Alpha Metallurgical Resources (AMR) 10-Q 9 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-38735
Entity Registrant Name	CONTURA ENERGY, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3015061
Entity Address, Address Line One	340 Martin Luther King Jr. Blvd.
Entity Address, City or Town	Bristol
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	37620
City Area Code	423
Local Phone Number	573-0300
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock
Trading Symbol	CTRA
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		18,308,838
Entity Central Index Key	0001704715
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Coal revenues	$ 399,954	$ 523,987	$ 1,278,935	$ 1,784,775
Other revenues	737	1,877	4,054	6,409
Total revenues	400,691	525,864	1,282,989	1,791,184
Costs and expenses:
Cost of coal sales (exclusive of items shown separately below)	367,277	467,658	1,148,416	1,480,098
Depreciation, depletion and amortization	50,739	60,842	154,466	184,927
Accretion on asset retirement obligations	9,127	6,846	23,806	19,925
Amortization of acquired intangibles, net	2,219	2,314	5,180	(4,712)
Asset impairment and restructuring	3,571	32	221,453	5,858
Selling, general and administrative expenses (exclusive of depreciation, depletion and amortization shown separately above)	14,501	17,387	42,010	53,121
Merger-related costs	0	68	0	1,055
Total other operating (income) loss:
Mark-to-market adjustment for acquisition-related obligations	3,624	(3,238)	(13,425)	(288)
Other (income) expense	(1,359)	166	(2,063)	(7,319)
Total costs and expenses	449,699	552,075	1,579,843	1,732,665
(Loss) income from operations	(49,008)	(26,211)	(296,854)	58,519
Other income (expense):
Interest expense	(18,389)	(18,847)	(54,808)	(50,079)
Interest income	378	1,763	6,889	5,584
Loss on modification and extinguishment of debt	0	0	0	(26,459)
Equity loss in affiliates	(1,295)	(1,845)	(3,085)	(4,804)
Miscellaneous loss, net	(368)	(1,523)	(1,088)	(2,912)
Total other expense, net	(19,674)	(20,452)	(52,092)	(78,670)
Loss from continuing operations before income taxes	(68,682)	(46,663)	(348,946)	(20,151)
Income tax benefit	45	3,102	2,200	8,880
Net loss from continuing operations	(68,637)	(43,561)	(346,746)	(11,271)
Discontinued operations:
Loss from discontinued operations before income taxes	0	(11,516)	0	(176,973)
Income tax (expense) benefit from discontinued operations	0	(13,455)	0	12,866
Loss from discontinued operations	0	(24,971)	0	(164,107)
Net loss	$ (68,637)	$ (68,532)	$ (346,746)	$ (175,378)
Earnings Per Share, Basic [Abstract]
(Loss) income from continuing operations (in dollars per share)	$ (3.75)	$ (2.29)	$ (18.96)	$ (0.59)
Loss from discontinued operations (in dollars per share)	0	(1.31)	0	(8.63)
Net loss (in dollars per share)	(3.75)	(3.60)	(18.96)	(9.22)
Earnings Per Share, Diluted [Abstract]
(Loss) income from continuing operations (in dollars per share)	(3.75)	(2.29)	(18.96)	(0.59)
Loss from discontinuing operations (in dollars per share)	0	(1.31)	0	(8.63)
Net loss (in dollars per share)	$ (3.75)	$ (3.60)	$ (18.96)	$ (9.22)
Weighted average shares - basic (in shares)	18,319,947	19,025,462	18,290,346	19,014,974
Weighted average shares - diluted (in shares)	18,319,947	19,025,462	18,290,346	19,014,974
Revenue from Contract with Customer, Product and Service [Extensible List]	us-gaap:PublicUtilitiesInventoryCoalMember	us-gaap:PublicUtilitiesInventoryCoalMember	us-gaap:PublicUtilitiesInventoryCoalMember	us-gaap:PublicUtilitiesInventoryCoalMember

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Other Comprehensive Income [Abstract]
Net loss	$ (68,637)	$ (68,532)	$ (346,746)	$ (175,378)
Employee benefit plans:
Amortization of and adjustments to employee benefit costs	1,133	(86)	(9,998)	1,340
Income tax expense	0	22	0	(350)
Total other comprehensive income (loss), net of tax	1,133	(64)	(9,998)	990
Total comprehensive loss	$ (67,504)	$ (68,596)	$ (356,744)	$ (174,388)

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 161,434	$ 212,793
Trade accounts receivable, net of allowance for doubtful accounts of $432 and $0 as of September 30, 2020 and December 31, 2019	179,671	244,666
Inventories, net	124,245	162,659
Prepaid expenses and other current assets	120,939	91,361
Total current assets	586,289	711,479
Property, plant, and equipment, net of accumulated depreciation and amortization of $395,397 and $314,276 as of September 30, 2020 and December 31, 2019	401,197	583,262
Owned and leased mineral rights, net of accumulated depletion and amortization of $40,623 and $27,877 as of September 30, 2020 and December 31, 2019	489,631	523,141
Other acquired intangibles, net of accumulated amortization of $38,806 and $32,686 as of September 30, 2020 and December 31, 2019	100,350	125,145
Long-term restricted cash	124,065	122,524
Deferred income taxes	0	33,065
Other non-current assets	221,591	204,207
Total assets	1,923,123	2,302,823
Current liabilities:
Current portion of long-term debt	44,864	28,485
Trade accounts payable	75,836	98,746
Acquisition-related obligations – current	18,206	33,639
Accrued expenses and other current liabilities	153,372	154,282
Total current liabilities	292,278	315,152
Long-term debt	552,676	564,481
Acquisition-related obligations - long-term	19,286	46,259
Workers’ compensation and black lung obligations	263,517	260,778
Pension obligations	186,089	204,086
Asset retirement obligations	210,998	184,130
Deferred income taxes	368	422
Other non-current liabilities	54,943	31,393
Total liabilities	1,580,155	1,606,701
Commitments and Contingencies (Note 18)
Stockholders’ Equity
Preferred stock - par value $0.01, 5.0 million shares authorized, none issued	0	0
Common stock - par value $0.01, 50.0 million shares authorized, 20.6 million issued and 18.3 million outstanding at September 30, 2020 and 20.5 million issued and 18.2 million outstanding at December 31, 2019	206	205
Additional paid-in capital	778,728	775,707
Accumulated other comprehensive loss	(68,614)	(58,616)
Treasury stock, at cost: 2.3 million shares at September 30, 2020 and December 31, 2019	(106,976)	(107,984)
Retained (deficit) earnings	(260,376)	86,810
Total stockholders’ equity	342,968	696,122
Total liabilities and stockholders’ equity	$ 1,923,123	$ 2,302,823

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - Parenthetical - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 432	$ 0
Property, plant and equipment, accumulated amortization, depreciation and amortization	395,397	314,276
Owned and lease mineral rights, accumulated depletion and amortization	40,623	27,877
Other acquired intangibles, accumulated amortization	$ 38,806	$ 32,686
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)	20,600,000	20,500,000
Common stock, shares outstanding (in shares)	18,300,000	18,200,000
Treasury stock, shares at cost (in shares)	2,300,000	2,300,000

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net loss	$ (346,746)	$ (175,378)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	154,466	330,840
Amortization of acquired intangibles, net	5,180	(4,712)
Accretion of acquisition-related obligations discount	2,882	4,367
Amortization of debt issuance costs and accretion of debt discount	11,087	10,446
Mark-to-market adjustment for acquisition-related obligations	(13,425)	(288)
(Gain) loss on disposal of assets	(2,179)	1,462
Gain on assets acquired in an exchange transaction	0	(9,083)
Loss on modification and extinguishment of debt	0	26,459
Asset impairment and restructuring	221,453	23,020
Accretion on asset retirement obligations	23,806	24,906
Employee benefit plans, net	15,135	14,513
Deferred income taxes	33,011	(22,021)
Stock-based compensation	4,200	7,512
Equity loss in affiliates	3,085	4,804
Other, net	(5,356)	351
Changes in operating assets and liabilities	(33,566)	(99,620)
Net cash provided by operating activities	73,033	137,578
Investing activities:
Capital expenditures	(118,896)	(144,183)
Proceeds on disposal of assets	3,131	1,170
Purchases of investment securities	(18,618)	(65,193)
Maturity of investment securities	12,678	50,775
Capital contributions to equity affiliates	(3,196)	(7,600)
Other, net	68	(2,548)
Net cash used in investing activities	(124,833)	(167,579)
Financing activities:
Proceeds from borrowings on debt	57,500	544,946
Principal repayments of debt	(43,364)	(551,405)
Principal repayments of notes payable	(14,951)	(14,054)
Principal repayments of financing lease obligations	(2,291)	(2,960)
Debt issuance costs	0	(6,104)
Common stock repurchases and related expenses	(171)	(35,485)
Other, net	0	952
Net cash used in financing activities	(3,277)	(64,110)
Net decrease in cash and cash equivalents and restricted cash	(55,077)	(94,111)
Cash and cash equivalents and restricted cash at beginning of period	347,680	477,246
Cash and cash equivalents and restricted cash at end of period	292,603	383,135
Reconciliation of Cash and Cash Equivalents and Restricted Cash
Total cash and cash equivalents and restricted cash shown in the Condensed Consolidated Statements of Cash Flows	$ 292,603	$ 383,135

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Treasury Stock at Cost	Retained (Deficit) Earnings	Cumulative effect	Cumulative effectRetained (Deficit) Earnings
Beginning 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 income (loss)	6,815					6,815
Other comprehensive income (loss), net	177			177
Stock-based compensation and net issuance of common stock for share vesting	6,377		6,377
Exercise of stock options	306	1	305
Common stock repurchases and related expenses	(4,171)				(4,171)
Ending balance at Mar. 31, 2019	1,080,644	203	767,983	(22,953)	(74,533)	409,944
Beginning 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 income (loss)	(175,378)
Other comprehensive income (loss), net	990
Ending balance at Sep. 30, 2019	868,938	205	770,822	(22,140)	(107,700)	227,751
Beginning balance at Mar. 31, 2019	1,080,644	203	767,983	(22,953)	(74,533)	409,944
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(113,661)					(113,661)
Other comprehensive income (loss), net	877			877
Stock-based compensation and net issuance of common stock for share vesting	(545)		(545)
Exercise of stock options	590	1	589
Warrant exercises	19		19
Common stock repurchases and related expenses	(703)				(703)
Ending balance at Jun. 30, 2019	967,221	204	768,046	(22,076)	(75,236)	296,283
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(68,532)					(68,532)
Other comprehensive income (loss), net	(64)			(64)
Stock-based compensation and net issuance of common stock for share vesting	2,739	1	2,738
Exercise of stock options	38		38
Common stock repurchases and related expenses	(32,464)				(32,464)
Ending balance at Sep. 30, 2019	868,938	205	770,822	(22,140)	(107,700)	227,751
Beginning balance at Dec. 31, 2019	$ 696,122	205	775,707	(58,616)	(107,984)	86,810	$ (440)	$ (440)
Ending balance at Jan. 01, 2020								(440)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance at Dec. 31, 2019	$ 696,122	205	775,707	(58,616)	(107,984)	86,810	(440)	(440)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(39,808)					(39,808)
Other comprehensive income (loss), net	(4,010)			(4,010)
Stock-based compensation and net issuance of common stock for share vesting	900		900
Common stock repurchases and related expenses	1,071				1,071
Ending balance at Mar. 31, 2020	$ 653,835	205	776,607	(62,626)	(106,913)	46,562
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance at Dec. 31, 2019	$ 696,122	205	775,707	(58,616)	(107,984)	86,810	$ (440)	$ (440)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(346,746)
Other comprehensive income (loss), net	(9,998)
Ending balance at Sep. 30, 2020	342,968	206	778,728	(68,614)	(106,976)	(260,376)
Beginning balance at Mar. 31, 2020	653,835	205	776,607	(62,626)	(106,913)	46,562
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(238,301)					(238,301)
Other comprehensive income (loss), net	(7,121)			(7,121)
Stock-based compensation and net issuance of common stock for share vesting	1,044	1	1,043
Common stock repurchases and related expenses	(42)				(42)
Ending balance at Jun. 30, 2020	409,415	206	777,650	(69,747)	(106,955)	(191,739)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(68,637)					(68,637)
Other comprehensive income (loss), net	1,133			1,133
Stock-based compensation and net issuance of common stock for share vesting	1,078		1,078
Common stock repurchases and related expenses	(21)				(21)
Ending balance at Sep. 30, 2020	$ 342,968	$ 206	$ 778,728	$ (68,614)	$ (106,976)	$ (260,376)

Business and Basis of Presentat

Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Basis of Presentation Together, the condensed consolidated statements of operations, comprehensive loss, balance sheets, cash flows and stockholders’ equity for the Company are referred to as the “Condensed Consolidated Financial Statements.” The Condensed Consolidated Financial Statements are also referenced across periods as “Condensed Consolidated Statements of Operations,” “Condensed Consolidated Statements of Comprehensive Loss,” “Condensed Consolidated Balance Sheets,” “Condensed Consolidated Statements of Cash Flows,” and “Condensed Consolidated Statements of Stockholders’ Equity.” The Condensed Consolidated Financial Statements include all wholly-owned subsidiaries’ results of operations for the three and nine months ended September 30, 2020 and 2019. All significant intercompany transactions have been eliminated in consolidation. The accompanying interim Condensed Consolidated Financial Statements are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) and in accordance with the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for Form 10-Q. Such rules and regulations allow the omission of certain information and footnote disclosures normally included in the financial statements prepared in accordance with U.S. GAAP as long as the financial statements are not misleading. In the opinion of management, these interim Condensed Consolidated Financial Statements reflect all normal and recurring adjustments necessary for a fair presentation of the results for the periods presented. Results of operations for the three and nine months ended September 30, 2020 are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or any other period. These interim Condensed Consolidated Financial Statements should be read in conjunction with the Company’s Consolidated Financial Statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. 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 believes it will have sufficient liquidity 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. COVID-19 Pandemic In the first quarter of 2020, the COVID-19 virus was declared a pandemic by the World Health Organization. The COVID-19 pandemic has had negative impacts on the Company’s business, results of operations, financial condition and cash flows. A continued period of reduced demand for the Company’s products could have significant adverse consequences. The full extent of the impact of the COVID-19 pandemic on the Company’s operational and financial performance will depend on certain developments, including the duration and spread of the outbreak, its impact on its customers and suppliers and the range of governmental and community reactions to the pandemic, which are still uncertain and cannot be fully predicted at this time. In response to the COVID-19 pandemic, on March 27, 2020, the “Coronavirus Aid, Relief, and Economic Security Act” (“CARES Act”) was enacted into law. As a result, the Company expects accelerated refunds of previously generated alternative minimum tax (“AMT”) credits from the Internal Revenue Service (“IRS”) as further described in Note 15 and expects to defer 2020 employer payroll taxes incurred after the date of enactment to future years. As further described in Note 11, on March 20, 2020, the Company borrowed funds under a senior secured asset-based revolving credit facility. The funds were borrowed to augment the Company’s short-term operational flexibility in the face of uncertainty created by the current spread of the COVID-19 virus and its potential effects. On April 3, 2020, the Company announced temporary operational changes in response to market conditions, existing coal inventory levels, and customer deferrals due to concern around the global economic impact of the COVID-19 pandemic. Beginning April 3, 2020, the majority of the Company’s operations were idled for a period of approximately 30 days, with some sites idling for shorter periods of time and a few continuing to operate at a near-normal rate of production. Location-specific schedules were implemented based on existing customer agreements, current inventory levels, and anticipated customer demand. Certain preparation plants, docks, and loadouts continued to operate to support business needs and customer shipments. As of May 4, 2020, all Company sites were back to nearly normal staffing levels and operating capacity with additional precautions in place to help reduce the risk of exposure to COVID-19. Refer to Note 8 for discussion of certain strategic actions announced during the second quarter of 2020 with respect to two thermal coal mining complexes in an effort to strengthen the Company’s financial performance. The Company will continue to evaluate market conditions amid the continuing uncertainty of the COVID-19 pandemic and expects to adjust its operations accordingly. Recently Adopted Accounting Guidance 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 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. The Company adopted ASU 2018-13 during the first quarter of 2020. The adoption of this ASU did not have a material impact on the Company's Condensed 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 amendments also improve consistent application of and simplify U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The Company adopted ASU 2019-12 during the first quarter of 2020. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Reference Rate Reform : In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). The amendments in this update provide optional expedients and exceptions, if certain criteria are met, for applying U.S. GAAP to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022, except for hedging relationships existing as of December 31, 2022, that an entity has elected certain optional expedients for and that are retained through the end of the hedging relationship. The Company adopted ASU 2020-04, with respect to topics in Accounting Standards Codification (“ASC”) 310 Receivables , ASC 470 Debt , ASC 815 Derivatives and Hedging and ASC 842 Leases , during the first quarter of 2020. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Recent Accounting Guidance Issued Not Yet Effective 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 Condensed Consolidated Financial Statements and related disclosures. Convertible Debt and Contracts in Entity’s Own Equity : In August 2020, the FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”). The amendments in this update simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts in an entity’s own equity, such as the Company’s outstanding Series A warrants. For public business entities, the standard is effective for fiscal years ending after December 15, 2021, with early adoption permitted. The adoption of this ASU is not expected to have a material impact on the Company’s Condensed Consolidated Financial Statements and related disclosures.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations Discontinued operations in the prior period consisted of activity related to the transactions with Blackjewel and ESM stemming from the sale of assets in the Company’s former PRB operations. On May 29, 2020, Contura Coal West, LLC and Contura Wyoming Land, LLC merged with certain subsidiaries of ESM and survived as wholly-owned subsidiaries of ESM. Contura Coal West, LLC holds, and will continue to hold, the mining permits for the Western Mines, which have been under the operational control of ESM since October 2019 pursuant to the ESM Transaction. Pursuant to terms of the transaction, the Company received from ESM approximately $625 in consideration for assets owned by Contura Coal West, LLC but not previously conveyed. There were no discontinued operations for the three and nine months ended September 30, 2020 and as of September 30, 2020. The major components of net loss from discontinued operations in the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2019 are as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Revenues: Total revenues (1) $ 4 $ 152 Costs and expenses: Depreciation, depletion and amortization (2) $ — $ 145,913 Accretion on asset retirement obligations (3) $ 4,981 $ 4,981 Asset impairment (4) $ 694 $ 17,162 Selling, general and administrative expenses $ 4,666 $ 4,673 Other expenses $ 1,032 $ 3,964 Other non-major expense (income) items, net $ 147 $ 432 (1) Total revenues for the three and nine months ended September 30, 2019 consisted entirely of other revenues. (2) The depreciation, depletion and amortization is related to an increase in the Company’s estimate of its asset retirement obligations with respect to the Western Mines as a result of the Blackjewel Chapter 11 bankruptcy filing on July 1, 2019. The Company remeasured its asset retirement obligations based on the expectation that the mining permits would not transfer to Blackjewel and Blackjewel would be unable to perform its contractual obligation to reclaim the properties. The increase in the asset retirement obligation was recorded to expense as the Company no longer owned the underlying mining assets. (3) The accretion on asset retirement obligations is related to the asset retirement obligation as a result of the Blackjewel bankruptcy filing. (4) The asset impairment is primarily related to the write-off of a tax receivable. The Company was considered to be the primary obligor for certain taxes that Blackjewel was contractually obligated to pay. During the nine months ended September 30, 2019, the Company recorded an impairment charge for the offsetting receivable from Blackjewel as a result of the Blackjewel bankruptcy filing. Refer to the Condensed Consolidated Statements of Operations for net loss per share information related to discontinued operations. There were no major components of asset and liabilities that are classified as discontinued operations in the Condensed Consolidated Balance Sheet as of December 31, 2019. The major components of cash flows related to discontinued operations are as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Other significant operating non-cash items related to discontinued operations: Depreciation, depletion and amortization $ — $ 145,913 Accretion on asset retirement obligations $ 4,981 $ 4,981 Asset impairment $ 694 $ 17,162

Revenue

Revenue	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Disaggregation of Revenue from Contracts with Customers 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: Three Months Ended September 30, 2020 Met Thermal Total Export coal revenues $ 202,339 $ 6,707 $ 209,046 Domestic coal revenues 84,675 106,233 190,908 Total coal revenues $ 287,014 $ 112,940 $ 399,954 Three Months Ended September 30, 2019 Met Thermal Total Export coal revenues $ 248,628 $ 13,187 $ 261,815 Domestic coal revenues 137,146 125,026 262,172 Total coal revenues $ 385,774 $ 138,213 $ 523,987 Nine Months Ended September 30, 2020 Met Thermal Total Export coal revenues $ 693,599 $ 24,459 $ 718,058 Domestic coal revenues 282,266 278,611 560,877 Total coal revenues $ 975,865 $ 303,070 $ 1,278,935 Nine Months Ended September 30, 2019 Met Thermal Total Export coal revenues $ 928,390 $ 39,569 $ 967,959 Domestic coal revenues 429,457 387,359 816,816 Total coal revenues $ 1,357,847 $ 426,928 $ 1,784,775 Performance Obligations The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied as of September 30, 2020. Remainder of 2020 2021 2022 2023 2024 2025 Total Estimated coal revenues $ 138,188 $ 268,185 $ 200,877 $ — $ — $ — $ 607,250

Accumulated Other Comprehensive

Accumulated Other Comprehensive (Loss) Income	9 Months Ended
	Sep. 30, 2020
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 nine months ended September 30, 2020 and 2019: Balance January 1, 2020 Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance September 30, 2020 Employee benefit costs $ (58,616) $ (14,154) $ 4,156 $ (68,614) Balance January 1, 2019 Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance September 30, 2019 Employee benefit costs $ (23,130) $ 458 $ 532 $ (22,140) The following table summarizes the amounts reclassified from accumulated other comprehensive (loss) income and the Condensed Consolidated Statements of Operations line items affected by the reclassification during the three and nine months ended September 30, 2020 and 2019: Details about accumulated other comprehensive (loss) income components Amounts reclassified from accumulated other comprehensive (loss) income Affected line item in the Condensed Consolidated Statements of Operations Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Employee benefit costs: Amortization of actuarial loss (1) $ 1,101 $ 258 $ 2,829 $ 719 Miscellaneous loss, net Settlement (1) 32 — 1,327 — Miscellaneous loss, net Total before income tax $ 1,133 $ 258 $ 4,156 $ 719 Income tax expense — (67) — (187) Income tax benefit Total, net of income tax $ 1,133 $ 191 $ 4,156 $ 532 (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 16.

Net (Loss) Income Per Common Sh

Net (Loss) Income Per Common Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Net (Loss) Income Per Common Share	Net (Loss) Income Per Common 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 income per common share is based on the number of common shares used to calculate basic net income per common 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 diluted effect of outstanding stock-based instruments is determined by application of the treasury stock method. The warrants become dilutive for diluted net income per common share calculations when the market price of the Company’s common stock exceeds the exercise price. Dilutive securities are not included in the computation of diluted net loss per common share as the impact would be anti-dilutive. Refer to the Condensed Consolidated Statements of Operations for net loss per common share for the three and nine months ended September 30, 2020 and 2019. For the three months ended September 30, 2020 and 2019, 1,243,866 and 1,136,318 warrants, stock options, and other stock-based instruments, respectively, were excluded from the computation of dilutive net loss per common share because they would have been anti-dilutive. For the nine months ended September 30, 2020 and 2019, 1,380,076 and 556,282 warrants, stock

Inventories, net

Inventories, net	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventories, net	Inventories, net Inventories, net consisted of the following: September 30, 2020 December 31, 2019 Raw coal $ 18,248 $ 30,274 Saleable coal 79,194 105,092 Materials, supplies and other, net (1) 26,803 27,293 Total inventories, net $ 124,245 $ 162,659

Acquired Intangibles

Acquired Intangibles	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
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 September 30, 2020 and December 31, 2019, net of accumulated amortization, are set forth in the following tables: September 30, 2020 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 185 $ (875) $ (690) Acquired mine permits, net 100,165 — 100,165 Total $ 100,350 $ (875) $ 99,475 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 (1) Included within other acquired intangibles, net of accumulated amortization on the Company’s Condensed Consolidated Balance Sheets. (2) Included within other non-current liabilities on the Company’s Condensed Consolidated Balance Sheets. During the three and six months ended June 30, 2020, the Company recorded a long-lived asset impairment which reduced the carrying value of acquired mine permits, net, by $8,653 and $14,471. Refer to Note 8. 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. The following table details the amortization of mine permits acquired as a result of the Merger and the amortization of above-market and below-market coal supply agreements: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Amortization of mine permits (1) $ 2,944 $ 6,266 $ 9,592 $ 17,871 Amortization of above-market coal supply agreements $ 145 $ 1,473 $ 732 $ 2,351 Amortization of below-market coal supply agreements (870) (5,425) (5,144) (24,934) Net income (1) $ (725) $ (3,952) $ (4,412) $ (22,583) (1) Included within amortization of acquired intangibles, net in the Condensed Consolidated Statements of Operations.

Asset Impairment and Restructur

Asset Impairment and Restructuring	9 Months Ended
	Sep. 30, 2020
Restructuring and Related Activities [Abstract]
Asset Impairment and Restructuring	Asset Impairment and Restructuring Strategic Actions During the second quarter of 2020, as a result of the weakening coal market conditions due in part to the impact of the global COVID-19 pandemic, the Company announced that it would take certain strategic actions with respect to two of its thermal coal mining complexes in an effort to strengthen its financial performance and improve forecasted liquidity. The Company announced that an underground mine and preparation plant located in West Virginia would be idled during the third quarter of 2020. In addition, the Company decided not to move forward with the construction of a new refuse impoundment at its Cumberland mine in Pennsylvania and would therefore no longer spend the significant capital required in connection with the project. As a result, the Cumberland mine is expected to cease production at the end of 2022, and in the meantime, the Company plans to actively market the Cumberland property for sale. During the third quarter of 2020, the Company entered into a collective bargaining agreement with the UMWA representing Cumberland mine employees replacing the prior expired collective bargaining agreement. Long-lived Asset Impairment During the three months ended March 31, 2020, due to declines in metallurgical and thermal coal pricing which reduced forecasted margins at certain locations to amounts below those required for full recoverability, the Company determined that indicators of impairment were present for four long-lived asset groups within its CAPP - Met reporting segment and three long-lived asset groups within its CAPP - Thermal reporting segment and performed impairment testing as of February 29, 2020. At February 29, 2020, the Company determined that the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. The Company estimated the fair value of these asset groups generally using a discounted cash flow analysis utilizing market-participant assumptions. As a result, after allocating the potential impairment to individual assets, the Company recorded a long-lived asset impairment of $33,709, of which $32,951 was recorded within CAPP - Met and $758 was recorded within CAPP - Thermal. The long-lived asset impairment reduced the carrying values of mineral rights by $21,825, property, plant, and equipment, net, by $6,066, and acquired mine permits, net, by $5,818. In connection with the preparation of the Company’s financial statements for the quarter ended June 30, 2020, the Company determined that the strategic actions taken by the Company during the three months ended June 30, 2020, discussed above, shortened the lives of two mining complexes, and that continued weakening in metallurgical and thermal coal pricing had resulted in forecasted margins at certain locations falling below amounts necessary for full recoverability. As a result of these determinations, the Company assessed that indicators of impairment were present for three long-lived asset groups within its CAPP - Met reporting segment and four long-lived asset groups within its CAPP - Thermal reporting segment. The Company therefore performed impairment testing on these assets and determined that, as of May 31, 2020, the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. The Company estimated the fair value of these asset groups generally using a discounted cash flow analysis utilizing market-participant assumptions. As a result, after allocating the potential impairment to individual assets, the Company recorded a long-lived asset impairment of $161,738, of which $144,348 was recorded within NAPP, $17,385 was recorded within CAPP - Thermal, and $5 recorded in All Other. No long-lived asset impairment was recorded within the CAPP - Met reporting segment as each of the three long-lived asset groups had previously been impaired. The long-lived asset impairment reduced the carrying values of mineral rights by $18,605, property, plant, and equipment, net, by $134,480, and acquired mine permits, net, by $8,653. In connection with the preparation of the Company’s financial statements for the quarter ended September 30, 2020, the Company determined forecasted margins at certain locations continued to fall below amounts necessary for full recoverability and therefore indicators of impairment were present for three long-lived asset groups within its CAPP - Met reporting segment and four long-lived asset groups within its CAPP - Thermal reporting segment. The Company therefore performed impairment testing on these assets and determined that, as of August 31, 2020, the carrying amounts of the asset groups exceeded both their undiscounted cash flows and their estimated fair values. The Company estimated the fair value of these asset groups generally using a discounted cash flow analysis utilizing market-participant assumptions. As a result, after allocating the potential impairment to individual assets, the Company recorded a long-lived asset impairment of $3,516, of which $3,297 was recorded within NAPP and $219 was recorded within CAPP - Thermal to reduce the carrying value of property, plant, and equipment, net, due to capital spending during the quarter at previously impaired locations requiring the impairment of certain additional assets not considered recoverable. No long-lived asset impairment was recorded within the CAPP - Met reporting segment as each of the three long-lived asset groups had previously been impaired. During the three and nine months ended September 30, 2019, the Company recorded an asset impairment of $32 and $5,858, respectively, primarily related to the write-off of prepaid purchased coal from Blackjewel as a result of Blackjewel’s Chapter 11 bankruptcy filing on July 1, 2019. Restructuring As a result of the strategic actions discussed above, the Company recorded restructuring expense during the three and nine months ended September 30, 2020 as follows: Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Affected line item in the Condensed Consolidated Balance Sheets Severance and employee-related benefits (1) $ 55 $ 20,608 Accrued expenses and other current liabilities and Other non-current liabilities Other costs (2) — 1,882 Inventories, net and Other non-current assets Total restructuring expense (3) $ 55 $ 22,490 (1) Severance and employee-related benefits were considered probable and estimable based on provisions of contractual agreements and existing employee benefit plans. (2) The nine months ended September 30, 2020 includes accelerated amortization of deferred longwall move expenses of $668, allowance for advanced mining royalties of $407, and allowance for obsolete materials and supplies inventory of $807. (3) During the three months ended September 30, 2020, total restructuring expenses of ($484), $89, and $450 were recorded within the reportable segments CAPP - Thermal, NAPP and All Other, respectively. During the nine months ended September 30, 2020, total restructuring expenses of $1,826, $18,221, and $2,443 were recorded within the reportable segments CAPP - Thermal, NAPP and All Other, respectively. There were no restructuring expenses recorded during the three and nine months ended September 30, 2019.

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	LeasesSubsequent to the adoption of ASC 842, Leases, 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 groups 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 nine months ended September 30, 2020 and 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 nine months ended September 30, 2020 and 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 September 30, 2020, the Company does not intend to exercise any termination options on existing leases. As of September 30, 2020 and December 31, 2019, the Company had the following right-of-use assets and lease liabilities within the Company’s Condensed Consolidated Balance Sheets: September 30, 2020 December 31, 2019 Assets Balance Sheet Classification Financing lease assets Property, plant, and equipment, net $ 5,921 $ 9,718 Operating lease right-of-use assets Other non-current assets 6,481 8,678 Total lease assets $ 12,402 $ 18,396 Liabilities Balance Sheet Classification Financing lease liabilities - current Current portion of long-term debt $ 3,222 $ 3,275 Operating lease liabilities - current Accrued expenses and other current liabilities 949 1,813 Financing lease liabilities - long-term Long-term debt 2,552 4,674 Operating lease liabilities - long-term Other non-current liabilities 5,532 6,866 Total lease liabilities $ 12,255 $ 16,628 Total lease costs and other lease information for the three and nine months ended September 30, 2020 and 2019 included the following: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Lease cost (1) Finance lease cost: Amortization of leased assets $ 805 $ 1,143 $ 2,546 $ 2,796 Interest on lease liabilities 81 108 277 366 Operating lease cost 509 732 1,603 2,062 Short-term lease cost 380 494 1,255 1,474 Total lease cost $ 1,775 $ 2,477 $ 5,681 $ 6,698 (1) The Company had no variable lease costs or sublease income for the nine months ended September 30, 2020 and 2019. Nine Months Ended September 30, 2020 2019 Other information Cash paid for amounts included in the measurement of lease liabilities $ 5,426 $ 6,862 Operating cash flows from finance leases $ 276 $ 366 Operating cash flows from operating leases $ 2,859 $ 3,536 Financing cash flows from finance leases $ 2,291 $ 2,960 Right-of-use assets obtained in exchange for new finance lease liabilities $ 243 $ 1,142 Right-of-use assets obtained in exchange for new operating lease liabilities $ (12) $ 140 Lease Term and Discount Rate Weighted-average remaining lease term in months - finance leases 22.9 32.8 Weighted-average remaining lease term in months - operating leases 95.4 94.6 Weighted-average discount rate - finance leases 6.3 % 5.2 % Weighted-average discount rate - operating leases 11.4 % 10.9 % The Company has elected to show net instead of gross amounts for right-of-use assets and liabilities within its Condensed 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 Condensed Consolidated Balance Sheet as of September 30, 2020: Finance Leases Operating Leases Lease cost Remainder of 2020 $ 945 $ 489 2021 3,110 1,489 2022 1,854 1,354 2023 272 1,101 2024 6 982 Thereafter — 4,915 Total future minimum lease payments $ 6,187 $ 10,330 Imputed interest (413) (3,849) Present value of future minimum lease payments $ 5,774 $ 6,481
Leases	LeasesSubsequent to the adoption of ASC 842, Leases, 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 groups 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 nine months ended September 30, 2020 and 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 nine months ended September 30, 2020 and 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 September 30, 2020, the Company does not intend to exercise any termination options on existing leases. As of September 30, 2020 and December 31, 2019, the Company had the following right-of-use assets and lease liabilities within the Company’s Condensed Consolidated Balance Sheets: September 30, 2020 December 31, 2019 Assets Balance Sheet Classification Financing lease assets Property, plant, and equipment, net $ 5,921 $ 9,718 Operating lease right-of-use assets Other non-current assets 6,481 8,678 Total lease assets $ 12,402 $ 18,396 Liabilities Balance Sheet Classification Financing lease liabilities - current Current portion of long-term debt $ 3,222 $ 3,275 Operating lease liabilities - current Accrued expenses and other current liabilities 949 1,813 Financing lease liabilities - long-term Long-term debt 2,552 4,674 Operating lease liabilities - long-term Other non-current liabilities 5,532 6,866 Total lease liabilities $ 12,255 $ 16,628 Total lease costs and other lease information for the three and nine months ended September 30, 2020 and 2019 included the following: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Lease cost (1) Finance lease cost: Amortization of leased assets $ 805 $ 1,143 $ 2,546 $ 2,796 Interest on lease liabilities 81 108 277 366 Operating lease cost 509 732 1,603 2,062 Short-term lease cost 380 494 1,255 1,474 Total lease cost $ 1,775 $ 2,477 $ 5,681 $ 6,698 (1) The Company had no variable lease costs or sublease income for the nine months ended September 30, 2020 and 2019. Nine Months Ended September 30, 2020 2019 Other information Cash paid for amounts included in the measurement of lease liabilities $ 5,426 $ 6,862 Operating cash flows from finance leases $ 276 $ 366 Operating cash flows from operating leases $ 2,859 $ 3,536 Financing cash flows from finance leases $ 2,291 $ 2,960 Right-of-use assets obtained in exchange for new finance lease liabilities $ 243 $ 1,142 Right-of-use assets obtained in exchange for new operating lease liabilities $ (12) $ 140 Lease Term and Discount Rate Weighted-average remaining lease term in months - finance leases 22.9 32.8 Weighted-average remaining lease term in months - operating leases 95.4 94.6 Weighted-average discount rate - finance leases 6.3 % 5.2 % Weighted-average discount rate - operating leases 11.4 % 10.9 % The Company has elected to show net instead of gross amounts for right-of-use assets and liabilities within its Condensed 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 Condensed Consolidated Balance Sheet as of September 30, 2020: Finance Leases Operating Leases Lease cost Remainder of 2020 $ 945 $ 489 2021 3,110 1,489 2022 1,854 1,354 2023 272 1,101 2024 6 982 Thereafter — 4,915 Total future minimum lease payments $ 6,187 $ 10,330 Imputed interest (413) (3,849) Present value of future minimum lease payments $ 5,774 $ 6,481

Stock Repurchases

Stock Repurchases	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Stock Repurchases	Stock Repurchases 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

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: September 30, 2020 December 31, 2019 Term Loan Credit Facility - due June 2024 $ 554,778 $ 558,991 ABL Facility - due April 2022 18,350 — LCC Note Payable 27,500 45,000 LCC Water Treatment Obligation 8,125 9,375 Other (1) 9,145 9,295 Debt discount and issuance costs (20,358) (29,695) Total long-term debt 597,540 592,966 Less current portion (44,864) (28,485) Long-term debt, net of current portion $ 552,676 $ 564,481 (1) Includes financing leases, refer to Note 9 for additional information. 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”). Each loan type bears interest at a rate per annum comprised of a base rate (as defined) plus an applicable percentage (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”)). The Eurocurrency base rate is subject to a 2.00% floor. 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 September 30, 2020, the borrowings made under the Term Loan Credit Facility were comprised of Eurocurrency Rate Loans with an interest rate of 9.00%, calculated as the Eurocurrency rate during the period plus an applicable rate of 7.00%. As of September 30, 2020, the carrying value of the Term Loan Credit Facility was $540,095, with $5,618 classified as current, within the Condensed Consolidated Balance Sheets. 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 Condensed Consolidated Balance Sheets. 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 Condensed Consolidated Statements of Operations for the nine months ended September 30, 2019. 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 September 30, 2020. 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 which includes a senior secured asset-based revolving credit facility (the “ABL Facility”). Under the ABL Facility, the Company may borrow cash from the Lenders (as defined therein) or cause the L/C Issuers (as defined therein) 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. Pursuant to terms of the Amended and Restated Asset-Based Revolving Credit Agreement at each notice period, the Company elects the character of the loan, the interest period, and may provide notice of continuation or conversion of the borrowed principal amount with the ability to repay the borrowed principal amount in advance of the maturity date without penalty. On March 20, 2020, the Company borrowed $57,500 principal amount under the ABL Facility. The funds were borrowed to augment the Company’s short-term operational flexibility in the face of uncertainty created by the current spread of the COVID-19 virus and its potential effects (see further discussion in Note 1). As of September 30, 2020, the borrowings made under the ABL Facility were comprised of Eurocurrency Rate Loans with an interest rate of 3.71%, calculated as the Eurocurrency rate during the period plus an applicable rate of 2.50%. The interest rate (which is subject to periodic adjustment) declined to 2.73% on October 7, 2020 and is subject to adjustment again on April 7, 2021. As of September 30, 2020, the carrying value of the ABL Facility was $18,350, with $15,000 classified as current (based on amounts repaid in October 2020) and the remainder classified as long-term (based on the maturity of the ABL Facility), within the Condensed Consolidated Balance Sheets. As of December 31, 2019, the Company had no borrowings under the ABL Facility. 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 fronting fee of 0.25% of the face amount under each letter of credit, payable to the ABL Facility’s administrative agent. As of September 30, 2020 and December 31, 2019, the Company had $122,366 and $99,876 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 is in compliance with all covenants under these agreements as of September 30, 2020. LCC Note Payable The Lexington Coal Company (“LCC”) Note Payable has no stated interest rate and an imputed interest rate of 12.45%. The carrying value of the LCC Note Payable was $23,638 and $37,695, with $17,500 and $17,500 reported within the current portion of long-term debt as of September 30, 2020 and December 31, 2019, respectively. LCC Water Treatment Stipulation 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 $6,674 and $7,211, with $2,500 and $1,875 reported within the current portion of long-term debt as of September 30, 2020 and December 31, 2019, respectively.

Acquisition-Related Obligations

Acquisition-Related Obligations	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Acquisition-Related Obligations	Acquisition-Related ObligationsAcquisition-related obligations consisted of the following: September 30, 2020 December 31, 2019 Contingent Revenue Obligation $ 24,292 $ 52,427 Environmental Settlement Obligations 11,152 16,305 Reclamation Funding Liability — 12,000 UMWA Funds Settlement Liability 4,000 4,000 Discount (1,952) (4,834) Total acquisition-related obligations 37,492 79,898 Less current portion (18,206) (33,639) Acquisition-related obligations, net of current portion $ 19,286 $ 46,259 Contingent Revenue Obligation As of September 30, 2020 and December 31, 2019 the carrying value of the Contingent Revenue Obligation was $24,292 and $52,427, with $10,511 and $14,646 classified as current, respectively, classified as an acquisition-related obligation in the Condensed Consolidated Balance Sheets. Refer to Note 14 for further disclosures related to the fair value assignment and methods used. During the second quarter of 2020, the Company paid $15,084, including $374 of unclaimed unsecured claims distributions, pursuant to terms of the Contingent Revenue Obligation. Environmental Settlement Obligations As of September 30, 2020 and December 31, 2019, the carrying value of the Environmental Settlement Obligations was $9,674 and $13,594, net of discounts of $1,478 and $2,711, with $5,694 and $6,185 classified as current, respectively, all of which was classified as an acquisition-related obligation in the Condensed Consolidated Balance Sheets. Reclamation Funding Agreement As of September 30, 2020, the Company has no remaining payments for the Funding of Restricted Cash Reclamation liability. As of December 31, 2019, the carrying value of the Funding of Restricted Cash Reclamation liability was $10,808, net of discounts of $1,192, all of which was classified as a current acquisition-related obligation in the Condensed Consolidated Balance Sheets.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2020
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The following table summarizes the changes in asset retirement obligations for the nine months ended September 30, 2020: Total asset retirement obligations at December 31, 2019 $ 224,704 Accretion for the period 23,806 Sites added during the period 621 Revisions in estimated cash flows (1) 13,244 Expenditures for the period (16,532) Total asset retirement obligations at September 30, 2020 245,843 Less current portion (2) (34,845) Long-term portion $ 210,998 (1) The revisions in estimated cash flows resulted from changes in mine plans primarily associated with the strategic actions impacting certain mines during the three months ended June 30, 2020 of which approximately $3,100 was recorded to depreciation, depletion and amortization. Refer to Note 8.

Fair Value of Financial Instrum

Fair Value of Financial Instruments and Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
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 September 30, 2020 and December 31, 2019 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 September 30, 2020 and December 31, 2019: September 30, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Term Loan Credit Facility - due June 2024 $ 540,095 $ 368,095 $ — $ 368,095 $ — ABL Facility - due April 2022 18,350 18,113 — — 18,113 LCC Note Payable 23,638 18,557 — — 18,557 LCC Water Treatment Obligation 6,674 5,099 — — 5,099 Total long-term debt $ 588,757 $ 409,864 $ — $ 368,095 $ 41,769 December 31, 2019 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs 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 (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 September 30, 2020 and December 31, 2019: September 30, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs UMWA Funds Settlement Liability $ 3,526 $ 3,135 $ — $ — $ 3,135 Environmental Settlement Obligations 9,674 7,810 — — 7,810 Total acquisition-related obligations $ 13,200 $ 10,945 $ — $ — $ 10,945 December 31, 2019 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs 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 (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 September 30, 2020 and December 31, 2019. 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. September 30, 2020 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 24,292 $ — $ — $ 24,292 Trading securities $ 26,015 $ 20,087 $ 5,928 $ — 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 $ — The following tables are 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, 2019 Payments Loss (Gain) Recognized in Earnings (1) Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2020 Contingent Revenue Obligation $ 52,427 $ (14,710) $ (13,425) $ — $ 24,292 (1) The gain recognized in earnings resulted primarily from a change in the forecasted future revenue associated with this obligation and an increase in annualized volatility as of September 30, 2020. December 31, 2018 Payments Measurement Period Adjustments Loss (Gain) Recognized in Earnings Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2019 Contingent Revenue Obligation $ 59,880 $ (9,627) $ 5,738 $ (288) $ — $ 55,703 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 - As of December 31, 2019, 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 Term Loan Credit Facility - due June 2024 - As of September 30, 2020, the fair value is based on the average between bid and ask prices provided by a third-party. As the fair value is based on observable market inputs, the Company has classified the fair value within Level 2 of the fair value hierarchy. Due to limited trading volume in the Term Loan Credit Facility, the Company reclassified the fair value from Level 1 within the fair value hierarchy during the three months ending September 30, 2020. 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 ABL Facility - due April 2022 - Observable transactions are not available to aid in determining the fair value of this item. 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 credit risk (discount rate of approximately 10%) as of September 30, 2020. LCC Note Payable, LCC Water Treatment Obligation, 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 credit risk (discount rates of approximately 35% and 21% as of September 30, 2020 and December 31, 2019, respectively). 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 U.S. 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. The range of significant unobservable inputs used to value the contingent revenue obligation as of September 30, 2020 and December 31, 2019, are set forth in the following table: September 30, 2020 December 31, 2019 Forecasted future revenue $0.8 - $0.9 billion $1.1 - $1.2 billion Stated royalty rate 1.0% - 1.5% 1.0% - 1.5% Annualized volatility 10.6% - 32.1% (26.8%) 9.4% - 28.1% (19.9%)

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesFor the nine months ended September 30, 2020, the Company recorded income tax benefit of $2,200 on a loss from continuing operations before income taxes of $348,946. The income tax benefit differs from the expected statutory amount primarily due to the increase in the valuation allowance, partially offset by the permanent impact of percentage depletion deductions, the impact of state income taxes, net of federal tax impact, and the recording of a discrete tax benefit related to the refundability of previously sequestered AMT Credits. The discrete income tax benefit of the previously sequestered AMT Credits is $2,123 and was recorded during the three months ended March 31, 2020. As of September 30, 2020, the Company anticipates that no current federal income tax liability will be generated in 2020. For the nine months ended September 30, 2019, the Company recorded income tax benefit of $8,880 on a loss from continuing operations before income taxes of $20,151. The income tax benefit differs from the expected statutory amount primarily due to the permanent impact of percentage depletion and stock-based compensation deductions, partially offset by an increase in the valuation allowance. During the nine months ended September 30, 2020, the Company recorded an increase of $92,804 to its deferred tax asset valuation allowance. The increase in the valuation allowance results from an increase in deferred tax assets for which the Company is unable to support realization. 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. For each reporting period, the Company updates its assessment regarding 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 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. 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. On March 27, 2020, the CARES Act was enacted into law. As a result of the CARES Act, the Company expects that AMT Credits of $68,252 will be fully refunded during the year ended December 31, 2020. As of September 30, 2020 and December 31, 2019, the Company classified the current portion of AMT Credit refunds receivable of $66,129 and $33,065, respectively, within prepaid expenses and other current assets on the Company’s Condensed Consolidated Balance Sheets. During the three months ended September 30, 2020, the Company recorded a decrease in unrecognized tax benefits of approximately $23,800, as a result of the issuance of final regulatory guidance from the IRS. The decrease in unrecognized tax benefits did not result in an amount of cash paid for income taxes and did not impact the Company’s effective tax rate for the three and nine months ended September 30, 2020. The IRS initiated a corporate income tax audit during the third quarter of 2020 for the Company’s 2016 tax year and related net operating loss carryback.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2020
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 multiemployer plans. The components of net periodic (benefit) expense other than the service cost component for pension, black lung, and life insurance benefits are included in the line item miscellaneous loss, net in the Condensed Consolidated Statements of Operations. Pension Effective as of the September 30, 2019 adjusted funding target attainment percentage certification date under Section 436 of the Internal Revenue Code, certain lump sum benefit restrictions were lifted for one of the qualified non-contributory defined benefit pension plans, allowing certain eligible participants the option to elect to receive lump sum benefits which resulted in a partial plan settlement and the accelerated recognition of a portion of the accumulated other comprehensive loss during the nine months ended September 30, 2020. Refer to the table below for further information on the partial plan settlement. The following table details the components of the net periodic benefit for pension obligations: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Interest cost $ 4,670 $ 6,636 $ 14,061 $ 19,929 Expected return on plan assets (6,752) (7,011) (20,312) (21,032) Amortization of net actuarial loss 511 199 1,501 597 Settlement — — 1,230 — Net periodic benefit $ (1,571) $ (176) $ (3,520) $ (506) Assets of the three qualified non-contributory defined pension plans (“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. In September 2020, the target allocation was adjusted by the Company’s Benefits Committee to transition to 60.0% equity securities and 40.0% fixed income funds in approximate 2.0% increments over a 10 month period. 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. Black Lung The following table details the components of the net periodic expense for black lung obligations: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Service cost $ 598 $ 751 $ 1,762 $ 1,558 Interest cost 747 1,567 2,493 3,386 Expected return on plan assets (14) (17) (40) (49) Amortization of net actuarial loss 596 72 1,346 162 Net periodic expense $ 1,927 $ 2,373 $ 5,561 $ 5,057 As a result of the strategic actions impacting certain mines during the three months ended June 30, 2020 (refer to Note 8), black lung obligations were revalued for curtailment and remeasured with an updated discount rate as of May 31, 2020, which resulted in an increase in the liability for black lung obligations of approximately $7,400 with the offset to accumulated other comprehensive loss and a slight increase in net periodic expense to be recognized subsequent to the remeasurement date. Life Insurance Benefits The following table details the components of the net periodic expense for life insurance benefit obligations: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Interest cost $ 84 $ 106 $ 253 $ 318 Amortization of net actuarial gain (12) (26) (36) (78) Net periodic expense $ 72 $ 80 $ 217 $ 240 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 three months ended September 30, 2020 and 2019 was $628 and $4,158, respectively. The Company’s total contributions to these plans for the nine months ended September 30, 2020 and 2019 was $6,520 and $23,461, respectively. During the second quarter of 2020, the Company’s matching contributions under the Contura Energy 401(k) Retirement Savings Plan were suspended due to current market conditions. Self-Insured Medical Plan

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions There were no material related party transactions for the nine months ended September 30, 2020. 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 11 for additional disclosures. On July 19, 2019, in association with the Blackjewel Chapter 11 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, 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. On September 12, 2019, the Company entered into a common stock repurchase agreement with Whitebox, shareholders of the Company. Refer to Note 10 for additional disclosures. There were no other material related party transactions for the nine months ended September 30, 2019.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
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 Condensed 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 9 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 $16,176 and $21,868 for the three months ended September 30, 2020 and 2019, respectively. Coal royalty expense was $52,092 and $73,119 for the nine months ended September 30, 2020 and 2019, respectively. Minimum royalty obligations under coal leases total $1,784, $15,974, $14,081, $13,064, $11,110, and $46,724 for the remainder of 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 the remainder of 2020 totaling an estimated $15,670. The Company has obligations under certain coal transportation agreements that contain minimum quantities to be shipped in 2021 totaling $8,793. The Company also has obligations under certain equipment purchase agreements that contain minimum quantities to be purchased in the remainder of 2020, 2021, and 2024 totaling $9,931, $8,968, and $1,157, 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. Future Federal Income Tax Refunds As of September 30, 2020, the Company has recorded $66,129 of federal income tax receivable related to AMT Credits. In addition, the Company has recorded a non-current federal income tax receivable of $64,160 and associated interest receivable of $5,126 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 set off the tax refund, refundable credits, and associated interest receivable 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 Condensed 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 Condensed 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 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 September 30, 2020, the Company had outstanding surety bonds with a total face amount of $349,772 to secure various obligations and commitments. To secure the Company’s reclamation-related obligations, the Company currently has $113,470 of collateral supporting these obligations. 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. Amounts included in restricted cash represent cash deposits primarily invested in interest bearing accounts that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral for securing the following obligations which have been written on the Company’s behalf: September 30, 2020 December 31, 2019 Workers' compensation $ 39,141 $ 38,944 Black lung 12,770 12,706 Reclamation-related obligations 69,148 67,868 Financial guarantees and other 3,006 3,006 Contingent revenue obligation escrow 7,104 12,363 Total restricted cash 131,169 134,887 Less current portion (1) (7,104) (12,363) Restricted cash, net of current portion $ 124,065 $ 122,524 (1) Included within prepaid expenses and other current assets on the Company’s Condensed 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 for securing the following obligations which have been written on the Company’s behalf: September 30, 2020 December 31, 2019 Workers' compensation $ 3,131 $ 3,100 Reclamation-related obligations 24,662 18,786 Total restricted investments (1), (2) $ 27,793 $ 21,886 (1) Included within other non-current assets on the Company’s Condensed Consolidated Balance Sheets. (2) As of September 30, 2020 and December 31, 2019, respectively, $26,015 and $13,508 are classified as trading securities and $1,778 and $8,378 are classified as held-to-maturity securities. Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2020 December 31, 2019 Reclamation-related obligations $ 19,660 $ 8,887 Other operating agreements 1,419 1,836 Total deposits (1) $ 21,079 $ 10,723 (1) Included within prepaid expenses and other current assets and other non-current assets on the Company’s Condensed Consolidated Balance Sheets. Letters of Credit As of September 30, 2020, the Company had $122,366 letters of credit outstanding under the Amended and Restated Asset-Based Revolving Credit Agreement. Additionally, as of September 30, 2020, the Company had $14,242 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 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. DCMWC Reauthorization Process 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 an application and supporting documentation for reauthorization to self-insure certain of its black lung obligations in October 2019. As a result of this application, the DCMWC notified the Company in a letter dated February 21, 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 agreed to extend to May 22, 2020. The Company exercised 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. (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.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2020
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. The Company has three reportable segments: CAPP - Met, CAPP - Thermal, and NAPP. CAPP - Met consists of four active mines and two preparation plants in Virginia, seventeen active mines and five preparation plants in West Virginia, as well as expenses associated with certain idled/closed mines. CAPP - Thermal consists of one active mine and one preparation plant 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. In addition to the three reportable segments, the All Other category includes general corporate overhead and corporate assets and liabilities 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 for the three months ended September 30, 2020 were as follows: Three Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 295,381 $ 39,835 $ 65,100 $ 375 $ 400,691 Depreciation, depletion, and amortization $ 41,177 $ 7,313 $ 1,504 $ 745 $ 50,739 Amortization of acquired intangibles, net $ 2,535 $ (486) $ 145 $ 25 $ 2,219 Adjusted EBITDA $ 17,847 $ 5,155 $ 7,250 $ (10,565) $ 19,687 Capital expenditures $ 22,668 $ 765 $ 4,299 $ 74 $ 27,806 Segment operating results and capital expenditures for the three months ended September 30, 2019 were as follows: Three Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 373,356 $ 80,432 $ 71,446 $ 630 $ 525,864 Depreciation, depletion, and amortization $ 38,212 $ 13,972 $ 6,241 $ 2,417 $ 60,842 Amortization of acquired intangibles, net $ 4,765 $ (3,359) $ 908 $ — $ 2,314 Adjusted EBITDA $ 58,796 $ 1,954 $ (4,152) $ (16,575) $ 40,023 Capital expenditures $ 47,316 $ 5,706 $ 7,114 $ 165 $ 60,301 Segment operating results and capital expenditures for the nine months ended September 30, 2020 were as follows: Nine Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 974,674 $ 115,416 $ 190,643 $ 2,256 $ 1,282,989 Depreciation, depletion, and amortization $ 121,699 $ 19,422 $ 10,525 $ 2,820 $ 154,466 Amortization of acquired intangibles, net $ 7,875 $ (3,484) $ 714 $ 75 $ 5,180 Adjusted EBITDA $ 104,668 $ 5,459 $ 20,645 $ (33,942) $ 96,830 Capital expenditures $ 83,449 $ 6,349 $ 28,468 $ 630 $ 118,896 Segment operating results and capital expenditures for the nine months ended September 30, 2019 were as follows: Nine Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,340,684 $ 225,698 $ 222,750 $ 2,052 $ 1,791,184 Depreciation, depletion, and amortization $ 113,714 $ 44,586 $ 19,390 $ 7,237 $ 184,927 Amortization of acquired intangibles, net $ 5,816 $ (12,142) $ 1,614 $ — $ (4,712) Adjusted EBITDA $ 283,483 $ 8,704 $ 21,900 $ (49,930) $ 264,157 Capital expenditures $ 105,008 $ 13,365 $ 23,317 $ 2,493 $ 144,183 The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the three months ended September 30, 2020: Three Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net (loss) income from continuing operations $ (29,545) $ (3,815) $ 149 $ (35,426) $ (68,637) Interest expense (189) 2 (357) 18,933 18,389 Interest income (3) — (1) (374) (378) Income tax benefit — — — (45) (45) Depreciation, depletion and amortization 41,177 7,313 1,504 745 50,739 Non-cash stock compensation expense 105 — — 973 1,078 Mark-to-market adjustment - acquisition-related obligations — — — 3,624 3,624 Accretion on asset retirement obligations 3,767 2,406 2,424 530 9,127 Asset impairment and restructuring (1) — (265) 3,386 450 3,571 Amortization of acquired intangibles, net 2,535 (486) 145 25 2,219 Adjusted EBITDA $ 17,847 $ 5,155 $ 7,250 $ (10,565) $ 19,687 (1) Asset impairment and restructuring for the three months ended September 30, 2020 includes long-lived asset impairments of $3,516 as a result of capital spending during the quarter at previously impaired locations requiring the impairment of certain additional assets not considered recoverable and restructuring expense of $55 as a result of the strategic actions with respect to two thermal coal mining complexes announced during the second quarter of 2020. Refer to Note 8 for further information. The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the three months ended September 30, 2019: Three Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 13,033 $ (11,338) $ (12,304) $ (32,952) $ (43,561) Interest expense 84 6 1 18,756 18,847 Interest income (4) — (15) (1,744) (1,763) Income tax benefit — — — (3,102) (3,102) Depreciation, depletion and amortization 38,212 13,972 6,241 2,417 60,842 Merger-related costs — — — 68 68 Non-cash stock compensation expense 348 3 — 2,387 2,738 Mark-to-market adjustment - acquisition-related obligations — — — (3,238) (3,238) Accretion on asset retirement obligations 2,326 2,670 1,017 833 6,846 Asset impairment 32 — — — 32 Amortization of acquired intangibles, net 4,765 (3,359) 908 — 2,314 Adjusted EBITDA $ 58,796 $ 1,954 $ (4,152) $ (16,575) $ 40,023 The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the nine months ended September 30, 2020: Nine Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net loss from continuing operations $ (67,996) $ (37,711) $ (158,983) $ (82,056) $ (346,746) Interest expense (1,495) 6 (1,431) 57,728 54,808 Interest income (63) — (15) (6,811) (6,889) Income tax benefit — — — (2,200) (2,200) Depreciation, depletion and amortization 121,699 19,422 10,525 2,820 154,466 Non-cash stock compensation expense 410 8 — 3,782 4,200 Mark-to-market adjustment - acquisition-related obligations — — — (13,425) (13,425) Accretion on asset retirement obligations 10,786 7,025 3,963 2,032 23,806 Asset impairment and restructuring (1) 32,951 20,188 165,866 2,448 221,453 Management restructuring costs (2) 501 5 6 435 947 Loss on partial settlement of benefit obligations — — — 1,230 1,230 Amortization of acquired intangibles, net 7,875 (3,484) 714 75 5,180 Adjusted EBITDA $ 104,668 $ 5,459 $ 20,645 $ (33,942) $ 96,830 (1) Asset impairment and restructuring for the nine months ended September 30, 2020 includes long-lived asset impairments of $198,963 and restructuring expense of $22,490 as a result of weakened coal prices and the strategic actions with respect to two thermal coal mining complexes announced during the second quarter of 2020 and capital spending during the third quarter of 2020 at previously impaired locations requiring the impairment of certain additional assets not considered recoverable. Refer to Note 8 for further information. (2) Management restructuring costs are related to severance expense associated with senior management changes during the three months ended March 31, 2020. The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the nine months ended September 30, 2019: Nine Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 154,020 $ (34,675) $ (2,118) $ (128,498) $ (11,271) Interest expense 306 16 2 49,755 50,079 Interest income (12) — (38) (5,534) (5,584) Income tax benefit — — — (8,880) (8,880) Depreciation, depletion and amortization 113,714 44,586 19,390 7,237 184,927 Merger related costs — — — 1,055 1,055 Non-cash stock compensation expense 1,127 60 — 6,276 7,463 Mark-to-market adjustment - acquisition-related obligations — — — (288) (288) Accretion on asset retirement obligations 6,986 7,401 3,050 2,488 19,925 Loss on modification and extinguishment of debt — — — 26,459 26,459 Asset impairment (1) 5,858 — — — 5,858 Cost impact of coal inventory fair value adjustment (2) 4,751 3,458 — — 8,209 Gain on assets acquired in an exchange transaction (3) (9,083) — — — (9,083) Amortization of acquired intangibles, net 5,816 (12,142) 1,614 — (4,712) Adjusted EBITDA $ 283,483 $ 8,704 $ 21,900 $ (49,930) $ 264,157 (1) Asset impairment primarily related to the write-off of prepaid purchased coal from Blackjewel as a result of Blackjewel’s Chapter 11 bankruptcy filing on July 1, 2019. (2) 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. (3) During the nine months ended September 30, 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. 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, Netherlands, and Italy. Export coal revenues were the following: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Total coal revenues $ 399,954 $ 523,987 $ 1,278,935 $ 1,784,775 Export coal revenues (1) $ 209,046 $ 261,815 $ 718,058 $ 967,959 Export coal revenues as % of total coal revenues 52 % 50 % 56 % 54 % (1) The amounts for the three months ended September 30, 2020 include $57,740 of export coal revenues from external customers in India, recorded within the CAPP - Met and CAPP - Thermal segments. The amounts for the nine months ended September 30, 2020 include $174,182 and $133,501 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 nine months ended September 30, 2019 include $228,754 of export coal revenues from external customers in India recorded within the CAPP - Met, CAPP - Thermal, and NAPP segments. Revenue is tracked within the Company’s accounting records based on the product destination.

Business and Basis of Present_2

Business and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Together, the condensed consolidated statements of operations, comprehensive loss, balance sheets, cash flows and stockholders’ equity for the Company are referred to as the “Condensed Consolidated Financial Statements.” The Condensed Consolidated Financial Statements are also referenced across periods as “Condensed Consolidated Statements of Operations,” “Condensed Consolidated Statements of Comprehensive Loss,” “Condensed Consolidated Balance Sheets,” “Condensed Consolidated Statements of Cash Flows,” and “Condensed Consolidated Statements of Stockholders’ Equity.” The Condensed Consolidated Financial Statements include all wholly-owned subsidiaries’ results of operations for the three and nine months ended September 30, 2020 and 2019. All significant intercompany transactions have been eliminated in consolidation.
Liquidity Risk and Uncertainties	Liquidity Risks and UncertaintiesWeak 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 believes it will have sufficient liquidity 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.
Recently Adopted Accounting Guidance	Recently Adopted Accounting Guidance 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 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. The Company adopted ASU 2018-13 during the first quarter of 2020. The adoption of this ASU did not have a material impact on the Company's Condensed 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 amendments also improve consistent application of and simplify U.S. GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The Company adopted ASU 2019-12 during the first quarter of 2020. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Reference Rate Reform : In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). The amendments in this update provide optional expedients and exceptions, if certain criteria are met, for applying U.S. GAAP to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022, except for hedging relationships existing as of December 31, 2022, that an entity has elected certain optional expedients for and that are retained through the end of the hedging relationship. The Company adopted ASU 2020-04, with respect to topics in Accounting Standards Codification (“ASC”) 310 Receivables , ASC 470 Debt , ASC 815 Derivatives and Hedging and ASC 842 Leases , during the first quarter of 2020. The adoption of this ASU did not have a material impact on the Company's Condensed Consolidated Financial Statements and related disclosures. Recent Accounting Guidance Issued Not Yet Effective 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 Condensed Consolidated Financial Statements and related disclosures. Convertible Debt and Contracts in Entity’s Own Equity : In August 2020, the FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06”). The amendments in this update simplify the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts in an entity’s own equity, such as the Company’s outstanding Series A warrants. For public business entities, the standard is effective for fiscal years ending after December 15, 2021, with early adoption permitted. The adoption of this ASU is not expected to have a material impact on the Company’s Condensed Consolidated Financial Statements and related disclosures.

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	The major components of net loss from discontinued operations in the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2019 are as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Revenues: Total revenues (1) $ 4 $ 152 Costs and expenses: Depreciation, depletion and amortization (2) $ — $ 145,913 Accretion on asset retirement obligations (3) $ 4,981 $ 4,981 Asset impairment (4) $ 694 $ 17,162 Selling, general and administrative expenses $ 4,666 $ 4,673 Other expenses $ 1,032 $ 3,964 Other non-major expense (income) items, net $ 147 $ 432 (1) Total revenues for the three and nine months ended September 30, 2019 consisted entirely of other revenues. (2) The depreciation, depletion and amortization is related to an increase in the Company’s estimate of its asset retirement obligations with respect to the Western Mines as a result of the Blackjewel Chapter 11 bankruptcy filing on July 1, 2019. The Company remeasured its asset retirement obligations based on the expectation that the mining permits would not transfer to Blackjewel and Blackjewel would be unable to perform its contractual obligation to reclaim the properties. The increase in the asset retirement obligation was recorded to expense as the Company no longer owned the underlying mining assets. (3) The accretion on asset retirement obligations is related to the asset retirement obligation as a result of the Blackjewel bankruptcy filing. (4) The asset impairment is primarily related to the write-off of a tax receivable. The Company was considered to be the primary obligor for certain taxes that Blackjewel was contractually obligated to pay. During the nine months ended September 30, 2019, the Company recorded an impairment charge for the offsetting receivable from Blackjewel as a result of the Blackjewel bankruptcy filing. The major components of cash flows related to discontinued operations are as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Other significant operating non-cash items related to discontinued operations: Depreciation, depletion and amortization $ — $ 145,913 Accretion on asset retirement obligations $ 4,981 $ 4,981 Asset impairment $ 694 $ 17,162

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2020
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: Three Months Ended September 30, 2020 Met Thermal Total Export coal revenues $ 202,339 $ 6,707 $ 209,046 Domestic coal revenues 84,675 106,233 190,908 Total coal revenues $ 287,014 $ 112,940 $ 399,954 Three Months Ended September 30, 2019 Met Thermal Total Export coal revenues $ 248,628 $ 13,187 $ 261,815 Domestic coal revenues 137,146 125,026 262,172 Total coal revenues $ 385,774 $ 138,213 $ 523,987 Nine Months Ended September 30, 2020 Met Thermal Total Export coal revenues $ 693,599 $ 24,459 $ 718,058 Domestic coal revenues 282,266 278,611 560,877 Total coal revenues $ 975,865 $ 303,070 $ 1,278,935 Nine Months Ended September 30, 2019 Met Thermal Total Export coal revenues $ 928,390 $ 39,569 $ 967,959 Domestic coal revenues 429,457 387,359 816,816 Total coal revenues $ 1,357,847 $ 426,928 $ 1,784,775
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 September 30, 2020. Remainder of 2020 2021 2022 2023 2024 2025 Total Estimated coal revenues $ 138,188 $ 268,185 $ 200,877 $ — $ — $ — $ 607,250

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive (Loss) Income (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables summarize the changes to accumulated other comprehensive (loss) income during the nine months ended September 30, 2020 and 2019: Balance January 1, 2020 Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance September 30, 2020 Employee benefit costs $ (58,616) $ (14,154) $ 4,156 $ (68,614) Balance January 1, 2019 Other comprehensive (loss) income before reclassifications Amounts reclassified from accumulated other comprehensive (loss) income Balance September 30, 2019 Employee benefit costs $ (23,130) $ 458 $ 532 $ (22,140) The following table summarizes the amounts reclassified from accumulated other comprehensive (loss) income and the Condensed Consolidated Statements of Operations line items affected by the reclassification during the three and nine months ended September 30, 2020 and 2019: Details about accumulated other comprehensive (loss) income components Amounts reclassified from accumulated other comprehensive (loss) income Affected line item in the Condensed Consolidated Statements of Operations Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Employee benefit costs: Amortization of actuarial loss (1) $ 1,101 $ 258 $ 2,829 $ 719 Miscellaneous loss, net Settlement (1) 32 — 1,327 — Miscellaneous loss, net Total before income tax $ 1,133 $ 258 $ 4,156 $ 719 Income tax expense — (67) — (187) Income tax benefit Total, net of income tax $ 1,133 $ 191 $ 4,156 $ 532 (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 16.

Inventories, net (Tables)

Inventories, net (Tables)	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventories, net consisted of the following: September 30, 2020 December 31, 2019 Raw coal $ 18,248 $ 30,274 Saleable coal 79,194 105,092 Materials, supplies and other, net (1) 26,803 27,293 Total inventories, net $ 124,245 $ 162,659

Acquired Intangibles (Tables)

Acquired Intangibles (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangibles	The balances and respective balance sheet classifications of such assets and liabilities as of September 30, 2020 and December 31, 2019, net of accumulated amortization, are set forth in the following tables: September 30, 2020 Assets (1) Liabilities (2) Net Total Coal supply agreements, net $ 185 $ (875) $ (690) Acquired mine permits, net 100,165 — 100,165 Total $ 100,350 $ (875) $ 99,475 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 (1) Included within other acquired intangibles, net of accumulated amortization on the Company’s Condensed Consolidated Balance Sheets. (2) Included within other non-current liabilities on the Company’s Condensed Consolidated Balance Sheets. Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Amortization of mine permits (1) $ 2,944 $ 6,266 $ 9,592 $ 17,871 Amortization of above-market coal supply agreements $ 145 $ 1,473 $ 732 $ 2,351 Amortization of below-market coal supply agreements (870) (5,425) (5,144) (24,934) Net income (1) $ (725) $ (3,952) $ (4,412) $ (22,583) (1) Included within amortization of acquired intangibles, net in the Condensed Consolidated Statements of Operations.

Asset Impairment and Restruct_2

Asset Impairment and Restructuring (Tables)	9 Months Ended
	Sep. 30, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	As a result of the strategic actions discussed above, the Company recorded restructuring expense during the three and nine months ended September 30, 2020 as follows: Three Months Ended September 30, 2020 Nine Months Ended September 30, 2020 Affected line item in the Condensed Consolidated Balance Sheets Severance and employee-related benefits (1) $ 55 $ 20,608 Accrued expenses and other current liabilities and Other non-current liabilities Other costs (2) — 1,882 Inventories, net and Other non-current assets Total restructuring expense (3) $ 55 $ 22,490 (1) Severance and employee-related benefits were considered probable and estimable based on provisions of contractual agreements and existing employee benefit plans. (2) The nine months ended September 30, 2020 includes accelerated amortization of deferred longwall move expenses of $668, allowance for advanced mining royalties of $407, and allowance for obsolete materials and supplies inventory of $807.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Right-of-use Assets and Lease Liabilities	As of September 30, 2020 and December 31, 2019, the Company had the following right-of-use assets and lease liabilities within the Company’s Condensed Consolidated Balance Sheets: September 30, 2020 December 31, 2019 Assets Balance Sheet Classification Financing lease assets Property, plant, and equipment, net $ 5,921 $ 9,718 Operating lease right-of-use assets Other non-current assets 6,481 8,678 Total lease assets $ 12,402 $ 18,396 Liabilities Balance Sheet Classification Financing lease liabilities - current Current portion of long-term debt $ 3,222 $ 3,275 Operating lease liabilities - current Accrued expenses and other current liabilities 949 1,813 Financing lease liabilities - long-term Long-term debt 2,552 4,674 Operating lease liabilities - long-term Other non-current liabilities 5,532 6,866 Total lease liabilities $ 12,255 $ 16,628
Lease Costs and Other Information	Total lease costs and other lease information for the three and nine months ended September 30, 2020 and 2019 included the following: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Lease cost (1) Finance lease cost: Amortization of leased assets $ 805 $ 1,143 $ 2,546 $ 2,796 Interest on lease liabilities 81 108 277 366 Operating lease cost 509 732 1,603 2,062 Short-term lease cost 380 494 1,255 1,474 Total lease cost $ 1,775 $ 2,477 $ 5,681 $ 6,698 (1) The Company had no variable lease costs or sublease income for the nine months ended September 30, 2020 and 2019. Nine Months Ended September 30, 2020 2019 Other information Cash paid for amounts included in the measurement of lease liabilities $ 5,426 $ 6,862 Operating cash flows from finance leases $ 276 $ 366 Operating cash flows from operating leases $ 2,859 $ 3,536 Financing cash flows from finance leases $ 2,291 $ 2,960 Right-of-use assets obtained in exchange for new finance lease liabilities $ 243 $ 1,142 Right-of-use assets obtained in exchange for new operating lease liabilities $ (12) $ 140 Lease Term and Discount Rate Weighted-average remaining lease term in months - finance leases 22.9 32.8 Weighted-average remaining lease term in months - operating leases 95.4 94.6 Weighted-average discount rate - finance leases 6.3 % 5.2 % Weighted-average discount rate - operating leases 11.4 % 10.9 %
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 Condensed Consolidated Balance Sheet as of September 30, 2020: Finance Leases Operating Leases Lease cost Remainder of 2020 $ 945 $ 489 2021 3,110 1,489 2022 1,854 1,354 2023 272 1,101 2024 6 982 Thereafter — 4,915 Total future minimum lease payments $ 6,187 $ 10,330 Imputed interest (413) (3,849) Present value of future minimum lease payments $ 5,774 $ 6,481
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 Condensed Consolidated Balance Sheet as of September 30, 2020: Finance Leases Operating Leases Lease cost Remainder of 2020 $ 945 $ 489 2021 3,110 1,489 2022 1,854 1,354 2023 272 1,101 2024 6 982 Thereafter — 4,915 Total future minimum lease payments $ 6,187 $ 10,330 Imputed interest (413) (3,849) Present value of future minimum lease payments $ 5,774 $ 6,481

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt consisted of the following: September 30, 2020 December 31, 2019 Term Loan Credit Facility - due June 2024 $ 554,778 $ 558,991 ABL Facility - due April 2022 18,350 — LCC Note Payable 27,500 45,000 LCC Water Treatment Obligation 8,125 9,375 Other (1) 9,145 9,295 Debt discount and issuance costs (20,358) (29,695) Total long-term debt 597,540 592,966 Less current portion (44,864) (28,485) Long-term debt, net of current portion $ 552,676 $ 564,481 (1) Includes financing leases, refer to Note 9 for additional information.

Acquisition-Related Obligatio_2

Acquisition-Related Obligations (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Acquisition-Related Obligations	Acquisition-related obligations consisted of the following: September 30, 2020 December 31, 2019 Contingent Revenue Obligation $ 24,292 $ 52,427 Environmental Settlement Obligations 11,152 16,305 Reclamation Funding Liability — 12,000 UMWA Funds Settlement Liability 4,000 4,000 Discount (1,952) (4,834) Total acquisition-related obligations 37,492 79,898 Less current portion (18,206) (33,639) Acquisition-related obligations, net of current portion $ 19,286 $ 46,259

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2020
Asset Retirement Obligation Disclosure [Abstract]
Summary of Changes in Asset Retirement Obligations	The following table summarizes the changes in asset retirement obligations for the nine months ended September 30, 2020: Total asset retirement obligations at December 31, 2019 $ 224,704 Accretion for the period 23,806 Sites added during the period 621 Revisions in estimated cash flows (1) 13,244 Expenditures for the period (16,532) Total asset retirement obligations at September 30, 2020 245,843 Less current portion (2) (34,845) Long-term portion $ 210,998 (1) The revisions in estimated cash flows resulted from changes in mine plans primarily associated with the strategic actions impacting certain mines during the three months ended June 30, 2020 of which approximately $3,100 was recorded to depreciation, depletion and amortization. Refer to Note 8.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments and Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements, Nonrecurring	The following tables set forth by level, within the fair value hierarchy, the Company’s long-term debt at fair value as of September 30, 2020 and December 31, 2019: September 30, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs Term Loan Credit Facility - due June 2024 $ 540,095 $ 368,095 $ — $ 368,095 $ — ABL Facility - due April 2022 18,350 18,113 — — 18,113 LCC Note Payable 23,638 18,557 — — 18,557 LCC Water Treatment Obligation 6,674 5,099 — — 5,099 Total long-term debt $ 588,757 $ 409,864 $ — $ 368,095 $ 41,769 December 31, 2019 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs 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 (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 September 30, 2020 and December 31, 2019: September 30, 2020 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs UMWA Funds Settlement Liability $ 3,526 $ 3,135 $ — $ — $ 3,135 Environmental Settlement Obligations 9,674 7,810 — — 7,810 Total acquisition-related obligations $ 13,200 $ 10,945 $ — $ — $ 10,945 December 31, 2019 Carrying Amount (1) Total Fair Value Quoted Prices in Active Markets Significant Other Observable Inputs Significant Unobservable Inputs 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 (1) Net of discounts.
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 September 30, 2020 and December 31, 2019. 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. September 30, 2020 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Contingent Revenue Obligation $ 24,292 $ — $ — $ 24,292 Trading securities $ 26,015 $ 20,087 $ 5,928 $ — 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 $ — The following tables are 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, 2019 Payments Loss (Gain) Recognized in Earnings (1) Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2020 Contingent Revenue Obligation $ 52,427 $ (14,710) $ (13,425) $ — $ 24,292 (1) The gain recognized in earnings resulted primarily from a change in the forecasted future revenue associated with this obligation and an increase in annualized volatility as of September 30, 2020. December 31, 2018 Payments Measurement Period Adjustments Loss (Gain) Recognized in Earnings Transfer In (Out) of Level 3 Fair Value Hierarchy September 30, 2019 Contingent Revenue Obligation $ 59,880 $ (9,627) $ 5,738 $ (288) $ — $ 55,703 September 30, 2020 December 31, 2019 Forecasted future revenue $0.8 - $0.9 billion $1.1 - $1.2 billion Stated royalty rate 1.0% - 1.5% 1.0% - 1.5% Annualized volatility 10.6% - 32.1% (26.8%) 9.4% - 28.1% (19.9%)

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2020
Compensation Related Costs [Abstract]
Schedule of Net Periodic Benefit Cost	The following table details the components of the net periodic benefit for pension obligations: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Interest cost $ 4,670 $ 6,636 $ 14,061 $ 19,929 Expected return on plan assets (6,752) (7,011) (20,312) (21,032) Amortization of net actuarial loss 511 199 1,501 597 Settlement — — 1,230 — Net periodic benefit $ (1,571) $ (176) $ (3,520) $ (506) The following table details the components of the net periodic expense for black lung obligations: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Service cost $ 598 $ 751 $ 1,762 $ 1,558 Interest cost 747 1,567 2,493 3,386 Expected return on plan assets (14) (17) (40) (49) Amortization of net actuarial loss 596 72 1,346 162 Net periodic expense $ 1,927 $ 2,373 $ 5,561 $ 5,057 The following table details the components of the net periodic expense for life insurance benefit obligations: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Interest cost $ 84 $ 106 $ 253 $ 318 Amortization of net actuarial gain (12) (26) (36) (78) Net periodic expense $ 72 $ 80 $ 217 $ 240

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of Restricted Cash Deposits	Amounts included in restricted cash represent cash deposits primarily invested in interest bearing accounts that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral for securing the following obligations which have been written on the Company’s behalf: September 30, 2020 December 31, 2019 Workers' compensation $ 39,141 $ 38,944 Black lung 12,770 12,706 Reclamation-related obligations 69,148 67,868 Financial guarantees and other 3,006 3,006 Contingent revenue obligation escrow 7,104 12,363 Total restricted cash 131,169 134,887 Less current portion (1) (7,104) (12,363) Restricted cash, net of current portion $ 124,065 $ 122,524 (1) Included within prepaid expenses and other current assets on the Company’s Condensed Consolidated Balance Sheets.
Schedule of Restricted Investments and Deposit Assets	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 for securing the following obligations which have been written on the Company’s behalf: September 30, 2020 December 31, 2019 Workers' compensation $ 3,131 $ 3,100 Reclamation-related obligations 24,662 18,786 Total restricted investments (1), (2) $ 27,793 $ 21,886 (1) Included within other non-current assets on the Company’s Condensed Consolidated Balance Sheets. (2) As of September 30, 2020 and December 31, 2019, respectively, $26,015 and $13,508 are classified as trading securities and $1,778 and $8,378 are classified as held-to-maturity securities. Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral to secure the following obligations which have been written on the Company’s behalf: September 30, 2020 December 31, 2019 Reclamation-related obligations $ 19,660 $ 8,887 Other operating agreements 1,419 1,836 Total deposits (1) $ 21,079 $ 10,723 (1) Included within prepaid expenses and other current assets and other non-current assets on the Company’s Condensed Consolidated Balance Sheets.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Schedule of Segment Operating Results and Capital Expenditures	Segment operating results and capital expenditures for the three months ended September 30, 2020 were as follows: Three Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 295,381 $ 39,835 $ 65,100 $ 375 $ 400,691 Depreciation, depletion, and amortization $ 41,177 $ 7,313 $ 1,504 $ 745 $ 50,739 Amortization of acquired intangibles, net $ 2,535 $ (486) $ 145 $ 25 $ 2,219 Adjusted EBITDA $ 17,847 $ 5,155 $ 7,250 $ (10,565) $ 19,687 Capital expenditures $ 22,668 $ 765 $ 4,299 $ 74 $ 27,806 Segment operating results and capital expenditures for the three months ended September 30, 2019 were as follows: Three Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 373,356 $ 80,432 $ 71,446 $ 630 $ 525,864 Depreciation, depletion, and amortization $ 38,212 $ 13,972 $ 6,241 $ 2,417 $ 60,842 Amortization of acquired intangibles, net $ 4,765 $ (3,359) $ 908 $ — $ 2,314 Adjusted EBITDA $ 58,796 $ 1,954 $ (4,152) $ (16,575) $ 40,023 Capital expenditures $ 47,316 $ 5,706 $ 7,114 $ 165 $ 60,301 Segment operating results and capital expenditures for the nine months ended September 30, 2020 were as follows: Nine Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 974,674 $ 115,416 $ 190,643 $ 2,256 $ 1,282,989 Depreciation, depletion, and amortization $ 121,699 $ 19,422 $ 10,525 $ 2,820 $ 154,466 Amortization of acquired intangibles, net $ 7,875 $ (3,484) $ 714 $ 75 $ 5,180 Adjusted EBITDA $ 104,668 $ 5,459 $ 20,645 $ (33,942) $ 96,830 Capital expenditures $ 83,449 $ 6,349 $ 28,468 $ 630 $ 118,896 Segment operating results and capital expenditures for the nine months ended September 30, 2019 were as follows: Nine Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Total revenues $ 1,340,684 $ 225,698 $ 222,750 $ 2,052 $ 1,791,184 Depreciation, depletion, and amortization $ 113,714 $ 44,586 $ 19,390 $ 7,237 $ 184,927 Amortization of acquired intangibles, net $ 5,816 $ (12,142) $ 1,614 $ — $ (4,712) Adjusted EBITDA $ 283,483 $ 8,704 $ 21,900 $ (49,930) $ 264,157 Capital expenditures $ 105,008 $ 13,365 $ 23,317 $ 2,493 $ 144,183 The Company markets produced, processed and purchased coal to customers in the United States and in international markets, primarily India, Brazil, Turkey, Netherlands, and Italy. Export coal revenues were the following: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Total coal revenues $ 399,954 $ 523,987 $ 1,278,935 $ 1,784,775 Export coal revenues (1) $ 209,046 $ 261,815 $ 718,058 $ 967,959 Export coal revenues as % of total coal revenues 52 % 50 % 56 % 54 % (1) The amounts for the three months ended September 30, 2020 include $57,740 of export coal revenues from external customers in India, recorded within the CAPP - Met and CAPP - Thermal segments. The amounts for the nine months ended September 30, 2020 include $174,182 and $133,501 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 nine months ended September 30, 2019 include $228,754 of export coal revenues from external customers in India recorded within the CAPP - Met, CAPP - Thermal, and NAPP segments. Revenue is tracked within the Company’s accounting records based on the product destination.
Reconciliation of Net Income (Loss) to Adjusted EBITDA	The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the three months ended September 30, 2020: Three Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net (loss) income from continuing operations $ (29,545) $ (3,815) $ 149 $ (35,426) $ (68,637) Interest expense (189) 2 (357) 18,933 18,389 Interest income (3) — (1) (374) (378) Income tax benefit — — — (45) (45) Depreciation, depletion and amortization 41,177 7,313 1,504 745 50,739 Non-cash stock compensation expense 105 — — 973 1,078 Mark-to-market adjustment - acquisition-related obligations — — — 3,624 3,624 Accretion on asset retirement obligations 3,767 2,406 2,424 530 9,127 Asset impairment and restructuring (1) — (265) 3,386 450 3,571 Amortization of acquired intangibles, net 2,535 (486) 145 25 2,219 Adjusted EBITDA $ 17,847 $ 5,155 $ 7,250 $ (10,565) $ 19,687 (1) Asset impairment and restructuring for the three months ended September 30, 2020 includes long-lived asset impairments of $3,516 as a result of capital spending during the quarter at previously impaired locations requiring the impairment of certain additional assets not considered recoverable and restructuring expense of $55 as a result of the strategic actions with respect to two thermal coal mining complexes announced during the second quarter of 2020. Refer to Note 8 for further information. The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the three months ended September 30, 2019: Three Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 13,033 $ (11,338) $ (12,304) $ (32,952) $ (43,561) Interest expense 84 6 1 18,756 18,847 Interest income (4) — (15) (1,744) (1,763) Income tax benefit — — — (3,102) (3,102) Depreciation, depletion and amortization 38,212 13,972 6,241 2,417 60,842 Merger-related costs — — — 68 68 Non-cash stock compensation expense 348 3 — 2,387 2,738 Mark-to-market adjustment - acquisition-related obligations — — — (3,238) (3,238) Accretion on asset retirement obligations 2,326 2,670 1,017 833 6,846 Asset impairment 32 — — — 32 Amortization of acquired intangibles, net 4,765 (3,359) 908 — 2,314 Adjusted EBITDA $ 58,796 $ 1,954 $ (4,152) $ (16,575) $ 40,023 The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the nine months ended September 30, 2020: Nine Months Ended September 30, 2020 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net loss from continuing operations $ (67,996) $ (37,711) $ (158,983) $ (82,056) $ (346,746) Interest expense (1,495) 6 (1,431) 57,728 54,808 Interest income (63) — (15) (6,811) (6,889) Income tax benefit — — — (2,200) (2,200) Depreciation, depletion and amortization 121,699 19,422 10,525 2,820 154,466 Non-cash stock compensation expense 410 8 — 3,782 4,200 Mark-to-market adjustment - acquisition-related obligations — — — (13,425) (13,425) Accretion on asset retirement obligations 10,786 7,025 3,963 2,032 23,806 Asset impairment and restructuring (1) 32,951 20,188 165,866 2,448 221,453 Management restructuring costs (2) 501 5 6 435 947 Loss on partial settlement of benefit obligations — — — 1,230 1,230 Amortization of acquired intangibles, net 7,875 (3,484) 714 75 5,180 Adjusted EBITDA $ 104,668 $ 5,459 $ 20,645 $ (33,942) $ 96,830 (1) Asset impairment and restructuring for the nine months ended September 30, 2020 includes long-lived asset impairments of $198,963 and restructuring expense of $22,490 as a result of weakened coal prices and the strategic actions with respect to two thermal coal mining complexes announced during the second quarter of 2020 and capital spending during the third quarter of 2020 at previously impaired locations requiring the impairment of certain additional assets not considered recoverable. Refer to Note 8 for further information. (2) Management restructuring costs are related to severance expense associated with senior management changes during the three months ended March 31, 2020. The following table presents a reconciliation of net income (loss) to Adjusted EBITDA for the nine months ended September 30, 2019: Nine Months Ended September 30, 2019 CAPP - Met CAPP - Thermal NAPP All Other Consolidated Net income (loss) from continuing operations $ 154,020 $ (34,675) $ (2,118) $ (128,498) $ (11,271) Interest expense 306 16 2 49,755 50,079 Interest income (12) — (38) (5,534) (5,584) Income tax benefit — — — (8,880) (8,880) Depreciation, depletion and amortization 113,714 44,586 19,390 7,237 184,927 Merger related costs — — — 1,055 1,055 Non-cash stock compensation expense 1,127 60 — 6,276 7,463 Mark-to-market adjustment - acquisition-related obligations — — — (288) (288) Accretion on asset retirement obligations 6,986 7,401 3,050 2,488 19,925 Loss on modification and extinguishment of debt — — — 26,459 26,459 Asset impairment (1) 5,858 — — — 5,858 Cost impact of coal inventory fair value adjustment (2) 4,751 3,458 — — 8,209 Gain on assets acquired in an exchange transaction (3) (9,083) — — — (9,083) Amortization of acquired intangibles, net 5,816 (12,142) 1,614 — (4,712) Adjusted EBITDA $ 283,483 $ 8,704 $ 21,900 $ (49,930) $ 264,157 (1) Asset impairment primarily related to the write-off of prepaid purchased coal from Blackjewel as a result of Blackjewel’s Chapter 11 bankruptcy filing on July 1, 2019. (2) 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. (3) During the nine months ended September 30, 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.

Business and Basis of Present_3

Business and Basis of Presentation (Details) - USD ($) $ in Thousands	Apr. 03, 2020	Jan. 01, 2020	Mar. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Idled operation term	30 days
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201613Member
Stockholder's equity			$ 653,835	$ 342,968	$ 409,415	$ 696,122	$ 868,938	$ 967,221	$ 1,080,644	$ 1,071,140
Retained (Deficit) Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholder's equity			$ 46,562	$ (260,376)	$ (191,739)	86,810	$ 227,751	$ 296,283	$ 409,944	$ 403,129
Cumulative effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholder's equity						(440)
Cumulative effect | Retained (Deficit) Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholder's equity		$ (440)				$ (440)

Discontinued Operations - Narra

Discontinued Operations - Narrative (Details) $ in Thousands	May 29, 2020USD ($)
PRB Transaction | Discontinued Operations
Guarantor Obligations [Line Items]
Consideration	$ 625

Discontinued Operations - Major

Discontinued Operations - Major Components of Net Income (Loss) (Details) - PRB Transaction - Discontinued Operations - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Revenues:
Total revenues	$ 4	$ 152
Costs and expenses:
Depreciation, Depletion and amortization	0	145,913
Accretion on asset retirement obligations	4,981	4,981
Asset impairment	694	17,162
Selling, general and administrative expenses	4,666	4,673
Other expenses	1,032	3,964
Other non-major expense (income) items, net	$ 147	$ 432

Discontinued Operations - Maj_2

Discontinued Operations - Major Components of Cash Flows (Details) - PRB Transaction - Discontinued Operations - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation, depletion and amortization	$ 0	$ 145,913
Accretion on asset retirement obligations	4,981	4,981
Asset impairment	$ 694	$ 17,162

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 399,954	$ 523,987	$ 1,278,935	$ 1,784,775
Coal
Disaggregation of Revenue [Line Items]
Revenues	399,954	523,987	1,278,935	1,784,775
Met
Disaggregation of Revenue [Line Items]
Revenues	287,014	385,774	975,865	1,357,847
Thermal
Disaggregation of Revenue [Line Items]
Revenues	112,940	138,213	303,070	426,928
Export coal revenues
Disaggregation of Revenue [Line Items]
Revenues	209,046	261,815	718,058	967,959
Export coal revenues | Coal
Disaggregation of Revenue [Line Items]
Revenues	209,046	261,815	718,058	967,959
Export coal revenues | Met
Disaggregation of Revenue [Line Items]
Revenues	202,339	248,628	693,599	928,390
Export coal revenues | Thermal
Disaggregation of Revenue [Line Items]
Revenues	6,707	13,187	24,459	39,569
Domestic coal revenues | Coal
Disaggregation of Revenue [Line Items]
Revenues	190,908	262,172	560,877	816,816
Domestic coal revenues | Met
Disaggregation of Revenue [Line Items]
Revenues	84,675	137,146	282,266	429,457
Domestic coal revenues | Thermal
Disaggregation of Revenue [Line Items]
Revenues	$ 106,233	$ 125,026	$ 278,611	$ 387,359

Revenue - Performance Obligatio

Revenue - Performance Obligations (Details) $ in Thousands	Sep. 30, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 607,250
Disaggregation of Revenue [Line Items]
Estimated coal revenues	607,250
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	138,188
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 138,188
Revenue, remaining performance obligation, period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 268,185
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 268,185
Revenue, remaining performance obligation, period	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	$ 200,877
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 200,877
Revenue, remaining performance obligation, period	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	$ 0
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Revenue, remaining performance obligation, period	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	$ 0
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Revenue, remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue from Contract with Customer [Abstract]
Estimated coal revenues	$ 0
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Revenue, remaining performance obligation, period	1 year

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive (Loss) Income - Changes to Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 696,122	$ 1,071,140
Ending balance	342,968	868,938
Employee benefit costs
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(58,616)	(23,130)
Other comprehensive (loss) income before reclassifications	(14,154)	458
Amounts reclassified from accumulated other comprehensive (loss) income	4,156	532
Ending balance	$ (68,614)	$ (22,140)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive (Loss) Income - Summary of Amounts Reclassified (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee benefit costs:
Miscellaneous loss, net	$ 368			$ 1,523			$ 1,088	$ 2,912
Loss from continuing operations before income taxes	(68,682)			(46,663)			(348,946)	(20,151)
Income tax expense	(45)			(3,102)			(2,200)	(8,880)
Net loss	(68,637)	$ (238,301)	$ (39,808)	(68,532)	$ (113,661)	$ 6,815	(346,746)	(175,378)
Amounts reclassified from accumulated other comprehensive (loss) income | Amortization of actuarial loss
Employee benefit costs:
Miscellaneous loss, net	1,101			258			2,829	719
Amounts reclassified from accumulated other comprehensive (loss) income | Settlement
Employee benefit costs:
Miscellaneous loss, net	32			0			1,327	0
Amounts reclassified from accumulated other comprehensive (loss) income | Employee benefit costs
Employee benefit costs:
Loss from continuing operations before income taxes	1,133			258			4,156	719
Income tax expense	0			67			0	187
Net loss	$ 1,133			$ 191			$ 4,156	$ 532

Net (Loss) Income Per Common _2

Net (Loss) Income Per Common Share - Narrative (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,243,866	1,136,318	1,380,076	556,282
Weighted-average antidilutive securities excluded from computation of earnings per share (in shares)	31,665	57,301	38,648	332,794

Inventories, net (Details)

Inventories, net (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Inventory [Line Items]
Total inventories, net		$ 124,245	$ 162,659
Allowance for obsolete materials and supplies inventory	$ 807
Coal
Inventory [Line Items]
Raw coal		18,248	30,274
Saleable coal		79,194	105,092
Material, supplies and other, net
Inventory [Line Items]
Materials, supplies and other, net		$ 26,803	$ 27,293

Acquired Intangibles (Details)

Acquired Intangibles (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Assets	$ 100,350	$ 125,145
Liabilities	(875)	(6,018)
Net Total	99,475	119,127
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Assets	185	917
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Assets	100,165	124,228
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Liabilities	(875)	(6,018)
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Liabilities	0	0
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Net Total	(690)	(5,101)
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Net Total	$ 100,165	$ 124,228

Acquired Intangibles - Narrativ

Acquired Intangibles - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020
Finite-Lived Intangible Assets [Line Items]
Asset impairment, change in carrying value		$ 33,709
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Asset impairment, change in carrying value	$ 8,653		$ 14,471

Acquired Intangibles - Amortiza

Acquired Intangibles - Amortization of Intangible Assets (Liabilities) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangibles, net	$ 2,219	$ 2,314	$ 5,180	$ (4,712)
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangibles, net	(725)	(3,952)	(4,412)	(22,583)
Acquired mine permits, net
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	2,944	6,266	9,592	17,871
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	145	1,473	732	2,351
Coal supply agreements, net
Finite-Lived Intangible Assets [Line Items]
Amortization of below-market coal supply agreements	$ (870)	$ (5,425)	$ (5,144)	$ (24,934)

Asset Impairment and Restruct_3

Asset Impairment and Restructuring - Narrative (Details)	3 Months Ended				9 Months Ended
	Sep. 30, 2020USD ($)asset_group	Jun. 30, 2020USD ($)asset_group	Mar. 31, 2020USD ($)asset_group	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment			$ 33,709,000
Asset impairment related to write-off of prepaid purchased coal				$ 32,000		$ 5,858,000
Restructuring expense				$ 0		$ 0
Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Impaired Long-Lived Assets Held and Used [Line Items]
Restructuring expense	$ 55,000				$ 22,490,000
Operating Segments
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		$ 161,738,000
All Other
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		$ 5,000
All Other | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Impaired Long-Lived Assets Held and Used [Line Items]
Restructuring expense	$ 450,000				2,443,000
CAPP - Met
Impaired Long-Lived Assets Held and Used [Line Items]
Number of assets impaired | asset_group	3	3	4
CAPP - Met | Operating Segments
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment	$ 0	$ 0	$ 32,951,000
CAPP - Thermal
Impaired Long-Lived Assets Held and Used [Line Items]
Number of assets impaired | asset_group	4	4	3
CAPP - Thermal | Operating Segments
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		$ 17,385,000	$ 758,000
CAPP - Thermal | Operating Segments | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Impaired Long-Lived Assets Held and Used [Line Items]
Restructuring expense	$ (484,000)				1,826,000
NAPP | Operating Segments
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		144,348,000
NAPP | Operating Segments | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Impaired Long-Lived Assets Held and Used [Line Items]
Restructuring expense	89,000				$ 18,221,000
Mineral rights
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		18,605,000	21,825,000
Property, plant and equipment
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		134,480,000	6,066,000
Property, plant and equipment | Operating Segments
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment	3,516,000
Property, plant and equipment | CAPP - Thermal | Operating Segments
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment	219,000
Property, plant and equipment | NAPP | Operating Segments
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment	$ 3,297,000
Acquired mine permits, net
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment		$ 8,653,000	$ 5,818,000

Asset Impairment and Restruct_4

Asset Impairment and Restructuring - Restructuring Expense (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Total restructuring expense			$ 0		$ 0
Allowance for obsolete materials and supplies inventory		$ 807,000
Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Restructuring Cost and Reserve [Line Items]
Severance and employee-related benefits	$ 55,000			$ 20,608,000
Other costs	0			1,882,000
Total restructuring expense	55,000			22,490,000
Deferred longwall move expenses				668,000
Allowance for advanced mining royalties				407,000
Allowance for obsolete materials and supplies inventory				807,000
All Other | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Restructuring Cost and Reserve [Line Items]
Total restructuring expense	450,000			2,443,000
CAPP - Thermal | Operating Segments | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Restructuring Cost and Reserve [Line Items]
Total restructuring expense	(484,000)			1,826,000
NAPP | Operating Segments | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Restructuring Cost and Reserve [Line Items]
Total restructuring expense	$ 89,000			$ 18,221,000

Leases - Right-of-use Assets an

Leases - Right-of-use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets
Financing lease assets	$ 5,921	$ 9,718
Financing lease assets	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Operating lease right-of-use assets	$ 6,481	$ 8,678
Operating lease right-of-use assets	us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Total lease assets	$ 12,402	$ 18,396
Liabilities
Financing lease liabilities - current	$ 3,222	$ 3,275
Financing lease liabilities - current	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Operating lease liabilities - current	$ 949	$ 1,813
Operating lease liabilities - current	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Financing lease liabilities - long-term	$ 2,552	$ 4,674
Financing lease liabilities - long-term	us-gaap:LongTermDebtAndCapitalLeaseObligations	us-gaap:LongTermDebtAndCapitalLeaseObligations
Operating lease liabilities - long-term	$ 5,532	$ 6,866
Operating lease liabilities - long-term	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Total lease liabilities	$ 12,255	$ 16,628

Leases - Lease Costs and Other

Leases - Lease Costs and Other Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Finance lease cost:
Amortization of leased assets	$ 805,000	$ 1,143,000	$ 2,546,000	$ 2,796,000
Interest on lease liabilities	81,000	108,000	277,000	366,000
Operating lease cost	509,000	732,000	1,603,000	2,062,000
Short-term lease cost	380,000	494,000	1,255,000	1,474,000
Total lease cost	$ 1,775,000	$ 2,477,000	5,681,000	6,698,000
Variable lease income			0	0
Sublease income			0
Other information
Cash paid for amounts included in the measurement of lease liabilities			5,426,000	6,862,000
Operating cash flows from finance leases			276,000	366,000
Operating cash flows from operating leases			2,859,000	3,536,000
Financing cash flows from finance leases			2,291,000	2,960,000
Right-of-use assets obtained in exchange for new finance lease liabilities			243,000	1,142,000
Right-of-use assets obtained in exchange for new operating lease liabilities			$ (12,000)	$ 140,000
Lease Term and Discount Rate
Weighted-average remaining lease term in months - finance leases	1 year 10 months 28 days	2 years 8 months 23 days	1 year 10 months 28 days	2 years 8 months 23 days
Weighted-average remaining lease term in months - operating leases	7 years 11 months 12 days	7 years 10 months 17 days	7 years 11 months 12 days	7 years 10 months 17 days
Weighted-average discount rate - finance leases	6.30%	5.20%	6.30%	5.20%
Weighted-average discount rate - operating leases	11.40%	10.90%	11.40%	10.90%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) $ in Thousands	Sep. 30, 2020USD ($)
Finance Leases
Remainder of 2020	$ 945
2021	3,110
2022	1,854
2023	272
2024	6
Thereafter	0
Total future minimum lease payments	6,187
Imputed interest	(413)
Present value of future minimum lease payments	5,774
Operating Leases
Remainder of 2020	489
2021	1,489
2022	1,354
2023	1,101
2024	982
Thereafter	4,915
Total future minimum lease payments	10,330
Imputed interest	(3,849)
Present value of future minimum lease payments	$ 6,481

Stock Repurchases (Details)

Stock Repurchases (Details) - Common Stock - USD ($) $ / shares in Units, $ in Thousands	Sep. 12, 2019	Sep. 30, 2019	Aug. 29, 2019	May 31, 2019
Capital Return Program
Equity, Class of Treasury Stock [Line Items]
Authorized share repurchases				$ 250,000
Company Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Authorized share repurchases			$ 100,000
Shares repurchased (in shares)		529,303
Shares repurchased, net		$ 15,969
Shares repurchased, gross		15,953
Fees related to stock repurchase		$ 16
Share repurchase price (in USD per share)		$ 30.17
Shareholders | Stockholders Common Stock Repurchase Agreement
Equity, Class of Treasury Stock [Line Items]
Shares repurchased (in shares)	500,000
Shares repurchased, net	$ 16,495
Share repurchase price (in USD per share)	$ 32.99

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Debt discount and issuance costs	$ (20,358)	$ (29,695)
Total long-term debt	597,540	592,966
Less current portion	(44,864)	(28,485)
Long-term debt, net of current portion	552,676	564,481
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024
Debt Instrument [Line Items]
Long-term debt, gross	554,778	558,991
Line of Credit | ABL Facility - due April 2022
Debt Instrument [Line Items]
Long-term debt, gross	18,350	0
Note Payable | LCC Note Payable
Debt Instrument [Line Items]
Long-term debt, gross	27,500	45,000
Note Payable | LCC Water Treatment Obligation
Debt Instrument [Line Items]
Long-term debt, gross	8,125	9,375
Other
Debt Instrument [Line Items]
Long-term debt, gross	$ 9,145	$ 9,295

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details) - USD ($)	Jun. 14, 2019	Nov. 09, 2018	Sep. 30, 2020	Oct. 07, 2020	Mar. 20, 2020	Dec. 31, 2019
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
Outstanding borrowings			$ 540,095,000			$ 538,765,000
Current portion of long-term debt			$ 5,618,000			5,618,000
Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Eurocurrency
Debt Instrument [Line Items]
Variable interest rate			7.00%
Variable interest rate floor	2.00%
Interest rate at period end			9.00%
Term Loan Credit Facility | Term Loan Credit Facility, due November 2025
Debt Instrument [Line Items]
Loans repaid	$ 543,125,000
Losses on modification of debt	255,000
Loss on extinguishment of debt	$ 26,204,000
Line of Credit | ABL Facility - due April 2022
Debt Instrument [Line Items]
Letters of credit outstanding			$ 122,366,000
Note Payable | LCC Note Payable
Debt Instrument [Line Items]
Outstanding borrowings			23,638,000			37,695,000
Current portion of long-term debt			$ 17,500,000			17,500,000
Stated interest rate			0.00%
Imputed interest rate			12.45%
Note Payable | LCC Water Treatment Obligation
Debt Instrument [Line Items]
Outstanding borrowings			$ 6,674,000			7,211,000
Current portion of long-term debt			$ 2,500,000			1,875,000
Stated interest rate			0.00%
Imputed interest rate			13.12%
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022
Debt Instrument [Line Items]
Outstanding borrowings			$ 18,350,000		$ 57,500,000	0
Current portion of long-term debt			15,000,000
Maximum borrowing capacity		$ 225,000,000
Fronting fee rate		0.25%
Letters of credit outstanding			$ 122,366,000			$ 99,876,000
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022 | Minimum
Debt Instrument [Line Items]
Commitment fee rate		0.25%
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022 | Maximum
Debt Instrument [Line Items]
Commitment fee rate		0.375%
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022 | Base Rate
Debt Instrument [Line Items]
Variable interest rate			2.50%
Interest rate at period end			3.71%	2.73%
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022 | Base Rate | Minimum
Debt Instrument [Line Items]
Variable interest rate		1.00%
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022 | Base Rate | Maximum
Debt Instrument [Line Items]
Variable interest rate		1.50%
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022 | Eurocurrency | Minimum
Debt Instrument [Line Items]
Variable interest rate		2.00%
Revolving Credit Facility | Line of Credit | ABL Facility - due April 2022 | Eurocurrency | Maximum
Debt Instrument [Line Items]
Variable interest rate		2.50%
Letter of Credit | Line of Credit | ABL Facility - due April 2022
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 200,000,000
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%
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%
Interest Rate Period Two | Term Loan Credit Facility | Term Loan Credit Facility - due June 2024 | Eurocurrency | Minimum
Debt Instrument [Line Items]
Variable interest rate	7.00%
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%

Acquisition-Related Obligatio_3

Acquisition-Related Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Option, Quantitative Disclosures [Line Items]
Discount	$ (1,952)	$ (4,834)
Total acquisition-related obligations	37,492	79,898
Less current portion	(18,206)	(33,639)
Acquisition-related obligations, net of current portion	19,286	46,259
Contingent Revenue Obligation
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations - long-term, gross	24,292	52,427
Total acquisition-related obligations	24,292	52,427
Less current portion	(10,511)	(14,646)
Environmental Settlement Obligations
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations - long-term, gross	11,152	16,305
Discount	(1,478)	(2,711)
Total acquisition-related obligations	9,674	13,594
Less current portion	(5,694)	(6,185)
Reclamation Funding Liability
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations - long-term, gross	0	12,000
Discount		(1,192)
Less current portion		(10,808)
UMWA Funds Settlement Liability
Fair Value, Option, Quantitative Disclosures [Line Items]
Total acquisition-related obligations - long-term, gross	$ 4,000	$ 4,000

Acquisition-Related Obligatio_4

Acquisition-Related Obligations - Narrative (Details) - USD ($)	3 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Business Acquisition, Contingent Consideration [Line Items]
Acquisition related obligations		$ 37,492,000	$ 79,898,000
Acquisition related obligations, current		18,206,000	33,639,000
Discount		1,952,000	4,834,000
Contingent Revenue Obligation
Business Acquisition, Contingent Consideration [Line Items]
Acquisition related obligations		24,292,000	52,427,000
Acquisition related obligations, current		10,511,000	14,646,000
Payments for acquisition-related obligations	$ 15,084,000
Payments for acquisition-related obligations, unclaimed	$ 374,000
Environmental Settlement Obligations
Business Acquisition, Contingent Consideration [Line Items]
Acquisition related obligations		9,674,000	13,594,000
Acquisition related obligations, current		5,694,000	6,185,000
Discount		1,478,000	2,711,000
Reclamation Funding Liability
Business Acquisition, Contingent Consideration [Line Items]
Acquisition related obligations, current			10,808,000
Remaining payments for acquisition-related obligations		$ 0
Discount			$ 1,192,000

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Asset Retirement Obligation [Line Items]
Revisions in estimated cash flows		$ 13,244
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Total asset retirement obligations at December 31, 2019		224,704
Accretion for the period		23,806
Sites added during the period		621
Revisions in estimated cash flows		13,244
Expenditures for the period		(16,532)
Total asset retirement obligations at September 30, 2020		$ 224,704	$ 245,843	$ 224,704
Less current portion			(34,845)
Long-term portion			$ 210,998	$ 184,130
Depreciation, Depletion And Amortization
Asset Retirement Obligation [Line Items]
Revisions in estimated cash flows	$ 3,100
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Revisions in estimated cash flows	$ 3,100

Fair Value of Financial Instr_3

Fair Value of Financial Instruments and Fair Value Measurements - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	$ 588,757	$ 583,671
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	540,095	538,765
Carrying Amount | Line of Credit | ABL Facility - due April 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	18,350
Carrying Amount | Note Payable | LCC Note Payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	23,638	37,695
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	6,674	7,211
Fair Value, Measurements, Nonrecurring | Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	409,864	501,566
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 long term debt	0	461,402
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 long term debt	368,095	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 long term debt	41,769	40,164
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	368,095	461,402
Fair Value, Measurements, Nonrecurring | Total Fair Value | 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	0	461,402
Fair Value, Measurements, Nonrecurring | Total Fair Value | 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	368,095	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | 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	0
Fair Value, Measurements, Nonrecurring | Total Fair Value | Line of Credit | ABL Facility - due April 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	18,113
Fair Value, Measurements, Nonrecurring | Total Fair Value | Line of Credit | ABL Facility - due April 2022 | 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
Fair Value, Measurements, Nonrecurring | Total Fair Value | Line of Credit | ABL Facility - due April 2022 | 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 | Total Fair Value | Line of Credit | ABL Facility - due April 2022 | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total long term debt	18,113
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	18,557	33,884
Fair Value, Measurements, Nonrecurring | Total Fair Value | 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 | Total Fair Value | 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 | Total Fair Value | 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	18,557	33,884
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	5,099	6,280
Fair Value, Measurements, Nonrecurring | Total Fair Value | 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 | Total Fair Value | 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 | Total Fair Value | 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	$ 5,099	$ 6,280

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	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	$ 13,200	$ 27,471
Carrying Amount | UMWA Funds Settlement Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	3,526	3,069
Carrying Amount | Reclamation Funding Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value		10,808
Carrying Amount | Environmental Settlement Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	9,674	13,594
Fair Value, Measurements, Nonrecurring | Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	10,945	25,784
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	10,945	25,784
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	3,135	2,929
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	3,135	2,929
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
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
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
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
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	7,810	12,197
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	$ 7,810	$ 12,197

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	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation	$ 24,292	$ 52,427
Trading securities	26,015	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	0	0
Trading securities	20,087	5,506
Significant Other Observable Inputs (Level 2)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation	0	0
Trading securities	5,928	8,002
Significant Unobservable Inputs (Level 3)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Contingent Revenue Obligation	24,292	52,427
Trading securities	$ 0	$ 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	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Measurement Period Adjustments		$ 5,738
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	$ 52,427	59,880
Payments	(14,710)	(9,627)
Loss (Gain) Recognized in Earnings	(13,425)	(288)
Transfer In (Out) of Level 3 Fair Value Hierarchy	0	0
Ending balance	$ 24,292	$ 55,703

Fair Value of Financial Instr_7

Fair Value of Financial Instruments and Fair Value Measurements - Level 3 Fair Value Measurements (Details) $ in Millions	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Black Scholes | Forecasted future revenue | Minimum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	800	1,100
Black Scholes | Forecasted future revenue | Maximum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	900	1,200
Black Scholes | Stated royalty rate | Minimum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.010	0.010
Black Scholes | Stated royalty rate | Maximum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.015	0.015
Black Scholes | Annualized volatility | Minimum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.106	0.094
Black Scholes | Annualized volatility | Maximum | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.321	0.281
Black Scholes | Annualized volatility | Weighted Average | Contingent Revenue Obligation
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Acquisition-related obligation, measurement input	0.268	0.199
Fair Value, Measurements, Recurring | Discounted cash flow | Significant Unobservable Inputs (Level 3) | Discount rate | Notes Payable, UMWA Funds Settlement Liability, Enviromental Settlement Obligations, and Reclaimation Funding Liability,
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt and acquisition-related obligation, measurement input	0.35	0.21
Line of Credit | Fair Value, Measurements, Recurring | Discounted cash flow | ABL Facility - due April 2022 | Significant Unobservable Inputs (Level 3) | Discount rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt, measurement input	0.10

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Mar. 27, 2020	Dec. 31, 2019
Income Tax [Line Items]
Income tax benefit	$ 45		$ 3,102	$ 2,200	$ 8,880
Income (loss) from continuing operations before income taxes	(68,682)		$ (46,663)	(348,946)	$ (20,151)
Discrete income tax benefit from AMT credit		$ 2,123
Increase in deferred tax asset valuation allowance				92,804
AMT credit to be refunded during year						$ 68,252
Decrease in unrecognized tax benefits				23,800
Prepaid Expenses and Other Current Assets
Income Tax [Line Items]
AMT credit	$ 66,129			$ 66,129			$ 33,065

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 4,670	$ 6,636	$ 14,061	$ 19,929
Expected return on plan assets	(6,752)	(7,011)	(20,312)	(21,032)
Amortization of net actuarial loss (gain)	511	199	1,501	597
Settlement	0	0	1,230	0
Net periodic expense	(1,571)	(176)	(3,520)	(506)
Black Lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	598	751	1,762	1,558
Interest cost	747	1,567	2,493	3,386
Expected return on plan assets	(14)	(17)	(40)	(49)
Amortization of net actuarial loss (gain)	596	72	1,346	162
Net periodic expense	1,927	2,373	5,561	5,057
Life Insurance Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	84	106	253	318
Amortization of net actuarial loss (gain)	(12)	(26)	(36)	(78)
Net periodic expense	$ 72	$ 80	$ 217	$ 240

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Period for incremental increase of target allocation	10 months
Total contributions		$ 628		$ 4,158	$ 6,520	$ 23,461
Self insurance, expenses incurred		$ 17,327		$ 20,976	$ 48,430	$ 58,873
Black Lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Increase in obligations for curtailment			$ 7,400
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Incremental increase in target allocation	2.00%	2.00%			2.00%
Pension | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation adjustments	60.00%	60.00%			60.00%
Pension | Fixed income funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation adjustments	40.00%	40.00%			40.00%

Related Party Transactions - Na

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

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Feb. 21, 2020	Feb. 20, 2020
Long-term Purchase Commitment [Line Items]
Coal royalty expense	$ 16,176	$ 21,868	$ 52,092	$ 73,119
Income tax receivable	66,129		66,129
Income tax receivable related to NOL carryback claim	64,160		64,160
Income tax receivable related to NOL carryback claim, interest receivable	5,126		5,126
Black Lung
Long-term Purchase Commitment [Line Items]
Collateral for self insurance black lunch obligations					$ 65,700	$ 2,600
Term Loan Credit Facility - due November 2025 | Line of Credit
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding	122,366		122,366
ANR, Inc. and Citibank, N.A. Credit Agreement | Line of Credit
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding	14,242		14,242
Credit and Security Agreement | Line of Credit
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding	613		613
Coal Purchase Agreements
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, 2020	15,670		15,670
Equipment Purchase Agreements
Long-term Purchase Commitment [Line Items]
Minimum quantities to be purchased, 2020	9,931		9,931
Minimum quantities to be purchased, 2021	8,968		8,968
Minimum quantities to be purchased, 2024	1,157		1,157
Shipping
Long-term Purchase Commitment [Line Items]
Minimum royalty obligations, 2021	8,793		8,793
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Guarantees	349,772		349,772
Collateral supporting guarantees	113,470		113,470
Royalty Agreements | Coal
Long-term Purchase Commitment [Line Items]
Minimum royalty obligations, 2020	1,784		1,784
Minimum royalty obligations, 2021	15,974		15,974
Minimum royalty obligations, 2022	14,081		14,081
Minimum royalty obligations, 2023	13,064		13,064
Minimum royalty obligations, 2024	11,110		11,110
Minimum royalty obligations, to be paid after 2024	$ 46,724		$ 46,724

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Restricted Cash Deposits (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Long-term Purchase Commitment [Line Items]
Total restricted cash	$ 131,169	$ 134,887
Less current portion	(7,104)	(12,363)	$ (21,456)
Long-term restricted cash	124,065	122,524	$ 209,041
Workers' compensation
Long-term Purchase Commitment [Line Items]
Total restricted cash	39,141	38,944
Black lung
Long-term Purchase Commitment [Line Items]
Total restricted cash	12,770	12,706
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total restricted cash	69,148	67,868
Financial guarantees and other
Long-term Purchase Commitment [Line Items]
Total restricted cash	3,006	3,006
Contingent revenue obligation escrow
Long-term Purchase Commitment [Line Items]
Total restricted cash	$ 7,104	$ 12,363

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Restricted Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Long-term Purchase Commitment [Line Items]
Total restricted investments	$ 27,793	$ 21,886
Restricted investments, trading	26,015	13,508
Restricted investments, held-to-maturity	1,778	8,378
Workers' compensation
Long-term Purchase Commitment [Line Items]
Total restricted investments	3,131	3,100
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total restricted investments	$ 24,662	$ 18,786

Commitments and Contingencies_4

Commitments and Contingencies - Cash Deposits Held by Third Parties (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Long-term Purchase Commitment [Line Items]
Total deposits	$ 21,079	$ 10,723
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total deposits	19,660	8,887
Other operating agreements
Long-term Purchase Commitment [Line Items]
Total deposits	$ 1,419	$ 1,836

Segment Information - Schedule

Segment Information - Schedule of Operating Results and Capital Expenditures (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)plantminesegment	Sep. 30, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			3
Total revenues	$ 400,691	$ 525,864	$ 1,282,989	$ 1,791,184
Depreciation, depletion and amortization	50,739	60,842	154,466	184,927
Amortization of acquired intangibles, net	2,219	2,314	5,180	(4,712)
Adjusted EBITDA	19,687	40,023	96,830	264,157
Capital expenditures	27,806	60,301	$ 118,896	144,183
CAPP - Met | Virginia
Segment Reporting Information [Line Items]
Number of active mines | mine			4
Number of preparation plants | plant			2
CAPP - Met | West Virginia
Segment Reporting Information [Line Items]
Number of active mines | mine			17
Number of preparation plants | plant			5
CAPP - Thermal | West Virginia
Segment Reporting Information [Line Items]
Number of active mines | mine			1
Number of preparation plants | plant			1
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
Operating Segments | CAPP - Met
Segment Reporting Information [Line Items]
Total revenues	295,381	373,356	$ 974,674	1,340,684
Depreciation, depletion and amortization	41,177	38,212	121,699	113,714
Amortization of acquired intangibles, net	2,535	4,765	7,875	5,816
Adjusted EBITDA	17,847	58,796	104,668	283,483
Capital expenditures	22,668	47,316	83,449	105,008
Operating Segments | CAPP - Thermal
Segment Reporting Information [Line Items]
Total revenues	39,835	80,432	115,416	225,698
Depreciation, depletion and amortization	7,313	13,972	19,422	44,586
Amortization of acquired intangibles, net	(486)	(3,359)	(3,484)	(12,142)
Adjusted EBITDA	5,155	1,954	5,459	8,704
Capital expenditures	765	5,706	6,349	13,365
Operating Segments | NAPP
Segment Reporting Information [Line Items]
Total revenues	65,100	71,446	190,643	222,750
Depreciation, depletion and amortization	1,504	6,241	10,525	19,390
Amortization of acquired intangibles, net	145	908	714	1,614
Adjusted EBITDA	7,250	(4,152)	20,645	21,900
Capital expenditures	4,299	7,114	28,468	23,317
All Other
Segment Reporting Information [Line Items]
Total revenues	375	630	2,256	2,052
Depreciation, depletion and amortization	745	2,417	2,820	7,237
Amortization of acquired intangibles, net	25	0	75	0
Adjusted EBITDA	(10,565)	(16,575)	(33,942)	(49,930)
Capital expenditures	$ 74	$ 165	$ 630	$ 2,493

Segment Information - Reconcili

Segment Information - Reconciliation of Net Income (Loss) to Adjusted EBITDA (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net loss from continuing operations	$ (68,637,000)	$ (43,561,000)	$ (346,746,000)	$ (11,271,000)
Interest expense	18,389,000	18,847,000	54,808,000	50,079,000
Interest income	(378,000)	(1,763,000)	(6,889,000)	(5,584,000)
Income tax expense (benefit)	(45,000)	(3,102,000)	(2,200,000)	(8,880,000)
Depreciation, depletion and amortization	50,739,000	60,842,000	154,466,000	184,927,000
Merger-related costs	0	68,000	0	1,055,000
Non-cash stock compensation expense	1,078,000	2,738,000	4,200,000	7,463,000
Mark-to-market adjustment - acquisition-related obligations		(3,238,000)	(13,425,000)	(288,000)
Mark-to-market adjustment for acquisition-related obligations	3,624,000	(3,238,000)	(13,425,000)	(288,000)
Accretion on asset retirement obligations	9,127,000	6,846,000	23,806,000	19,925,000
Loss on modification and extinguishment of debt	0	0	0	26,459,000
Asset impairment	3,516,000	32,000	198,963,000	5,858,000
Asset impairment and restructuring			221,453,000	23,020,000
Loss on partial settlement of benefit obligations			1,230,000
Cost impact of coal inventory fair value adjustment				8,209,000
Gain on assets acquired in an exchange transaction			0	(9,083,000)
Amortization of acquired intangibles, net	2,219,000	2,314,000	5,180,000	(4,712,000)
Adjusted EBITDA	19,687,000	40,023,000	96,830,000	264,157,000
Restructuring expense		0		0
Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Asset impairment and restructuring	3,571,000		221,453,000
Management restructuring costs	55,000		20,608,000
Restructuring expense	55,000		22,490,000
Senior Management Changes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Management restructuring costs			947,000
Operating Segments | CAPP - Met
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net loss from continuing operations	(29,545,000)	13,033,000	(67,996,000)	154,020,000
Interest expense	(189,000)	84,000	(1,495,000)	306,000
Interest income	(3,000)	(4,000)	(63,000)	(12,000)
Income tax expense (benefit)	0	0	0	0
Depreciation, depletion and amortization	41,177,000	38,212,000	121,699,000	113,714,000
Merger-related costs		0		0
Non-cash stock compensation expense	105,000	348,000	410,000	1,127,000
Mark-to-market adjustment - acquisition-related obligations		0	0	0
Mark-to-market adjustment for acquisition-related obligations	0
Accretion on asset retirement obligations	3,767,000	2,326,000	10,786,000	6,986,000
Loss on modification and extinguishment of debt				0
Asset impairment		32,000		5,858,000
Loss on partial settlement of benefit obligations			0
Cost impact of coal inventory fair value adjustment				4,751,000
Gain on assets acquired in an exchange transaction				(9,083,000)
Amortization of acquired intangibles, net	2,535,000	4,765,000	7,875,000	5,816,000
Adjusted EBITDA	17,847,000	58,796,000	104,668,000	283,483,000
Operating Segments | CAPP - Met | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Asset impairment and restructuring	0		32,951,000
Operating Segments | CAPP - Met | Senior Management Changes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Management restructuring costs			501,000
Operating Segments | CAPP - Thermal
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net loss from continuing operations	(3,815,000)	(11,338,000)	(37,711,000)	(34,675,000)
Interest expense	2,000	6,000	6,000	16,000
Interest income	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Depreciation, depletion and amortization	7,313,000	13,972,000	19,422,000	44,586,000
Merger-related costs		0		0
Non-cash stock compensation expense	0	3,000	8,000	60,000
Mark-to-market adjustment - acquisition-related obligations		0	0	0
Mark-to-market adjustment for acquisition-related obligations	0
Accretion on asset retirement obligations	2,406,000	2,670,000	7,025,000	7,401,000
Loss on modification and extinguishment of debt				0
Asset impairment		0		0
Loss on partial settlement of benefit obligations			0
Cost impact of coal inventory fair value adjustment				3,458,000
Gain on assets acquired in an exchange transaction				0
Amortization of acquired intangibles, net	(486,000)	(3,359,000)	(3,484,000)	(12,142,000)
Adjusted EBITDA	5,155,000	1,954,000	5,459,000	8,704,000
Operating Segments | CAPP - Thermal | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Asset impairment and restructuring	(265,000)		20,188,000
Restructuring expense	(484,000)		1,826,000
Operating Segments | CAPP - Thermal | Senior Management Changes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Management restructuring costs			5,000
Operating Segments | NAPP
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net loss from continuing operations	149,000	(12,304,000)	(158,983,000)	(2,118,000)
Interest expense	(357,000)	1,000	(1,431,000)	2,000
Interest income	(1,000)	(15,000)	(15,000)	(38,000)
Income tax expense (benefit)	0	0	0	0
Depreciation, depletion and amortization	1,504,000	6,241,000	10,525,000	19,390,000
Merger-related costs		0		0
Non-cash stock compensation expense	0	0	0	0
Mark-to-market adjustment - acquisition-related obligations		0	0	0
Mark-to-market adjustment for acquisition-related obligations	0
Accretion on asset retirement obligations	2,424,000	1,017,000	3,963,000	3,050,000
Loss on modification and extinguishment of debt				0
Asset impairment		0		0
Loss on partial settlement of benefit obligations			0
Cost impact of coal inventory fair value adjustment				0
Gain on assets acquired in an exchange transaction				0
Amortization of acquired intangibles, net	145,000	908,000	714,000	1,614,000
Adjusted EBITDA	7,250,000	(4,152,000)	20,645,000	21,900,000
Operating Segments | NAPP | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Asset impairment and restructuring	3,386,000		165,866,000
Restructuring expense	89,000		18,221,000
Operating Segments | NAPP | Senior Management Changes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Management restructuring costs			6,000
All Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net loss from continuing operations	(35,426,000)	(32,952,000)	(82,056,000)	(128,498,000)
Interest expense	18,933,000	18,756,000	57,728,000	49,755,000
Interest income	(374,000)	(1,744,000)	(6,811,000)	(5,534,000)
Income tax expense (benefit)	(45,000)	(3,102,000)	(2,200,000)	(8,880,000)
Depreciation, depletion and amortization	745,000	2,417,000	2,820,000	7,237,000
Merger-related costs		68,000		1,055,000
Non-cash stock compensation expense	973,000	2,387,000	3,782,000	6,276,000
Mark-to-market adjustment - acquisition-related obligations		(3,238,000)	(13,425,000)	(288,000)
Mark-to-market adjustment for acquisition-related obligations	3,624,000
Accretion on asset retirement obligations	530,000	833,000	2,032,000	2,488,000
Loss on modification and extinguishment of debt				26,459,000
Asset impairment		0		0
Loss on partial settlement of benefit obligations			1,230,000
Cost impact of coal inventory fair value adjustment				0
Gain on assets acquired in an exchange transaction				0
Amortization of acquired intangibles, net	25,000	0	75,000	0
Adjusted EBITDA	(10,565,000)	$ (16,575,000)	(33,942,000)	$ (49,930,000)
All Other | Strategic Actions with Respect to Two Thermal Coal Mining Complexes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Asset impairment and restructuring	450,000		2,448,000
Restructuring expense	$ 450,000		2,443,000
All Other | Senior Management Changes
Segment Reporting, Other Significant Reconciling Item [Line Items]
Management restructuring costs			$ 435,000

Segment Information - Revenue f

Segment Information - Revenue from External Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Coal revenues	$ 399,954	$ 523,987	$ 1,278,935	$ 1,784,775
Export coal revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Coal revenues	209,046	$ 261,815	718,058	967,959
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Coal revenues	$ 57,740		174,182	$ 228,754
Brazil
Revenues from External Customers and Long-Lived Assets [Line Items]
Coal revenues			$ 133,501
Geographic Concentration Risk | Export coal revenues | Revenues
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	52.00%	50.00%	56.00%	54.00%