. When a loss related to such matters is considered probable and can reasonably be estimated, the Company records a liability. Per terms of the Back-to-Back Coal Supply Agreements, the Company is required to purchase and sell 1,337 tons of coal in 2020 totaling $13,878 . For the year ended December 31, 2019 , the Company purchased and sold 929 tons, totaling $9,941 under the Back-to-Back Coal Supply Agreements. For the year ended December 31, 2018 , the Company purchased and sold 5,719 tons, totaling $62,093 under the Back-to-Back Coal Supply Agreements. For the year ended December 31, 2017, the Company purchased and sold 2,000 tons, totaling $21,707 under the Back-to-Back Coal Supply Agreements. In October 2018, the State of Wyoming Department of Revenue invoiced Blackjewel for approximately $7,800 in severance taxes owed by Blackjewel in connection with the Wyoming properties it previously acquired from the Company. In connection with this invoice, the Department purported to assert liens over Contura Coal West, LLC, one of the Company’s subsidiaries. In connection with Blackjewel’s bankruptcy filing and the subsequent closing of the Eagle Specialty Materials Transaction (refer to Note 4 ), the State of Wyoming Department of Revenue also released the Company of any outstanding claims related to state tax obligations arising from or related to the Belle Ayr and Eagle Butte mines for any period through and including the closing date of the transaction. Refer to Note 27 for the subsequent event related to the new authorization process for self-insured coal mine operators being implemented by the U.S. Department of Labor (Division of Coal Mine Workers’ Compensation). Future Federal Income Tax Refunds As of December 31, 2019 , the Company has recorded $33,065 of federal income tax receivable and $33,065 of federal deferred tax asset related to AMT Credits. In addition, the Company has recorded a non-current federal income tax receivable of $64,160 related to an NOL carryback claim. Because the federal government was a creditor in the Alpha Natural Resources, Inc. (“Predecessor Alpha”) bankruptcy proceedings, it is possible that the federal government could withhold some or all of the tax refund attributable to the NOL carryback claim and the refundable AMT Credits and assert a right to setoff the tax refund and refundable credits against its prepetition bankruptcy claims. (c) Guarantees and Financial Instruments with Off-Balance Sheet Risk In the normal course of business, the Company is a party to certain guarantees and financial instruments with off-balance sheet risk, such as bank letters of credit, performance or surety bonds, and other guarantees and indemnities related to the obligations of affiliated entities which are not reflected in the Company’s Consolidated Balance Sheets. However, the underlying liabilities that they secure, such as asset retirement obligations, workers’ compensation liabilities, and royalty obligations, are reflected in the Company’s Consolidated Balance Sheets. The Company is required to provide financial assurance in order to perform the post-mining reclamation required by its mining permits, pay its federal production royalties, pay workers’ compensation claims under workers’ compensation laws in various states, pay federal black lung benefits, and perform certain other obligations. In order to provide the required financial assurance, the Company generally uses surety bonds for post-mining reclamation and workers’ compensation obligations. The Company can also use bank letters of credit to collateralize certain obligations. As of December 31, 2019 , the Company had outstanding surety bonds with a total face amount of $343,695 to secure various obligations and commitments. To secure the Company’s reclamation-related obligations, the Company currently has $95,542 of collateral supporting these obligations. Amounts included in restricted cash represent cash deposits that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $38,944 , $12,706 , $67,868 , and $3,006 as of December 31, 2019 for securing the Company’s obligations under certain worker’s compensation, black lung, reclamation-related obligations, and financial guarantees and other, respectively, which have been written on the Company’s behalf. Additionally, the Company has $12,363 of short-term restricted cash held in escrow related to the Company’s contingent revenue obligation. Refer to Note 16 for further information regarding the contingent revenue obligation. The Company’s restricted cash is primarily invested in interest bearing accounts. This restricted cash is classified as both short-term and long-term on the Company’s Consolidated Balance Sheets. Amounts included in restricted investments consist of certificates of deposit, mutual funds, and U.S. treasury bills that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $3,100 and $18,786 as of December 31, 2019 for securing the Company’s obligations under certain worker’s compensation and reclamation-related obligations, respectively, which have been written on the Company’s behalf. These restricted investments are classified as long-term on the Company’s Consolidated Balance Sheets. Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral. At December 31, 2019 , the Company had cash collateral in the form of deposits in the amounts of $8,887 and $1,836 to secure the Company’s obligations under reclamation-related obligations and various other operating agreements, respectively. These deposits are classified as both short-term and long-term on the Company’s Consolidated Balance Sheets. The Company meets frequently with its surety providers and has discussions with certain providers regarding the extent of and the terms of their participation in the program. These discussions may cause the Company to shift surety bonds between providers or to alter the terms of their participation in our program. To the extent that surety bonds become unavailable or the Company’s surety bond providers require additional collateral, the Company would seek to secure its obligations with letters of credit, cash deposits or other suitable forms of collateral. The Company’s failure to maintain, or inability to acquire, surety bonds or to provide a suitable alternative would have a material adverse effect on its liquidity. These failures could result from a variety of factors including lack of availability, higher cost or unfavorable market terms of new surety bonds, and the exercise by third-party surety bond issuers of their right to refuse to renew the surety. Letters of Credit As of December 31, 2019 , the Company had $99,876 in letters of credit outstanding under the Amended and Restated Asset-Based Revolving Credit Agreement. Additionally, as of December 31, 2019 , the Company had $33,399 in letters of credit outstanding under the Amended and Restated Letter of Credit Agreement dated November 9, 2018 between ANR, Inc. and Citibank, N.A. and $613 in letters of credit outstanding under the Credit and Security Agreement dated June 30, 2017, and related amendments, between ANR, Inc. and First Tennessee Bank National Association. (d) Legal Proceedings The Company is party to legal proceedings from time to time. These proceedings, as well as governmental examinations, could involve various business units and a variety of claims including, but not limited to, contract disputes, personal injury claims, property damage claims (including those resulting from blasting, trucking and flooding), environmental and safety issues, securities-related matters and employment matters. While some legal matters may specify the damages claimed by the plaintiffs, many seek an unquantified amount of damages. Even when the amount of damages claimed against the Company or its subsidiaries is stated, (i) the claimed amount may be exaggerated or unsupported; (ii) the claim may be based on a novel legal theory or involve a large number of parties; (iii) there may be uncertainty as to the likelihood of a class being certified or the ultimate size of the class; (iv) there may be uncertainty as to the outcome of pending appeals or motions; and/or (v) there may be significant factual issues to be resolved. As a result, if such legal matters arise in the future, the Company may be unable to estimate a range of possible loss for matters that have not yet progressed sufficiently through discovery and development of important factual information and legal issues. The Company records accruals based on an estimate of the ultimate outcome of these matters, but these estimates can be difficult to determine and involve significant judgment.

Concentration of Credit Risk an

Concentration of Credit Risk and Major Customers	12 Months Ended
	Dec. 31, 2019
Risks and Uncertainties [Abstract]
Concentration of Credit Risk and Major Customers	Concentration of Credit Risk and Major Customers The Company markets its coal principally to electric utilities in the United States and international and domestic steel producers. Credit is extended based on an evaluation of the customer’s financial condition and collateral is generally not required. Credit losses are provided for in the Financial Statements and were minimal for the years ended December 31, 2019 , 2018 and 2017 . Top customers as a percentage of total revenue and met and thermal coal as % of coal sales volume were as follows: Year Ended December 31, 2019 2018 2017 Total revenue $ 2,290,260 $ 2,031,205 $ 1,649,969 Top customer as % of total revenue (1) 12 % 17 % 15 % Top 10 customers as % of total revenue (2) 56 % 60 % 65 % Met coal as % of coal sales volume 55 % 63 % 57 % Thermal coal as % of coal sales volume 45 % 37 % 43 % (1) Revenues from the top customer are included in the CAPP - Met, CAPP - Thermal, and NAPP segments for the year ended December 31, 2019, the CAPP - Met and NAPP segments for the year ended December 31, 2018, and the CAPP - Met segment for the year ended December 31, 2017. (2) In addition to the top customer, the Company had another customer with total revenues of 10% of total revenues included in the CAPP - Met and CAPP - Thermal segments for the year ended December 31, 2019 and another customer with total revenues of 13% of total revenues included in the CAPP - Met and NAPP segments for the year ended December 31, 2018. Additionally, one of the Company’s customers had an outstanding balance in excess of 10% of the total accounts receivable balance as of December 31, 2019 , and two of the Company’s customers had outstanding balances each in excess of 10% of the total accounts receivable balance as of December 31, 2018 . The Company sold 2,327 tons of coal purchased from third parties, excluding tons sold related to the Back-to-Back Coal Supply Agreements, for the year ended December 31, 2019 , representing approximately 10% of total coal sales volume during such period. The Company sold 5,968 tons of coal purchased from third parties, excluding tons sold related to the Back-to-Back Coal Supply Agreements, for the year ended December 31, 2018 , representing approximately 34% of total coal sales volume during such period. The Company purchased 3,993 tons of this coal from Alpha during the year ended December 31, 2018 . The Company sold 4,998 tons of coal purchased from third parties for the year ended December 31, 2017, excluding tons sold related to the Back-to-Back Coal Supply Agreements, representing approximately 32% of total coal sales volume during such period. The Company purchased 4,189 tons of this coal from Alpha during the year ended December 31, 2017.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information The Company extracts, processes and markets met and thermal coal from surface and deep mines for sale to steel and coke producers, industrial customers, and electric utilities. The Company conducts mining operations only in the United States with mines in Central and Northern Appalachia. As of December 31, 2019 , the Company has three reportable segments: CAPP - Met, CAPP - Thermal, and NAPP. CAPP - Met consists of seven active mines and two preparation plants in Virginia, sixteen active mines and five preparation plants in West Virginia, as well as expenses associated with certain idled/closed mines. CAPP - Thermal consists of five active mines and two preparation plants in West Virginia, as well as expenses associated with certain idled/closed mines. NAPP consists of one active mine in Pennsylvania and one preparation plant, as well as expenses associated with one closed mine. Prior to the third quarter of 2019, the Company had four reportable segments: CAPP - Met, CAPP - Thermal, NAPP, and Trading and Logistics. As a result of the changes in key operating personnel during the third quarter of 2019 including changes to the Company’s Chief Operating Decision Maker (“CODM”), the Company was required to re-evaluate its previous conclusions with respect to its segment reporting during the period. To conform to the current period reportable segments presentation, the prior periods have been restated to reflect the change in reportable segments. Prior to the Merger, the Company had three reportable segments: CAPP, NAPP, and Trading and Logistics. In addition to the three reportable segments, the All Other category includes general corporate overhead and corporate assets and liabilities, idled and closed mine costs, and the elimination of certain intercompany activity. The operating results of these reportable segments are regularly reviewed by the “CODM,” who is the Chief Executive Officer of the Company. Segment operating results and capital expenditures from continuing operations for the year ended December 31, 2019 were as follows: Year Ended December 31, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,711,252 $ 286,486 $ 288,988 $ 3,534 $ 2,290,260 Depreciation, depletion, and amortization $ 153,006 $ 57,483 $ 12,864 $ 5,439 $ 228,792 Amortization of acquired intangibles, net $ 10,389 $ (13,578 ) $ 3,101 $ — $ (88 ) Adjusted EBITDA $ 316,324 $ 11,981 $ 31,185 $ (63,883 ) $ 295,607 Capital expenditures $ 140,250 $ 17,545 $ 31,964 $ 2,652 $ 192,411 Segment operating results and capital expenditures from continuing operations for the year ended December 31, 2018 were as follows: Year Ended December 31, 2018 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,671,219 $ 39,650 $ 317,039 $ 3,297 $ 2,031,205 Depreciation, depletion, and amortization $ 40,330 $ 10,596 $ 23,273 $ 3,350 $ 77,549 Amortization of acquired intangibles, net $ (12,334 ) $ (7,516 ) $ 14,458 $ — $ (5,392 ) Adjusted EBITDA $ 335,135 $ (875 ) $ 44,368 $ (43,552 ) $ 335,076 Capital expenditures $ 39,634 $ 1,280 $ 40,635 $ 332 $ 81,881 Segment operating results and capital expenditures from continuing operations for the year ended December 31, 2017 were as follows: Year Ended December 31, 2017 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,329,734 $ — $ 319,400 $ 835 $ 1,649,969 Depreciation, depletion, and amortization $ 18,941 $ — $ 15,087 $ 882 $ 34,910 Amortization of acquired intangibles, net $ 34,737 $ — $ 24,270 $ — $ 59,007 Adjusted EBITDA $ 264,314 $ — $ 54,433 $ (40,281 ) $ 278,466 Capital expenditures $ 20,494 $ — $ 51,007 $ 1,200 $ 72,701 The following table presents a reconciliation of net income (loss) from continuing operations to Adjusted EBITDA for the year ended December 31, 2019 : Year Ended December 31, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 8,224 $ (97,398 ) $ 11,926 $ (125,894 ) $ (203,142 ) Interest expense (1,209 ) 23 (723 ) 68,707 66,798 Interest income (100 ) — (49 ) (7,147 ) (7,296 ) Income tax benefit — — — (57,557 ) (57,557 ) Depreciation, depletion and amortization 153,006 57,483 12,864 5,439 228,792 Merger-related costs — — — 1,090 1,090 Non-cash stock compensation expense 1,494 71 — 10,783 12,348 Mark-to-market adjustment - acquisition-related obligations — — — (3,564 ) (3,564 ) Accretion on asset retirement obligations 9,466 10,929 4,066 3,337 27,798 Loss on modification and extinguishment of debt — — — 26,459 26,459 Asset impairment (1) 15,034 50,993 — 297 66,324 Goodwill impairment (2) 124,353 — — — 124,353 Cost impact of coal inventory fair value adjustment (3) 4,751 3,458 — — 8,209 Gain on assets acquired in an exchange transaction (4) (9,083 ) — — — (9,083 ) Management restructuring costs (5) — — — 7,720 7,720 Loss on partial settlement of benefit obligations (1 ) — — 6,447 6,446 Amortization of acquired intangibles, net 10,389 (13,578 ) 3,101 — (88 ) Adjusted EBITDA $ 316,324 $ 11,981 $ 31,185 $ (63,883 ) $ 295,607 (1) Asset impairment for the year ended December 31, 2019 includes a long-lived asset impairment of $60,169 related to asset groups recorded within the CAPP - Met and CAPP - Thermal reporting segments and an asset impairment of $6,155 primarily related to the write-off of prepaid purchased coal as a result of Blackjewel’s Chapter 11 bankruptcy filing on July 1, 2019. Refer to Note 2 and Note 4 for further information. (2) The goodwill impairment testing as of December 31, 2019 resulted in a goodwill impairment of $124,353 to write down the full carrying value of goodwill. Refer to Note 2 for further information. (3) The cost impact of the coal inventory fair value adjustment as a result of the Alpha Merger was completed during the three months ended June 30, 2019. (4) During the year ended December 31, 2019 , the Company entered into an exchange transaction which primarily included the release of the PRB overriding royalty interest owed to the Company in exchange for met coal reserves which resulted in a gain of $9,083 . (5) Management restructuring costs are related to severance expense associated with senior management changes in the year ended December 31, 2019. The following table presents a reconciliation of net income (loss) from continuing operations to Adjusted EBITDA for the year ended December 31, 2018 : Year Ended December 31, 2018 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 306,898 $ (10,796 ) $ 4,193 $ 2,559 $ 302,854 Interest expense 260 1 (1,286 ) 39,835 38,810 Interest income (40 ) — (34 ) (1,875 ) (1,949 ) Income tax benefit — — — (165,363 ) (165,363 ) Depreciation, depletion and amortization 40,330 10,596 23,273 3,350 77,549 Merger-related costs 22 1 — 51,777 51,800 Management restructuring costs (1) — — — 2,659 2,659 Non-cash stock compensation expense 408 24 — 11,546 11,978 Mark-to-market adjustment - acquisition-related obligations — — — 24 24 Gain on settlement of acquisition-related obligations — — — (580 ) (580 ) Gain on sale of disposal group (2) (16,386 ) — — — (16,386 ) Accretion on asset retirement obligations 4,430 1,298 3,764 474 9,966 Loss on modification and extinguishment of debt — — — 12,042 12,042 Cost impact of coal inventory fair value adjustment (3) 11,547 5,517 — — 17,064 Amortization of acquired intangibles, net (12,334 ) (7,516 ) 14,458 — (5,392 ) Adjusted EBITDA $ 335,135 $ (875 ) $ 44,368 $ (43,552 ) $ 335,076 (1) Management restructuring costs are related to severance expense associated with senior management changes in the year ended December 31, 2018 . (2) The Company recorded a gain on disposal of assets of $16,386 within other (income) expense within the Consolidated Statements of Operations. (3) The cost impact of the coal inventory fair value adjustment as a result of the Alpha Merger was completed during the three months ended June 30, 2019. The following table presents a reconciliation of net income (loss) from continuing operations to Adjusted EBITDA for the year ended December 31, 2017 : Year Ended December 31, 2017 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 204,213 $ — $ 12,334 $ (42,812 ) $ 173,735 Interest expense (90 ) — (1,505 ) 37,572 35,977 Interest income (22 ) — (1 ) (187 ) (210 ) Income tax benefit — — — (67,979 ) (67,979 ) Depreciation, depletion and amortization 18,941 — 15,087 882 34,910 Non-cash stock compensation expense 650 — — 19,559 20,209 Mark-to-market adjustment - acquisition-related obligations — — — 3,221 3,221 Gain on settlement of acquisition-related obligations — — — (38,886 ) (38,886 ) Secondary offering costs — — — 4,491 4,491 Loss on modification and extinguishment of debt — — — 38,701 38,701 Bargain purchase gain — — — (1,011 ) (1,011 ) Accretion on asset retirement obligations 5,770 — 4,164 — 9,934 Amortization of acquired intangibles, net 34,737 — 24,270 — 59,007 Expenses related to the dividend 115 — 84 6,168 6,367 Adjusted EBITDA $ 264,314 $ — $ 54,433 $ (40,281 ) $ 278,466 No asset information has been provided for these reportable segments as the CODM does not regularly review asset information by reportable segment. The Company markets produced, processed and purchased coal to customers in the United States and in international markets, primarily India, Brazil, Turkey, the Netherlands, and France. Export coal revenues were the following: Year Ended December 31, 2019 2018 2017 Total coal revenues (1) $ 2,282,007 $ 2,020,889 $ 1,639,883 Export coal revenues (1) (2) $ 1,247,614 $ 1,671,646 $ 1,265,320 Export coal revenues as % of total coal revenues (1) 55 % 83 % 77 % (1) Amounts include freight and handling revenues. (2) The amounts for the year ended December 31, 2019 include $288,344 of export coal revenues from external customers in India, recorded within the CAPP - Met, CAPP - Thermal, and NAPP segments. The amounts for the year ended December 31, 2018 include $420,919 and $285,120 of export coal revenues from external customers in India and Brazil, respectively, recorded within the CAPP - Met, CAPP - Thermal, and NAPP segments. The amounts for the year ended December 31, 2017 include $356,673 of export coal revenues, including freight and handling revenues, from external customers in India, recorded within the CAPP - Met and NAPP segments. Revenue is tracked within the Company’s accounting records based on the product destination.

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	Quarterly Financial Information (Unaudited) Year Ended December 31, 2019 First Quarter (1) Second Quarter (2) Third Quarter (2) Fourth Quarter (3) Total revenues $ 609,114 $ 656,206 $ 525,864 $ 499,076 Net income (loss) from continuing operations $ 7,990 $ 24,300 $ (43,561 ) $ (191,871 ) Net (loss) income from discontinued operations (1,175 ) (137,961 ) (24,971 ) 50,930 Net income (loss) $ 6,815 $ (113,661 ) $ (68,532 ) $ (140,941 ) Weighted average shares - basic 18,894,315 19,123,705 19,025,462 18,195,651 Weighted average shares - diluted 19,538,629 19,420,471 19,025,462 18,195,651 Basic income (loss) per share: Income (loss) from continuing operations $ 0.42 $ 1.27 $ (2.29 ) $ (10.54 ) (Loss) income from discontinued operations (0.06 ) (7.21 ) (1.31 ) 2.79 Net income (loss) $ 0.36 $ (5.94 ) $ (3.60 ) $ (7.75 ) Diluted income (loss) per share: Income (loss) from continuing operations $ 0.41 $ 1.25 $ (2.29 ) $ (10.54 ) (Loss) income from discontinued operations (0.06 ) (7.10 ) (1.31 ) 2.79 Net income (loss) $ 0.35 $ (5.85 ) $ (3.60 ) $ (7.75 ) (1) Net income from continuing operations in the first quarter of 2019 includes a gain on assets acquired in an exchange transaction of $9,083 within other income within the Company’s Statements of Operations. Refer to Note 25 . (2) Net income from continuing operations in the second quarter and third quarter of 2019 include asset impairment of $5,826 and $32 , respectively. Refer to Note 2 . Net income from continuing operations in the second quarter of 2019 includes a loss on modification and extinguishment of debt of $26,459 . Refer to Note 15 . (3) Net loss from continuing operations in the fourth quarter of 2019 includes asset impairment of $60,466 and goodwill impairment of $124,353 . Refer to Note 2 . Year Ended December 31, 2018 First Quarter Second Quarter (2) Third Quarter Fourth Quarter (3) Total revenues $ 482,332 $ 528,918 $ 447,871 $ 572,084 Net income from continuing operations (1) $ 58,300 $ 74,642 $ 14,011 $ 155,901 Net (loss) income from discontinued operations (1,359 ) (854 ) (2,117 ) 641 Net income $ 56,941 $ 73,788 $ 11,894 $ 156,542 Weighted average shares - basic 9,548,613 9,625,874 9,633,164 15,014,994 Weighted average shares - diluted 10,292,607 10,306,043 10,384,513 15,822,037 Basic income (loss) per share: Income from continuing operations $ 6.11 $ 7.75 $ 1.45 $ 10.38 (Loss) income from discontinued operations (0.15 ) (0.08 ) (0.22 ) 0.04 Net income $ 5.96 $ 7.67 $ 1.23 $ 10.42 Diluted (loss) income per share: Income from continuing operations $ 5.66 $ 7.24 $ 1.35 $ 9.85 (Loss) income from discontinued operations (0.13 ) (0.08 ) (0.20 ) 0.04 Net income $ 5.53 $ 7.16 $ 1.15 $ 9.89 (1) Net income from continuing operations includes merger-related costs of $460 , $3,423 , $1,181 , and $46,736 for each of the four quarters of 2018, respectively. (2) Net income from continuing operations in the second quarter of 2018 includes a gain on sale of a disposal group of ($16,386) within other (income) expense within the Company’s Statements of Operations. Refer to Note 2 for further information. (3) Net income from continuing operations in the fourth quarter of 2018 includes an income tax benefit of $165,496 . Refer to Note 19 for further information. Additionally, net income from continuing operations in the fourth quarter of 2018 included a loss on modification and extinguishment of debt of ($12,042) . Refer to Note 15 for further information.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In July 2019, the U.S. Department of Labor (Division of Coal Mine Workers’ Compensation or “DCMWC”) began implementing a new authorization process for all self-insured coal mine operators. As requested by the DCMWC, the Company filed in October 2019 an application and supporting documentation for reauthorization to self-insure certain of its black lung obligations. As a result of this application, the DCMWC notified the Company in a letter dated February 21, 2020 and received on February 24, 2020, that the Company was reauthorized to self-insure certain of its black lung obligations for a period of one-year from February 21, 2020. The DCMWC reauthorization is contingent, however, upon the Company’s providing collateral of $65,700 to secure certain of its black lung obligations. This proposed collateral requirement is an increase from the approximate $2,600 in collateral that the Company currently provides to secure these self-insured black lung obligations. The reauthorization process provided the Company with the right to appeal the security determination in writing within 30 days of the date of the notification, which appeal period the DCMWC has agreed to extend to April 22, 2020 . The Company plans to exercise this right of appeal in connection with the substantial increase in the amount of required collateral. If the Company’s appeal is unsuccessful, the Company may be required to provide additional letters of credit to receive the self-insurance reauthorization from the DCMWC or alternatively insure these black lung obligations through a third party provider that would likely also require the Company to provide collateral. Either of these outcomes could potentially reduce the Company’s liquidity.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Together, the consolidated balance sheet and consolidated statements of operations, comprehensive (loss) income, cash flows and stockholders’ equity for the Company are referred to as the “Financial Statements.” The Financial Statements are also referred to as “Consolidated” and references across periods are generally labeled “Balance Sheets,” “Statements of Operations,” and “Statements of Cash Flows.” The Consolidated Financial Statements include all wholly owned subsidiaries’ results of operations for the years ended December 31, 2019 , 2018 and 2017 . All significant intercompany transactions have been eliminated in consolidation. For the year ended December 31, 2018, the Alpha Companies’ financial results are included in the Financial Statements for the period from November 9, 2018 through December 31, 2018. The Alpha Companies’ financial results are not included in the Financial Statements in periods prior to November 9, 2018. Refer to Note 3 for information on Alpha Merger. On December 8, 2017, the Company closed a transaction with Blackjewel L.L.C. (“Buyer”) to sell the Eagle Butte and Belle Ayr mines located in the Powder River Basin (“PRB”), Wyoming, along with related coal reserves, equipment, infrastructure and other real properties. The PRB results of operations and financial position are reported as discontinued operations in the Consolidated Financial Statements. The historical information in the accompanying Notes to the Consolidated Financial Statements has been restated to reflect the effects of the PRB operations being reported as discontinued operations in the Consolidated Financial Statements. Refer to Note 4 for further information on discontinued operations. The accompanying Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”).
Liquidity	Liquidity Risks and Uncertainties Weak market conditions and depressed coal prices have resulted in operating losses. If market conditions do not improve, the Company may experience continued operating losses and cash outflows in the coming quarters, which would adversely affect its liquidity. The Company may need to raise additional funds more quickly if market conditions deteriorate, and may not be able to do so in a timely fashion, or at all. The Company has cash on hand which will be sufficient to meet its working capital requirements, anticipated capital expenditures, debt service requirements, acquisition-related obligations, and reclamation obligations for the 12 months subsequent to the issuance of these financial statements. The Company relies on a number of assumptions in budgeting for future activities. These include the costs for mine development to sustain capacity of its operating mines, cash flows from operations, effects of regulation and taxes by governmental agencies, mining technology improvements and reclamation costs. These assumptions are inherently subject to significant business, political, economic, regulatory, environmental and competitive uncertainties, contingencies and risks, all of which are difficult to predict and many of which are beyond the Company’s control. Therefore, the cash on hand and from future operations will be subject to any significant changes in these assumptions.
Reclassifications	Reclassifications Freight and handling costs has been reclassified in the prior year periods from a separate line item into cost of coal sales in the Consolidated Statements of Operations to conform to the current year presentation.
Use of Estimates	Use of Estimates The preparation of the Company’s Consolidated Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include inventories; mineral reserves; asset impairments; goodwill impairment; reclamation obligations; post-employment and other employee benefit obligations; useful lives, depletion and amortization; reserves for workers’ compensation and black lung claims; deferred income taxes; income taxes refundable and receivable; reserves for contingencies and litigation; fair value of financial instruments; and fair value adjustments for acquisition accounting. Estimates are based on facts and circumstances believed to be reasonable at the time; however, actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash held with reputable depository institutions and highly liquid, short-term investments with original maturities of three months or less. Cash and cash equivalents are stated at cost, which approximates fair value. As of December 31, 2019 and December 31, 2018 , the Company’s cash equivalents of $212,793 and $233,599 , respectively, consisted of highly-rated money market funds.
Restricted Cash	Restricted Cash Amounts included in restricted cash represent cash deposits that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $38,944 , $12,706 , $67,868 , and $3,006 as of December 31, 2019 for securing the Company’s obligations under certain workers’ compensation, black lung, reclamation-related obligations, and financial guarantees and other, respectively, which have been written on the Company’s behalf. Additionally, the Company had $12,363 of short-term restricted cash held in escrow related to the Company’s contingent revenue payment obligation as of December 31, 2019. As of December 31, 2018 , collateral was provided in the amounts of $90,759 , $29,611 , $86,217 , $27,386 , and $2,833 for securing the Company’s obligations under certain workers’ compensation, black lung, reclamation-related obligations, general liabilities, and financial guarantees, respectively, which have been written on the Company’s behalf. Additionally, the Company had $6,841 of short-term restricted cash held in escrow related to the Company’s contingent revenue payment obligation as of December 31, 2018. Refer to Note 16 for further information regarding the contingent payment revenue obligation. The Company’s restricted cash is primarily invested in interest-bearing accounts. This restricted cash is classified as both short-term and long-term on the Company’s Consolidated Balance Sheets.
Restricted Investments	Restricted Investments Amounts included in restricted investments consist of certificates of deposit, mutual funds, and U.S. treasury bills classified as either trading securities or held-to-maturity securities. The trading securities are recorded initially at cost and adjusted to fair value at each reporting period. The trading securities’ unrealized gains and losses resulting from fair value adjustments are recorded in current period earnings or loss. The held-to-maturity securities are recorded at amortized cost with interest income recorded in current period earnings. These restricted investments are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral in the amounts of $3,100 and $18,786 as of December 31, 2019 for securing the Company’s obligations under certain workers’ compensation and reclamation-related obligations, respectively, which have been written on the Company’s behalf, of which $13,508 are classified as trading securities and $8,378 are classified as held-to-maturity securities. As of December 31, 2018, collateral was provided in the amounts of $1,888 , $27,049 , and $200 for securing the Company’s obligations under certain workers’ compensation, reclamation-related obligations, and general liabilities, respectively, which have been written on the Company’s behalf, of which all were classified as held-to-maturity securities. These restricted investments are classified as long-term on the Company’s Consolidated Balance Sheets.
Deposits	Deposits Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral. The Company had cash collateral in the form of deposits in the amounts of $8,887 and $1,836 as of December 31, 2019 and $24,002 and $1,390 as of December 31, 2018 to secure the Company’s obligations under reclamation-related obligations and various other operating agreements, respectively. These deposits are classified as both short-term and long-term on the Company’s Consolidated Balance Sheets.
Trade Accounts Receivable and Allowance for Doubtful Accounts	Trade Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are recorded at the invoiced amount and do not bear interest. The Company records an allowance for doubtful accounts at the estimate of the amount of probable credit losses in the Company’s existing accounts receivable. The Company establishes provisions for losses on accounts receivable when it is probable that all or part of the outstanding balance will not be collected. The Company regularly reviews its accounts receivable balances and establishes or adjusts the allowance as necessary primarily using the specific identification method. The allowance for doubtful accounts was $0 at both December 31, 2019 and 2018 . Account balances are written off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote.
Inventories	Inventories Coal is reported as inventory at the point in time the coal is extracted from the mine. Raw coal represents coal stockpiles that may be sold in current condition or may be further processed prior to shipment to a customer. Saleable coal represents coal stockpiles that require no further processing prior to shipment to a customer. Coal inventories are valued at the lower of average cost or net realizable value. The cost of coal inventories is determined based on the average cost of production, which includes labor, supplies, equipment costs, operating overhead, depreciation, and other related costs. Net realizable value considers the projected future sales price of the product, less estimated preparation and selling costs. Material and supplies inventories are valued at average cost, less an allowance for obsolete and surplus items.
Discontinued Operations	Discontinued Operations In accordance with Accounting Standards Codification (“ASC”) 205-20-45, the Company treats a disposal transaction as a discontinued operation when the disposal of a component or group of components represents a strategic shift that will have a major effect on the Company’s operations and financial results. In the period in which the discontinued operations criteria are met, the assets and liabilities of the discontinued operations are separately presented on the Company's Consolidated Balance Sheets and the results of operations, including any gain or loss recognized, is reclassified to discontinued operations on the Company’s Consolidated Statement of Operations. Refer to Note 4 for further information on discontinued operations.
Deferred Longwall Move Expenses	Deferred Longwall Move Expenses The Company defers the direct costs, including labor and supplies, associated with moving longwall equipment, the related equipment refurbishment costs, costs to drill vent holes and plug existing gas wells in advance of the longwall panel. These deferred costs are amortized on a units-of-production basis into cost of coal sales over the life of the related panel of coal mined by the longwall equipment.
Advanced Mining Royalties	Advanced Mining Royalties Lease rights to coal reserves are often acquired in exchange for royalty payments. Advance mining royalties are advance payments made to lessors under terms of mineral lease agreements that are recoupable against future production royalties. These advance payments are deferred and charged to operations as the coal reserves are mined. The Company regularly reviews recoverability of advance mining royalties and establishes or adjusts the allowance for advance mining royalties as necessary using the specific identification method. Advance royalty balances are generally charged off against the allowance when they are no longer recoupable.
Property, Plant and Equipment, Net	Property, Plant, and Equipment, Net Costs for mine development incurred to expand capacity of operating mines or to develop new mines are capitalized and charged to operations on the units-of-production method over the estimated proven and probable reserve tons directly benefiting from the capital expenditures. Mine development costs include costs incurred for site preparation and development of the mines during the development stage less any incidental revenue generated during the development stage. Mining equipment, buildings and other fixed assets are stated at cost and depreciated on a straight-line basis over estimated useful lives ranging from one to 47 years. Leasehold improvements are amortized using the straight-line method, over the shorter of the estimated useful lives or term of the lease. Major repairs and betterments that significantly extend original useful lives or improve productivity are capitalized and depreciated over the period benefited. Maintenance and repairs are expensed as incurred. When equipment is retired or disposed, the related cost and accumulated depreciation are removed from the respective accounts and any profit or loss on disposal is recognized in other (income) expense in the Company’s Consolidated Statements of Operations. Costs to obtain owned and leased mineral rights are capitalized and amortized to operations as depletion expense using the units-of-production method. Only proven and probable reserves are included in the depletion base.
Owned and Leased Mineral Rights	Costs to obtain owned and leased mineral rights are capitalized and amortized to operations as depletion expense using the units-of-production method. Only proven and probable reserves are included in the depletion base.
Acquired Intangibles	Acquired Intangibles The Company has recognized assets for acquired above market-priced coal supply agreements and acquired mine permits and liabilities for acquired below market-priced coal supply agreements. The coal supply agreements were valued based on the present value of the difference between the expected net contractual cash flows based on the stated contract terms, and the estimated net contractual cash flows derived from applying forward market prices at the Merger or acquisition date for new contracts of similar terms and conditions. The acquired mine permits were valued based on the replacement cost and lost profits method as of the Merger date. The balances and respective balance sheet classifications of such assets and liabilities as of December 31, 2019 and 2018 , net of accumulated amortization, are set forth in the following tables: December 31, 2019 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 917 $ (6,018 ) $ (5,101 ) Acquired mine permits, net 124,228 — 124,228 Total $ 125,145 $ (6,018 ) $ 119,127 December 31, 2018 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 4,687 $ (33,912 ) $ (29,225 ) Acquired mine permits, net 149,897 — 149,897 Total $ 154,584 $ (33,912 ) $ 120,672 (1) Included within other acquired intangibles, net of accumulated amortization, on the Company’s Consolidated Balance Sheets. (2) Included within other non-current liabilities on the Company’s Consolidated Balance Sheets. During the year ended December 31, 2019, the Company recorded a long-lived asset impairment which reduced the carrying value of acquired mine permits, net, by $5,997 . Refer to the asset impairment disclosure included in Note 2 . The acquired mine permits are amortized over the estimated life of the associated mine. The coal supply agreement assets and liabilities are amortized over the actual number of tons shipped over the life of each contract. Amortization of mine permits acquired as a result of the Merger was $23,921 and $3,409 for the years ended December 31, 2019 and 2018, respectively, which is reported within amortization of acquired intangibles, net, in the Consolidated Statements of Operations. Amortization of above-market coal supply agreements was $3,884 , $14,506 , and $59,007 , and amortization of below-market coal supply agreements was ($27,893) , ($23,307) , and $0 , resulting in a net (income) expense of ($24,009) , ($8,801) , and $59,007 for the years ended December 31, 2019 , 2018 , and 2017, respectively, which is reported within amortization of acquired intangibles, net, in the Consolidated Statements of Operation
Goodwill	Goodwill Goodwill represents the excess of the purchase price over the fair value of the net identifiable tangible and intangible assets of acquired companies. In connection with the Merger, the Company recorded goodwill of $124,353 and allocated it to the CAPP - Met reportable segment. Refer to Note 3 for further information. Goodwill is not amortized; instead, it is tested for impairment annually as of October 31 of each year or more frequently if indicators of impairment exist. The Company performed an interim goodwill impairment test as of August 31, 2019 due to a decline in the Company’s market capitalization to amounts below book value combined with a decline in global metallurgical coal pricing which indicated that the fair value of the CAPP - Met segment reporting unit may have been below its carrying value. Following the quantitative testing, the Company concluded that the fair value of the reporting unit exceeded its carrying value and no amounts of goodwill were impaired. As of October 31, 2019, the Company performed its annual goodwill impairment test and concluded that more likely than not the fair value of its CAPP - Met reporting unit to which the Company’s goodwill is allocated exceeded its carrying value. As a result, no amounts of goodwill were considered impaired as a result of impairment testing at October 31, 2019. However, due to the continued weakening in coal market pricing combined with a significant market price decline for the Company’s stock late in the fourth quarter of 2019, the Company performed an interim goodwill impairment test as of December 31, 2019. Following the quantitative testing, the Company concluded that the carrying value of the CAPP - Met reporting unit exceeded its fair value and recorded a goodwill impairment of $124,353 to write down the full carrying amount of goodwill. The Company early adopted Accounting Standards Update (“ASU”) 2017-04 for the period ended December 31, 2017, which eliminated Step 2 of the quantitative goodwill impairment test. The Company first assesses goodwill for impairment on a qualitative basis. If the Company determines that more likely than not the fair value of a reporting unit containing goodwill exceeds its carrying amount, no further impairment testing is required. If the qualitative assessment indicates that an impairment potentially exists, then the Company quantitatively tests goodwill for impairment by comparing the fair value of the reporting unit to its carrying amount. If the fair value of the reporting unit is lower than its carrying amount, its goodwill is written down by the lesser of the amount by which the reporting units carrying amount exceeded its fair value or its carrying amount of goodwill. The valuation methodology utilized to estimate the fair value of the reporting units is based on both a market and income approach and is within the range of fair values yielded under each approach. The income approach is based on a discounted cash flow methodology in which expected future net cash flows are discounted to present value, using an appropriate after-tax weighted average cost of capital (discount rate). The market approach is based on a guideline company and similar transaction methodology. Under the guideline company approach, certain metrics from a selected group of publicly traded guideline companies that have similar operations to the Company’s reporting units are used to estimate the fair value of the reporting units. Under the similar transactions approach, recent merger and acquisition transactions for companies that have similar operations to the Company’s reporting units are used to estimate the fair value of the Company’s reporting units.
Asset Impairment	Asset Impairment Long-lived assets, such as property, plant, and equipment, and acquired intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset groups may not be recoverable. Recoverability of assets or asset groups to be held and used is measured by a comparison of the carrying amount of an asset or asset group to the estimated undiscounted future cash flows expected to be generated by the asset or asset group. Long-lived assets located in a close geographic area are grouped together for purposes of impairment testing when, after considering revenue and cost interdependencies, circumstances indicate the assets are used together to produce future cash flows. The Company’s asset groups generally consist of the assets and applicable liabilities of one or more mines and preparation plants and associated coal reserves for which cash flows are largely independent of cash flows of other mines, preparation plants, and associated coal reserves. If the carrying amount of an asset or asset group exceeds its estimated future cash flows, the potential impairment is equal to the amount by which the carrying amount of the asset or asset group exceeds the fair value of the asset or asset group. The Company estimates the fair value of an asset group using discounted cash flow analyses utilizing marketplace participant assumptions. The amount of impairment, if any, is allocated to the long-lived assets on a pro-rata basis, except that the carrying value of the individual long-lived assets are not reduced below their estimated fair value. During the year ended December 31, 2019, the Company determined that indicators of impairment were present for three long-lived asset groups within each of its CAPP - Met and CAPP - Thermal reporting segments and performed impairment testing as of December 31, 2019. At December 31, 2019, the Company determined that the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. As a result, after allocating the potential impairment to individual assets, the Company recorded a long-lived asset impairment of $60,169 , of which $9,176 was recorded within CAPP - Met and $50,993 was recorded within CAPP - Thermal. The long-lived asset impairment reduced the carrying values of mineral rights by $35,445 , property, plant, and equipment, net, by $17,056 , acquired mine permits, net, by $5,997 , and long-lived assets related to asset retirement obligations by $1,671 . There were no asset impairments during the years ended December 31, 2018 and 2017. Additionally, during the year ended December 31, 2019, the Company recorded an asset impairment of $6,155 primarily related to the write-off of prepaid purchased coal as a result of Blackjewel’s Chapter 11 bankruptcy filing on July 1, 2019. Refer to Note 4 for further information.
Asset Retirement Obligations	Asset Retirement Obligations Minimum standards for mine reclamation have been established by various regulatory agencies and dictate the reclamation requirements at the Company’s operations. The Company’s asset retirement obligations consist principally of costs to reclaim acreage disturbed at surface operations and estimated costs to reclaim support acreage, treat mine water discharge, and perform other related functions at underground mines. The Company records these reclamation obligations at fair value in the period in which the legal obligation associated with the retirement of the long-lived asset is incurred. Changes to the liability at operations that are not currently being reclaimed are offset by increasing or decreasing the carrying amount of the related long-lived asset. Changes to the liability at operations that are currently being reclaimed are recorded to depreciation, depletion, and amortization. Over time, the liability is accreted and any capitalized cost is depreciated or depleted over the useful life of the related asset. To settle the liability, the obligation is paid, and to the extent there is a difference between the liability and the amount of cash paid, a gain or loss upon settlement is recorded. The Company annually reviews its estimated future cash flows for its asset retirement obligations. Refer to Note 17 for further disclosures related to asset retirement obligations.
Income Taxes	Income Taxes The Company recognizes deferred tax assets and liabilities using enacted tax rates for the effect of temporary differences between the book and tax basis of recorded assets and liabilities. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax asset will not be realized. In evaluating its ability to recover deferred tax assets within the jurisdiction in which they arise, the Company considers all available positive and negative evidence, including the expected reversals of taxable temporary differences, projected future taxable income, taxable income available via carryback to prior years, tax planning strategies, and results of recent operations. The Company assesses the realizability of its deferred tax assets, including scheduling the reversal of its deferred tax assets and liabilities, to determine the amount of valuation allowance needed. Scheduling the reversal of deferred tax asset and liability balances requires judgment and estimation. The Company believes that the deferred tax liabilities relied upon as future taxable income in its assessment will reverse in the same period and jurisdiction and are of the same character as the temporary differences giving rise to the deferred tax assets that will be realized.
Revenue Recognition	Revenue Recognition The Company adopted ASC 606 Revenue from Contracts with Customers (“ASC 606”), with a date of initial application of January 1, 2018, using the modified retrospective method. The Company applied the guidance only to contracts that were not completed as of the date of adoption, with no cumulative adjustment to retained earnings as a result of the adoption of this guidance. As a result, the Company made changes to its accounting policy for revenue recognition as outlined below. Subsequent to the adoption of ASC 606, the Company measures revenue based on the consideration specified in a contract with a customer and recognizes revenue as a result of satisfying its promise to transfer goods or services in a contract with a customer using the following general revenue recognition five-step model: (1) identify the contract; (2) identify performance obligations; (3) determine transaction price; (4) allocate transaction price; and (5) recognize revenue. Freight and handling costs paid to third-party carriers and invoiced to coal customers are recorded as freight and handling costs and freight and handling fulfillment revenues within cost of coal sales and coal revenues, respectively. Prior to the adoption of ASC 606, the Company earned revenues primarily through the sale of coal produced at Company operations and coal purchased from third parties. The Company recognized revenue using the following general revenue recognition criteria: (i) persuasive evidence of an arrangement exists; (ii) delivery had occurred or services have been rendered; (iii) the price to the buyer was fixed or determinable; and (iv) collectability was reasonably assured. Delivery on the Company’s coal sales was determined to be complete for revenue recognition purposes when title and risk of loss had passed to the customer in accordance with stated contractual terms and there are no other future obligations related to the shipment. For domestic shipments, title and risk of loss generally passed as the coal is loaded into transport carriers for delivery to the customer. For international shipments, title generally passed at the time coal is loaded onto the shipping vessel. Freight and handling costs paid to third-party carriers and invoiced to coal customers were recorded as freight and handling costs and freight and handling revenues, respectively. Adoption of ASC 606 Subsequent to adoption of ASC 606, freight and handling revenues are now classified within coal revenues. Under ASC 606, the Company has elected to treat all shipping and handling costs as fulfillment costs and to recognize these amounts within coal revenues upon control transfer. Prior to the adoption of ASC 606, all freight and handling activities occurring subsequent to control transfer were accounted for as deferred revenue and recognized within freight and handling revenues as the Company fulfilled the related shipping activity. Refer to Note 5 for further disclosure requirements under the new standard. The following table summarizes the impact of the adoption of ASC 606 to the Company’s Consolidated Statements of Operations: Year Ended December 31, 2018 As reported Adjustments (1) Balances prior to adoption of ASC 606 Revenues: Coal revenues $ 2,020,889 $ (363,128 ) $ 1,657,761 Freight and handling revenues — 362,346 362,346 Other revenues 10,316 — 10,316 Total revenues $ 2,031,205 $ (782 ) $ 2,030,423 Freight and handling costs $ 363,128 $ (782 ) $ 362,346 (1) Adjustments primarily represent freight and handling revenues being treated as fulfillments costs and included within coal revenues under ASC 606. The remainder of these adjustments represent freight and handling activity occurring subsequent to control transfer also impacting freight and handling costs and prepaid expenses.
Deferred Financing Costs	Deferred Financing Costs The costs to obtain new debt financing or amend existing financing agreements are generally deferred and amortized to interest expense over the life of the related indebtedness or credit facility using the effective interest method. Unamortized deferred financing costs are presented in the Consolidated Balance Sheet as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts or premiums. Unamortized deferred financing costs associated with undrawn credit facilities are included in the Consolidated Balance Sheets within other non-current assets.
Workers' Compensation and Pneumoconiosis (Black Lung) Benefits, Pension and Life Insurance Benefits	Workers’ Compensation and Pneumoconiosis (Black Lung) Benefits Workers’ Compensation As of December 31, 2019 , the Company’s subsidiaries generally utilize high-deductible insurance programs for workers’ compensation claims at its operations with the exception of certain subsidiaries in which the Company is a qualified self-insurer for workers’ compensation related obligations. The liabilities for workers’ compensation claims are estimates of the ultimate losses incurred based on the Company’s experience, and include a provision for incurred but not reported losses. Adjustments to the probable ultimate liabilities are made annually based on an actuarial study and adjustments to the liability are recorded based on the results of this study. These short-term and long-term obligations are included in the Consolidated Balance Sheets within accrued expenses and other current liabilities and workers’ compensation and black lung obligations, respectively, with an offsetting insurance receivable within prepaid expenses and other current assets and other non-current assets. As of December 31, 2019 and 2018, the workers’ compensation liability was net of a discount of $24,458 and $24,655 , respectively, related to fair value adjustments associated with acquisition accounting. Refer to Note 20 for further disclosures related to workers’ compensation. Black Lung Benefits The Company is required by federal and state statutes to provide benefits to employees for awards related to black lung. As of December 31, 2019 , certain of the Company’s subsidiaries are insured for black lung obligations by a third-party insurance provider and certain subsidiaries are self-insured for state black lung obligations. Certain other subsidiaries are self-insured for federal black lung benefits and may fund benefit payments through Section 501(c)(21) tax-exempt trust fund. Charges are made to operations for black lung claims, as determined by an independent actuary at the present value of the actuarially computed liability for such benefits over the employee’s applicable term of service. The Company recognizes in its balance sheet the amount of the Company’s unfunded Accumulated Benefit Obligation (“ABO”) at the end of the year. Amounts recognized in accumulated other comprehensive income (loss) are adjusted out of accumulated other comprehensive income (loss) when they are subsequently recognized as components of net periodic benefit cost. These short-term and long-term obligations are included in the Consolidated Balance Sheets within accrued expenses and other current liabilities and workers’ compensation and black lung obligations, respectively. Refer to Note 20 for further disclosures related to black lung benefits. Pension The Company is required to recognize the overfunded or underfunded status of a defined benefit pension plan as an asset or liability in its Consolidated Balance Sheets and to recognize changes in that funded status in the year in which the changes occur through other comprehensive (loss) income. The Company is required to measure plan assets and benefit obligations as of the date of the Company’s fiscal year-end Consolidated Balance Sheet and provide the required disclosures as of the end of each fiscal year. Refer to Note 20 for further disclosures related to pension. Life Insurance Benefits As part of the Alpha Restructuring and the Retiree Committee Settlement Agreement, the Company assumed the liability for life insurance benefits for certain disabled and non-union retired employees. Provisions are made for estimated benefits based on annual evaluations prepared by independent actuaries. Adjustments to the probable ultimate liabilities are made annually based on an actuarial study and adjustments to the liability are recorded based on the results of this study. These obligations are included in the Consolidated Balance Sheet as accrued expenses and other current liabilities and other non-current liabilities. Refer to Note 20 for further disclosures related to life insurance benefits.
Net (Loss) Income Per Share	Net (Loss) Income per Share Basic net (loss) income per share is computed by dividing net (loss) income by the weighted-average number of outstanding common shares for the period. Diluted (loss) earnings per share reflects the potential dilution that could occur if instruments that may require the issuance of common shares in the future were settled and the underlying common shares were issued. Diluted (loss) earnings per share is computed by increasing the weighted-average number of outstanding common shares computed in basic (loss) earnings per share to include the additional common shares that would be outstanding after issuance and adjusting net (loss) income for changes that would result from the issuance. Only those securities that are dilutive are included in the calculation. In periods of loss, the number of shares used to calculate diluted earnings is the same as basic earnings per share. Refer to Note 7 for further disclosures related to net (loss) income per share.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes expense for stock-based compensation awards based on their grant-date fair value. The expense is recorded over the respective service period of the underlying award. Liability classified stock-based compensation awards are remeasured each reporting period at fair value until the award is settled. The Company recognizes forfeitures of stock-based compensation awards as they occur. Refer to Note 21 for further disclosures related to stock-based compensation arrangements.
Warrants	Warrants On July 26, 2016 (the “Initial Issue Date”), the Company issued 810,811 warrants, which are classified as equity instruments, each with an initial Exercise Price, as defined in the Series A Warrants Agreement (the “Warrants Agreement”), of $55.93 per share of common stock and exercisable for one share of the Company’s common stock, par value $0.01 per share. Pursuant to the Warrants Agreement, the warrants are exercisable for cash or on a cashless basis at any time from the Initial Issue Date until July 26, 2023, and no fractional shares shall be issued upon warrant exercises. The exercise price and the warrant share number will be adjusted in respect of certain dilutive events with respect to the common stock (namely, dividends or distributions on the common stock, share splits and combinations, above-market tender offers for common stock by Contura or a subsidiary thereof, and discounted issuances of common stock or rights or options to purchase common stock or securities convertible or exchangeable into common stock). Additionally, in the case of any reorganization (i.e., a consolidation, merger, or sale of all or substantially all of the consolidated assets of Contura) pursuant to which the common stock is converted into cash, securities or other property, the warrants would become exercisable for such property. During the year ended December 31, 2017, the Exercise Price and the Warrant Share Number, as defined in the Warrants Agreement, were adjusted as a result of the occurrence of the Special Dividend. The Warrant Share Number was adjusted from 1.00 to 1.15 , and the Exercise Price was adjusted from $55.93 per share to $48.741 per share as of the July 5, 2017 record date. The United States Bankruptcy Court for the Eastern District of Virginia issued an order and final decree on June 28, 2018, granting a motion to close the Chapter 11 case of Alpha Natural Resources, Inc. and its affiliates, as reorganized debtors (the “Reorganized Debtors”), and authorizing the Reorganized Debtors to make a distribution (the “Distribution”) of additional cash as defined in the Warrants Agreement. The Distribution was effected on October 26, 2018 (the “Distribution Date”) in the aggregate amount of approximately $18,350 . During the year ended December 31, 2018, the Exercise Price was adjusted as a result of the occurrence of the Distribution. The Exercise Price was adjusted from $48.741 per share to $46.911 per share as of the Distribution Date. The Warrant Share Number remained equal to 1.15 . As of December 31, 2018, of the 810,811 warrants that were originally issued, 801,730 remained outstanding, with a total of 921,990 shares underlying the un-exercised warrants. For the year ended December 31, 2018, the Company issued 325 shares of common stock resulting from exercises of its Series A Warrants and, pursuant to the terms of the Warrants Agreement, withheld 125 of the issued shares in satisfaction of the Warrant Exercise Price, which were subsequently reclassified as treasury stock. As of December 31, 2019, of the 810,811 warrants that were originally issued, 801,370 remained outstanding, with a total of 921,576 shares underlying the un-exercised warrants. For the year ended December 31, 2019, the Company issued 414 shares of common stock resulting from exercises of its Series A Warrants and, pursuant to the terms of the Warrants Agreement, withheld five of the issued shares in satisfaction of the Warrant Exercise Price, which were subsequently reclassified as treasury stock.
Equity Method Investments	Equity Method Investments Investments in unconsolidated affiliates that the Company has the ability to exercise significant influence over, but not control, are accounted for under the equity method of accounting. Under the equity method of accounting, the Company records its proportionate share of the entity’s net income or loss at each reporting period in the Consolidated Statements of Operations in other income (expense), with a corresponding entry to increase or decrease the carrying value of the investment.
New Accounting Pronouncements	Recently Adopted Accounting Guidance Leases : I n February 2016, the Financial Accounting Standards Board (the “FASB”) issued an Accounting Standards Update and subsequent amendments related to ASC 842, Leases, (“ASC 842”). ASC 842 requires a lessee to recognize a right-of-use asset and a lease liability on the balance sheet. The Company adopted ASC 842 effective January 1, 2019 and elected the option not to restate comparative periods in transition and also elected the hindsight practical expedient, which allows the Company to use hindsight when considering lessee options to extend or terminate leases when determining the lease term of lease arrangements for classification purposes, and the package of practical expedients for all leases 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 elected the transition practical expedient to continue to account for existing and expired land easements at transition as executory contracts. Only land easements entered into or modified after the effective date of ASC 842 are accounted for as leases by the Company. As a result of the adoption, the Company recorded operating lease right-of-use assets and lease liabilities on our Consolidated Balance Sheet. The following table summarizes the impact of the adoption of ASC 842 to the Company’s Consolidated Balance Sheet: Balance at December 31, 2018 (1) Adjustments Balance at January 1, 2019 Assets Balance Sheet Classification Operating lease right-of-use assets Other non-current assets $ — $ 11,845 $ 11,845 Financing lease assets Property, plant, and equipment, net 9,786 — 9,786 Total lease assets $ 9,786 $ 11,845 $ 21,631 Liabilities Balance Sheet Classification Operating lease liabilities - current Accrued expenses and other current liabilities $ — $ 3,624 $ 3,624 Financing lease liabilities - current Current portion of long-term debt 2,110 — 2,110 Operating lease liabilities - long-term Other non-current liabilities — 8,221 8,221 Financing lease liabilities - long-term Long-term debt 4,313 — 4,313 Total lease liabilities $ 6,423 $ 11,845 $ 18,268 (1) Balances do not include measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments recorded during the period. The adoption of ASC 842 did not have a material impact on our Consolidated Statements of Operations, Consolidated Statements of Comprehensive (Loss) Income, or Consolidated Statements of Cash Flows. Refer to Note 12 for further disclosure requirements under the new standard. Stock Compensation : In June 2018, the FASB issued ASU 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting (“ASU 2018-07”). The amendments in this update expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The Company adopted ASU 2018-07 during the first quarter of 2019. The adoption of this ASU did not have a material impact on the Company's Consolidated Financial Statements and related disclosures. Recent Accounting Guidance Issued Not Yet Effective Credit Losses: In June 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Credit Losses (“ASU 2016-13”). ASU 2016-13, along with related amendments and improvements issued in 2018 and 2019, replaces the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable supportable information to inform credit loss estimates. The Company will adopt ASU 2016-13 during the first quarter of 2020. The adoption of this ASU is not expected to have a material impact on the Company's Consolidated Financial Statements and related disclosures. Fair Value Measurement : 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 (“ASU 2018-13”). The amendments in this update modify the disclosure requirements for fair value measurements. For public business entities, the standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated financial statements and related disclosures. Defined Benefit Plans : 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”). The amendments in this update modify the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. For public business entities, the standard is effective for fiscal years ending after December 15, 2020. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated financial statements and related disclosures. Income Taxes : In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”) . The amendments in this update simplify the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The a mendments also improve consistent application of and simplify U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. For public business entities, ASU 2019-12 is effective for annual reporting periods beginning after December 15, 2020, with early adoption permitted. The Company is currently assessing the impact of this ASU on the Company’s consolidated financial statements and related disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Intangibles	The balances and respective balance sheet classifications of such assets and liabilities as of December 31, 2019 and 2018 , net of accumulated amortization, are set forth in the following tables: December 31, 2019 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 917 $ (6,018 ) $ (5,101 ) Acquired mine permits, net 124,228 — 124,228 Total $ 125,145 $ (6,018 ) $ 119,127 December 31, 2018 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 4,687 $ (33,912 ) $ (29,225 ) Acquired mine permits, net 149,897 — 149,897 Total $ 154,584 $ (33,912 ) $ 120,672 (1) Included within other acquired intangibles, net of accumulated amortization, on the Company’s Consolidated Balance Sheets. (2) Included within other non-current liabilities on the Company’s Consolidated Balance Sheets.
Schedule of Future Amortization Expense	Future net amortization expense related to acquired intangibles is expected to be as follows: 2020 $ 15,204 2021 12,556 2022 12,584 2023 10,709 2024 8,657 Thereafter 59,417 Total net future amortization expense $ 119,127
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The following table summarizes the impact of the adoption of ASC 842 to the Company’s Consolidated Balance Sheet: Balance at December 31, 2018 (1) Adjustments Balance at January 1, 2019 Assets Balance Sheet Classification Operating lease right-of-use assets Other non-current assets $ — $ 11,845 $ 11,845 Financing lease assets Property, plant, and equipment, net 9,786 — 9,786 Total lease assets $ 9,786 $ 11,845 $ 21,631 Liabilities Balance Sheet Classification Operating lease liabilities - current Accrued expenses and other current liabilities $ — $ 3,624 $ 3,624 Financing lease liabilities - current Current portion of long-term debt 2,110 — 2,110 Operating lease liabilities - long-term Other non-current liabilities — 8,221 8,221 Financing lease liabilities - long-term Long-term debt 4,313 — 4,313 Total lease liabilities $ 6,423 $ 11,845 $ 18,268 (1) Balances do not include measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments recorded during the period. The following table summarizes the impact of the adoption of ASC 606 to the Company’s Consolidated Statements of Operations: Year Ended December 31, 2018 As reported Adjustments (1) Balances prior to adoption of ASC 606 Revenues: Coal revenues $ 2,020,889 $ (363,128 ) $ 1,657,761 Freight and handling revenues — 362,346 362,346 Other revenues 10,316 — 10,316 Total revenues $ 2,031,205 $ (782 ) $ 2,030,423 Freight and handling costs $ 363,128 $ (782 ) $ 362,346 (1) Adjustments primarily represent freight and handling revenues being treated as fulfillments costs and included within coal revenues under ASC 606. The remainder of these adjustments represent freight and handling activity occurring subsequent to control transfer also impacting freight and handling costs and prepaid expenses.

Mergers and Acquisitions (Table

Mergers and Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following table presents the details of the finalized purchase price of $688,534 : Final Fair value of common stock issued $ 703,365 Issued and redeemed equity awards (1) 32,217 Net balances due to Alpha deemed effectively settled (47,048 ) Purchase Price (2) $ 688,534 (1) Amount includes $20,681 of tax withholdings related to share settlements of option exercises, $1,905 paid to certain former ANR employees pursuant to change in control provisions, $6,570 of shares repurchased from certain former ANR directors pursuant to the Merger Agreement, $3,056 of pre-Merger service period value of restricted stock unit ANR employee awards, and $5 in cash paid in lieu of fractional shares of Contura common stock issued pursuant to the Merger Agreement. Of these amounts, $24,074 were obligations assumed and paid by Contura. (2) Purchase price of $688,534 is composed of equity consideration of $664,460 and cash consideration of $24,074 .
Schedule of Acquired Intangible Assets and Liabilities	The finalized purchase price of $688,534 has been allocated to the net tangible and intangible assets of Alpha Companies as follows: Provisional as of December 31, 2018 Adjustments Final Cash and cash equivalents $ 29,939 $ — $ 29,939 Trade and other receivables 60,714 — 60,714 Inventories 85,635 — 85,635 Short-term restricted cash 10,592 — 10,592 Other current assets 38,495 10,087 48,582 Property, plant, and equipment 504,852 (33,930 ) 470,922 Owned and leased mineral rights 516,201 23,571 539,772 Other intangible assets 154,041 4,363 158,404 Long-term restricted cash 182,049 — 182,049 Long-term restricted investments 28,809 — 28,809 Other non-current assets 68,022 (3,353 ) 64,669 Total assets $ 1,679,349 $ 738 $ 1,680,087 Accounts payable 69,049 (2,504 ) 66,545 Accrued expenses and other current liabilities 76,774 2,491 79,265 Long-term debt, including current portion 144,832 3,626 148,458 Acquisition-related obligations 74,346 5,738 80,084 Pension obligations 158,005 3,596 161,601 Asset retirement obligation, including current portion 163,636 12,718 176,354 Deferred income taxes, including current portion 134,924 (8,484 ) 126,440 Other intangible liabilities 57,219 — 57,219 Other non-current liabilities 207,654 12,286 219,940 Total liabilities $ 1,086,439 $ 29,467 $ 1,115,906 Goodwill $ 95,624 $ 28,729 $ 124,353 Allocation of purchase price $ 688,534 $ — $ 688,534
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination	The following table represents the intangible assets and the weighted-average amortization periods as of the acquisition date: Final Weighted-Average Amortization Period Mining permits $ 157,555 12.30 Above-market coal supply agreements 849 1.03 Below-market coal supply agreements (57,219 ) 2.10 Total acquired intangibles: $ 101,185 10.16
Business Acquisition, Pro Forma Information	The following unaudited pro forma information has been prepared for illustrative purposes only and assumes the Merger occurred on January 1, 2017. The unaudited pro forma results have been prepared based on estimates and assumptions, which the Company believes are reasonable; however, they are not necessarily indicative of the consolidated results of operations had the Merger occurred on January 1, 2017, or of future results of operations. Year Ended December 31, 2018 Year Ended December 31, 2017 Total revenues As reported $ 2,031,205 $ 1,649,969 Pro forma $ 2,630,824 $ 2,309,503 Income from continuing operations As reported $ 302,854 $ 173,735 Pro forma $ 314,735 $ 231,504

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Settlement Agreement	The following table presents the details of the ESM transaction: Year Ended December 31, 2019 Cash $ 90,000 DIP obligation (1) 3,008 Other 331 Total consideration $ 93,339 ARO liabilities transferred (152,882 ) Gain on sale (2) $ (59,543 ) (1) The Company paid certain Blackjewel debtor-in-possession lenders $3,008 of principal and interest pursuant to an existing agreement between the Company and those lenders. Refer to Note 22 . (2) The Company recorded a $59,543 gain within the depreciation, depletion, and amortization within discontinued operations in the Consolidated Statements of Operations during the year ended December 31, 2019 as a result of the reduction of the reclamation obligation partially offset by the consideration paid.
Discontinued Operations	The major components of net income (loss) from discontinued operations in the Consolidated Statements of Operations are as follows: Year Ended December 31, 2019 2018 2017 Revenues: Total revenues (1) $ 227 $ 1,296 $ 346,621 Costs and expenses: Cost of coal sales (exclusive of items shown separately below) $ — $ — $ 299,005 Depreciation, depletion and amortization (2) $ 86,370 $ — $ 30,090 Accretion on asset retirement obligations (3) $ 5,961 $ — $ 11,341 Asset impairment (4) $ 17,161 $ — $ — Selling, general and administrative expenses (5) $ 3,744 $ 43 $ 773 Other expenses $ 4,742 $ 4,107 $ — Other non-major (income) expense items, net $ (360 ) $ 2,140 $ 5,475 Loss on sale $ — $ — $ 36,831 (1) Total revenues for the years ended December 31, 2019 and 2018 consisted entirely of other revenues. (2) During the year ended December 31, 2019 , $145,913 of the depreciation, depletion and amortization was related to an increase in the Company’s estimate of its asset retirement obligations which was partially offset by ($59,543) as a result of the ESM transaction. Refer to the disclosures above for details. (3) The accretion on asset retirement obligations for the year ended December 31, 2019 was related to the asset retirement obligation as a result of Blackjewel’s bankruptcy filing. Refer to the above disclosures for further details. (4) The asset impairment for the year ended December 31, 2019 is primarily related to the write-off of tax related indemnification receivables from Blackjewel. Refer to the disclosures below for further details. (5) Represents professional and legal fees. The major components of cash flows related to discontinued operations were as follows: Year Ended December 31, 2019 2018 2017 Depreciation, depletion and amortization $ 86,370 $ — $ 30,090 Capital expenditures $ — $ — $ (10,420 ) Other significant operating non-cash items related to discontinued operations: Accretion on asset retirement obligations $ 5,961 $ — $ 11,341 Asset impairment $ 17,161 $ — $ — The major components of assets and liabilities that are classified as discontinued operations in the Consolidated Balance Sheets are as follows: December 31, 2019 2018 Assets: Prepaid expenses and other current assets $ — $ 22,475 Liabilities: Trade accounts payable, accrued expenses and other current liabilities $ — $ 21,892 Other non-current liabilities $ — $ 94

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables disaggregate the Company’s coal revenues by product category and by market to depict how the nature, amount, timing, and uncertainty of the Company’s coal revenues and cash flows are affected by economic factors: Year Ended December 31, 2019 Met Thermal Total Export coal revenues $ 1,196,816 $ 50,798 $ 1,247,614 Domestic coal revenues 551,806 482,587 1,034,393 Total coal revenues $ 1,748,622 $ 533,385 $ 2,282,007 Year Ended December 31, 2018 Met Thermal Total Export coal revenues $ 1,620,277 $ 51,369 $ 1,671,646 Domestic coal revenues 105,587 — 243,656 349,243 Total coal revenues $ 1,725,864 $ 295,025 $ 2,020,889 Year Ended December 31, 2017 (1) Met Thermal Total Export coal revenues $ 1,253,834 $ 11,486 $ 1,265,320 Domestic coal revenues 91,170 283,393 374,563 Total coal revenues $ 1,345,004 $ 294,879 $ 1,639,883 (1) Includes freight and handling revenues.
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied as of December 31, 2019 . 2020 2021 2022 2023 2024 Total Estimated coal revenues (1) $ 391,469 $ 264,690 $ 190,644 $ 130,268 $ 46,000 $ 1,023,071 (1) Amounts only include estimated coal revenues associated with contracts with customers with fixed pricing with original expected duration of more than one year. The Company has elected not to disclose the aggregate amount of the transaction price allocated to the performance obligations that are unsatisfied (or partially unsatisfied) as of the end of the reporting period for performance obligations with either of the following conditions: 1) the remaining performance obligation is part of a contract that has an original expected duration of one year or less; or 2) the remaining performance obligation has variable consideration that is allocated entirely to a wholly unsatisfied performance obligation.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive (Loss) Income (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables summarize the changes to accumulated other comprehensive (loss) income during the years ended December 31, 2019 , 2018 and 2017 : Balance Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance Employee benefit costs $ (23,130 ) $ (42,891 ) $ 7,405 $ (58,616 ) Balance Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance December 31, 2018 Employee benefit costs $ (1,948 ) $ (21,323 ) $ 141 $ (23,130 ) Balance January 1, 2017 Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance December 31, 2017 Employee benefit costs $ 2,087 $ (3,832 ) $ (203 ) $ (1,948 ) The following table summarizes the amounts reclassified from accumulated other comprehensive (loss) income and the Statements of Operations line items affected by the reclassification during the years ended December 31, 2019 , 2018 and 2017 : Details about accumulated other comprehensive (loss) income components Amounts reclassified from accumulated other comprehensive (loss) income Affected line item in the Statements of Operations Year Ended December 31, 2019 2018 2017 Employee benefit costs: Amortization of actuarial (gain) loss $ 959 $ 155 $ (203 ) (1) Miscellaneous (loss) income, net Settlement 6,446 — — (1) Miscellaneous (loss) income, net Total before income tax $ 7,405 $ 155 $ (203 ) Income tax expense — (14 ) — Income tax benefit Total, net of income tax $ 7,405 $ 141 $ (203 ) (1) These accumulated other comprehensive (loss) income components are included in the computation of net periodic benefit costs for certain employee benefit plans. Refer to Note 20 .

Net (Loss) Income per Share (Ta

Net (Loss) Income per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents the net (loss) income per common share for the years ended December 31, 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 Net (loss) income (Loss) income from continuing operations $ (203,142 ) $ 302,854 $ 173,735 Loss from discontinued operations (113,177 ) (3,689 ) (19,213 ) Net (loss) income $ (316,319 ) $ 299,165 $ 154,522 Basic Weighted average common shares outstanding - basic 18,808,460 10,967,014 10,216,464 Basic (loss) income per common share: (Loss) income from continuing operations $ (10.80 ) $ 27.61 $ 17.01 Loss from discontinued operations (6.02 ) (0.33 ) (1.89 ) Net (loss) income $ (16.82 ) $ 27.28 $ 15.12 Diluted Weighted average common shares outstanding - basic 18,808,460 10,967,014 10,216,464 Diluted effect of warrants — 280,969 170,178 Diluted effect of stock options — 262,714 274,456 Diluted effect of restricted stock units and restricted stock — 201,956 108,907 Weighted average common shares outstanding - diluted 18,808,460 11,712,653 10,770,005 Diluted (loss) income per common share: (Loss) income from continuing operations $ (10.80 ) $ 25.86 $ 16.13 Loss from discontinued operations (6.02 ) (0.32 ) (1.78 ) Net (loss) income $ (16.82 ) $ 25.54 $ 14.35

Inventories, net (Tables)

Inventories, net (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventories, net consisted of the following: December 31, 2019 2018 Raw coal $ 30,274 $ 33,607 Saleable coal 105,092 63,767 Materials, supplies and other, net 27,293 24,591 Total inventories, net $ 162,659 $ 121,965

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following: December 31, 2019 2018 Prepaid freight $ 8,268 $ 9,839 Deferred longwall move expenses 7,624 9,308 Notes and other receivables 8,931 16,116 Short-term restricted cash 12,363 16,474 Short-term deposits 689 16,181 Prepaid insurance 9,591 8,162 Refundable income taxes 33,915 74,536 Prepaid bond premium 5,471 2,849 Other prepaid expenses 4,509 5,480 Total prepaid expenses and other current assets $ 91,361 $ 158,945

Property, Plant, and Equipmen_2

Property, Plant, and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant, and Equipment, Net	Property, plant, and equipment, net, consisted of the following: December 31, 2019 2018 Plant and mining equipment $ 740,009 $ 695,756 Mine development 84,332 47,550 Land 39,925 38,810 Office equipment, software and other 1,582 1,169 Construction in progress 31,690 23,471 Total property, equipment and mine development costs 897,538 806,756 Less accumulated depreciation, depletion and amortization 314,276 106,766 Total property, plant, and equipment, net $ 583,262 $ 699,990

Other Non-Current Assets (Table

Other Non-Current Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Non-Current Assets	Other non-current assets consisted of the following: December 31, 2019 2018 Operating lease right-of-use assets $ 8,678 $ — Long-term deposits 10,034 9,211 Long-term restricted investments 21,886 29,137 Equity method investments 18,413 15,236 Federal income tax receivable 64,160 43,770 Workers' compensation receivables 58,498 67,776 Other 22,538 18,545 Total other non-current assets $ 204,207 $ 183,675

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Right-of-use Assets and Lease Liabilities	As of December 31, 2019 , the Company had the following right-of-use assets and lease liabilities within the Company’s Consolidated Balance Sheets: December 31, 2019 Assets Balance Sheet Classification Financing lease assets Property, plant, and equipment, net $ 9,718 Operating lease right-of-use assets Other non-current assets 8,678 Total lease assets $ 18,396 Liabilities Balance Sheet Classification Financing lease liabilities - current Current portion of long-term debt $ 3,275 Operating lease liabilities - current Accrued expenses and other current liabilities 1,813 Financing lease liabilities - long-term Long-term debt 4,674 Operating lease liabilities - long-term Other non-current liabilities 6,866 Total lease liabilities $ 16,628
Lease Costs and Other Information	Total lease costs and other lease information for the year ended December 31, 2019 included the following: Year Ended December 31, 2019 Lease cost (1) Financing lease cost: Amortization of leased assets $ 3,747 Interest on lease liabilities 480 Operating lease cost 2,771 Short-term lease cost 2,300 Total lease cost $ 9,298 (1) The Company had no variable lease costs or sublease income for the year ended December 31, 2019 . Year Ended December 31, 2019 Other information Cash paid for amounts included in the measurement of lease liabilities $ 9,191 Operating cash flows from financing leases 466 Operating cash flows from operating leases 5,071 Financing cash flows from financing leases 3,654 Right-of-use assets obtained in exchange for new financing lease liabilities 1,459 Lease Term and Discount Rate Weighted-average remaining lease term in months - financing leases 33.7 Weighted-average remaining lease term in months - operating leases 96.3 Weighted-average discount rate - financing leases 5.4 % Weighted-average discount rate - operating leases 11.2 %
Finance Lease Maturity	The following table summarizes the maturity of the Company’s lease liabilities on an undiscounted cash flow basis and a reconciliation to the lease liabilities recognized in the Company’s Consolidated Balance Sheet as of December 31, 2019 : Financing Leases Operating Leases Lease cost 2020 $ 3,729 $ 2,378 2021 2,985 1,957 2022 1,729 1,665 2023 184 1,193 2024 — 1,079 Thereafter — 5,203 Total future minimum lease payments $ 8,627 $ 13,475 Imputed interest (678 ) (4,796 ) Present value of future minimum lease payments $ 7,949 $ 8,679
Operating Lease Maturity	The following table summarizes the maturity of the Company’s lease liabilities on an undiscounted cash flow basis and a reconciliation to the lease liabilities recognized in the Company’s Consolidated Balance Sheet as of December 31, 2019 : Financing Leases Operating Leases Lease cost 2020 $ 3,729 $ 2,378 2021 2,985 1,957 2022 1,729 1,665 2023 184 1,193 2024 — 1,079 Thereafter — 5,203 Total future minimum lease payments $ 8,627 $ 13,475 Imputed interest (678 ) (4,796 ) Present value of future minimum lease payments $ 7,949 $ 8,679

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following: December 31, 2019 2018 Operating lease liabilities $ 1,813 $ — Wages and benefits 45,577 51,026 Workers’ compensation 15,695 16,676 Black lung 7,472 8,133 Taxes other than income taxes 24,946 24,140 Current portion of asset retirement obligations 40,574 24,754 Freight accrual 5,851 10,785 Other 12,354 13,185 Total accrued expenses and other current liabilities $ 154,282 $ 148,699

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following: December 31, 2019 2018 Term Loan Credit Facility - due November 2025 $ — $ 550,000 Term Loan Credit Facility - due June 2024 558,991 — LCC Note Payable 45,000 62,500 LCC Water Treatment Obligation 9,375 11,875 Other 9,295 8,395 Debt discount and issuance costs (29,695 ) (44,758 ) Total long-term debt 592,966 588,012 Less current portion (28,485 ) (42,743 ) Long-term debt, net of current portion $ 564,481 $ 545,269
Schedule of Maturities of Long-term Debt	Future maturities of long-term debt as of December 31, 2019 are as follows: 2020 $ 28,485 2021 29,036 2022 20,324 2023 8,297 2024 536,519 Total long-term debt $ 622,661

Acquisition-Related Obligatio_2

Acquisition-Related Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Acquisition-Related Obligations	Acquisition-related obligations consisted of the following: December 31, 2019 2018 Contingent Revenue Obligation $ 52,427 $ 59,880 Environmental Settlement Obligations 16,305 19,306 Reclamation Funding Liability 12,000 22,000 Retiree Committee VEBA Funding Settlement Liability — 3,500 UMWA Funds Settlement Liability 4,000 6,000 Discount (4,834 ) (10,356 ) Total acquisition-related obligations 79,898 100,330 Less current portion (33,639 ) (27,334 ) Acquisition-related obligations, net of current portion $ 46,259 $ 72,996

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation Disclosure [Abstract]
Summary of Changes in Asset Retirement Obligations	The following table summarizes the changes in asset retirement obligations for the years ended December 31, 2019 and 2018 : Total asset retirement obligations at December 31, 2017 $ 59,205 Accretion for the period 8,961 Sites added during the period (1) 163,636 Revisions in estimated cash flows (2) 1,100 Expenditures for the period (3,175 ) Reclassification to liabilities held for sale (1,279 ) Total asset retirement obligations at December 31, 2018 $ 228,448 Measurement-period adjustments (3) 12,718 Accretion for the period (4) 27,785 Sites added during the period 5,113 Revisions in estimated cash flows (2) (25,244 ) Expenditures for the period (24,116 ) Total asset retirement obligations at December 31, 2019 $ 224,704 Less current portion (40,574 ) Long-term portion $ 184,130 (1) Represents amounts assumed in connection with the Merger. (2) The revisions in estimated cash flows resulted primarily from discount rate adjustments and changes in mine plans. (3) Refer to Note 3 for additional information on the Merger and related measurement-period adjustments recorded during the year ended December 31, 2019 . (4) Amount does not include the accretion related to asset retirement obligations classified as liabilities held for sale.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments and Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements, Nonrecurring	The following tables set forth by level, within the fair value hierarchy, the Company’s acquisition-related obligations at fair value as of December 31, 2019 and 2018 : December 31, 2019 Carrying (1) Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) UMWA Funds Settlement Liability $ 3,069 $ 2,929 $ — $ — $ 2,929 Reclamation Funding Liability 10,808 10,658 — — 10,658 Environmental Settlement Obligations 13,594 12,197 — — 12,197 Total acquisition-related obligations $ 27,471 $ 25,784 $ — $ — $ 25,784 December 31, 2018 Carrying (1) Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Retiree Committee VEBA Funding Settlement Liability $ 3,337 $ 3,391 $ — $ — $ 3,391 UMWA Funds Settlement Liability 4,239 4,729 — — 4,729 Reclamation Funding Liability 18,106 19,362 — — 19,362 Environmental Settlement Obligations 14,768 14,936 — — 14,936 Total acquisition-related obligations $ 40,450 $ 42,418 $ — $ — $ 42,418 (1) Net of discounts. The following tables set forth by level, within the fair value hierarchy, the Company’s long-term debt at fair value as of December 31, 2019 and 2018 : December 31, 2019 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Term Loan Credit Facility - due June 2024 $ 538,765 $ 461,402 $ 461,402 $ — $ — LCC Note Payable 37,695 33,884 — — 33,884 LCC Water Treatment Obligation 7,211 6,280 — — 6,280 Total long term debt $ 583,671 $ 501,566 $ 461,402 $ — $ 40,164 December 31, 2018 Carrying (1) Total Fair Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Term Loan Credit Facility - due November 2025 $ 521,667 $ 540,375 $ 540,375 $ — $ — LCC Note Payable 49,361 50,606 — — 50,606 LCC Water Treatment Obligation 8,589 8,827 — — 8,827 Total long term debt $ 579,617 $ 599,808 $ 540,375 $ — $ 59,433 (1) Net of debt discounts and debt issuance costs.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table sets forth by level, within the fair value hierarchy, the Company’s financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis as of December 31, 2019 and 2018 . Financial and non-financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the determination of fair value for assets and liabilities and their placement within the fair value hierarchy levels. December 31, 2019 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 52,427 $ — $ — $ 52,427 Trading securities $ 13,508 $ 5,506 $ 8,002 $ — December 31, 2018 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 59,880 $ — $ — $ 59,880 The following table is a reconciliation of the financial and non-financial assets and liabilities that were accounted for at fair value on a recurring basis and that were categorized within Level 3 of the fair value hierarchy: December 31, 2018 Payments Measurement Period Adjustments (1) Loss Recognized in Earnings Transfer In (Out) of Level 3 Fair Value Hierarchy December 31, 2019 Contingent Revenue Obligation $ 59,880 $ (9,627 ) 5,738 $ (3,564 ) $ — $ 52,427 (1) Refer to Note 3 for additional information on the Merger and related measurement-period adjustments recorded during the year ended December 31, 2019 . December 31, 2017 Acquisitions Loss (Gain) Recognized in Earnings Transfer In (Out) of Level 3 Fair Value Hierarchy December 31, 2018 Contingent Revenue Obligation — 59,856 24 — 59,880

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Allocation of Income Tax Expense (Benefit)	Total income tax benefit provided on income (loss) before income taxes was allocated as follows: Year Ended December 31, 2019 2018 2017 Continuing operations $ (57,557 ) $ (165,363 ) $ (67,979 ) Discontinued operations (4,214 ) (1,305 ) (17,681 ) Total $ (61,771 ) $ (166,668 ) $ (85,660 )
Schedule of Components of Income Tax Expense (Benefit)	Significant components of income tax expense (benefit) from continuing operations were as follows: Year Ended December 31, 2019 2018 2017 Current tax (benefit) expense: Federal $ (49,943 ) $ (99,965 ) $ 10,078 State 824 (21 ) 687 Total current $ (49,119 ) $ (99,986 ) $ 10,765 Deferred tax (benefit) expense: Federal $ 704 $ (49,322 ) $ (78,744 ) State (9,142 ) (16,055 ) — Total deferred $ (8,438 ) $ (65,377 ) $ (78,744 ) Total income tax (benefit) expense: Federal $ (49,239 ) $ (149,287 ) $ (68,666 ) State (8,318 ) (16,076 ) 687 Total $ (57,557 ) $ (165,363 ) $ (67,979 )
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of statutory federal income tax expense (benefit) on income from continuing operations to the actual income tax expense (benefit) is as follows: Year Ended December 31, 2019 2018 2017 Federal statutory income tax expense (benefit) $ (54,747 ) $ 28,873 $ 37,015 Increase (reductions) in taxes due to: Percentage depletion allowance (6,270 ) (3,770 ) (5,164 ) Federal tax rate change — — 179,825 SAB 118 finalization — (6,735 ) — Estimated sequestration impact — (7,139 ) 5,640 State taxes, net of federal tax impact (10,498 ) 6,569 1,059 State tax rate and NOL change, net of federal tax impact (4,172 ) (4,779 ) (4,705 ) Change in valuation allowances 4,329 (208,474 ) (280,094 ) Net operating loss carryback (14,234 ) (59,404 ) — Amended return - capital loss impact 919 69,430 — Non-taxable bargain purchase gain — — (354 ) Non-deductible goodwill impairment 26,114 — — Non-deductible transaction costs — 1,706 — Stock-based compensation (1,085 ) (687 ) (1,144 ) Charitable contribution carryforward expiration 486 9,634 — Provision to return adjustment (869 ) 5,022 — Other, net 2,470 4,391 (57 ) Income tax benefit $ (57,557 ) $ (165,363 ) $ (67,979 )
Schedule of Deferred Tax Assets and Liabilities	The net deferred tax assets and liabilities included in the Consolidated Balance Sheets include the following amounts: Year Ended December 31, 2019 2018 Deferred tax assets: Asset retirement obligations $ 51,114 $ 59,973 Reserves and accruals not currently deductible 8,265 9,163 Workers’ compensation benefit obligations 54,128 56,859 Pension obligations 44,413 47,256 Equity method investments 2,509 3,506 Charitable contribution carryforwards 306 724 Alternative minimum tax credit carryforwards 33,065 68,774 Loss carryforwards, net of Section 382 limitation 142,510 109,850 Acquisition-related obligations 17,902 25,590 Other 11,993 11,909 Gross deferred tax assets 366,205 393,604 Less valuation allowance (133,020 ) (94,802 ) Deferred tax assets $ 233,185 $ 298,802 Deferred tax liabilities: Property, plant and mineral reserves $ (145,487 ) $ (189,232 ) Acquired intangibles, net (27,140 ) (31,540 ) Prepaid expenses (6,780 ) (6,882 ) Restricted cash (20,313 ) (55,112 ) Other (822 ) (3,975 ) Total deferred tax liabilities (200,542 ) (286,741 ) Net deferred tax assets $ 32,643 $ 12,061
Summary of Valuation Allowance	Changes in the valuation allowance were as follows: Year Ended December 31, 2019 2018 2017 Valuation allowance beginning of period $ 94,802 $ 298,892 $ 531,054 Increase (decrease) in valuation allowance recorded to income tax expense (benefit) 29,950 (208,474 ) (288,177 ) Increase in valuation allowance not affecting income tax expense 8,268 4,384 56,015 Valuation allowance end of period $ 133,020 $ 94,802 $ 298,892
Schedule of Liability for Uncertain Tax Positions	The following reconciliation illustrates the Company’s liability for uncertain tax positions: Year Ended December 31, 2019 2018 2017 Unrecognized tax benefits - beginning of period $ — $ — $ — Additions for tax positions of prior years 5,740 — — Additions for tax positions of current year 15,048 — — Unrecognized tax benefits - end of period $ 20,788 $ — $ —

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Compensation Related Costs [Abstract]
Changes in Accumulated Benefits Obligations, Fair Value of Plan Assets and Funded Status of Plan	The following tables set forth the plans’ accumulated benefit obligations, fair value of plan assets and funded status for the years ended December 31, 2019 and 2018 . For the year ended December 31, 2018, the change in benefit obligations and change in fair value of plan assets only represents activity related to the post-Merger period. Year Ended December 31, 2019 2018 Change in benefit obligations: Accumulated benefit obligation at beginning of period: $ 675,482 $ — Interest cost (1) 26,564 4,500 Actuarial loss 91,287 22,410 Benefits paid (31,371 ) (5,295 ) Acquisition (1) 1,910 653,867 Settlement (89,433 ) — Accumulated benefit obligation at end of period $ 674,439 $ 675,482 Change in fair value of plan assets: Fair value of plan assets at beginning of period $ 494,680 $ — Actual return on plan assets 87,129 4,112 Employer contributions 9,348 — Benefits paid (31,371 ) (5,295 ) Acquisition — 495,863 Settlement (89,433 ) — Fair value of plan assets at end of period $ 470,353 $ 494,680 Funded status $ (204,086 ) $ (180,802 ) Accrued benefit cost at end of period (2) $ (204,086 ) $ (180,802 ) (1) For the year ended December 31, 2019, interest cost includes $22 of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. (2) Amounts are classified as long-term on the Consolidated Balance Sheets as there are sufficient plan assets to make expected benefit payments to plan participants in the succeeding twelve months. The following tables set forth the accumulated black lung benefit obligations, fair value of plan assets and funded status for the years ended December 31, 2019 and 2018 : Year Ended December 31, 2019 2018 Change in benefit obligation: Accumulated benefit obligation at beginning of period $ 94,805 $ 18,370 Service cost (1) 2,057 930 Interest cost (1) 4,474 1,185 Actuarial loss 11,166 272 Benefits paid (6,543 ) (1,462 ) Acquisition (1) 16,829 75,510 Accumulated benefit obligation at end of period $ 122,788 $ 94,805 Change in fair value of plan assets: Fair value of plan assets at beginning of period $ 2,597 $ — Actual return on plan assets 63 28 Benefits paid (6,543 ) (1,462 ) Employer contributions 6,543 1,462 Acquisition — 2,569 Fair value of plan assets at end of period (2) 2,660 2,597 Funded status $ (120,128 ) $ (92,208 ) Accrued benefit cost at end of period $ (120,128 ) $ (92,208 ) Summary of accrued benefit cost at end of period: Continuing operations (120,128 ) (92,114 ) Discontinued operations — (94 ) Total accrued benefit cost at end of period $ (120,128 ) $ (92,208 ) (1) For the year ended December 31, 2019, service cost and interest cost include $61 and $120 , respectively, of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. (2) Assets of the plan are held in a Section 501(c)(21) tax-exempt trust fund and consist primarily of government debt securities. All assets are classified as Level 1 and valued based on quoted market prices. The following tables set forth the accumulated life insurance benefit obligations, fair value of plan assets and funded status for the years ended December 31, 2019 and 2018 : December 31, 2019 2018 Change in benefit obligation: Accumulated benefit obligation at beginning of period $ 11,368 $ 12,640 Interest cost 426 388 Actuarial loss (gain) 1,002 (1,164 ) Benefits paid (455 ) (496 ) Accumulated benefit obligation at end of period $ 12,341 $ 11,368 Change in fair value of plan assets: Benefits paid (1) (455 ) (496 ) Employer contributions (1) 455 496 Fair value of plan assets at end of period $ — $ — Funded status (12,341 ) (11,368 ) Accrued benefit cost at end of year $ (12,341 ) $ (11,368 ) Amounts recognized in the consolidated balance sheets: Current liabilities $ 719 $ 787 Long-term liabilities 11,622 10,581 $ 12,341 $ 11,368 (1) Amount is comprised of premium payments to commercial life insurance provider.
Schedule of Amounts Recognized in Accumulated Other Comprehensive (Income) Loss	Gross amounts related to pension obligations recognized in accumulated other comprehensive loss consisted of the following as of December 31, 2019 and 2018 : December 31, 2019 2018 Net actuarial loss $ 46,568 $ 23,075 Gross amounts related to the black lung obligations recognized in accumulated other comprehensive loss consisted of the following as of December 31, 2019 and 2018 : December 31, 2019 2018 Net actuarial loss $ 12,980 $ 1,684 Gross amounts related to the life insurance benefit obligations recognized in accumulated other comprehensive income consisted of the following as of December 31, 2019 and 2018 : December 31, 2019 2018 Net actuarial gain $ (872 ) $ (1,979 ) Accumulated other comprehensive income $ (872 ) $ (1,979 )
Schedule of Net Periodic Benefit Cost	The following table details the components of the net periodic benefit cost for life insurance benefit obligations: December 31, 2019 2018 Interest cost $ 426 $ 388 Amortization of net actuarial gain (105 ) (46 ) Net periodic benefit cost $ 321 $ 342 The following table details the components of net periodic benefit cost (credit): Year Ended December 31, 2019 2018 Interest cost (1) $ 26,564 $ 4,500 Expected return on plan assets (28,042 ) (4,777 ) Amortization of net losses 797 — Settlement (2) 6,224 — Net periodic benefit cost (credit) $ 5,543 $ (277 ) (1) For the year ended December 31, 2019, interest cost includes $22 of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. (2) For the year ended December 31, 2019, the settlement is recorded within miscellaneous (loss) income, net, within the Consolidated Statements of Operations. The following table details the components of the net periodic benefit cost for black lung obligations: Year Ended December 31, 2019 2018 2017 Service cost (1) $ 2,057 $ 930 $ 651 Interest cost (1) 4,474 1,185 633 Expected return on plan assets (65 ) (11 ) — Amortization of net actuarial loss (gain) 216 199 (149 ) Net periodic benefit cost $ 6,682 $ 2,303 $ 1,135 Summary net periodic benefit cost: Continuing operations $ 6,682 $ 2,304 $ 1,125 Discontinued operations — (1 ) 10 Total net periodic benefit cost $ 6,682 $ 2,303 $ 1,135 (1) For the year ended December 31, 2019, service cost and interest cost include $61 and $120 , respectively, of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments.
Schedule of Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Income) Loss	Other changes in plan assets and benefit obligations recognized in other comprehensive loss are as follows: Year Ended December 31, 2019 2018 Actuarial loss (1) $ 30,514 $ 23,075 Amortization of net actuarial loss (797 ) — Settlement (6,224 ) — Total recognized in other comprehensive loss $ 23,493 $ 23,075 Other changes in the black lung plan assets and benefit obligations recognized in other comprehensive loss are as follows: Year Ended December 31, 2019 2018 2017 Actuarial loss (1) $ 11,512 $ 255 $ 3,661 Amortization of net actuarial (loss) gain (216 ) (199 ) 149 Total recognized in other comprehensive loss $ 11,296 $ 56 $ 3,810 (1) For the year ended December 31, 2019, the balance includes $344 of measurement-period adjustments recorded during the period. Refer to Note 3 for further details on measurement-period adjustments. Other changes in the life insurance plan assets and benefit obligations recognized in other comprehensive income (loss) are as follows: December 31, 2019 2018 Actuarial loss (gain) $ 1,002 $ (1,164 ) Amortization of net actuarial gain 105 46 Total recognized in other comprehensive income (loss) $ 1,107 $ (1,118 )
Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets	The following table presents information applicable to plans with accumulated benefit obligations in excess of plan assets: Year Ended December 31, 2019 2018 Projected benefit obligation $ 674,439 $ 675,482 Accumulated benefit obligation $ 674,439 $ 675,482 Fair value of plan assets $ 470,353 $ 494,680
Schedule of Assumptions Used	The weighted-average actuarial assumption used in determining the benefit obligations as of December 31, 2019 and 2018 was as follows: December 31, 2019 2018 Discount rate 3.36 % 4.33 % The weighted-average actuarial assumptions used to determine net periodic benefit cost for the years ended December 31, 2019 and 2018 were as follows: Year Ended December 31, 2019 2018 Discount rate for benefit obligation 4.33 % 4.50 % Discount rate for interest cost 4.01 % 4.23 % Expected return on plan assets 5.80 % 5.80 % The weighted-average assumptions related to black lung obligations used to determine the benefit obligation as of December 31, 2019 and 2018 were as follows: December 31, 2019 2018 Discount rate 3.47 % 4.36 % Federal black lung benefit trend rate 2.00 % 2.50 % Black lung medical benefit trend rate 5.00 % 5.00 % Black lung benefit expense inflation rate 2.00 % 2.50 % The weighted-average assumptions related to black lung obligations used to determine net periodic benefit cost were as follows: Year Ended December 31, 2019 2018 2017 Discount rate for benefit obligation 4.36 % 4.37 % 4.29 % Discount rate for service cost 4.54 % 3.90 % 4.32 % Discount rate for interest cost 3.99 % 3.83 % 4.20 % Federal black lung benefit trend rate 2.50 % 2.50 % 2.50 % Black lung medical benefit trend rate 5.00 % 5.00 % 5.00 % Black lung benefit expense inflation rate 2.50 % 2.50 % 2.50 % Expected return on plan assets 2.50 % 2.50 % N/A The weighted-average assumptions related to life insurance benefit obligations used to determine the benefit obligation as of December 31, 2019 and 2018 was as follows: December 31, 2019 2018 Discount rate 3.22 % 4.21 % The weighted-average assumptions related to life insurance benefit obligations used to determine net periodic benefit cost were as follows: Year Ended December 31, 2019 2018 Discount rate for benefit obligations 4.21 % 3.56 % Discount rate for interest cost 3.90 % 3.18 %
Schedule of Allocation of Plan Assets	The target allocation for 2020 and the actual asset allocation as reported at December 31, 2019 are as follows: Target Allocation Percentages 2020 Percentage of Plan Assets 2019 Equity securities 40.0 % 39.3 % Fixed income funds 60.0 % 58.0 % Other — % 2.7 % Total 100.0 % 100.0 %
Schedule of Estimated Cash Payments	Estimated future cash payments related to life insurance benefit obligations for the next 10 years ending after December 31, 2019 are as follows: Year ending December 31: 2020 $ 719 2021 667 2022 658 2023 650 2024 645 2025-2029 3,179 $ 6,518 The following represents expected future pension benefit payments for the next ten years: 2020 $ 30,992 2021 31,148 2022 31,691 2023 32,414 2024 32,901 2025-2029 166,350 $ 325,496 Estimated future cash payments related to black lung obligations for the next 10 years ending after December 31, 2019 are as follows: Year ending December 31: 2020 $ 7,472 2021 6,457 2022 6,751 2023 6,894 2024 6,981 2025-2029 19,900 $ 54,455
Schedule of Changes in Fair Value of Plan Assets	Changes in Level 3 plan assets for the period ended December 31, 2018 were as follows: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Guaranteed Insurance Contract Beginning balance, December 31, 2017 $ — Acquisition 11,266 Actual return on plan assets: Relating to assets still held at the reporting date 11 Purchases, sales and settlements (391 ) Ending balance, December 31, 2018 $ 10,886 The fair values of the Company’s Pension Plans’ assets as of December 31, 2019 , by asset category are as follows: Asset Category Total Quoted Market Prices in Active Market for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Equity securities: Multi-asset fund (1) $ 182,782 $ — $ 182,782 $ — Fixed income funds: Bond fund (2) 272,239 — 272,239 — Commingled short-term fund (3) 1,572 — 1,572 — Other types of investments: Guaranteed insurance contract 11,155 — — 11,155 Total $ 467,748 $ — $ 456,593 $ 11,155 Receivable (4) 1,061 Total assets at fair value 468,809 Private equity funds measured at net asset value practical expedient (5) 1,544 Total plan assets $ 470,353 (1) This fund contains equities (domestic and international), real estate and bonds. (2) This fund contains bonds representing a diversity of sectors and maturities. This fund also includes mortgage-backed securities and U.S. Treasuries. (3) This fund contains cash and highly liquid short-term investments in a collective investment fund. (4) Receivable for investments sold at December 31, 2019 , which approximates fair value. (5) In accordance with Accounting Standards Update 2015-07, 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. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the total value of assets of the plans. Changes in Level 3 plan assets for the period ended December 31, 2019 were as follows: Fair Value Measurements Using Significant Unobservable Inputs (Level 3) Guaranteed Insurance Contract Beginning balance, December 31, 2018 $ 10,886 Actual return on plan assets: Relating to assets still held at the reporting date 644 Purchases, sales and settlements (375 ) Ending balance, December 31, 2019 $ 11,155 The fair values of the Company’s Pension Plans’ assets as of December 31, 2018 , by asset category are as follows: Asset Category Total Quoted Market Prices in Active Market for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Equity securities: Multi-asset fund (1) $ 195,278 $ — $ 195,278 $ — Fixed income funds: Bond fund (2) 283,517 — 283,517 — Commingled short-term fund (3) 1,654 — 1,654 — Other types of investments: Guaranteed insurance contract 10,886 — — 10,886 Total $ 491,335 $ — $ 480,449 $ 10,886 Receivable (4) 921 Total assets at fair value 492,256 Private equity funds measured at net asset value practical expedient (5) 2,424 Total plan assets $ 494,680 (1) This fund contains equities (domestic and international), real estate and bonds. (2) This fund contains bonds representing a diversity of sectors and maturities. This fund also includes mortgage-backed securities and U.S. Treasuries. (3) This fund contains cash and highly liquid short-term investments in a collective investment fund. (4) Receivable for investments sold at December 31, 2018 , which approximates fair value. (5) In accordance with Accounting Standards Update 2015-07, 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. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the total value of assets of the plans.
Schedule of Amounts Recognized in Balance Sheet	The table below presents amounts recognized in the Balance Sheets: December 31, 2019 2018 Current liabilities $ 7,472 $ 8,133 Long-term liabilities 112,656 83,981 Long-term liabilities - discontinued operations — 94 $ 120,128 $ 92,208

Stock-Based Compensation Awar_2

Stock-Based Compensation Awards (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Valuation Assumptions	The Monte Carlo simulations incorporate the assumptions as presented in the following tables: Relative performance-based restricted stock units Start price (1) $ 66.06 Dividend adjusted stock price (2) $ 61.27 Expected volatility (3) 29.98 % Risk-free interest rate (4) 2.42 % Expected dividend yield (5) — % (1) The start price for the Company represents the average closing stock price over the ten trading days ending on December 31, 2018, assuming dividends distributed during this period were reinvested in additional shares of the Company’s stock on the ex-dividend date. (2) The dividend adjusted stock price represents the closing price on the grant date assuming dividends distributed during the period since December 17, 2018, were reinvested in additional shares of the Company’s stock on the ex-dividend date. (3) The expected volatility assumption is based on the historical volatility of the price of the Company’s stock. (4) The annual risk-free interest rate equals the yield on zero coupon U.S. Treasury Separate Trading of Registered Interest and Principal of Securities (“STRIPS”) that have a term equal to the length of the remaining performance measurement period as of the valuation date. (5) The expected dividend yield represents the investments return to a share of the Company’s stock that is not available to the holder of an absolute performance-based restricted stock unit. Absolute performance-based restricted stock units Valuation date stock price $ 61.27 Expected volatility (1) 29.98 % Risk-free interest rate (2) 2.42 % Expected dividend yield (3) — % (1) The expected volatility assumption is based on the historical volatility of the price of the Company’s stock. (2) The annual risk-free interest rate equals the yield on zero coupon U.S. Treasury STRIPS that have a term equal to the length of the remaining performance measurement period as of the valuation date. (3) The expected dividend yield represents the investments return to a share of the Company’s stock that is not available to the holder of an absolute performance-based restricted stock unit. The Black-Scholes pricing model incorporates the assumptions as presented in the following table: Stock price $ 65.50 Exercise price $ 66.13 Expected term (1) 6.00 Annual risk-free interest rate (2) 2.18 % Annualized volatility (3) 60.9 % (1) The expected term represents the period of time that awards granted are expected to be outstanding. (2) The annual risk-free interest rate is based on the U.S. Constant Maturity Curve with a term equal to the award’s expected term on date of grant. (3) The annualized volatility is calculated by observing volatilities for comparable companies with adjustments for the Company’s size and leverage.
Schedule of Restricted Stock Shares and Restricted Share Units Activity	Time-based restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares outstanding at December 31, 2018 251,875 $ 74.71 Granted 79,474 $ 49.47 Vested (1) (121,251 ) $ 72.59 Forfeited or Expired (52,016 ) $ 71.09 Non-vested shares outstanding at December 31, 2019 158,082 $ 64.84 (1) Includes 3,274 shares with deferred settlement pursuant to the award agreement. Time-based cash restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Fair Value (1) Non-vested shares outstanding at December 31, 2018 18,063 $ 65.74 Granted — $ — Vested (1) (18,063 ) $ 61.27 Forfeited or Expired — $ — Non-vested shares outstanding at December 31, 2019 — $ — (1) Pursuant to the award agreement, shares were available for issuance on the applicable vesting date and these shares were ultimately settled in equity. Restricted stock activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Grant Date Fair Value Non-vested shares outstanding at December 31, 2018 264,799 $ 65.55 Granted — $ — Vested (161,468 ) $ 65.55 Forfeited or Expired (79,733 ) $ 65.55 Non-vested shares outstanding at December 31, 2019 23,598 $ 65.55
Schedule of Performance Shares Activity	Absolute performance-based restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Fair Value Non-vested shares outstanding at December 31, 2018 — $ — Granted 27,042 $ 50.60 Vested (1) (7,443 ) $ 50.60 Forfeited or Expired (9,050 ) $ 50.60 Non-vested shares outstanding at December 31, 2019 (1) 10,549 $ 50.60 (1) Includes 7,443 of vested shares due to the employment criteria being satisfied during the period. Until the performance criteria is satisfied, these shares will remain unsettled. Relative performance-based restricted stock unit activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Fair Value Non-vested shares outstanding at December 31, 2018 — $ — Granted 81,065 $ 65.70 Vested (1) (22,322 ) $ 65.70 Forfeited or Expired (27,144 ) $ 65.70 Non-vested shares outstanding at December 31, 2019 (1) 31,599 $ 65.70 (1) Includes 22,322 of vested shares due to the employment criteria being satisfied during the period. Until the performance criteria is satisfied, these shares will remain unsettled.
Schedule of Stock Option Activity	Fixed price option activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (1) Outstanding at December 31, 2018 126,128 $ 2.50 7.57 $ 7,976 Exercisable at December 31, 2018 126,128 $ 2.50 7.57 $ 7,976 Granted — $ — Exercised (126,128 ) $ 2.50 $ 6,879 Forfeited or Expired — $ — Outstanding at December 31, 2019 — $ — — $ — Exercisable at December 31, 2019 — $ — — $ — (1) The aggregate intrinsic value of outstanding and exercisable options is calculated as the difference between the exercise price and the Company’s stock price at each reporting period end. The aggregate intrinsic value of exercised options is calculated as the difference between the exercise price and the Company’s stock price on the exercise date. During the year ended December 31, 2018, the aggregate intrinsic value of options exercised was $1,214 . No options were exercised during the year ended December 31, 2017. 30-day VWAP stock option activity for the year ended December 31, 2019 is summarized in the following table: Number of Shares Weighted-Average Exercise Price Per Share Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (1) Outstanding at December 31, 2018 255,648 $ 35.97 7.88 $ 7,611 Exercisable at December 31, 2018 177,152 $ 22.61 7.74 $ 7,641 Granted — $ — Exercised (123,876 ) $ 5.00 $ 6,305 Forfeited or Expired (80,413 ) $ 66.13 Outstanding at December 31, 2019 51,359 $ 63.45 7.15 $ (2,794 ) Exercisable at December 31, 2019 44,356 $ 63.03 7.15 $ (2,394 ) (1) The aggregate intrinsic value of outstanding and exercisable options is calculated as the difference between the exercise price and the Company’s stock price at each reporting period end. The aggregate intrinsic value of exercised options is calculated as the difference between the exercise price and the Company’s stock price on the exercise date. During the year ended December 31, 2018, the aggregate intrinsic value of options exercised was $1,169 . No options were exercised during the year ended December 31, 2017.

Concentration of Credit Risk _2

Concentration of Credit Risk and Major Customers (Tables)	12 Months Ended
	Dec. 31, 2019
Risks and Uncertainties [Abstract]
Schedule of Concentration of Credit Risk and Major Customers	Top customers as a percentage of total revenue and met and thermal coal as % of coal sales volume were as follows: Year Ended December 31, 2019 2018 2017 Total revenue $ 2,290,260 $ 2,031,205 $ 1,649,969 Top customer as % of total revenue (1) 12 % 17 % 15 % Top 10 customers as % of total revenue (2) 56 % 60 % 65 % Met coal as % of coal sales volume 55 % 63 % 57 % Thermal coal as % of coal sales volume 45 % 37 % 43 % (1) Revenues from the top customer are included in the CAPP - Met, CAPP - Thermal, and NAPP segments for the year ended December 31, 2019, the CAPP - Met and NAPP segments for the year ended December 31, 2018, and the CAPP - Met segment for the year ended December 31, 2017. (2) In addition to the top customer, the Company had another customer with total revenues of 10% of total revenues included in the CAPP - Met and CAPP - Thermal segments for the year ended December 31, 2019 and another customer with total revenues of 13% of total revenues included in the CAPP - Met and NAPP segments for the year ended December 31, 2018.

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Schedule of Segment Operating Results and Capital Expenditures	The Company markets produced, processed and purchased coal to customers in the United States and in international markets, primarily India, Brazil, Turkey, the Netherlands, and France. Export coal revenues were the following: Year Ended December 31, 2019 2018 2017 Total coal revenues (1) $ 2,282,007 $ 2,020,889 $ 1,639,883 Export coal revenues (1) (2) $ 1,247,614 $ 1,671,646 $ 1,265,320 Export coal revenues as % of total coal revenues (1) 55 % 83 % 77 % (1) Amounts include freight and handling revenues. (2) The amounts for the year ended December 31, 2019 include $288,344 of export coal revenues from external customers in India, recorded within the CAPP - Met, CAPP - Thermal, and NAPP segments. The amounts for the year ended December 31, 2018 include $420,919 and $285,120 of export coal revenues from external customers in India and Brazil, respectively, recorded within the CAPP - Met, CAPP - Thermal, and NAPP segments. The amounts for the year ended December 31, 2017 include $356,673 of export coal revenues, including freight and handling revenues, from external customers in India, recorded within the CAPP - Met and NAPP segments. Revenue is tracked within the Company’s accounting records based on the product destination. Segment operating results and capital expenditures from continuing operations for the year ended December 31, 2019 were as follows: Year Ended December 31, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,711,252 $ 286,486 $ 288,988 $ 3,534 $ 2,290,260 Depreciation, depletion, and amortization $ 153,006 $ 57,483 $ 12,864 $ 5,439 $ 228,792 Amortization of acquired intangibles, net $ 10,389 $ (13,578 ) $ 3,101 $ — $ (88 ) Adjusted EBITDA $ 316,324 $ 11,981 $ 31,185 $ (63,883 ) $ 295,607 Capital expenditures $ 140,250 $ 17,545 $ 31,964 $ 2,652 $ 192,411 Segment operating results and capital expenditures from continuing operations for the year ended December 31, 2018 were as follows: Year Ended December 31, 2018 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,671,219 $ 39,650 $ 317,039 $ 3,297 $ 2,031,205 Depreciation, depletion, and amortization $ 40,330 $ 10,596 $ 23,273 $ 3,350 $ 77,549 Amortization of acquired intangibles, net $ (12,334 ) $ (7,516 ) $ 14,458 $ — $ (5,392 ) Adjusted EBITDA $ 335,135 $ (875 ) $ 44,368 $ (43,552 ) $ 335,076 Capital expenditures $ 39,634 $ 1,280 $ 40,635 $ 332 $ 81,881 Segment operating results and capital expenditures from continuing operations for the year ended December 31, 2017 were as follows: Year Ended December 31, 2017 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,329,734 $ — $ 319,400 $ 835 $ 1,649,969 Depreciation, depletion, and amortization $ 18,941 $ — $ 15,087 $ 882 $ 34,910 Amortization of acquired intangibles, net $ 34,737 $ — $ 24,270 $ — $ 59,007 Adjusted EBITDA $ 264,314 $ — $ 54,433 $ (40,281 ) $ 278,466 Capital expenditures $ 20,494 $ — $ 51,007 $ 1,200 $ 72,701
Reconciliation of Net Income (Loss) to Adjusted EBITDA	The following table presents a reconciliation of net income (loss) from continuing operations to Adjusted EBITDA for the year ended December 31, 2019 : Year Ended December 31, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 8,224 $ (97,398 ) $ 11,926 $ (125,894 ) $ (203,142 ) Interest expense (1,209 ) 23 (723 ) 68,707 66,798 Interest income (100 ) — (49 ) (7,147 ) (7,296 ) Income tax benefit — — — (57,557 ) (57,557 ) Depreciation, depletion and amortization 153,006 57,483 12,864 5,439 228,792 Merger-related costs — — — 1,090 1,090 Non-cash stock compensation expense 1,494 71 — 10,783 12,348 Mark-to-market adjustment - acquisition-related obligations — — — (3,564 ) (3,564 ) Accretion on asset retirement obligations 9,466 10,929 4,066 3,337 27,798 Loss on modification and extinguishment of debt — — — 26,459 26,459 Asset impairment (1) 15,034 50,993 — 297 66,324 Goodwill impairment (2) 124,353 — — — 124,353 Cost impact of coal inventory fair value adjustment (3) 4,751 3,458 — — 8,209 Gain on assets acquired in an exchange transaction (4) (9,083 ) — — — (9,083 ) Management restructuring costs (5) — — — 7,720 7,720 Loss on partial settlement of benefit obligations (1 ) — — 6,447 6,446 Amortization of acquired intangibles, net 10,389 (13,578 ) 3,101 — (88 ) Adjusted EBITDA $ 316,324 $ 11,981 $ 31,185 $ (63,883 ) $ 295,607 (1) Asset impairment for the year ended December 31, 2019 includes a long-lived asset impairment of $60,169 related to asset groups recorded within the CAPP - Met and CAPP - Thermal reporting segments and an asset impairment of $6,155 primarily related to the write-off of prepaid purchased coal as a result of Blackjewel’s Chapter 11 bankruptcy filing on July 1, 2019. Refer to Note 2 and Note 4 for further information. (2) The goodwill impairment testing as of December 31, 2019 resulted in a goodwill impairment of $124,353 to write down the full carrying value of goodwill. Refer to Note 2 for further information. (3) The cost impact of the coal inventory fair value adjustment as a result of the Alpha Merger was completed during the three months ended June 30, 2019. (4) During the year ended December 31, 2019 , the Company entered into an exchange transaction which primarily included the release of the PRB overriding royalty interest owed to the Company in exchange for met coal reserves which resulted in a gain of $9,083 . (5) Management restructuring costs are related to severance expense associated with senior management changes in the year ended December 31, 2019. The following table presents a reconciliation of net income (loss) from continuing operations to Adjusted EBITDA for the year ended December 31, 2018 : Year Ended December 31, 2018 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 306,898 $ (10,796 ) $ 4,193 $ 2,559 $ 302,854 Interest expense 260 1 (1,286 ) 39,835 38,810 Interest income (40 ) — (34 ) (1,875 ) (1,949 ) Income tax benefit — — — (165,363 ) (165,363 ) Depreciation, depletion and amortization 40,330 10,596 23,273 3,350 77,549 Merger-related costs 22 1 — 51,777 51,800 Management restructuring costs (1) — — — 2,659 2,659 Non-cash stock compensation expense 408 24 — 11,546 11,978 Mark-to-market adjustment - acquisition-related obligations — — — 24 24 Gain on settlement of acquisition-related obligations — — — (580 ) (580 ) Gain on sale of disposal group (2) (16,386 ) — — — (16,386 ) Accretion on asset retirement obligations 4,430 1,298 3,764 474 9,966 Loss on modification and extinguishment of debt — — — 12,042 12,042 Cost impact of coal inventory fair value adjustment (3) 11,547 5,517 — — 17,064 Amortization of acquired intangibles, net (12,334 ) (7,516 ) 14,458 — (5,392 ) Adjusted EBITDA $ 335,135 $ (875 ) $ 44,368 $ (43,552 ) $ 335,076 (1) Management restructuring costs are related to severance expense associated with senior management changes in the year ended December 31, 2018 . (2) The Company recorded a gain on disposal of assets of $16,386 within other (income) expense within the Consolidated Statements of Operations. (3) The cost impact of the coal inventory fair value adjustment as a result of the Alpha Merger was completed during the three months ended June 30, 2019. The following table presents a reconciliation of net income (loss) from continuing operations to Adjusted EBITDA for the year ended December 31, 2017 : Year Ended December 31, 2017 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 204,213 $ — $ 12,334 $ (42,812 ) $ 173,735 Interest expense (90 ) — (1,505 ) 37,572 35,977 Interest income (22 ) — (1 ) (187 ) (210 ) Income tax benefit — — — (67,979 ) (67,979 ) Depreciation, depletion and amortization 18,941 — 15,087 882 34,910 Non-cash stock compensation expense 650 — — 19,559 20,209 Mark-to-market adjustment - acquisition-related obligations — — — 3,221 3,221 Gain on settlement of acquisition-related obligations — — — (38,886 ) (38,886 ) Secondary offering costs — — — 4,491 4,491 Loss on modification and extinguishment of debt — — — 38,701 38,701 Bargain purchase gain — — — (1,011 ) (1,011 ) Accretion on asset retirement obligations 5,770 — 4,164 — 9,934 Amortization of acquired intangibles, net 34,737 — 24,270 — 59,007 Expenses related to the dividend 115 — 84 6,168 6,367 Adjusted EBITDA $ 264,314 $ — $ 54,433 $ (40,281 ) $ 278,466

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	Year Ended December 31, 2019 First Quarter (1) Second Quarter (2) Third Quarter (2) Fourth Quarter (3) Total revenues $ 609,114 $ 656,206 $ 525,864 $ 499,076 Net income (loss) from continuing operations $ 7,990 $ 24,300 $ (43,561 ) $ (191,871 ) Net (loss) income from discontinued operations (1,175 ) (137,961 ) (24,971 ) 50,930 Net income (loss) $ 6,815 $ (113,661 ) $ (68,532 ) $ (140,941 ) Weighted average shares - basic 18,894,315 19,123,705 19,025,462 18,195,651 Weighted average shares - diluted 19,538,629 19,420,471 19,025,462 18,195,651 Basic income (loss) per share: Income (loss) from continuing operations $ 0.42 $ 1.27 $ (2.29 ) $ (10.54 ) (Loss) income from discontinued operations (0.06 ) (7.21 ) (1.31 ) 2.79 Net income (loss) $ 0.36 $ (5.94 ) $ (3.60 ) $ (7.75 ) Diluted income (loss) per share: Income (loss) from continuing operations $ 0.41 $ 1.25 $ (2.29 ) $ (10.54 ) (Loss) income from discontinued operations (0.06 ) (7.10 ) (1.31 ) 2.79 Net income (loss) $ 0.35 $ (5.85 ) $ (3.60 ) $ (7.75 ) (1) Net income from continuing operations in the first quarter of 2019 includes a gain on assets acquired in an exchange transaction of $9,083 within other income within the Company’s Statements of Operations. Refer to Note 25 . (2) Net income from continuing operations in the second quarter and third quarter of 2019 include asset impairment of $5,826 and $32 , respectively. Refer to Note 2 . Net income from continuing operations in the second quarter of 2019 includes a loss on modification and extinguishment of debt of $26,459 . Refer to Note 15 . (3) Net loss from continuing operations in the fourth quarter of 2019 includes asset impairment of $60,466 and goodwill impairment of $124,353 . Refer to Note 2 . Year Ended December 31, 2018 First Quarter Second Quarter (2) Third Quarter Fourth Quarter (3) Total revenues $ 482,332 $ 528,918 $ 447,871 $ 572,084 Net income from continuing operations (1) $ 58,300 $ 74,642 $ 14,011 $ 155,901 Net (loss) income from discontinued operations (1,359 ) (854 ) (2,117 ) 641 Net income $ 56,941 $ 73,788 $ 11,894 $ 156,542 Weighted average shares - basic 9,548,613 9,625,874 9,633,164 15,014,994 Weighted average shares - diluted 10,292,607 10,306,043 10,384,513 15,822,037 Basic income (loss) per share: Income from continuing operations $ 6.11 $ 7.75 $ 1.45 $ 10.38 (Loss) income from discontinued operations (0.15 ) (0.08 ) (0.22 ) 0.04 Net income $ 5.96 $ 7.67 $ 1.23 $ 10.42 Diluted (loss) income per share: Income from continuing operations $ 5.66 $ 7.24 $ 1.35 $ 9.85 (Loss) income from discontinued operations (0.13 ) (0.08 ) (0.20 ) 0.04 Net income $ 5.53 $ 7.16 $ 1.15 $ 9.89 (1) Net income from continuing operations includes merger-related costs of $460 , $3,423 , $1,181 , and $46,736 for each of the four quarters of 2018, respectively. (2) Net income from continuing operations in the second quarter of 2018 includes a gain on sale of a disposal group of ($16,386) within other (income) expense within the Company’s Statements of Operations. Refer to Note 2 for further information. (3) Net income from continuing operations in the fourth quarter of 2018 includes an income tax benefit of $165,496 . Refer to Note 19 for further information. Additionally, net income from continuing operations in the fourth quarter of 2018 included a loss on modification and extinguishment of debt of ($12,042) . Refer to Note 15 for further information.

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	Oct. 26, 2018	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 05, 2017	Jul. 26, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents		$ 212,793,000	$ 212,793,000	$ 233,599,000	$ 141,924,000
Short-term restricted cash		12,363,000	12,363,000	16,474,000	11,615,000
Allowance for doubtful accounts		0	0	0
Deferred longwall move expenses		11,852,000	11,852,000	9,822,000
Owned and leased mineral rights, net of accumulated depletion and amortization of $27,877 and $11,390 as of December 31, 2019 and 2018		523,141,000	523,141,000	528,232,000
Asset retirement obligation assets		36,772,000	36,772,000	47,276,000
Revision in estimate for asset retirement obligation			(25,244,000)	1,100,000
Amortization of intangibles			(88,000)	(5,392,000)	59,007,000
Goodwill		0	0	95,624,000
Goodwill impairment		124,353,000	124,353,000	0	$ 0
Asset impairment			60,169,000
Impairment of intangible assets			5,997,000
Asset impairment related to write-off of prepaid purchased coal			6,155,000
Worker's compensation discount		$ 24,458,000	$ 24,458,000	$ 24,655,000
Number of warrants outstanding (in shares)		801,370	801,370	801,730			810,811
Exercise price of warrants (in dollars per share)	$ 46.911					$ 48.741	$ 55.93
Cash distribution	$ 18,350,000
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01	$ 0.01			$ 0.01
Number of securities called by each warrant (in shares)				1.15	1.15		1
Number of securities called by outstanding warrants (in shares)		921,576	921,576	921,990
Shares issued upon exercise of warrants (in shares)			414	325
Shares withheld upon exercise of warrants (in shares)			5	125
Equity method investments		$ 18,413,000	$ 18,413,000	$ 15,236,000
Met
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Asset impairment			9,176,000
Thermal
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Asset impairment			50,993,000
Acquired mine permits, net
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization of intangible assets			23,921,000	3,409,000
Coal supply agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization of intangible assets			3,884,000	14,506,000	$ 59,007,000
Coal supply agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization of intangible liabilities			(27,893,000)	(23,307,000)	0
Coal supply agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization of intangibles			(24,009,000)	(8,801,000)	59,007,000
Mineral rights
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment of long-lived assets			35,445,000
Depletion			2,140,000	6,804,000	2,954,000
Revision in estimate for asset retirement obligation			19,973,000	1,907,000	$ (821,000)
Acquired mine permits, net
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment of long-lived assets			5,997,000
Property, plant and equipment, net
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment of long-lived assets			17,056,000
Long-lived assets related to asset retirement obligations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment of long-lived assets			$ 1,671,000
Mining equipment, buildings and other fixed assets | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful lives			1 year
Mining equipment, buildings and other fixed assets | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful lives			47 years
Trading Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted investments		13,508,000	$ 13,508,000
Held-to-maturity Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted investments		8,378,000	8,378,000
Worker's compensation
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash		38,944,000	38,944,000	90,759,000
Restricted investments		3,100,000	3,100,000
Worker's compensation | Held-to-maturity Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted investments				1,888,000
Black lung
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash		12,706,000	12,706,000	29,611,000
Reclamation Related Obligations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash		67,868,000	67,868,000	86,217,000
Restricted investments		18,786,000	18,786,000
Long-term deposits		8,887,000	8,887,000	24,002,000
Reclamation Related Obligations | Held-to-maturity Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted investments				27,049,000
Financial guarantee and other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash		3,006,000	3,006,000
General Liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash				27,386,000
General Liabilities | Held-to-maturity Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted investments				200,000
Financial guarantees
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash				2,833,000
Contingent Revenue Obligation
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Short-term restricted cash		12,363,000	12,363,000	6,841,000
Other operating agreements
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Long-term deposits		$ 1,836,000	$ 1,836,000	$ 1,390,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Acquired Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Assets	$ 125,145	$ 154,584
Liabilities	(6,018)	(33,912)
Assets, net	119,127	120,672
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Assets	917	4,687
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Assets	124,228	149,897
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Liabilities	(6,018)	(33,912)
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Liabilities	0	0
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Liabilities, net	(5,101)	(29,225)
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Assets, net	$ 124,228	$ 149,897

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Future Amortization Expense of Acquired Intangibles (Details) $ in Thousands	Dec. 31, 2019USD ($)
Accounting Policies [Abstract]
2020	$ 15,204
2021	12,556
2022	12,584
2023	10,709
2024	8,657
Thereafter	59,417
Total net future amortization expense	$ 119,127

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - ASC 842 (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 8,678	$ 11,845	$ 0
Financing lease assets			9,786
Financing lease assets	9,718	9,786
Total lease assets	18,396	21,631
Operating lease liabilities - current	1,813	3,624
Financing lease liabilities - current			2,110
Financing lease liabilities - current	3,275	2,110
Operating lease liabilities - long-term	6,866	8,221
Financing lease liabilities - long-term			4,313
Financing lease liabilities - long-term	4,674	4,313
Total lease liabilities			$ 6,423
Total lease liabilities	$ 16,628	18,268
Adjustments | Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		11,845
Financing lease assets		0
Total lease assets		11,845
Operating lease liabilities - current		3,624
Financing lease liabilities - current		0
Operating lease liabilities - long-term		8,221
Financing lease liabilities - long-term		0
Total lease liabilities		$ 11,845

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - ASC 606 (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Product Information [Line Items]
Revenue from contract with customer									$ 2,282,007	$ 2,020,889	$ 1,639,883
Other revenues									8,253	10,316	10,086
Total revenues	$ 499,076	$ 525,864	$ 656,206	$ 609,114	$ 572,084	$ 447,871	$ 528,918	$ 482,332	2,290,260	2,031,205	1,649,969
Freight and handling costs									2,447,792	1,837,445	1,467,611
Coal revenues
Product Information [Line Items]
Revenue from contract with customer									2,282,007	2,020,889	1,392,481
Freight and handling revenues
Product Information [Line Items]
Revenue from contract with customer									$ 0	0	$ 247,402
Freight and handling costs										363,128
Balances prior to adoption of ASC 606
Product Information [Line Items]
Other revenues										10,316
Total revenues										2,030,423
Balances prior to adoption of ASC 606 | Coal revenues
Product Information [Line Items]
Revenue from contract with customer										1,657,761
Balances prior to adoption of ASC 606 | Freight and handling revenues
Product Information [Line Items]
Revenue from contract with customer										362,346
Freight and handling costs										362,346
Accounting Standards Update 2014-09 | Adjustments
Product Information [Line Items]
Other revenues										0
Total revenues										(782)
Accounting Standards Update 2014-09 | Adjustments | Coal revenues
Product Information [Line Items]
Revenue from contract with customer										(363,128)
Accounting Standards Update 2014-09 | Adjustments | Freight and handling revenues
Product Information [Line Items]
Revenue from contract with customer										362,346
Freight and handling costs										$ (782)

Mergers and Acquisitions - Narr

Mergers and Acquisitions - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 09, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Stock price (in USD per share)	$ 75
Form S-4 costs											$ 3,918
Goodwill		$ 0				$ 95,624				$ 0	95,624
(Loss) income from continuing operations		(191,871)	$ (43,561)	$ 24,300	$ 7,990	155,901	$ 14,011	$ 74,642	$ 58,300	(203,142)	302,854	$ 173,735
Total revenues		499,076	$ 525,864	$ 656,206	$ 609,114	572,084	$ 447,871	$ 528,918	$ 482,332	2,290,260	2,031,205	$ 1,649,969
Alpha Companies
Business Acquisition [Line Items]
Ownership interest acquired	100.00%
Shares to be exchanged for each aquiree share (in shares)	0.4417
Ownership in merged entity held by acquiree	48.50%
Shares issued for merger (in shares)	9,378,199
Special cash dividend to be received by acquiree shareholders (in USD per share)	$ 2.725
Purchase price	$ 688,534
Provisional goodwill acquired										95,624
Increase of provisional goodwill										28,729
Goodwill		$ 124,353				$ 95,624				124,353	95,624
Total revenues											149,161
Alpha Companies | Acquisition Costs
Business Acquisition [Line Items]
(Loss) income from continuing operations										$ 1,090	20,571
Alpha Companies | Merger-related Costs
Business Acquisition [Line Items]
(Loss) income from continuing operations											51,800
Alpha Companies | Employee Severance Costs
Business Acquisition [Line Items]
(Loss) income from continuing operations											31,229
Alpha Companies | Inventory Step Up
Business Acquisition [Line Items]
(Loss) income from continuing operations											17,064
Alpha Companies | Reduction in Deferred Tax Asset Valuation Allowance
Business Acquisition [Line Items]
(Loss) income from continuing operations											$ 126,440

Mergers and Acquisitions - Purc

Mergers and Acquisitions - Purchase Price (Details) - Alpha Companies $ in Thousands	Nov. 09, 2018USD ($)
Business Acquisition [Line Items]
Net balances due to Alpha deemed effectively settled	$ (47,048)
Purchase Price	688,534
Equity consideration	664,460
Cash paid	24,074
Common Stock
Business Acquisition [Line Items]
Equity issued and redeemed	703,365
Equity Awards
Business Acquisition [Line Items]
Equity issued and redeemed	32,217
Tax Withholdings Related to Share Settlements of Option Exercises
Business Acquisition [Line Items]
Equity issued and redeemed	20,681
Payments Issued in Conjunction with Change in Control Provisions
Business Acquisition [Line Items]
Equity issued and redeemed	1,905
Repurchased Shares
Business Acquisition [Line Items]
Equity issued and redeemed	6,570
Pre-Merger Service Period Vale of RSU ANR Employee Awards
Business Acquisition [Line Items]
Equity issued and redeemed	3,056
Cash Paid in Lieu of Fractional Shares
Business Acquisition [Line Items]
Equity issued and redeemed	5
Obligations Assumed
Business Acquisition [Line Items]
Equity issued and redeemed	$ 24,074

Mergers and Acquisitions - Prel

Mergers and Acquisitions - Preliminary Purchase Price Allocation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill	$ 0	$ 95,624
Alpha Companies
Business Acquisition [Line Items]
Cash and cash equivalents	29,939	29,939
Cash and cash equivalents	0
Trade and other receivables	60,714	60,714
Trade and other receivables	0
Inventories	85,635	85,635
Inventories	0
Short-term restricted cash	10,592	10,592
Short-term restricted cash	0
Other current assets	48,582	38,495
Other current assets	10,087
Property, plant, and equipment	470,922	504,852
Property, plant, and equipment	(33,930)
Owned and leased mineral rights	539,772	516,201
Owned and leased mineral rights	23,571
Other intangible assets	158,404	154,041
Other intangible assets	4,363
Long-term restricted cash	182,049	182,049
Long-term restricted cash	0
Long-term restricted investments		28,809
Long-term restricted investments	0
Long-term restricted investments	28,809
Other non-current assets	64,669	68,022
Other non-current assets	(3,353)
Total assets	1,680,087	1,679,349
Total assets	738
Accounts payable	66,545	69,049
Accounts payable	(2,504)
Accrued expenses and other current liabilities	79,265	76,774
Accrued expenses and other current liabilities	2,491
Long-term debt, including current portion	148,458	144,832
Long-term debt, including current portion	3,626
Acquisition-related obligations	80,084	74,346
Acquisition-related obligations	5,738
Pension obligations	161,601	158,005
Pension obligations	3,596
Asset retirement obligation, including current portion	176,354	163,636
Asset retirement obligation, including current portion	12,718
Deferred income taxes, including current portion	126,440	134,924
Deferred income taxes, including current portion	(8,484)
Other intangible liabilities	57,219	57,219
Other intangible liabilities	0
Other non-current liabilities	219,940	207,654
Other non-current liabilities	12,286
Total liabilities	1,115,906	1,086,439
Total liabilities	29,467
Goodwill	124,353	95,624
Goodwill	28,729
Allocation of purchase price	688,534	$ 688,534
Allocation of purchase price	$ 0

Mergers and Acquisitions - Inta

Mergers and Acquisitions - IntangiIble Assets Acquired (Details) - Alpha Companies $ in Thousands	Nov. 09, 2018USD ($)
Business Acquisition [Line Items]
Total acquired intangibles:	$ 101,185
Total acquired intangibles, weighted-average amortization period	10 years 1 month 28 days
Mining permits
Business Acquisition [Line Items]
Acquisitions	$ 157,555
Total acquired intangible assets, weighted-average amortization period	12 years 3 months 18 days
Coal supply agreements
Business Acquisition [Line Items]
Acquisitions	$ 849
Total acquired intangible assets, weighted-average amortization period	1 year 11 days
Below-market coal supply agreements	$ (57,219)
Below-market coal supply agreements, weighted-average amortization period	2 years 1 month 6 days

Mergers and Acquisitions - Pro

Mergers and Acquisitions - Pro Forma Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total revenues
As reported	$ 499,076	$ 525,864	$ 656,206	$ 609,114	$ 572,084	$ 447,871	$ 528,918	$ 482,332	$ 2,290,260	$ 2,031,205	$ 1,649,969
Income from continuing operations
As reported	$ (191,871)	$ (43,561)	$ 24,300	$ 7,990	$ 155,901	$ 14,011	$ 74,642	$ 58,300	$ (203,142)	302,854	173,735
Alpha Companies
Total revenues
As reported										149,161
Pro forma										2,630,824	2,309,503
Income from continuing operations
Pro forma										$ 314,735	$ 231,504

Discontinued Operations - Narra

Discontinued Operations - Narrative (Details) $ in Thousands	Oct. 18, 2019USD ($)
Eagle Specialty Materials, LLC
Guarantor Obligations [Line Items]
Back taxes paid	$ 13,500

Discontinued Operations - Detai

Discontinued Operations - Details of ESM Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
ARO liabilities transferred	$ (224,704)	$ (228,448)	$ (59,205)
Eagle Specialty Materials, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	90,000
DIP obligation	3,008
Other	331
Total consideration	93,339
Gain on sale	(59,543)
Eagle Butte and Belle Ayr Mines | Eagle Specialty Materials, LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
ARO liabilities transferred	$ (152,882)

Discontinued Operations - Major

Discontinued Operations - Major Components of Net Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Costs and expenses:
Depreciation, depletion and amortization	$ 145,913
PRB Transaction | Discontinued operations
Revenues:
Total revenues	227	$ 1,296	$ 346,621
Costs and expenses:
Cost of coal sales (exclusive of items shown separately below)	0	0	299,005
Depreciation, depletion and amortization	86,370	0	30,090
Accretion on asset retirement obligations	5,961	0	11,341
Asset impairment	17,161	0	0
Selling, general and administrative expenses	3,744	43	773
Other expenses	4,742	4,107	0
Other non-major (income) expense items, net	(360)	2,140	5,475
Loss on sale	0	$ 0	$ 36,831
Eagle Specialty Materials, LLC
Costs and expenses:
Gain on sale	$ (59,543)

Discontinued Operations - Maj_2

Discontinued Operations - Major Components of Asset and Liabilities (Details) - PRB Transaction - Discontinued operations - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets:
Prepaid expenses and other current assets	$ 0	$ 22,475
Liabilities:
Trade accounts payable, accrued expenses and other current liabilities	0	21,892
Other non-current liabilities	$ 0	$ 94

Discontinued Operations - Maj_3

Discontinued Operations - Major Components of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation, depletion and amortization	$ 145,913
PRB Transaction | Discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation, depletion and amortization	86,370	$ 0	$ 30,090
Capital expenditures	0	0	(10,420)
Other significant operating non-cash items related to discontinued operations:
Accretion on asset retirement obligations	5,961	0	11,341
Asset impairment	$ 17,161	$ 0	$ 0

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue by Segment (Details) $ in Thousands	Nov. 08, 2018segment	Jun. 30, 2019segments	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Revenue from Contract with Customer [Abstract]
Number of reportable segments	3	4	3
Disaggregation of Revenue [Line Items]
Revenues			$ 2,282,007	$ 2,020,889	$ 1,639,883
Met
Disaggregation of Revenue [Line Items]
Revenues			1,748,622	1,725,864
Thermal
Disaggregation of Revenue [Line Items]
Revenues			533,385	295,025
Met
Disaggregation of Revenue [Line Items]
Revenues					1,345,004
Thermal
Disaggregation of Revenue [Line Items]
Revenues					294,879
Export
Disaggregation of Revenue [Line Items]
Revenues			1,247,614	1,671,646	1,265,320
Export | Met
Disaggregation of Revenue [Line Items]
Revenues			1,196,816	1,620,277
Export | Thermal
Disaggregation of Revenue [Line Items]
Revenues			50,798	51,369
Export | Met
Disaggregation of Revenue [Line Items]
Revenues					1,253,834
Export | Thermal
Disaggregation of Revenue [Line Items]
Revenues					11,486
Domestic
Disaggregation of Revenue [Line Items]
Revenues			1,034,393	349,243	374,563
Domestic | Met
Disaggregation of Revenue [Line Items]
Revenues			551,806	105,587
Domestic | Thermal
Disaggregation of Revenue [Line Items]
Revenues			$ 482,587	$ 243,656
Domestic | Met
Disaggregation of Revenue [Line Items]
Revenues					91,170
Domestic | Thermal
Disaggregation of Revenue [Line Items]
Revenues					$ 283,393

Revenue Revenue - Performance O

Revenue Revenue - Performance Obligations (Details) $ in Thousands	Dec. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 1,023,071
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 391,469
Disaggregation of Revenue [Line Items]
Estimated coal revenues	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 264,690
Disaggregation of Revenue [Line Items]
Estimated coal revenues	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 190,644
Disaggregation of Revenue [Line Items]
Estimated coal revenues	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 130,268
Disaggregation of Revenue [Line Items]
Estimated coal revenues	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 46,000
Disaggregation of Revenue [Line Items]
Estimated coal revenues	1 year

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive (Loss) Income - Changes to Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,071,140	$ 92,648	$ 37,224
Ending balance	696,122	1,071,140	92,648
Employee benefit costs
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(23,130)	(1,948)	2,087
Other comprehensive (loss) income before reclassifications	(42,891)	(21,323)	(3,832)
Amounts reclassified from accumulated other comprehensive (loss) income	7,405	141	(203)
Ending balance	$ (58,616)	$ (23,130)	$ (1,948)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive (Loss) Income - Summary of Amounts Reclassified (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee benefit costs:
(Loss) income from continuing operations before income taxes									$ (260,699)	$ 137,491	$ 105,756
Income tax benefit					$ 165,496				57,557	165,363	67,979
Net (loss) income	$ (140,941)	$ (68,532)	$ (113,661)	$ 6,815	$ 156,542	$ 11,894	$ 73,788	$ 56,941	(316,319)	299,165	154,522
Reclassification out of Accumulated Other Comprehensive Income | Amortization of actuarial (gain) loss
Employee benefit costs:
Miscellaneous income									959	155	(203)
Reclassification out of Accumulated Other Comprehensive Income | Settlement
Employee benefit costs:
Miscellaneous income									6,446	0	0
Reclassification out of Accumulated Other Comprehensive Income | Employee benefit costs
Employee benefit costs:
(Loss) income from continuing operations before income taxes									7,405	155	(203)
Income tax benefit									0	(14)	0
Net (loss) income									$ 7,405	$ 141	$ (203)

Net (Loss) Income per Share - N

Net (Loss) Income per Share - Narrative (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Stock option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	129,520	129,520
Other Stock Based Instrument
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)		108,657

Net (Loss) Income per Share - S

Net (Loss) Income per Share - Schedule of Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net (loss) income
(Loss) income from continuing operations	$ (191,871)	$ (43,561)	$ 24,300	$ 7,990	$ 155,901	$ 14,011	$ 74,642	$ 58,300	$ (203,142)	$ 302,854	$ 173,735
Loss from discontinued operations	50,930	(24,971)	(137,961)	(1,175)	641	(2,117)	(854)	(1,359)	(113,177)	(3,689)	(19,213)
Net (loss) income	$ (140,941)	$ (68,532)	$ (113,661)	$ 6,815	$ 156,542	$ 11,894	$ 73,788	$ 56,941	$ (316,319)	$ 299,165	$ 154,522
Basic
Weighted average shares - basic (in shares)	18,195,651	19,025,462	19,123,705	18,894,315	15,014,994	9,633,164	9,625,874	9,548,613	18,808,460	10,967,014	10,216,464
Basic (loss) income per common share:
(Loss) Income from continuing operations (in dollars per share)	$ (10.54)	$ (2.29)	$ 1.27	$ 0.42	$ 10.38	$ 1.45	$ 7.75	$ 6.11	$ (10.80)	$ 27.61	$ 17.01
Loss from discontinued operations (in dollars per share)	2.79	(1.31)	(7.21)	(0.06)	0.04	(0.22)	(0.08)	(0.15)	(6.02)	(0.33)	(1.89)
Net (loss) income (in dollars per share)	$ (7.75)	$ (3.60)	$ (5.94)	$ 0.36	$ 10.42	$ 1.23	$ 7.67	$ 5.96	$ (16.82)	$ 27.28	$ 15.12
Diluted
Weighted average common shares outstanding - basic (in shares)	18,195,651	19,025,462	19,123,705	18,894,315	15,014,994	9,633,164	9,625,874	9,548,613	18,808,460	10,967,014	10,216,464
Weighted average common shares outstanding - diluted (in shares)	18,195,651	19,025,462	19,420,471	19,538,629	15,822,037	10,384,513	10,306,043	10,292,607	18,808,460	11,712,653	10,770,005
Diluted (loss) income per common share:
(Loss) income from continuing operations (in dollars per share)	$ (10.54)	$ (2.29)	$ 1.25	$ 0.41	$ 9.85	$ 1.35	$ 7.24	$ 5.66	$ (10.80)	$ 25.86	$ 16.13
Loss from discontinuing operations (in dollars per share)	2.79	(1.31)	(7.10)	(0.06)	0.04	(0.20)	(0.08)	(0.13)	(6.02)	(0.32)	(1.78)
Net (loss) income (in dollars per share)	$ (7.75)	$ (3.60)	$ (5.85)	$ 0.35	$ 9.89	$ 1.15	$ 7.16	$ 5.53	$ (16.82)	$ 25.54	$ 14.35
Warrants
Diluted
Diluted effect of share-based payment awards (in shares)									0	280,969	170,178
Stock option
Diluted
Diluted effect of share-based payment awards (in shares)									0	262,714	274,456
Restricted Share Units and Restricted Stock Shares
Diluted
Diluted effect of share-based payment awards (in shares)									0	201,956	108,907

Inventories, net (Details)

Inventories, net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory [Line Items]
Total inventories, net	$ 162,659	$ 121,965
Coal revenues
Inventory [Line Items]
Raw coal	30,274	33,607
Saleable coal	105,092	63,767
Materials, supplies and other, net
Inventory [Line Items]
Materials, supplies and other, net	$ 27,293	$ 24,591

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid freight	$ 8,268	$ 9,839
Deferred longwall move expenses	7,624	9,308
Notes and other receivables	8,931	16,116
Short-term restricted cash	12,363	16,474	$ 11,615
Short-term deposits	689	16,181
Prepaid insurance	9,591	8,162
Refundable income taxes	33,915	74,536
Prepaid bond premium	5,471	2,849
Other prepaid expenses	4,509	5,480
Total prepaid expenses and other current assets	$ 91,361	$ 158,945

Property, Plant, and Equipmen_3

Property, Plant, and Equipment, Net - Schedule of Property, Plant, and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property, equipment and mine development costs	$ 897,538
Less accumulated depreciation, depletion and amortization	314,276
Total property, plant, and equipment, net	583,262
Total property, equipment and mine development costs		$ 806,756
Less accumulated depreciation, depletion and amortization		106,766
Total property, plant, and equipment, net		699,990
Plant and mining equipment
Property, Plant and Equipment [Line Items]
Total property, equipment and mine development costs	740,009
Total property, equipment and mine development costs		695,756
Mine development
Property, Plant and Equipment [Line Items]
Total property, equipment and mine development costs	84,332
Total property, equipment and mine development costs		47,550
Land
Property, Plant and Equipment [Line Items]
Total property, equipment and mine development costs	39,925
Total property, equipment and mine development costs		38,810
Office equipment, software and other
Property, Plant and Equipment [Line Items]
Total property, equipment and mine development costs	1,582
Total property, equipment and mine development costs		1,169
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, equipment and mine development costs	$ 31,690
Total property, equipment and mine development costs		$ 23,471

Property, Plant, and Equipmen_4

Property, Plant, and Equipment, Net - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Plant and mining equipment - finance lease	$ 14,368
Plant and mining equipment		$ 806,756
Accumulated depreciation - finance lease	4,650
Accumulated depreciation		106,766
Depreciation, depletion and amortization associated with property, plant and equipment	226,652	70,745	$ 31,956
Revisions to asset retirement obligations	25,244	(1,100)
Equipment Purchase Commitments
Property, Plant and Equipment [Line Items]
Purchase commitment, 2020	19,283
Purchase commitment, 2022	279
Property, plant and equipment, net
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets	17,056
Depreciation
Property, Plant and Equipment [Line Items]
Revisions to asset retirement obligations	$ (1,522)	233	$ (898)
Assets under Capital Leases
Property, Plant and Equipment [Line Items]
Plant and mining equipment		20,888
Accumulated depreciation		$ 1,162

Other Non-Current Assets (Detai

Other Non-Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Operating lease right-of-use assets	$ 8,678	$ 11,845	$ 0
Long-term deposits	10,034		9,211
Long-term restricted investments	21,886		29,137
Equity method investments	18,413		15,236
Federal income tax receivable	64,160		43,770
Workers' compensation receivables	58,498		67,776
Workers' compensation receivables	22,538		18,545
Total other non-current assets	$ 204,207		$ 183,675

Leases - Right-of-use Assets an

Leases - Right-of-use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Financing lease assets	$ 9,718	$ 9,786
Operating lease right-of-use assets	8,678	11,845	$ 0
Total lease assets	18,396	21,631
Liabilities
Financing lease liabilities - current	3,275	2,110
Operating lease liabilities - current	1,813	3,624
Financing lease liabilities - long-term	4,674	4,313
Operating lease liabilities - long-term	6,866	8,221
Total lease liabilities	$ 16,628	$ 18,268

Leases - Lease Costs and Other

Leases - Lease Costs and Other Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)
Financing lease cost:
Amortization of leased assets	$ 3,747,000
Interest on lease liabilities	480,000
Operating lease cost	2,771,000
Short-term lease cost	2,300,000
Total lease cost	9,298,000
Sublease income	0
Variable lease income	0
Other information
Cash paid for amounts included in the measurement of lease liabilities	9,191,000
Operating cash flows from financing leases	466,000
Operating cash flows from operating leases	5,071,000
Financing cash flows from financing leases	3,654,000
Right-of-use assets obtained in exchange for new financing lease liabilities	$ 1,459,000
Lease Term and Discount Rate
Weighted-average remaining lease term in months - financing leases	2 years 9 months 21 days
Weighted-average remaining lease term in months - operating leases	8 years 9 days
Weighted-average discount rate - financing leases	5.40%
Weighted-average discount rate - operating leases	11.20%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Financing Leases
2020	$ 3,729
2021	2,985
2022	1,729
2023	184
2024	0
Thereafter	0
Total future minimum lease payments	8,627
Imputed interest	(678)
Present value of future minimum lease payments	7,949
Operating Leases
2020	2,378
2021	1,957
2022	1,665
2023	1,193
2024	1,079
Thereafter	5,203
Total future minimum lease payments	13,475
Imputed interest	(4,796)
Present value of future minimum lease payments	$ 8,679

Stock Repurchase and Dividend (

Stock Repurchase and Dividend (Details) - USD ($)

Sep. 12, 2019

Dec. 21, 2017

Sep. 15, 2017

Jul. 13, 2017

Sep. 30, 2019

Dec. 31, 2017

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Aug. 29, 2019

May 31, 2019

Dec. 06, 2018

Nov. 09, 2018

Sep. 26, 2017

Jun. 16, 2017

Jun. 13, 2017

Debt Instrument [Line Items]

Shares repurchased, net

$ 37,622,000

$ 20,266,000

$ 50,040,000

Total share repurchase price

$ 37,622,000

$ 20,270,000

$ 49,932,000

Special Dividend

Debt Instrument [Line Items]

Dividends declared

$ 92,786,000

Dividend Equivalent Payments

Debt Instrument [Line Items]

Dividends declared

$ 7,949,000

Asset Based Revolving Credit Facility and Term Loan Facility Due March 2024 | Revolving Credit Agreement and Term Loan Agreement

Debt Instrument [Line Items]

Amount authorized under credit agreement for cash dividend or share repurchases

$ 150,000,000

Term Loan Facility Due March 2024 | Term Loan Agreement

Debt Instrument [Line Items]

Loans repaid

$ 10,000,000

2018 Stock Repurchase Program

Debt Instrument [Line Items]

Authorized share repurchases

$ 15,000,000

$ 15,000,000

Shares repurchased (in shares)

223,218

Total share repurchase price

$ 15,007,000

Share repurchase price excluding fees

15,000,000

Share repurchase price, fees

$ 7,000

MIP

Debt Instrument [Line Items]

Shares repurchased (in shares)

309,310

Share repurchase price (in USD per share)

$ 56.40

Total share repurchase price

$ 17,445,000

Dutch Auction Tender Offer

Debt Instrument [Line Items]

Authorized share repurchases

$ 31,800,000

Shares repurchased (in shares)

530,000,000

Share repurchase price (in USD per share)

$ 60

Total share repurchase price

$ 32,595,000

Share repurchase price excluding fees

31,800,000

Share repurchase price, fees

$ 795,000

Common Stock | Capital Return Program

Debt Instrument [Line Items]

Authorized share repurchases

$ 250,000,000

Common Stock | Company Repurchase Plan

Debt Instrument [Line Items]

Authorized share repurchases

$ 100,000,000

Shares repurchased (in shares)

529,303,000

Shares repurchased, net

$ 15,969,000

Shares repurchased, gross

15,953,000

Fees related to stock repurchase

$ 16,000

Share repurchase price (in USD per share)

$ 30.17

Common Stock | Affiliated Entity | Stockholders Common Stock Repurchase Agreement

Debt Instrument [Line Items]

Shares repurchased (in shares)

500,000

Shares repurchased, net

$ 16,495,000

Share repurchase price (in USD per share)

$ 32.99

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Operating lease liabilities	$ 1,813	$ 3,624
Operating lease liabilities	8,679
Wages and benefits	45,577		$ 51,026
Workers’ compensation	15,695		16,676
Taxes other than income taxes	24,946		24,140
Current portion of asset retirement obligations	40,574		24,754
Freight accrual	5,851		10,785
Other	12,354		13,185
Total accrued expenses and other current liabilities	154,282		148,699
Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Black lung	$ 7,472		$ 8,133

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt discount and issuance costs	$ (29,695)	$ (44,758)
Total long-term debt	592,966	588,012
Less current portion	(28,485)	(42,743)
Long-term debt, net of current portion	564,481	545,269
Term Loan Credit Facility | Term Loan Credit Facility - due November 2025
Debt Instrument [Line Items]
Total long-term debt, gross	0	550,000
Total long-term debt		521,667
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024
Debt Instrument [Line Items]
Total long-term debt, gross	558,991	0
Total long-term debt	538,765
Note Payable | LCC Note Payable
Debt Instrument [Line Items]
Total long-term debt, gross	45,000	62,500
Note Payable | LCC Water Treatment Obligation
Debt Instrument [Line Items]
Total long-term debt, gross	9,375	11,875
Other
Debt Instrument [Line Items]
Total long-term debt, gross	$ 9,295	$ 8,395

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details) - USD ($)	Jun. 14, 2019	Nov. 09, 2018	Jul. 13, 2017	Apr. 03, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jun. 09, 2017	Mar. 17, 2017	Mar. 07, 2017
Debt Instrument [Line Items]
Long-term debt					$ 592,966,000	$ 588,012,000
Repayment of debt					552,809,000	471,704,000	$ 369,500,000
Letters of credit outstanding							11,300,000
Outstanding borrowings					622,661,000
Finance lease liability					7,949,000
Finance lease liability						6,423,000
Financing lease liabilities - current					3,275,000			$ 2,110,000
Financing lease liabilities - current						$ 2,110,000
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024
Debt Instrument [Line Items]
Aggregate amount of debt	$ 561,800,000
Principal payments due in March, June, September and December	1,405,000
Long-term debt					538,765,000
Current portion of long-term debt					$ 5,618,000
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Eurocurrency
Debt Instrument [Line Items]
Variable interest rate					7.00%
Interest rate at period end					9.00%
Term Loan Credit Facility | Term Loan Credit Facility - due November 2025
Debt Instrument [Line Items]
Aggregate amount of debt		$ 550,000,000
Interest rate at period end						7.39%
Long-term debt						$ 521,667,000
Current portion of long-term debt						$ 20,625,000
Loans repaid	543,125,000
Loss on modification of debt	255,000
Loss on modification and extinguishment of debt	$ 26,204,000
Quarterly principal repayments		$ 6,875,000
Term Loan Credit Facility | Term Loan Credit Facility - due November 2025 | Eurodollar or Base Rate | Minimum
Debt Instrument [Line Items]
Variable interest rate		4.00%
Term Loan Credit Facility | Term Loan Credit Facility - due November 2025 | Eurodollar or Base Rate | Maximum
Debt Instrument [Line Items]
Variable interest rate		5.00%
Term Loan Credit Facility | Term Loan Credit Facility - due November 2025 | Eurocurrency
Debt Instrument [Line Items]
Variable interest rate						5.00%
Term Loan Credit Facility | Alpha Term Loan
Debt Instrument [Line Items]
Repayment of debt		$ 82,811,000
Term Loan Credit Facility | Alpha Term Loan and Term Loan Facility Due March 2024
Debt Instrument [Line Items]
Loss on modification of debt		9,370,000
Loss on modification and extinguishment of debt		2,591,000
Term Loan Credit Facility | Term Loan Facility Due March 2024
Debt Instrument [Line Items]
Loans repaid			$ 10,000,000
Repayment of debt		380,667,000
Term Loan Credit Facility | Term Loan Facility Due 2020
Debt Instrument [Line Items]
Aggregate amount of debt											$ 42,500,000
Term Loan Credit Facility | Closing Tranche Term Loan Due 2018
Debt Instrument [Line Items]
Aggregate amount of debt										$ 8,500,000
Senior Notes | Senior Secured First Lien Notes Due 2021
Debt Instrument [Line Items]
Aggregate amount of debt										$ 300,000,000
Stated interest rate										10.00%
Senior Notes | General Unsecured Claims Note Due 2018
Debt Instrument [Line Items]
Stated interest rate										10.00%
Line of Credit | Old Asset-Based Revolving Credit Agreement | Base Rate | Minimum
Debt Instrument [Line Items]
Variable interest rate				1.00%
Line of Credit | Old Asset-Based Revolving Credit Agreement | Base Rate | Maximum
Debt Instrument [Line Items]
Variable interest rate				1.50%
Line of Credit | Old Asset-Based Revolving Credit Agreement | Eurocurrency | Minimum
Debt Instrument [Line Items]
Variable interest rate				2.00%
Line of Credit | Old Asset-Based Revolving Credit Agreement | Eurocurrency | Maximum
Debt Instrument [Line Items]
Variable interest rate				2.50%
Note Payable | General Unsecured Claims Note Due 2018
Debt Instrument [Line Items]
Aggregate amount of debt										$ 5,500,000
Note Payable | LCC Note Payable
Debt Instrument [Line Items]
Aggregate amount of debt		62,500,000
Current portion of long-term debt					$ 17,500,000	$ 17,500,000
Imputed interest rate					12.45%
Annual debt repayments		17,500,000
Outstanding borrowings					$ 37,695,000	49,361,000
Final debt repayment		10,000,000
Note Payable | LCC Water Treatment Obligation
Debt Instrument [Line Items]
Aggregate amount of debt		12,500,000
Current portion of long-term debt					$ 1,875,000	1,875,000
Imputed interest rate					13.12%
Annual debt repayments		625,000
Outstanding borrowings					$ 7,211,000	8,589,000
Term Loan Credit Facility and Note Payable | Senior Secured First Lien Notes Due 2021 and General Unsecured Claims Note Due 2018
Debt Instrument [Line Items]
Loss on modification and extinguishment of debt							$ 38,701,000
Revolving Credit Facility | Line of Credit | Asset-Based Revolving Credit Facility
Debt Instrument [Line Items]
Amount of credit facility		$ 225,000,000
Fronting fee		0.25%
Letters of credit outstanding					99,876,000	28,700,000
Outstanding borrowings					0	$ 0
Revolving Credit Facility | Line of Credit | Asset-Based Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Commitment fee		0.25%
Revolving Credit Facility | Line of Credit | Asset-Based Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Commitment fee		0.375%
Revolving Credit Facility | Line of Credit | Asset-Based Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Variable interest rate		1.00%
Revolving Credit Facility | Line of Credit | Asset-Based Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Variable interest rate		1.50%
Revolving Credit Facility | Line of Credit | Asset-Based Revolving Credit Facility | Eurocurrency | Minimum
Debt Instrument [Line Items]
Variable interest rate		2.00%
Revolving Credit Facility | Line of Credit | Asset-Based Revolving Credit Facility | Eurocurrency | Maximum
Debt Instrument [Line Items]
Variable interest rate		2.50%
Revolving Credit Facility | Line of Credit | Old Asset-Based Revolving Credit Agreement
Debt Instrument [Line Items]
Loss on modification and extinguishment of debt					$ 81,000
Amount of credit facility				$ 125,000,000
Debt proceeds permitted to be used for dividend or repurchase of common stock									$ 150,000,000
Letter of Credit | Line of Credit | Asset-Based Revolving Credit Facility
Debt Instrument [Line Items]
Amount of credit facility		$ 200,000,000
Letter of Credit | Line of Credit | Old Asset-Based Revolving Credit Agreement
Debt Instrument [Line Items]
Amount of credit facility				$ 80,000,000
Fronting fee				0.25%
Letter of Credit | Line of Credit | Old Asset-Based Revolving Credit Agreement | Minimum
Debt Instrument [Line Items]
Commitment fee				0.25%
Letter of Credit | Line of Credit | Old Asset-Based Revolving Credit Agreement | Maximum
Debt Instrument [Line Items]
Commitment fee				0.375%
Debt Instrument, Interest Rate, Period One | Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Base Rate
Debt Instrument [Line Items]
Variable interest rate	6.00%
Debt Instrument, Interest Rate, Period One | Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Eurocurrency
Debt Instrument [Line Items]
Variable interest rate	7.00%
Debt Instrument, Interest Rate, Period Two | Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Base Rate | Minimum
Debt Instrument [Line Items]
Variable interest rate	7.00%
Debt Instrument, Interest Rate, Period Two | Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Eurocurrency | Maximum
Debt Instrument [Line Items]
Variable interest rate	8.00%

Long-Term Debt - Schedule of _2

Long-Term Debt - Schedule of Long-Term Debt Maturities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Debt Disclosure [Abstract]
2020	$ 28,485
2021	29,036
2022	20,324
2023	8,297
2024	536,519
Total long-term debt	$ 622,661

Acquisition-Related Obligatio_3

Acquisition-Related Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jul. 12, 2016
Fair Value, Option, Quantitative Disclosures [Line Items]
Discount	$ (4,834)	$ (10,356)
Total acquisition-related obligations	79,898	100,330
Less current portion	(33,639)	(27,334)
Acquisition-related obligations, net of current portion	46,259	72,996
Contingent Revenue Obligation
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations	52,427	59,880
Total acquisition-related obligations	52,427	59,880
Less current portion	(14,646)	(9,459)
Environmental Settlement Obligations
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations	16,305	19,306
Discount	(2,711)	(4,538)
Total acquisition-related obligations	13,594	14,768
Less current portion	(6,185)	(3,375)
Reclamation Funding Liability
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations	12,000	22,000	$ 50,000
Discount	(1,192)	(3,894)
Total acquisition-related obligations	10,808	18,106
Less current portion	(10,808)	(10,000)
Retiree Committee VEBA Funding Settlement Liability
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations	0	3,500
UMWA Funds Settlement Liability
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations	$ 4,000	$ 6,000

Acquisition-Related Obligatio_4

Acquisition-Related Obligations - Narrative (Details) - USD ($)	3 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Nov. 09, 2018	Jul. 12, 2016
Business Acquisition, Contingent Consideration [Line Items]
Liabilities held for sale		$ 79,898,000	$ 100,330,000
Acquisition related obligations, current		33,639,000	27,334,000
Discount		4,834,000	10,356,000
Contingent Revenue Obligation, Threshold One
Business Acquisition, Contingent Consideration [Line Items]
Revenue threshold				$ 500,000,000
Percentage of revenue				1.50%
Contingent Revenue Obligation, Threshold Two
Business Acquisition, Contingent Consideration [Line Items]
Revenue threshold				$ 500,000,000
Percentage of revenue				1.00%
Contingent Revenue Obligation
Business Acquisition, Contingent Consideration [Line Items]
Liabilities held for sale		52,427,000	59,880,000
Acquisition related obligations, current		14,646,000	9,459,000
Payment of contingent revenue obligation	$ 9,627,000
Payments due		52,427,000	59,880,000
Environmental Settlement Obligations
Business Acquisition, Contingent Consideration [Line Items]
Liabilities held for sale		13,594,000	14,768,000
Acquisition related obligations, current		6,185,000	3,375,000
Discount		2,711,000	4,538,000
Payments due		16,305,000	19,306,000
Reclamation Funding Liability
Business Acquisition, Contingent Consideration [Line Items]
Liabilities held for sale		10,808,000	18,106,000
Acquisition related obligations, current		10,808,000	10,000,000
Discount		1,192,000	3,894,000
Payments due		$ 12,000,000	$ 22,000,000		$ 50,000,000
Payments due immediately					8,000,000
Payments due 2017					10,000,000
Payments due 2018					10,000,000
Payments due 2019					10,000,000
Payments due 2020					$ 12,000,000

Asset Retirement Obligation (De

Asset Retirement Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation Disclosure [Abstract]
Total asset retirement obligations, beginning balance	$ 228,448	$ 59,205
Accretion for the period	27,785	8,961
Sites added during the period	5,113	163,636
Revisions in estimated cash flows	(25,244)	1,100
Expenditures for the period	(24,116)	(3,175)
Reclassification to liabilities held for sale		(1,279)
Total assets retirement obligation, ending balance	224,704	228,448
Measurement-period adjustments	12,718
Less current portion	(40,574)	(24,754)
Long-term portion	$ 184,130	$ 203,694

Fair Value of Financial Instr_3

Fair Value of Financial Instruments and Fair Value Measurements - Total Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	$ 583,671	$ 579,617
Carrying Amount | Term Loan Agreement | Term Loan Credit Facility - due June 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	538,765
Carrying Amount | Term Loan Agreement | Term Loan Credit Facility - due November 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		521,667
Carrying Amount | Note Payable | LCC Note Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	37,695	49,361
Carrying Amount | Note Payable | LCC Water Treatment Obligation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	7,211	8,589
Fair Value, Measurements, Nonrecurring | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	461,402	540,375
Fair Value, Measurements, Nonrecurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	40,164	59,433
Fair Value, Measurements, Nonrecurring | Term Loan Agreement | Term Loan Credit Facility - due June 2024 | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	461,402
Fair Value, Measurements, Nonrecurring | Term Loan Agreement | Term Loan Credit Facility - due June 2024 | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0
Fair Value, Measurements, Nonrecurring | Term Loan Agreement | Term Loan Credit Facility - due June 2024 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0
Fair Value, Measurements, Nonrecurring | Term Loan Agreement | Term Loan Credit Facility - due November 2025 | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		540,375
Fair Value, Measurements, Nonrecurring | Term Loan Agreement | Term Loan Credit Facility - due November 2025 | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		0
Fair Value, Measurements, Nonrecurring | Term Loan Agreement | Term Loan Credit Facility - due November 2025 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		0
Fair Value, Measurements, Nonrecurring | Note Payable | LCC Note Payable | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Note Payable | LCC Note Payable | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Note Payable | LCC Note Payable | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	33,884	50,606
Fair Value, Measurements, Nonrecurring | Note Payable | LCC Water Treatment Obligation | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Note Payable | LCC Water Treatment Obligation | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	0	0
Fair Value, Measurements, Nonrecurring | Note Payable | LCC Water Treatment Obligation | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	6,280	8,827
Fair Value, Measurements, Nonrecurring | Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	501,566	599,808
Fair Value, Measurements, Nonrecurring | Total Fair Value | Term Loan Agreement | Term Loan Credit Facility - due June 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	461,402
Fair Value, Measurements, Nonrecurring | Total Fair Value | Term Loan Agreement | Term Loan Credit Facility - due November 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt		540,375
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Note Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	33,884	50,606
Fair Value, Measurements, Nonrecurring | Total Fair Value | Note Payable | LCC Water Treatment Obligation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	$ 6,280	$ 8,827

Fair Value of Financial Instr_4

Fair Value of Financial Instruments and Fair Value Measurements - Acquisition-related Obligations at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	$ 27,471	$ 40,450
Carrying Amount | Retiree Committee VEBA Funding Settlement Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value		3,337
Carrying Amount | UMWA Funds Settlement Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	3,069	4,239
Carrying Amount | Reclamation Funding Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	10,808	18,106
Carrying Amount | Environmental Settlement Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	13,594	14,768
Fair Value, Measurements, Nonrecurring | Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	25,784	42,418
Fair Value, Measurements, Nonrecurring | Total Fair Value | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	25,784	42,418
Fair Value, Measurements, Nonrecurring | Total Fair Value | Retiree Committee VEBA Funding Settlement Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value		3,391
Fair Value, Measurements, Nonrecurring | Total Fair Value | Retiree Committee VEBA Funding Settlement Liability | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value		0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Retiree Committee VEBA Funding Settlement Liability | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value		0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Retiree Committee VEBA Funding Settlement Liability | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value		3,391
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	2,929	4,729
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | UMWA Funds Settlement Liability | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	2,929	4,729
Fair Value, Measurements, Nonrecurring | Total Fair Value | Reclamation Funding Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	10,658	19,362
Fair Value, Measurements, Nonrecurring | Total Fair Value | Reclamation Funding Liability | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Reclamation Funding Liability | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Reclamation Funding Liability | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	10,658	19,362
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	12,197	14,936
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	0	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Environmental Settlement Obligations | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	$ 12,197	$ 14,936

Fair Value of Financial Instr_5

Fair Value of Financial Instruments and Fair Value Measurements - Schedule of Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation, Fair Value Disclosure	$ 52,427	$ 59,880
Trading securities	13,508
Quoted Prices in Active Markets (Level 1)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation, Fair Value Disclosure	0	0
Trading securities	5,506
Significant Other Observable Inputs (Level 2)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation, Fair Value Disclosure	0	0
Trading securities	8,002
Significant Unobservable Inputs (Level 3)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation, Fair Value Disclosure	52,427	$ 59,880
Trading securities	$ 0

Fair Value of Financial Instr_6

Fair Value of Financial Instruments and Fair Value Measurements - Level 3 of the Fair Value Hierarchy (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 59,880	$ 0
Payments	(9,627)
Acquisitions		59,856
Loss (Gain) Recognized in Earnings	(3,564)	24
Transfer In (Out) of Level 3 Fair Value Hierarchy	0	0
Ending balance	52,427	$ 59,880
Significant Unobservable Inputs (Level 3)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Measurement Period Adjustments	$ 5,738

Income Taxes - Total Income Tax

Income Taxes - Total Income Tax Expense (Benefit) Provided on Income Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Continuing operations	$ (165,496)	$ (57,557)	$ (165,363)	$ (67,979)
Discontinued operations		(4,214)	(1,305)	(17,681)
Total		$ (61,771)	$ (166,668)	$ (85,660)

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current tax (benefit) expense:
Federal		$ (49,943)	$ (99,965)	$ 10,078
State		824	(21)	687
Total current		(49,119)	(99,986)	10,765
Deferred tax (benefit) expense:
Federal		704	(49,322)	(78,744)
State		(9,142)	(16,055)	0
Total deferred		(8,438)	(65,377)	(78,744)
Total income tax (benefit) expense:
Federal		(49,239)	(149,287)	(68,666)
State		(8,318)	(16,076)	687
Total	$ (165,496)	$ (57,557)	$ (165,363)	$ (67,979)

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal statutory income tax expense (benefit)		$ (54,747)	$ 28,873	$ 37,015
Increase (reductions) in taxes due to:
Percentage depletion allowance		(6,270)	(3,770)	(5,164)
Federal tax rate change		0	0	179,825
SAB 118 finalization		0	(6,735)	0
Estimated sequestration impact		0	(7,139)	5,640
State taxes, net of federal tax impact		(10,498)	6,569	1,059
State tax rate and NOL change, net of federal tax impact		(4,172)	(4,779)	(4,705)
Change in valuation allowances		4,329	(208,474)	(280,094)
Net operating loss carryback		(14,234)	(59,404)	0
Amended return - capital loss impact		919	69,430	0
Non-taxable bargain purchase gain		0	0	(354)
Non-deductible goodwill impairment		26,114	0	0
Non-deductible transaction costs		0	1,706	0
Stock-based compensation		(1,085)	(687)	(1,144)
Charitable contribution carryforward expiration		486	9,634	0
Provision to return adjustment		(869)	5,022	0
Other, net		2,470	4,391	(57)
Total	$ (165,496)	$ (57,557)	$ (165,363)	$ (67,979)

Income Taxes - Deferred Income

Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Asset retirement obligations	$ 51,114	$ 59,973
Reserves and accruals not currently deductible	8,265	9,163
Workers’ compensation benefit obligations	54,128	56,859
Pension obligations	44,413	47,256
Equity method investments	2,509	3,506
Charitable contribution carryforwards	306	724
Alternative minimum tax credit carryforwards	33,065	68,774
Loss carryforwards, net of Section 382 limitation	142,510	109,850
Acquisition-related obligations	17,902	25,590
Other	11,993	11,909
Gross deferred tax assets	366,205	393,604
Less valuation allowance	(133,020)	(94,802)	$ (298,892)	$ (531,054)
Deferred tax assets	233,185	298,802
Deferred tax liabilities:
Property, plant and mineral reserves	(145,487)	(189,232)
Acquired intangibles, net	(27,140)	(31,540)
Prepaid expenses	(6,780)	(6,882)
Restricted cash	(20,313)	(55,112)
Other	(822)	(3,975)
Total deferred tax liabilities	(200,542)	(286,741)
Net deferred tax assets	$ 32,643	$ 12,061

Income Taxes - Valuation Allowa

Income Taxes - Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance, Deferred Tax Asset, Increase (Decrease) [Roll Forward]
Valuation allowance beginning of period	$ 94,802	$ 298,892	$ 531,054
Increase (decrease) in valuation allowance recorded to income tax expense (benefit)	29,950	(208,474)	(288,177)
Increase in valuation allowance not affecting income tax expense	8,268	4,384	56,015
Valuation allowance end of period	$ 133,020	$ 94,802	$ 298,892

Income Taxes - Narrative (Deta

Income Taxes - Narrative (Details) - USD ($)	Dec. 22, 2017	Dec. 22, 2018	Dec. 31, 2019	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Preliminary reduction in the value of net deferred tax assets from Tax Cuts and Jobs Act	$ 179,825,000
Preliminary release of valuation allowance related to net deferred tax assets from Tax Cuts and Jobs Act	$ 179,825,000
Benefit from adjustment of value of net deferred tax assets from Tax Cuts and Jobs Act		$ 6,735,000
Income tax receivable from AMT tax credits			$ 33,065,000
Deferred tax assets related to AMT credits			33,065,000	$ 68,774,000
Operating loss carryforwards			1,427,000,000
Operating loss carryforwards available to offset regular federal taxable income			1,011,000,000
Operating loss carryforwards section 382 limitation one			1,000,000
Operating loss carryforwards subject to section 382 limitation one			56,000,000
Operating loss carryforwards section 382 limitation two			18,300,000
Operating loss carryforwards subject to section 382 limitation two			299,000,000
Operating loss carryforwards section 382 limitation three			17,500,000
Operating loss carryforwards, indefinite carryforwards			61,000,000
Capital loss carryforwards section 382 limitation one			1,000,000
Capital loss carryforwards subject to section 382 limitation two			51,000,000
Capital loss carryforwards section 382 limitation two			17,500,000
Charitable contribution carryforwards			102,394,000
Unrecognized tax benefits that would affect tax rate			0
Reasonably possible decrease in unrecognized tax benefits			20,788,000
Interest and penalties related to uncertain tax positions			0	$ 0
Capital Loss Carryforward
Tax Credit Carryforward [Line Items]
Capital loss carryforwards			117,000,000
Capital loss carryforwards subject to section 382 limitation one			$ 66,000,000

Income Taxes - Reconciliation f

Income Taxes - Reconciliation for Uncertain Tax Position (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits - beginning of period	$ 0	$ 0	$ 0
Additions for tax positions of prior years	5,740	0	0
Additions for tax positions of current year	15,048	0	0
Unrecognized tax benefits - end of period	$ 20,788	$ 0	$ 0

Employee Benefit Plans - Narra

Employee Benefit Plans - Narrative (Details) $ in Thousands	Oct. 01, 2019plan	Nov. 09, 2018plan	Dec. 31, 2020	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of plans amended | plan	2
Workers' compensation liability				$ 163,818	$ 181,989
Workers' compensation liability, current				15,695	16,676
Insurance receivable for worker's compensation, current				2,375	2,661
Insurance receivable for worker's compensation, noncurrent				58,498	67,776
High-deductible insurance premium expense for worker's compensation and black lung claims				13,851	5,868	$ 4,948
Workers' compensation expense for high-deductible insurance plans				6,665	7,953	9,366
Contributions to defined contribution and profit sharing plans				27,231	10,242	8,823
Self-insured medical expense				$ 79,896	$ 37,958	$ 31,318
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets				5.80%	5.80%
Expected contributions in next fiscal year				$ 23,174
Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets				2.50%	2.50%
Alpha Companies
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of plans assumed | plan		3
Forecast | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected return on plan assets			5.90%

Employee Benefit Plans - Change

Employee Benefit Plans - Changes in Accumulated Benefits Obligations, Fair Value of Plan Assets and Funded Status of Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Change in benefit obligation:
Accumulated benefit obligation at beginning of period	$ 675,482	$ 0
Interest cost	26,564	4,500
Actuarial loss (gain)	91,287	22,410
Benefits paid	(31,371)	(5,295)
Acquisition	1,910	653,867
Settlement	(89,433)	0
Accumulated benefit obligation at end of period	674,439	675,482	$ 0
Change in fair value of plan assets:
Beginning balance	494,680	0
Actual return on plan assets	87,129	4,112
Employer contributions	9,348	0
Benefits paid	(31,371)	(5,295)
Acquisition	0	495,863
Settlement	(89,433)	0
Ending balance	470,353	494,680	0
Funded status	(204,086)	(180,802)
Summary of accrued benefit cost at end of period:
Accrued benefit cost at end of period	(204,086)	(180,802)
Black lung
Change in benefit obligation:
Accumulated benefit obligation at beginning of period	94,805	18,370
Service cost	2,057	930	651
Interest cost	4,474	1,185	633
Actuarial loss (gain)	11,166	272
Benefits paid	(6,543)	(1,462)
Acquisition	16,829	75,510
Accumulated benefit obligation at end of period	122,788	94,805	18,370
Change in fair value of plan assets:
Beginning balance	2,597	0
Actual return on plan assets	63	28
Employer contributions	6,543	1,462
Benefits paid	(6,543)	(1,462)
Acquisition	0	2,569
Ending balance	2,660	2,597	0
Funded status	(120,128)	(92,208)
Summary of accrued benefit cost at end of period:
Accrued benefit cost at end of period	(120,128)	(92,208)
Black lung | Continuing operations
Summary of accrued benefit cost at end of period:
Accrued benefit cost at end of period	(120,128)	(92,114)
Black lung | Discontinued operations
Summary of accrued benefit cost at end of period:
Accrued benefit cost at end of period	0	(94)
Life insurance benefits
Change in benefit obligation:
Accumulated benefit obligation at beginning of period	11,368	12,640
Interest cost	426	388
Actuarial loss (gain)	1,002	(1,164)
Benefits paid	(455)	(496)
Accumulated benefit obligation at end of period	12,341	11,368	$ 12,640
Change in fair value of plan assets:
Beginning balance	0
Employer contributions	455	496
Benefits paid	(455)	(496)
Ending balance	0	0
Funded status	(12,341)	(11,368)
Summary of accrued benefit cost at end of period:
Accrued benefit cost at end of period	(12,341)	(11,368)
Life insurance benefits | Current liabilities
Summary of accrued benefit cost at end of period:
Accrued benefit cost at end of period	(719)	(787)
Life insurance benefits | Long-term liabilities
Summary of accrued benefit cost at end of period:
Accrued benefit cost at end of period	(11,622)	$ (10,581)
Alpha Companies | Pension Plan
Change in benefit obligation:
Interest cost	22
Alpha Companies | Black lung
Change in benefit obligation:
Service cost	61
Interest cost	$ 120

Employee Benefit Plans - Gross

Employee Benefit Plans - Gross Amounts Recognized in Accumulated Other Comprehensive (Income) Loss (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial gain (loss)	$ 46,568	$ 23,075
Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial gain (loss)	12,980	1,684
Life insurance benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial gain (loss)	(872)	(1,979)
Accumulated other comprehensive income	$ (872)	$ (1,979)

Employee Benefit Plans - Sched

Employee Benefit Plans - Schedule of Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 26,564	$ 4,500
Expected return on plan assets	(28,042)	(4,777)
Amortization of net actuarial loss (gain)	797	0
Settlement	6,224	0
Net periodic benefit cost (credit)	5,543	(277)
Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	2,057	930	$ 651
Interest cost	4,474	1,185	633
Expected return on plan assets	(65)	(11)	0
Amortization of net actuarial loss (gain)	216	199	(149)
Net periodic benefit cost (credit)	6,682	2,303	1,135
Life insurance benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	426	388
Amortization of net actuarial loss (gain)	(105)	(46)
Net periodic benefit cost (credit)	321	342
Continuing operations | Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost (credit)	6,682	2,304	1,125
Discontinued operations | Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic benefit cost (credit)	0	$ (1)	$ 10
Alpha Companies | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	22
Alpha Companies | Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	61
Interest cost	$ 120

Employee Benefit Plans - Chang

Employee Benefit Plans - Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Income) Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss (gain)	$ 42,891	$ 22,895	$ 3,832
Amortization of net actuarial (loss) gain	(7,405)	(155)	203
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss (gain)	30,514	23,075
Amortization of net actuarial (loss) gain	(797)	0
Settlement	(6,224)	0
Total recognized in other comprehensive loss	23,493	23,075
Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss (gain)	11,512	255	3,661
Amortization of net actuarial (loss) gain	(216)	(199)	149
Total recognized in other comprehensive loss	11,296	56	$ 3,810
Life insurance benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss (gain)	1,002	(1,164)
Amortization of net actuarial (loss) gain	105	46
Total recognized in other comprehensive loss	1,107	$ (1,118)
Alpha Companies | Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss (gain)	1,686
Alpha Companies | Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Actuarial loss (gain)	$ (344)

Employee Benefit Plans - Sch_2

Employee Benefit Plans - Schedule of Plans with Benefit Obligations in Excess of Plan Assets (Details) - Pension Plan - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 674,439	$ 675,482
Accumulated benefit obligation	674,439	675,482
Fair value of plan assets	$ 470,353	$ 494,680

Employee Benefit Plans - Assump

Employee Benefit Plans - Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Weighted-Average Assumptions to Determine Benefit Obligations
Discount rate	3.36%	4.33%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate for benefit obligation	4.33%	4.50%
Discount rate for interest cost	4.01%	4.23%
Expected return on plan assets	5.80%	5.80%
Black lung
Weighted-Average Assumptions to Determine Benefit Obligations
Discount rate	3.47%	4.36%
Federal black lung benefit trend rate	2.00%	2.50%
Black lung medical benefit trend rate	5.00%	5.00%
Black lung benefit expense inflation rate	2.00%	2.50%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate for benefit obligation	4.36%	4.37%	4.29%
Discount rate for service cost	4.54%	3.90%	4.32%
Discount rate for interest cost	3.99%	3.83%	4.20%
Federal black lung benefit trend rate	2.50%	2.50%	2.50%
Black lung medical benefit trend rate	5.00%	5.00%	5.00%
Black lung benefit expense inflation rate	2.50%	2.50%	2.50%
Expected return on plan assets	2.50%	2.50%
Life insurance benefits
Weighted-Average Assumptions to Determine Benefit Obligations
Discount rate	3.22%	4.21%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate for benefit obligation	4.21%	3.56%
Discount rate for interest cost	3.90%	3.18%

Employee Benefit Plans - Alloca

Employee Benefit Plans - Allocation of Plan Assets (Details) - Pension Plan	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentages 2020	100.00%
Percentage of plan assets	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentages 2020	40.00%
Percentage of plan assets	39.30%
Fixed income funds
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentages 2020	60.00%
Percentage of plan assets	58.00%
Other
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentages 2020	0.00%
Percentage of plan assets	2.70%

Employee Benefit Plans - Estima

Employee Benefit Plans - Estimated Cash Payments (Details) $ in Thousands	Dec. 31, 2019USD ($)
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	$ 30,992
2021	31,148
2022	31,691
2023	32,414
2024	32,901
2025-2029	166,350
Estimated future cash payments	325,496
Black lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	7,472
2021	6,457
2022	6,751
2023	6,894
2024	6,981
2025-2029	19,900
Estimated future cash payments	54,455
Life insurance benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	719
2021	667
2022	658
2023	650
2024	645
2025-2029	3,179
Estimated future cash payments	$ 6,518

Employee Benefit Plans - Fair V

Employee Benefit Plans - Fair Value of Plan Assets (Details) - Pension Plan - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 470,353	$ 494,680	$ 0
Total
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	468,809	492,256
Quoted Prices in Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0
Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	456,593
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	11,155	10,886	$ 0
Equity securities | Total
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	182,782	195,278
Equity securities | Quoted Prices in Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Equity securities | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	182,782	195,278
Equity securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fixed income funds | Total
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	272,239	283,517
Fixed income funds | Quoted Prices in Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fixed income funds | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	272,239	283,517
Fixed income funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Commingled short-term fund | Total
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	1,572	1,654
Commingled short-term fund | Quoted Prices in Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Commingled short-term fund | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	1,572	1,654
Commingled short-term fund | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Guaranteed insurance contract | Total
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	11,155	10,886
Guaranteed insurance contract | Quoted Prices in Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Guaranteed insurance contract | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Guaranteed insurance contract | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	11,155	10,886
Total, excluding receivables | Total
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	467,748	491,335
Total, excluding receivables | Quoted Prices in Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		0
Total, excluding receivables | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		480,449
Total, excluding receivables | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		10,886
Receivable | Total
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	1,061	921
Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 1,544
Private equity funds | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Total plan assets		$ 2,424

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of Changes in Level 3 Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Acquisition		$ 11,266
Pension Plan
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	$ 494,680	0
Ending balance	470,353	494,680
Pension Plan | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	10,886	0
Relating to assets still held at the reporting date	644	11
Purchases, sales and settlements	(375)	(391)
Ending balance	$ 11,155	$ 10,886

Employee Benefit Plans - Amoun

Employee Benefit Plans - Amounts Recognized in Balance Sheet (Details) - Black lung - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued benefit cost at end of period	$ (120,128)	$ (92,208)
Current liabilities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued benefit cost at end of period	(7,472)	(8,133)
Long-term liabilities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued benefit cost at end of period	(112,656)	(83,981)
Long-term liabilities - discontinued operations
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued benefit cost at end of period	$ 0	$ (94)

Stock-Based Compensation Awar_3

Stock-Based Compensation Awards (Details) $ / shares in Units, $ in Thousands	Nov. 09, 2018shares	Sep. 15, 2017USD ($)$ / sharesshares	Jul. 11, 2017USD ($)	Dec. 31, 2019USD ($)award_type$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of award types | award_type				4
Stock compensation expense | $				$ 12,397	$ 13,354	$ 20,372
Shares repurchased, amount | $				37,622	20,266	$ 50,040
Vesting period						3 years
Payments of special dividend | $				$ 0	$ 0	$ 100,735
Relative performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				81,065
Grant date fair value (in USD per share) | $ / shares				$ 65.70
Unrecognized compensation cost of non-vested shares | $				$ 1,459
Unrecognized compensation cost, period for recognition				2 years 1 month 10 days
Absolute performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				27,042
Grant date fair value (in USD per share) | $ / shares				$ 50.60
Unrecognized compensation cost of non-vested shares | $				$ 375
Unrecognized compensation cost, period for recognition				2 years 1 month 10 days
Time-based restricted stock, cash units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				0	18,063
Grant date fair value (in USD per share) | $ / shares				$ 0	$ 65
Outstanding liability awards | $				$ 0	$ 1,058
Unrecognized compensation cost of non-vested shares | $					$ 0
Time-based restricted stock, share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				79,474		5,504
Grant date fair value (in USD per share) | $ / shares				$ 49.47	$ 74.73	$ 73.37
Unrecognized compensation cost of non-vested shares | $				$ 3,687
Unrecognized compensation cost, period for recognition				1 year 3 months 7 days
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				0
Grant date fair value (in USD per share) | $ / shares				$ 0		$ 65.55
Unrecognized compensation cost of non-vested shares | $				$ 81
Fixed price stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)				0
30-Day volume-weighted average price stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)				0
Unrecognized compensation cost | $				$ 12
MIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)				1,201,202
Number of shares available for grant (in shares)				277,266
Shares repurchased (in shares)		309,310
Shares repurchased, amount | $		$ 17,445
Share repurchase price (in USD per share) | $ / shares		$ 56.40
Options granted (in shares)						129,520
Payments of special dividend | $			$ 7,949
Accelerated stock-based compensation expense | $			5,113
Reduction in additional paid in capital from special dividend | $			$ 7,949
MIP | Time-based restricted stock, cash units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)						6,700
Grant date fair value (in USD per share) | $ / shares						$ 62.55
MIP | Time-based restricted stock, share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)					180,156
MIP | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)						437,450
MIP | Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value (in USD per share) | $ / shares						$ 37.44
Expiration period						10 years
LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)				1,000,000
Number of shares available for grant (in shares)				756,507
LTIP | Relative performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				81,065
Grant date fair value (in USD per share) | $ / shares				$ 65.70
LTIP | Absolute performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)				27,042
Grant date fair value (in USD per share) | $ / shares				$ 50.60
ANR EIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares)				0
Number of shares available for grant (in shares)				0
Number of awards granted (in shares)	89,766
ANR EIP | Time-based restricted stock, share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards granted (in shares)					89,766
MIP, LTIP, and ANR EIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares repurchased (in shares)				118,935	76,648
Shares repurchased, amount | $				$ 5,159	$ 5,240
Share repurchase price (in USD per share) | $ / shares				$ 43.37	$ 68.36
Maximum | Relative performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential distribution of shares, percentage				400.00%
Maximum | Absolute performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential distribution of shares, percentage				200.00%
Minimum | Relative performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential distribution of shares, percentage				0.00%
Minimum | Absolute performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential distribution of shares, percentage				0.00%
Key Employees | Maximum | Time-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years	4 years
Key Employees | Minimum | Time-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				1 year	2 years
Directors | Time-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					1 year
Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense, percent				76.00%	90.00%	94.00%

Stock-Based Compensation Awar_4

Stock-Based Compensation Awards - Valuation Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017	Nov. 09, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price (in USD per share)			$ 75
Relative performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Start price (in USD per share)	$ 66.06
Stock price (in USD per share)	$ 61.27
Volatility	29.98%
Risk-free interest rate	2.42%
Expected dividend yield	0.00%
Absolute performance-based restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock price (in USD per share)	$ 61.27
Volatility	29.98%
Risk-free interest rate	2.42%
Expected dividend yield	0.00%
Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price (in USD per share)		$ 66.13
Stock price (in USD per share)		$ 65.50
Volatility		60.90%
Risk-free interest rate		2.18%
Expected term		6 years

Stock-Based Compensation Awar_5

Stock-Based Compensation Awards - Award Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted stock
Number of Shares
Beginning balance (in shares)	264,799
Granted (in shares)	0
Vested (in shares)	(161,468)
Forfeited or Expired (in shares)	(79,733)
Ending balance (in shares)	23,598	264,799
Weighted-Average Grant Date Fair Value
Beginning balance (in USD per share)	$ 65.55
Granted (in USD per share)	0		$ 65.55
Vested (in USD per share)	65.55
Forfeited or Expired (in USD per share)	65.55
Ending balance (in USD per share)	$ 65.55	$ 65.55
Time-based restricted stock, share units
Number of Shares
Beginning balance (in shares)	251,875
Granted (in shares)	79,474		5,504
Vested (in shares)	(121,251)
Forfeited or Expired (in shares)	(52,016)
Ending balance (in shares)	158,082	251,875
Weighted-Average Grant Date Fair Value
Beginning balance (in USD per share)	$ 74.71
Granted (in USD per share)	49.47	$ 74.73	$ 73.37
Vested (in USD per share)	72.59
Forfeited or Expired (in USD per share)	71.09
Ending balance (in USD per share)	$ 64.84	$ 74.71
Restricted stock units and deferred settlements
Number of Shares
Vested (in shares)	(3,274)
Time-based restricted stock, cash units
Number of Shares
Beginning balance (in shares)	18,063
Granted (in shares)	0	18,063
Vested (in shares)	(18,063)
Forfeited or Expired (in shares)	0
Ending balance (in shares)	0	18,063
Weighted-Average Grant Date Fair Value
Beginning balance (in USD per share)	$ 65.74
Granted (in USD per share)	0	$ 65
Vested (in USD per share)	61.27
Forfeited or Expired (in USD per share)	0
Ending balance (in USD per share)	$ 0	$ 65.74
Relative performance-based restricted stock units
Number of Shares
Beginning balance (in shares)	0
Granted (in shares)	81,065
Vested (in shares)	(22,322)
Forfeited or Expired (in shares)	(27,144)
Ending balance (in shares)	31,599	0
Weighted-Average Grant Date Fair Value
Beginning balance (in USD per share)	$ 0
Granted (in USD per share)	65.70
Vested (in USD per share)	65.70
Forfeited or Expired (in USD per share)	65.70
Ending balance (in USD per share)	$ 65.70	$ 0
Relative performance-based restricted stock units, unsettled
Number of Shares
Vested (in shares)	(22,322)
Absolute performance-based restricted stock units
Number of Shares
Beginning balance (in shares)	0
Granted (in shares)	27,042
Vested (in shares)	(7,443)
Forfeited or Expired (in shares)	(9,050)
Ending balance (in shares)	10,549	0
Weighted-Average Grant Date Fair Value
Beginning balance (in USD per share)	$ 0
Granted (in USD per share)	50.60
Vested (in USD per share)	50.60
Forfeited or Expired (in USD per share)	50.60
Ending balance (in USD per share)	$ 50.60	$ 0
Absolute performance-based restricted stock units, unsettled
Number of Shares
Vested (in shares)	(7,443)

Stock-Based Compensation Awar_6

Stock-Based Compensation Awards - Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fixed price stock options
Number of Shares
Beginning balance (in shares)	126,128
Granted (in shares)	0
Exercised (in shares)	(126,128)
Forfeited or Expired (in shares)	0
Ending balance (in shares)	0	126,128
Exercisable (in shares)	0	126,128
Weighted-Average Exercise Price Per Share
Beginning balance (in USD per share)	$ 2.50
Granted (in USD per share)	0
Exercised (in USD per share)	2.50
Forfeited or Expired (in USD per share)	0
Ending balance (in USD per share)	0	$ 2.50
Exercisable (in USD per share)	$ 0	$ 2.50
Weighted-Average Remaining Contractual Term (Years)
Outstanding	0 years	7 years 6 months 26 days
Exercisable	0 years	7 years 6 months 26 days
Aggregate Intrinsic Value
Beginning balance	$ 7,976,000
Exercised	6,879,000	$ 1,214,000	$ 0
Ending balance	0	7,976,000
Exercisable	$ 0	$ 7,976,000
30-Day volume-weighted average price stock options
Number of Shares
Beginning balance (in shares)	255,648
Granted (in shares)	0
Exercised (in shares)	(123,876)
Forfeited or Expired (in shares)	(80,413)
Ending balance (in shares)	51,359	255,648
Exercisable (in shares)	44,356	177,152
Weighted-Average Exercise Price Per Share
Beginning balance (in USD per share)	$ 35.97
Granted (in USD per share)	0
Exercised (in USD per share)	5
Forfeited or Expired (in USD per share)	66.13
Ending balance (in USD per share)	63.45	$ 35.97
Exercisable (in USD per share)	$ 63.03	$ 22.61
Weighted-Average Remaining Contractual Term (Years)
Outstanding	7 years 1 month 24 days	7 years 10 months 17 days
Exercisable	7 years 1 month 24 days	7 years 8 months 27 days
Aggregate Intrinsic Value
Beginning balance	$ 7,611,000
Exercised	6,305,000	$ 1,169,000	$ 0
Ending balance	(2,794,000)	7,611,000
Exercisable	$ (2,394,000)	$ 7,641,000

Related Party Transactions - Na

Related Party Transactions - Narrative (Details) $ in Thousands	Jul. 19, 2019USD ($)
Affiliated Entity | Expenses Allocated from Alpha
Related Party Transaction [Line Items]
Allocated expenses	$ 2,900

Commitments and Contingencies (

Commitments and Contingencies (Details) T in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)T	Dec. 31, 2019USD ($)T	Dec. 31, 2018USD ($)T	Dec. 31, 2017USD ($)T	Oct. 31, 2018USD ($)
Long-term Purchase Commitment [Line Items]
Coal royalty expense		$ 91,994	$ 34,485	$ 21,707
Income tax receivable		33,065
Deferred tax assets related to AMT credits		33,065	68,774
Income tax receivable related to NOL carryback claim		64,160
Restricted cash, current		12,363	16,474	11,615
Letters of credit outstanding				$ 11,300
Asset-Based Revolving Credit Facility | Line of Credit | Revolving Credit Facility
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding		99,876	28,700
ANR, Inc. and Citibank, N.A. Credit Agreement | Line of Credit | Letter of Credit
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding		33,399
Credit and Security Agreement | Line of Credit | Revolving Credit Facility
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding		613
Worker's compensation
Long-term Purchase Commitment [Line Items]
Restricted cash		38,944	90,759
Restricted investments		3,100
Black lung
Long-term Purchase Commitment [Line Items]
Restricted cash		12,706	29,611
Reclamation related obligations
Long-term Purchase Commitment [Line Items]
Restricted cash		67,868	86,217
Restricted investments		18,786
Long-term deposits		8,887	24,002
Financial guarantee and other
Long-term Purchase Commitment [Line Items]
Restricted cash		3,006
Other operating agreements
Long-term Purchase Commitment [Line Items]
Long-term deposits		1,836	1,390
Contingent Revenue Obligation
Long-term Purchase Commitment [Line Items]
Restricted cash, current		12,363	$ 6,841
Surety Bond
Long-term Purchase Commitment [Line Items]
Outstanding surety bonds		343,695
Collateral for surety bonds		95,542
Blackjewel L.L.C
Long-term Purchase Commitment [Line Items]
Severance taxes invoiced					$ 7,800
Coal purchase agreements
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, next fiscal year		47,865
Coal Purchase agreements, vendors with historical performance less than 20%
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, next fiscal year		3,677
Equipment purchase agreements
Long-term Purchase Commitment [Line Items]
Purchase commitment, 2020		19,283
Purchase commitment, 2022		$ 279
Back-to-Back Coal Supply Agreements
Long-term Purchase Commitment [Line Items]
Purchased and sold, tons | T		929	5,719	2,000
Purchased and sold		$ 9,941	$ 62,093	$ 21,707
Freight and handling
Long-term Purchase Commitment [Line Items]
Minimum obligation, 2020		6,582
Forecast | Back-to-Back Coal Supply Agreements
Long-term Purchase Commitment [Line Items]
Purchased and sold, tons | T	1,337
Purchased and sold	$ 13,878
Royalty Obligations | Coal revenues
Long-term Purchase Commitment [Line Items]
Minimum obligation, 2020		14,692
Minimum obligation, 2021		13,762
Minimum obligation, 2022		11,866
Minimum obligation, 2023		10,846
Minimum obligation, 2024		8,692
Minimum obligation, after 2024		$ 34,274

Concentration of Credit Risk _3

Concentration of Credit Risk and Major Customer (Details) T in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019USD ($)customer	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)customer	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)customerT	Dec. 31, 2018USD ($)customerT	Dec. 31, 2017USD ($)T
Concentration Risk [Line Items]
Total revenues | $	$ 499,076	$ 525,864	$ 656,206	$ 609,114	$ 572,084	$ 447,871	$ 528,918	$ 482,332	$ 2,290,260	$ 2,031,205	$ 1,649,969
Coal purchased from third parties excluding coal sold under Back-to-Back Coal Supply Agreements									2,327	5,968	4,998
Accounts Receivable | Customer Concentration Risk
Concentration Risk [Line Items]
Number of customers | customer	1				2				1	2
Coal Purchased From Third Parties Sold | Product Supplied By Third Party Concentration Risk
Concentration Risk [Line Items]
Concentration risk									10.00%	34.00%	32.00%
Top Customer | Revenues | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk									12.00%	17.00%	15.00%
Top 10 Customers | Revenues | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk									56.00%	60.00%	65.00%
Another Customer | Revenues | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk									13.00%
Met coal | Coal Sales Volume | Product Concentration Risk
Concentration Risk [Line Items]
Concentration risk									55.00%	63.00%	57.00%
Thermal | Coal Sales Volume | Product Concentration Risk
Concentration Risk [Line Items]
Concentration risk									45.00%	37.00%	43.00%
Alpha Companies
Concentration Risk [Line Items]
Coal purchased from Alpha										3,993	4,189

Segment Information - Schedule

Segment Information - Schedule of Operating Results and Capital Expenditures (Details) $ in Thousands	Nov. 08, 2018segment	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Jun. 30, 2019segments	Dec. 31, 2019USD ($)segmentplantmine	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments	3									4	3
Total revenues		$ 499,076	$ 525,864	$ 656,206	$ 609,114	$ 572,084	$ 447,871	$ 528,918	$ 482,332		$ 2,290,260	$ 2,031,205	$ 1,649,969
Depreciation, depletion and amortization											228,792	77,549	34,910
Amortization of acquired intangibles, net											(88)	(5,392)	59,007
Adjusted EBITDA											295,607	335,076	278,466
Capital expenditures											192,411	81,881	72,701
All Other
Segment Reporting Information [Line Items]
Total revenues											3,534	3,297	835
Depreciation, depletion and amortization											5,439	3,350	882
Amortization of acquired intangibles, net											0	0	0
Adjusted EBITDA											(63,883)	(43,552)	(40,281)
Capital expenditures											2,652	332	1,200
Met | Operating Segments
Segment Reporting Information [Line Items]
Total revenues											1,711,252	1,671,219	1,329,734
Depreciation, depletion and amortization											153,006	40,330	18,941
Amortization of acquired intangibles, net											10,389	(12,334)	34,737
Adjusted EBITDA											316,324	335,135	264,314
Capital expenditures											$ 140,250	39,634	20,494
Met | Virgina
Segment Reporting Information [Line Items]
Number of active mines | mine											7
Number of preparation plants | plant											2
Met | West Virgina
Segment Reporting Information [Line Items]
Number of active mines | mine											16
Number of preparation plants | plant											5
Thermal | Operating Segments
Segment Reporting Information [Line Items]
Total revenues											$ 286,486	39,650	0
Depreciation, depletion and amortization											57,483	10,596	0
Amortization of acquired intangibles, net											(13,578)	(7,516)	0
Adjusted EBITDA											11,981	(875)	0
Capital expenditures											$ 17,545	1,280	0
Thermal | West Virgina
Segment Reporting Information [Line Items]
Number of active mines | mine											5
Number of preparation plants | plant											2
NAPP | Operating Segments
Segment Reporting Information [Line Items]
Total revenues											$ 288,988	317,039	319,400
Depreciation, depletion and amortization											12,864	23,273	15,087
Amortization of acquired intangibles, net											3,101	14,458	24,270
Adjusted EBITDA											31,185	44,368	54,433
Capital expenditures											$ 31,964	$ 40,635	$ 51,007
NAPP | Pennsylvania
Segment Reporting Information [Line Items]
Number of active mines | mine											1
Number of preparation plants | plant											1
Number of closed mines | mine											1

Segment Information - Reconcili

Segment Information - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations	$ (191,871)	$ (43,561)	$ 24,300	$ 7,990	$ 155,901	$ 14,011	$ 74,642	$ 58,300	$ (203,142)	$ 302,854	$ 173,735
Interest expense									66,798	38,810	35,977
Interest income									(7,296)	(1,949)	(210)
Income tax benefit					(165,496)				(57,557)	(165,363)	(67,979)
Depreciation, depletion and amortization									228,792	77,549	34,910
Merger-related costs					46,736	$ 1,181	$ 3,423	$ 460	1,090	51,800	0
Non-cash stock compensation expense									12,348	11,978	20,209
Mark-to-market adjustment for acquisition-related obligations									(3,564)	24	3,221
Accretion on asset retirement obligations									27,798	9,966	9,934
Loss on modification and extinguishment of debt			26,459		$ (12,042)				26,459	12,042	38,701
Asset impairment	60,466	$ 32	$ 5,826						66,324
Goodwill impairment	$ 124,353								124,353	0	0
Cost impact of coal inventory fair value adjustment									8,209	17,064
Gain on assets acquired in an exchange transaction				$ (9,083)					(9,083)	0	0
Management restructuring costs									7,720	2,659
Loss on partial settlement of benefit obligations									6,446
Gain on settlement of acquisition-related obligations									0	(580)	(38,886)
Amortization of acquired intangibles, net									(88)	(5,392)	59,007
Gain on sale of disposal group										(16,386)
Secondary offering costs									0	0	4,491
Bargain purchase gain									0	0	(1,011)
Expenses related to the dividend											6,367
Adjusted EBITDA									295,607	335,076	278,466
Asset impairment									60,169
Asset impairment related to write-off of prepaid purchased coal									6,155
Met
Segment Reporting, Other Significant Reconciling Item [Line Items]
Asset impairment									9,176
Thermal
Segment Reporting, Other Significant Reconciling Item [Line Items]
Asset impairment									50,993
Operating Segments | Met
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations									8,224	306,898	204,213
Interest expense									(1,209)	260	(90)
Interest income									(100)	(40)	(22)
Income tax benefit									0	0	0
Depreciation, depletion and amortization									153,006	40,330	18,941
Merger-related costs									0	22
Non-cash stock compensation expense									1,494	408	650
Mark-to-market adjustment for acquisition-related obligations									0	0	0
Accretion on asset retirement obligations									9,466	4,430	5,770
Loss on modification and extinguishment of debt									0	0	0
Asset impairment									15,034
Goodwill impairment									124,353
Cost impact of coal inventory fair value adjustment									4,751	11,547
Gain on assets acquired in an exchange transaction									(9,083)
Management restructuring costs									0	0
Loss on partial settlement of benefit obligations									(1)
Gain on settlement of acquisition-related obligations										0	0
Amortization of acquired intangibles, net									10,389	(12,334)	34,737
Gain on sale of disposal group										(16,386)
Secondary offering costs											0
Bargain purchase gain											0
Expenses related to the dividend											115
Adjusted EBITDA									316,324	335,135	264,314
Operating Segments | Thermal
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations									(97,398)	(10,796)	0
Interest expense									23	1	0
Interest income									0	0	0
Income tax benefit									0	0	0
Depreciation, depletion and amortization									57,483	10,596	0
Merger-related costs									0	1
Non-cash stock compensation expense									71	24	0
Mark-to-market adjustment for acquisition-related obligations									0	0	0
Accretion on asset retirement obligations									10,929	1,298	0
Loss on modification and extinguishment of debt									0	0	0
Asset impairment									50,993
Goodwill impairment									0
Cost impact of coal inventory fair value adjustment									3,458	5,517
Gain on assets acquired in an exchange transaction									0
Management restructuring costs									0	0
Loss on partial settlement of benefit obligations									0
Gain on settlement of acquisition-related obligations										0	0
Amortization of acquired intangibles, net									(13,578)	(7,516)	0
Gain on sale of disposal group										0
Secondary offering costs											0
Bargain purchase gain											0
Expenses related to the dividend											0
Adjusted EBITDA									11,981	(875)	0
Operating Segments | NAPP
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations									11,926	4,193	12,334
Interest expense									(723)	(1,286)	(1,505)
Interest income									(49)	(34)	(1)
Income tax benefit									0	0	0
Depreciation, depletion and amortization									12,864	23,273	15,087
Merger-related costs									0	0
Non-cash stock compensation expense									0	0	0
Mark-to-market adjustment for acquisition-related obligations									0	0	0
Accretion on asset retirement obligations									4,066	3,764	4,164
Loss on modification and extinguishment of debt									0	0	0
Asset impairment									0
Goodwill impairment									0
Cost impact of coal inventory fair value adjustment									0	0
Gain on assets acquired in an exchange transaction									0
Management restructuring costs									0	0
Loss on partial settlement of benefit obligations									0
Gain on settlement of acquisition-related obligations										0	0
Amortization of acquired intangibles, net									3,101	14,458	24,270
Gain on sale of disposal group										0
Secondary offering costs											0
Bargain purchase gain											0
Expenses related to the dividend											84
Adjusted EBITDA									31,185	44,368	54,433
All Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income (loss) from continuing operations									(125,894)	2,559	(42,812)
Interest expense									68,707	39,835	37,572
Interest income									(7,147)	(1,875)	(187)
Income tax benefit									(57,557)	(165,363)	(67,979)
Depreciation, depletion and amortization									5,439	3,350	882
Merger-related costs									1,090	51,777
Non-cash stock compensation expense									10,783	11,546	19,559
Mark-to-market adjustment for acquisition-related obligations									(3,564)	24	3,221
Accretion on asset retirement obligations									3,337	474	0
Loss on modification and extinguishment of debt									26,459	12,042	38,701
Asset impairment									297
Goodwill impairment									0
Cost impact of coal inventory fair value adjustment									0	0
Gain on assets acquired in an exchange transaction									0
Management restructuring costs									7,720	2,659
Loss on partial settlement of benefit obligations									6,447
Gain on settlement of acquisition-related obligations										(580)	(38,886)
Amortization of acquired intangibles, net									0	0	0
Gain on sale of disposal group										0
Secondary offering costs											4,491
Bargain purchase gain											(1,011)
Expenses related to the dividend											6,168
Adjusted EBITDA									$ (63,883)	$ (43,552)	$ (40,281)

Segment Information - Revenue f

Segment Information - Revenue from External Customers (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer	$ 2,282,007	$ 2,020,889	$ 1,639,883
Non-US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer	$ 1,247,614	$ 1,671,646	$ 1,265,320
Non-US | Geographic Concentration Risk | Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk	55.00%	83.00%	77.00%
INDIA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer	$ 288,344	$ 420,919	$ 356,673
BRAZIL
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer		285,120
Coal
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer	2,282,007	2,020,889	1,392,481
Coal | Non-US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer	$ 1,247,614	$ 1,671,646
Coal
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer			1,639,883
Coal | Non-US
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from contract with customer			$ 1,265,320

Quarterly Financial Informati_3

Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 499,076	$ 525,864	$ 656,206	$ 609,114	$ 572,084	$ 447,871	$ 528,918	$ 482,332	$ 2,290,260	$ 2,031,205	$ 1,649,969
(Loss) income from continuing operations	(191,871)	(43,561)	24,300	7,990	155,901	14,011	74,642	58,300	(203,142)	302,854	173,735
Net (loss) income from discontinued operations	50,930	(24,971)	(137,961)	(1,175)	641	(2,117)	(854)	(1,359)	(113,177)	(3,689)	(19,213)
Net (loss) income	$ (140,941)	$ (68,532)	$ (113,661)	$ 6,815	$ 156,542	$ 11,894	$ 73,788	$ 56,941	$ (316,319)	$ 299,165	$ 154,522
Weighted average shares - basic (in shares)	18,195,651	19,025,462	19,123,705	18,894,315	15,014,994	9,633,164	9,625,874	9,548,613	18,808,460	10,967,014	10,216,464
Weighted average shares - diluted (in shares)	18,195,651	19,025,462	19,420,471	19,538,629	15,822,037	10,384,513	10,306,043	10,292,607	18,808,460	11,712,653	10,770,005
Basic (loss) income per common share:
(Loss) Income from continuing operations (in dollars per share)	$ (10.54)	$ (2.29)	$ 1.27	$ 0.42	$ 10.38	$ 1.45	$ 7.75	$ 6.11	$ (10.80)	$ 27.61	$ 17.01
(Loss) income from discontinued operations (in dollars per share)	2.79	(1.31)	(7.21)	(0.06)	0.04	(0.22)	(0.08)	(0.15)	(6.02)	(0.33)	(1.89)
Net (loss) income (in dollars per share)	(7.75)	(3.60)	(5.94)	0.36	10.42	1.23	7.67	5.96	(16.82)	27.28	15.12
Diluted (loss) income per common share:
(Loss) income from continuing operations (in dollars per share)	(10.54)	(2.29)	1.25	0.41	9.85	1.35	7.24	5.66	(10.80)	25.86	16.13
(Loss) income from discontinued operations (in dollars per share)	2.79	(1.31)	(7.10)	(0.06)	0.04	(0.20)	(0.08)	(0.13)	(6.02)	(0.32)	(1.78)
Net (loss) income (in dollars per share)	$ (7.75)	$ (3.60)	$ (5.85)	$ 0.35	$ 9.89	$ 1.15	$ 7.16	$ 5.53	$ (16.82)	$ 25.54	$ 14.35
Merger-related costs					$ 46,736	$ 1,181	$ 3,423	$ 460	$ 1,090	$ 51,800	$ 0
Gain on assets acquired in an exchange transaction				$ 9,083					9,083	0	0
Gain on disposal transaction							$ (16,386)
Asset impairment	$ 60,466	$ 32	$ 5,826						66,324
Goodwill impairment	$ 124,353								124,353	0	0
Income tax benefit					165,496				57,557	165,363	67,979
Loss on modification and extinguishment of debt			$ 26,459		$ (12,042)				$ 26,459	$ 12,042	$ 38,701

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	Feb. 21, 2020	Feb. 20, 2020
Black lung | Subsequent Event
Subsequent Event [Line Items]
Collateral	$ 65,700	$ 2,600