Alpha Metallurgical Resources (AMR) 10-Q 5 Aug 24 2024 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2024	Jul. 31, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	001-38735
Entity Registrant Name	ALPHA METALLURGICAL RESOURCES, 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
Title of 12(b) Security	Common Stock
Trading Symbol	AMR
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		13,016,010
Entity Central Index Key	0001704715
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues:
Coal revenues	$ 800,130	$ 853,807	$ 1,661,413	$ 1,760,505
Other revenues	3,839	4,564	6,628	9,101
Total revenues	803,969	858,371	1,668,041	1,769,606
Costs and expenses:
Cost of coal sales (exclusive of items shown separately below)	663,809	583,514	1,312,122	1,122,651
Depreciation, depletion and amortization	43,380	32,226	84,081	61,649
Accretion on asset retirement obligations	6,257	6,376	12,400	12,753
Amortization of acquired intangibles, net	1,675	2,192	3,350	4,389
Selling, general and administrative expenses (exclusive of depreciation, depletion and amortization shown separately above)	18,805	17,506	41,182	38,198
Other operating (income) loss	(633)	(1,546)	2,352	(2,638)
Total costs and expenses	733,293	640,268	1,455,487	1,237,002
Income from operations	70,676	218,103	212,554	532,604
Other (expense) income:
Interest expense	(1,101)	(1,856)	(2,187)	(3,576)
Interest income	4,140	2,754	8,111	4,272
Equity loss in affiliates	(5,917)	(3,174)	(7,557)	(4,922)
Miscellaneous expense, net	(3,611)	(874)	(5,574)	(243)
Total other expense, net	(6,489)	(3,150)	(7,207)	(4,469)
Income before income taxes	64,187	214,953	205,347	528,135
Income tax expense	(5,278)	(33,598)	(19,443)	(76,009)
Net income	$ 58,909	$ 181,355	$ 185,904	$ 452,126
Basic income per common share (in dollars per share)	$ 4.53	$ 12.63	$ 14.29	$ 30.52
Diluted income per common share (in dollars per share)	$ 4.49	$ 12.16	$ 14.11	$ 29.34
Weighted average shares - basic (in shares)	13,013,684	14,362,072	13,007,905	14,814,099
Weighted average shares - diluted (in shares)	13,111,010	14,910,633	13,173,803	15,410,994

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Other Comprehensive Income [Abstract]
Net income	$ 58,909	$ 181,355	$ 185,904	$ 452,126
Employee benefit plans:
Amortization of and adjustments to employee benefit costs	(10,902)	(4,165)	(9,938)	(4,792)
Income tax benefit	2,419	924	2,205	1,063
Total other comprehensive loss, net of tax	(8,483)	(3,241)	(7,733)	(3,729)
Total comprehensive income	$ 50,426	$ 178,114	$ 178,171	$ 448,397

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 336,148	$ 268,207
Trade accounts receivable, net of allowance for credit losses of $291 and $234 as of June 30, 2024 and December 31, 2023, respectively	505,094	509,682
Inventories, net	221,815	231,344
Prepaid expenses and other current assets	32,866	39,064
Total current assets	1,095,923	1,048,297
Property, plant, and equipment, net of accumulated depreciation and amortization of $621,187 and $558,905 as of June 30, 2024 and December 31, 2023, respectively	626,380	588,992
Owned and leased mineral rights, net of accumulated depletion and amortization of $113,757 and $99,826 as of June 30, 2024 and December 31, 2023, respectively	448,138	451,160
Other acquired intangibles, net of accumulated amortization of $41,893 and $38,543 as of June 30, 2024 and December 31, 2023, respectively	43,229	46,579
Long-term restricted investments	42,196	40,597
Long-term restricted cash	119,107	115,918
Deferred income taxes	8,627	8,028
Other non-current assets	109,352	106,486
Total assets	2,492,952	2,406,057
Current liabilities:
Current portion of long-term debt	3,263	3,582
Trade accounts payable	122,522	128,836
Accrued expenses and other current liabilities	182,869	177,512
Total current liabilities	308,654	309,930
Long-term debt	5,301	6,792
Workers’ compensation and black lung obligations	183,325	189,226
Pension obligations	111,290	101,908
Asset retirement obligations	175,814	166,509
Deferred income taxes	43,877	39,142
Other non-current liabilities	21,121	18,622
Total liabilities	849,382	832,129
Commitments and Contingencies (Note 14)
Stockholders’ Equity
Preferred stock - par value $0.01, 5,000,000 shares authorized, none issued	0	0
Common stock - par value $0.01, 50,000,000 shares authorized, 22,382,945 issued and 13,016,010 outstanding at June 30, 2024 and 22,058,135 issued and 12,938,679 outstanding at December 31, 2023	224	221
Additional paid-in capital	833,790	834,482
Accumulated other comprehensive loss	(48,320)	(40,587)
Treasury stock, at cost: 9,366,935 shares at June 30, 2024 and 9,119,456 shares at December 31, 2023	(1,296,916)	(1,189,715)
Retained earnings	2,154,792	1,969,527
Total stockholders’ equity	1,643,570	1,573,928
Total liabilities and stockholders’ equity	$ 2,492,952	$ 2,406,057

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Allowance for credit losses	$ 291	$ 234
Property, plant and equipment, accumulated amortization, depreciation and amortization	621,187	558,905
Owned and lease mineral rights, accumulated depletion and amortization	113,757	99,826
Other acquired intangibles, accumulated amortization	$ 41,893	$ 38,543
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)	22,382,945	22,058,135
Common stock, shares outstanding (in shares)	13,016,010	12,938,679
Treasury stock, shares at cost (in shares)	9,366,935	9,119,456

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Operating activities:
Net income	$ 58,909	$ 181,355	$ 185,904	$ 452,126
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	43,380	32,226	84,081	61,649
Amortization of acquired intangibles, net	1,675	2,192	3,350	4,389
Amortization of debt issuance costs and accretion of debt discount			559	1,060
Gain on disposal of assets			(321)	(5,578)
Accretion on asset retirement obligations	6,257	6,376	12,400	12,753
Employee benefit plans, net			9,592	6,463
Deferred income taxes			6,341	25,440
Stock-based compensation	3,535	3,645	6,304	6,679
Equity loss in affiliates	5,917	3,174	7,557	4,922
Other, net			(516)	(66)
Changes in operating assets and liabilities			18,948	(75,231)
Net cash provided by operating activities			334,199	494,606
Investing activities:
Capital expenditures			(124,718)	(129,111)
Proceeds on disposal of assets			594	6,839
Cash paid for business acquired			0	(11,919)
Purchases of investment securities			(26,940)	(158,835)
Sales and maturities of investment securities			26,179	236,650
Capital contributions to equity affiliates			(15,659)	(14,943)
Other, net			13	18
Net cash used in investing activities			(140,531)	(71,301)
Financing activities:
Principal repayments of long-term debt			(1,191)	(1,050)
Dividend and dividend equivalents paid			(3,077)	(92,649)
Common stock repurchases and related expenses			(117,648)	(301,201)
Other, net			(622)	(100)
Net cash used in financing activities			(122,538)	(395,000)
Net increase in cash and cash equivalents and restricted cash			71,130	28,305
Cash and cash equivalents and restricted cash at beginning of period			384,125	355,394
Cash and cash equivalents and restricted cash at end of period	455,255	383,699	455,255	383,699
Supplemental disclosure of noncash investing and financing activities:
Financing leases and capital financing - equipment			1	1,994
Accrued capital expenditures			6,379	13,948
Accrued common stock repurchases and stock repurchase excise tax			4,652	6,642
Accrued dividend payable	424	9,541	424	9,541
Reconciliation of Cash and Cash Equivalents and Restricted Cash
Cash and cash equivalents	336,148	312,400	336,148	312,400
Long-term restricted cash	119,107	71,299	119,107	71,299
Total cash and cash equivalents and restricted cash shown in the Condensed Consolidated Statements of Cash Flows	$ 455,255	$ 383,699	$ 455,255	$ 383,699

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Treasury Stock at Cost	Retained Earnings
Beginning balance at Dec. 31, 2022	$ 1,429,755	$ 217	$ 815,442	$ (12,162)	$ (649,061)	$ 1,275,319
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	270,771					270,771
Other comprehensive income (loss), net	(488)			(488)
Stock-based compensation, issuance of common stock for share vesting, and common stock reissuances	3,034	1	(3,444)		6,477
Common stock repurchases and related expenses	(148,973)				(148,973)
Warrants exercises	1,301		1,301
Cash dividend and dividend equivalents declared	(6,825)					(6,825)
Ending balance at Mar. 31, 2023	1,548,575	218	813,299	(12,650)	(791,557)	1,539,265
Beginning balance at Dec. 31, 2022	1,429,755	217	815,442	(12,162)	(649,061)	1,275,319
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	452,126
Other comprehensive income (loss), net	(3,729)
Ending balance at Jun. 30, 2023	1,566,734	219	818,221	(15,891)	(949,202)	1,713,387
Beginning balance at Mar. 31, 2023	1,548,575	218	813,299	(12,650)	(791,557)	1,539,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	181,355					181,355
Other comprehensive income (loss), net	(3,241)			(3,241)
Stock-based compensation, issuance of common stock for share vesting, and common stock reissuances	3,645	1	3,644
Common stock repurchases and related expenses	(157,645)				(157,645)
Warrants exercises	1,278		1,278
Cash dividend and dividend equivalents declared	(7,233)					(7,233)
Ending balance at Jun. 30, 2023	1,566,734	219	818,221	(15,891)	(949,202)	1,713,387
Beginning balance at Dec. 31, 2023	1,573,928	221	834,482	(40,587)	(1,189,715)	1,969,527
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	126,995					126,995
Other comprehensive income (loss), net	750			750
Stock-based compensation, issuance of common stock for share vesting, and common stock reissuances	2,769	3	(3,946)		6,712
Common stock repurchases and related expenses	(112,636)				(112,636)
Dividend equivalents	(662)					(662)
Ending balance at Mar. 31, 2024	1,591,144	224	830,536	(39,837)	(1,295,639)	2,095,860
Beginning balance at Dec. 31, 2023	1,573,928	221	834,482	(40,587)	(1,189,715)	1,969,527
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	185,904
Other comprehensive income (loss), net	(7,733)
Ending balance at Jun. 30, 2024	1,643,570	224	833,790	(48,320)	(1,296,916)	2,154,792
Beginning balance at Mar. 31, 2024	1,591,144	224	830,536	(39,837)	(1,295,639)	2,095,860
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	58,909					58,909
Other comprehensive income (loss), net	(8,483)			(8,483)
Stock-based compensation, issuance of common stock for share vesting, and common stock reissuances	3,535		3,254		281
Common stock repurchases and related expenses	(1,558)				(1,558)
Dividend equivalents	23					23
Ending balance at Jun. 30, 2024	$ 1,643,570	$ 224	$ 833,790	$ (48,320)	$ (1,296,916)	$ 2,154,792

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Jun. 30, 2023	Mar. 31, 2023
Statement of Stockholders' Equity [Abstract]
Cash dividend and dividend equivalents declared per share (in dollars per share)	$ 0.50	$ 0.44

Business and Basis of Presentat

Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Business Alpha is a Tennessee-based mining company with operations in Virginia and West Virginia. With customers across the globe, high-quality reserves and significant port capacity, Alpha is a leading U.S. supplier of metallurgical coal products for the steel industry. Basis of Presentation Together, the condensed consolidated statements of operations, comprehensive income, 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 Income,” “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 six months ended June 30, 2024 and 2023. 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 six months ended June 30, 2024 are not necessarily indicative of the results to be expected for the year ending December 31, 2024 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, 2023. Reclassifications For comparability purposes, certain immaterial segment information for the three and six months ended June 30, 2023 in the notes to the Condensed Consolidated Financials Statements has been recast to conform to the current year presentation. Refer to Note 15. Recent Accounting Guidance Refer to the Recent Accounting Guidance section of Note 2 contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2024
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Disaggregation of Revenue from Contracts with Customers The Company earns revenues primarily through the sale of coal produced by Company operations and coal purchased from third parties. The Company extracts, processes and markets met and thermal coal from deep and surface mines for sale to steel and coke producers, industrial customers, and electric utilities. The Company has disaggregated revenue between met coal and thermal coal and export and domestic revenues which depicts the pricing and contract differences between the two. Export revenue generally is derived by spot or short-term contracts with pricing determined at the time of shipment or based on a market index, whereas domestic revenue is characterized by contracts that typically have a term of one year or longer and with fixed pricing terms. 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 June 30, Six Months Ended June 30, 2024 2023 2024 2023 Export met coal revenues $ 634,176 $ 580,328 $ 1,306,915 $ 1,228,260 Export thermal coal revenues 12,684 36,244 41,246 66,443 Total export coal revenues $ 646,860 $ 616,572 $ 1,348,161 $ 1,294,703 Domestic met coal revenues $ 145,815 $ 225,658 $ 299,110 $ 435,705 Domestic thermal coal revenues 7,455 11,577 14,142 30,097 Total domestic coal revenues $ 153,270 $ 237,235 $ 313,252 $ 465,802 Total met coal revenues $ 779,991 $ 805,986 $ 1,606,025 $ 1,663,965 Total thermal coal revenues 20,139 47,821 55,388 96,540 Total coal revenues $ 800,130 $ 853,807 $ 1,661,413 $ 1,760,505 Performance Obligations The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied as of June 30, 2024: Remainder of 2024 2025 2026 2027 2028 Total Estimated coal revenues (1) $ 47,905 $ — $ 12,000 $ — $ — $ 59,905 (1)

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The following tables summarize the changes to accumulated other comprehensive loss during the six months ended June 30, 2024 and 2023: Balance January 1, 2024 Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance June 30, 2024 Employee benefit costs $ (40,587) $ (9,442) $ 1,709 $ (48,320) Balance January 1, 2023 Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance June 30, 2023 Employee benefit costs $ (12,162) $ (2,825) $ (904) $ (15,891) The following table summarizes the amounts reclassified from accumulated other comprehensive loss and the Condensed Consolidated Statements of Operations line items affected by reclassification during the three and six months ended June 30, 2024 and 2023: Details about accumulated other comprehensive loss components Amounts reclassified from accumulated other comprehensive loss Affected line item in the Condensed Consolidated Statements of Operations Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Employee benefit costs: Amortization of net actuarial loss (gain) (1) $ 1,232 $ (535) $ 2,196 $ (1,162) Miscellaneous expense, net Income tax (expense) benefit (273) 119 (487) 258 Income tax expense Total, net of income tax $ 959 $ (416) $ 1,709 $ (904) (1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit costs for certain employee benefit plans. Refer to Note 12.

Net Income Per Share

Net Income Per Share	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Net Income Per Share	Net Income Per Share The number of shares used to calculate basic net 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 effect of potentially dilutive securities outstanding during the period, which is determined by the application of the treasury stock method. When applying the treasury stock method, anti-dilution generally occurs when the exercise prices or unrecognized compensation cost per share are higher than the Company’s average stock price during an applicable period. For the three and six months ended June 30, 2024, 26,573 and 13,287 securities, respectively, were excluded from the computation of dilutive net income per common share because they would have been anti-dilutive. For the three and six months ended June 30, 2023, 7,441 and 3,721 securities, respectively, were excluded from the computation of dilutive net income per common share because they would have been anti-dilutive. The following table presents the net income per common share for the three and six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Basic Net income $ 58,909 $ 181,355 $ 185,904 $ 452,126 Weighted average common shares outstanding - basic 13,013,684 14,362,072 13,007,905 14,814,099 Net income per common share - basic $ 4.53 $ 12.63 $ 14.29 $ 30.52 Diluted Weighted average common shares outstanding - basic 13,013,684 14,362,072 13,007,905 14,814,099 Dilutive effect of warrants — 135,436 — 146,870 Dilutive effect of stock options — 1,933 — 1,966 Dilutive effect of other stock-based instruments 97,326 411,192 165,898 448,059 Weighted average common shares outstanding - diluted 13,111,010 14,910,633 13,173,803 15,410,994 Net income per common share - diluted $ 4.49 $ 12.16 $ 14.11 $ 29.34

Inventories, net

Inventories, net	6 Months Ended
	Jun. 30, 2024
Inventory Disclosure [Abstract]
Inventories, net	Inventories, net Inventories, net consisted of the following: June 30, 2024 December 31, 2023 Raw coal $ 47,896 $ 52,508 Saleable coal 111,837 120,000 Materials, supplies and other, net 62,082 58,836 Total inventories, net $ 221,815 $ 231,344

Capital Stock

Capital Stock	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Capital Stock	Capital Stock Share Repurchase Program The total authorization to repurchase the Company’s stock under the existing common share repurchase program adopted by the Company’s Board of Directors (the “Board”) on March 4, 2022 is $1,500,000. As of June 30, 2024, the Company had repurchased an aggregate of 6,630,535 shares under the plan for an aggregate purchase price of approximately $1,098,916 (comprised of $1,098,717 of share repurchases and $199 of related fees). The Company has also accrued a stock repurchase excise tax of $4,652 related to the share repurchase program as of June 30, 2024, which is recorded in treasury stock at cost.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: June 30, 2024 December 31, 2023 Wages and benefits $ 61,962 $ 62,811 Workers’ compensation 10,467 10,482 Black lung 10,687 10,687 Taxes other than income taxes 32,241 31,236 Asset retirement obligations 41,108 38,915 Dividend payable 334 2,342 Freight accrual 16,791 8,461 Other 9,279 12,578 Total accrued expenses and other current liabilities $ 182,869 $ 177,512

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2024
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: June 30, 2024 December 31, 2023 Notes payable and other $ 3,910 $ 5,097 Financing leases 4,654 5,277 Total long-term debt 8,564 10,374 Less current portion (3,263) (3,582) Long-term debt, net of current portion $ 5,301 $ 6,792 ABL Agreement On October 27, 2023, the Company, along with certain of its directly and indirectly owned subsidiaries (the “Borrowers”), entered into a credit agreement (the “ABL Agreement”) with Regions Bank, as lender, swingline lender, letter of credit (“LC”) issuer, administrative agent, collateral agent, and lead arranger, along with ServisFirst Bank and Texas Capital Bank, as joint lead arrangers and the other lenders party thereto. The ABL Agreement includes an asset-based revolving credit facility (the “ABL Facility”) which allows the Company to borrow cash or obtain LCs, on a revolving basis, in an aggregate amount of up to $155,000. Availability under the ABL Facility is calculated monthly and fluctuates based on qualifying amounts of coal inventory, trade accounts receivable, and in certain circumstances specified amounts of cash. The ABL Facility matures on October 27, 2027. As of June 30, 2024 and December 31, 2023, the Company had no amounts borrowed and $59,410 and $60,896 LCs outstanding under the ABL Facility, respectively. The ABL Agreement contains negative and affirmative covenants and requires the Company to maintain minimum Liquidity, as defined in the ABL Agreement, of $75,000. The Company is in compliance with all covenants under the ABL Agreement as of June 30, 2024.

Asset Retirement Obligations

Asset Retirement Obligations	6 Months Ended
	Jun. 30, 2024
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The following table summarizes the changes in asset retirement obligations for the six months ended June 30, 2024: Total asset retirement obligations at December 31, 2023 $ 205,424 Accretion for the period 12,400 Sites added during the period 5,381 Revisions in estimated cash flows (1) 6,503 Expenditures for the period (12,786) Total asset retirement obligations at June 30, 2024 216,922 Less current portion (2) (41,108) Long-term portion $ 175,814 (1) The revisions in estimated cash flows resulted primarily from changes in mine plans and reclamation timing. (2) Included within Accrued expenses and other current liabilities on the Company’s Condensed Consolidated Balance Sheets. Refer to Note 7.

Fair Value of Financial Instrum

Fair Value of Financial Instruments and Fair Value Measurements	6 Months Ended
	Jun. 30, 2024
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, restricted cash, deposits, trade accounts payable, notes payable and other, financing leases, and accrued expenses and other current liabilities approximate fair value as of June 30, 2024 and December 31, 2023 due to the short maturity of these instruments. The following tables set 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 June 30, 2024 and December 31, 2023. 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. June 30, 2024 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Trading securities $ 42,196 $ — $ 42,196 $ — December 31, 2023 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Trading securities $ 40,597 $ — $ 40,597 $ — The following methods and assumptions were used to estimate the fair values of the assets and liabilities in the tables above: Level 2 Fair Value Measurements Trading Securities - Typically includes U.S. government securities. The fair values 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.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the six months ended June 30, 2024, the Company recorded income tax expense of $19,443 on income before income taxes of $205,347. The income tax expense differs from the expected statutory amount primarily due to the permanent impact of stock compensation, percentage depletion, and foreign-derived intangible income deductions, partially offset by the impact of non-deductible compensation and state income taxes, net of federal impact. For the six months ended June 30, 2023, the Company recorded income tax expense of $76,009 on income before income taxes of $528,135. The income tax expense differs from the expected statutory amount primarily due to the permanent impact of percentage depletion and foreign-derived intangible income deductions, partially offset by the impact of state income taxes, net of federal impact.

Employee Benefit Plans

Employee Benefit Plans	6 Months Ended
	Jun. 30, 2024
Compensation Related Costs [Abstract]
Employee Benefit Plans	Employee Benefit Plans The components of net periodic benefit cost other than the service cost component for black lung are included in the line item miscellaneous expense, net in the Condensed Consolidated Statements of Operations. Pension The following table details the components of the net periodic benefit cost for pension obligations: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Interest cost $ 6,066 $ 6,028 $ 11,815 $ 11,986 Expected return on plan assets (4,713) (5,514) (10,455) (10,998) Amortization of net actuarial loss 566 228 864 365 Net periodic benefit cost $ 1,919 $ 742 $ 2,224 $ 1,353 During the three months ended June 30, 2024, an annual census data actuarial revaluation of pension obligations was performed, which resulted in an increase in the liability for pension obligations of approximately $12,135 with the offset to accumulated other comprehensive loss and a slight increase in net periodic benefit cost to be recognized subsequent to the revaluation date. An annual census data actuarial revaluation of pension obligations was also performed during the three months ended June 30, 2023, which resulted in an increase in the liability for pension obligations of approximately $3,630 with the offset to accumulated other comprehensive loss and a slight increase in net periodic benefit cost to be recognized subsequent to the revaluation date. The expected long-term rate of return on assets of the pension plan is utilized for the determination of the net periodic benefit cost. During the three months ended June 30, 2024, the Company updated the expected long-term rate of return on plan assets from 6.20% to 5.70% based on a weighted basis of the beginning and more recently assumed rate as the pension plan’s target allocation was updated to 50% equity securities and 50% fixed income funds in the interim period. The Company expects to pay $12,320 in minimum required contributions to the pension plan in 2024. Black Lung The following table details the components of the net periodic benefit cost for black lung obligations: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Service cost $ 601 $ 513 $ 1,202 $ 1,026 Interest cost 1,307 1,165 2,614 2,330 Expected return on plan assets (13) (13) (26) (26) Amortization of net actuarial loss (gain) 721 (708) 1,442 (1,416) Net periodic benefit cost $ 2,616 $ 957 $ 5,232 $ 1,914 Defined Contribution and Profit Sharing Plans During the three months ended June 30, 2024, the Company’s matching contributions under the Alpha Metallurgical Resources 401(k) Retirement Savings Plan were suspended due to weak market conditions at that time.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions There were no material related party transactions for the six months ended June 30, 2024 or 2023.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2024
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. In addition, the Company leases mineral interests and surface rights from landowners under various terms and royalty rates. Coal royalty expense was $37,404 and $45,523 for the three months ended June 30, 2024 and 2023, respectively. Coal royalty expense was $81,232 and $97,024 for the six months ended June 30, 2024 and 2023, respectively. Other Commitments The Company has outstanding unconditional purchase obligations, including an estimated $33,000 in the remainder of 2024 for funding of Dominion Terminal Associates (“DTA”). Under the terms of its partnership related agreements with respect to its investment in DTA, the Company is required to fund its proportionate share of DTA’s ongoing operating and capital costs. In November 2023, the Company, together with DTA management announced that DTA needs additional capital investment to maximize functionality and minimize downtime due to mechanical issues. Beyond the Company’s share of routine operating costs, it expects to invest up to an incremental $25,000 per year for infrastructure and equipment upgrades at DTA over the next 6 years. In addition, to mitigate the risk of shipment delays during the upgrade period, in April 2024, the Company entered into a 3-year agreement which allows for the loading of 1,200 to 2,000 tons of coal annually at a third party terminal in Newport News, VA. The uses of the Company’s 2024 funding of DTA include routine operating and capital costs and infrastructure and equipment upgrades. 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. (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 LCs, 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 LCs to collateralize certain obligations and commitments. As of June 30, 2024, the Company had $59,410 LCs outstanding under the ABL Facility. As of June 30, 2024, the Company had outstanding surety bonds with a total face amount of $179,918 to secure various obligations and commitments. To secure the Company’s reclamation-related obligations, the Company has $34,194 of collateral in the form of restricted cash and restricted investments supporting these obligations as of June 30, 2024. 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 LCs, 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 the 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 bonds. Amounts included in restricted cash provide collateral to secure the following obligations: June 30, 2024 December 31, 2023 Workers’ compensation and black lung obligations $ 109,260 $ 104,998 Reclamation-related obligations 727 685 Financial payments and other performance obligations 9,120 10,235 Total restricted cash $ 119,107 $ 115,918 Amounts included in restricted investments provide collateral to secure the following obligations: June 30, 2024 December 31, 2023 Workers’ compensation obligations $ 3,262 $ 2,514 Reclamation-related obligations 33,467 33,173 Financial payments and other performance obligations 5,467 4,910 Total restricted investments (1) $ 42,196 $ 40,597 (1) Classified as long-term trading securities as of June 30, 2024 and December 31, 2023. Amounts included in deposits provide collateral to secure the following obligations: June 30, 2024 December 31, 2023 Workers’ compensation obligations $ 4,500 $ 4,500 Financial payments and other performance obligations — 32 Other operating agreements 847 850 Total deposits 5,347 5,382 Less current portion — (32) Total deposits, net of current portion (1) $ 5,347 $ 5,350 (1) Included within Other non-current assets on the Company’s Condensed Consolidated Balance Sheets. 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 was contingent, however, upon the Company’s providing collateral of $65,700 to secure certain of its black lung obligations. This proposed collateral requirement would have been 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. In February 2021, the U.S. Department of Labor (“DOL”) withdrew its Federal Register notice seeking comments on its bulletin describing its new method of calculating collateral requirements. The DOL removed the bulletin from its website in May 2021. On February 10, 2022, a telephone conference was held with DCMWC and DOL decision makers wherein the Company presented facts and arguments in support of its appeal. No ruling has been made on the appeal, but during the call the Company indicated that it would be willing to allocate an additional $10,000 in collateral. If the Company’s appeal is unsuccessful, the Company may be required to provide additional LCs 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 additional collateral. In January 2023, the DOL proposed for public comment new regulations which, if adopted, would substantially increase the collateral required to secure self-insured federal black lung obligations (the “2023 Proposed Regulations”). Under the proposed 120% minimum collateral requirement, the Company estimates it could be required to provide approximately $80,000 to $100,000 of collateral to secure certain of its black lung obligations. It is unclear when this regulation will become effective; however, the Company will continue to monitor developments. A significant increase in these collateral obligations could have a materially adverse effect on the Company’s liquidity. Supreme Court’s Decision on the Chevron Deference Standard The United States Supreme Court's decision in Loper Bright Enterprises v. Raimondo, issued on June 28, 2024, eliminated a 40-year old precedent of judicial deference to regulatory agencies' interpretation of federal laws. Federal agencies such as the DOL and EPA have relied on this now-overturned principle, known as “Chevron deference” in defense of various regulations. Although the Court's decision does not explicitly affect any prior agency decisions, regulations made final in the future, such as the DOL's 2023 Proposed Regulations, which have not yet been adopted, may be subject to more intense scrutiny by the courts if they are challenged by any affected party. For example, on July 18, 2024, the Fifth Circuit Court of Appeals directed the lower District Court to reconsider its dismissal of a lawsuit challenging a DOL rule that permits retirement plan fiduciaries to consider environmental, social and governance factors when selecting investments. In the case of State of Utah v. Su, et al., the Court of Appeals stated that in order to determine whether the DOL exceeded its statutory authority, “given the upended legal landscape,” the District Court needed to reassess the merits of the plaintiffs' challenge to the DOL rule. In view of this new “upended legal” landscape, it is uncertain whether the 2023 Proposed Regulations will be challenged after it is finalized and enacted and if so, the extent, if any, the Supreme Court's decision in Loper may impact such a challenge. (d) Legal Proceedings Certain of our subsidiaries are involved in litigation in which the plaintiffs assert violations of the Fair Labor Standards Act due to alleged failure to compensate for time required for “donning” and “doffing” equipment and claim consequent effects upon the calculation of overtime rates and pay. The plaintiffs seek collective action certification. We continue to evaluate the potential effects of this litigation upon the Company. Although we cannot reasonably estimate a range of potential exposure at this time, it is possible that the effects of this litigation upon our liquidity and results of operations could be materially adverse. In addition, the Company is party to other 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 the 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	6 Months Ended
	Jun. 30, 2024
Segment Reporting [Abstract]
Segment Information	Segment Information As a result of the closure of Slabcamp, the Company’s last remaining thermal mine, in August 2023, the Company changed its method of allocating certain corporate level income and expense items among its operating segments starting in 2024. Certain expenses not previously allocated to operating segments (e.g. selling, general and administrative expenses) began to be allocated. Certain other income or expense items previously allocated to operating segments began to be fully allocated to the Company’s primary Met reportable segment. For comparability purposes, prior period segment information has been recast to conform to the current year presentation. The Company’s mining operations are located within the Central Appalachian coal basin in Virginia and West Virginia. The Company’s strategic focus is on the production of metallurgical quality coal for sale to the steel industry. The Company’s reportable segment, Met, is comprised of the Company’s mining complexes which produce, as a primary product, metallurgical quality coal and thermal coal as a byproduct. The All Other category included the Company’s former CAPP – Thermal operating segment which was comprised of the Company’s mining complexes which produced, as a primary product, thermal quality coal. Segment operating results are regularly reviewed by the Chief Operating Decision Maker (“CODM”), who is the Chief Executive Officer of the Company. Segment information and reconciliations to consolidated amounts for the three and six months ended June 30, 2024 and 2023 are as follows: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Coal revenues - Met $ 800,130 $ 833,974 $ 1,661,413 $ 1,720,981 Other revenues - Met 3,839 4,564 6,628 9,101 Total revenues - Met $ 803,969 $ 838,538 $ 1,668,041 $ 1,730,082 Coal revenues - All Other — 19,833 — 39,524 Total revenues $ 803,969 $ 858,371 $ 1,668,041 $ 1,769,606 No asset information has been disclosed as the CODM does not regularly review asset information by segment. A reconciliation of net income to Adjusted EBITDA for the three and six months ended June 30, 2024 and 2023 is as follows: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Net income $ 58,909 $ 181,355 $ 185,904 $ 452,126 Interest expense 1,101 1,856 2,187 3,576 Interest income (4,140) (2,754) (8,111) (4,272) Income tax expense 5,278 33,598 19,443 76,009 Depreciation, depletion, and amortization 43,380 32,226 84,081 61,649 Non-cash stock compensation expense 3,535 3,645 6,304 6,679 Accretion on asset retirement obligations 6,257 6,376 12,400 12,753 Amortization of acquired intangibles, net 1,675 2,192 3,350 4,389 Adjusted EBITDA $ 115,995 $ 258,494 $ 305,558 $ 612,909 Adjusted EBITDA - Met $ 115,995 $ 257,887 $ 305,558 $ 607,933 Adjusted EBITDA - All Other — 607 — 4,976 Total Adjusted EBITDA $ 115,995 $ 258,494 $ 305,558 $ 612,909 The Company markets produced, processed and purchased coal to customers in the United States and in international markets. Revenue is tracked within the Company’s accounting records based on the product destination. The following tables present additional information on our revenues and top customers: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Total coal revenues $ 800,130 $ 853,807 $ 1,661,413 $ 1,760,505 Total revenues $ 803,969 $ 858,371 $ 1,668,041 $ 1,769,606 Export coal revenues $ 646,860 $ 616,572 $ 1,348,161 $ 1,294,703 Export coal revenues as % of total coal revenues 81 % 72 % 81 % 74 % Countries with export coal revenue exceeding 10% of total revenues India, Brazil India, Brazil India, Brazil India, Brazil Top customer as % of total revenues 16 % 12 % 16 % 12 % Top 10 customers as % of total revenues 78 % 71 % 78 % 72 % Number of customers exceeding 10% of total revenues 3 2 3 4 As of June 30, 2024 2023 Number of customers exceeding 10% of total trade accounts receivable, net 2 2

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net income	$ 58,909	$ 126,995	$ 181,355	$ 270,771	$ 185,904	$ 452,126

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Jun. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Business and Basis of Present_2

Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Together, the condensed consolidated statements of operations, comprehensive income, 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 Income,” “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 six months ended June 30, 2024 and 2023. All significant intercompany transactions have been eliminated in consolidation.
Reclassifications	Reclassifications
Recent Accounting Guidance	Recent Accounting Guidance Refer to the Recent Accounting Guidance section of Note 2 contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2024
Revenue from Contract with Customer [Abstract]
Schedule of 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 June 30, Six Months Ended June 30, 2024 2023 2024 2023 Export met coal revenues $ 634,176 $ 580,328 $ 1,306,915 $ 1,228,260 Export thermal coal revenues 12,684 36,244 41,246 66,443 Total export coal revenues $ 646,860 $ 616,572 $ 1,348,161 $ 1,294,703 Domestic met coal revenues $ 145,815 $ 225,658 $ 299,110 $ 435,705 Domestic thermal coal revenues 7,455 11,577 14,142 30,097 Total domestic coal revenues $ 153,270 $ 237,235 $ 313,252 $ 465,802 Total met coal revenues $ 779,991 $ 805,986 $ 1,606,025 $ 1,663,965 Total thermal coal revenues 20,139 47,821 55,388 96,540 Total coal revenues $ 800,130 $ 853,807 $ 1,661,413 $ 1,760,505
Schedule of 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 June 30, 2024: Remainder of 2024 2025 2026 2027 2028 Total Estimated coal revenues (1) $ 47,905 $ — $ 12,000 $ — $ — $ 59,905 (1)

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2024
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Loss	The following tables summarize the changes to accumulated other comprehensive loss during the six months ended June 30, 2024 and 2023: Balance January 1, 2024 Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance June 30, 2024 Employee benefit costs $ (40,587) $ (9,442) $ 1,709 $ (48,320) Balance January 1, 2023 Other comprehensive income (loss) before reclassifications Amounts reclassified from accumulated other comprehensive loss Balance June 30, 2023 Employee benefit costs $ (12,162) $ (2,825) $ (904) $ (15,891) The following table summarizes the amounts reclassified from accumulated other comprehensive loss and the Condensed Consolidated Statements of Operations line items affected by reclassification during the three and six months ended June 30, 2024 and 2023: Details about accumulated other comprehensive loss components Amounts reclassified from accumulated other comprehensive loss Affected line item in the Condensed Consolidated Statements of Operations Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Employee benefit costs: Amortization of net actuarial loss (gain) (1) $ 1,232 $ (535) $ 2,196 $ (1,162) Miscellaneous expense, net Income tax (expense) benefit (273) 119 (487) 258 Income tax expense Total, net of income tax $ 959 $ (416) $ 1,709 $ (904) (1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit costs for certain employee benefit plans. Refer to Note 12.

Net Income Per Share (Tables)

Net Income Per Share (Tables)	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Schedule of Net Income Per Common Share, Basic and Diluted	The following table presents the net income per common share for the three and six months ended June 30, 2024 and 2023: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Basic Net income $ 58,909 $ 181,355 $ 185,904 $ 452,126 Weighted average common shares outstanding - basic 13,013,684 14,362,072 13,007,905 14,814,099 Net income per common share - basic $ 4.53 $ 12.63 $ 14.29 $ 30.52 Diluted Weighted average common shares outstanding - basic 13,013,684 14,362,072 13,007,905 14,814,099 Dilutive effect of warrants — 135,436 — 146,870 Dilutive effect of stock options — 1,933 — 1,966 Dilutive effect of other stock-based instruments 97,326 411,192 165,898 448,059 Weighted average common shares outstanding - diluted 13,111,010 14,910,633 13,173,803 15,410,994 Net income per common share - diluted $ 4.49 $ 12.16 $ 14.11 $ 29.34

Inventories, net (Tables)

Inventories, net (Tables)	6 Months Ended
	Jun. 30, 2024
Inventory Disclosure [Abstract]
Schedule of Inventories, Net	Inventories, net consisted of the following: June 30, 2024 December 31, 2023 Raw coal $ 47,896 $ 52,508 Saleable coal 111,837 120,000 Materials, supplies and other, net 62,082 58,836 Total inventories, net $ 221,815 $ 231,344

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following: June 30, 2024 December 31, 2023 Wages and benefits $ 61,962 $ 62,811 Workers’ compensation 10,467 10,482 Black lung 10,687 10,687 Taxes other than income taxes 32,241 31,236 Asset retirement obligations 41,108 38,915 Dividend payable 334 2,342 Freight accrual 16,791 8,461 Other 9,279 12,578 Total accrued expenses and other current liabilities $ 182,869 $ 177,512

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2024
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt consisted of the following: June 30, 2024 December 31, 2023 Notes payable and other $ 3,910 $ 5,097 Financing leases 4,654 5,277 Total long-term debt 8,564 10,374 Less current portion (3,263) (3,582) Long-term debt, net of current portion $ 5,301 $ 6,792

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	6 Months Ended
	Jun. 30, 2024
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Changes in Asset Retirement Obligations	The following table summarizes the changes in asset retirement obligations for the six months ended June 30, 2024: Total asset retirement obligations at December 31, 2023 $ 205,424 Accretion for the period 12,400 Sites added during the period 5,381 Revisions in estimated cash flows (1) 6,503 Expenditures for the period (12,786) Total asset retirement obligations at June 30, 2024 216,922 Less current portion (2) (41,108) Long-term portion $ 175,814 (1) The revisions in estimated cash flows resulted primarily from changes in mine plans and reclamation timing. (2) Included within Accrued expenses and other current liabilities on the Company’s Condensed Consolidated Balance Sheets. Refer to Note 7.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments and Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables set 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 June 30, 2024 and December 31, 2023. 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. June 30, 2024 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Trading securities $ 42,196 $ — $ 42,196 $ — December 31, 2023 Total Fair Value Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Trading securities $ 40,597 $ — $ 40,597 $ —

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2024
Compensation Related Costs [Abstract]
Schedule of Net Periodic Benefit Cost	The following table details the components of the net periodic benefit cost for pension obligations: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Interest cost $ 6,066 $ 6,028 $ 11,815 $ 11,986 Expected return on plan assets (4,713) (5,514) (10,455) (10,998) Amortization of net actuarial loss 566 228 864 365 Net periodic benefit cost $ 1,919 $ 742 $ 2,224 $ 1,353 The following table details the components of the net periodic benefit cost for black lung obligations: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Service cost $ 601 $ 513 $ 1,202 $ 1,026 Interest cost 1,307 1,165 2,614 2,330 Expected return on plan assets (13) (13) (26) (26) Amortization of net actuarial loss (gain) 721 (708) 1,442 (1,416) Net periodic benefit cost $ 2,616 $ 957 $ 5,232 $ 1,914

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Restricted Cash Deposits	Amounts included in restricted cash provide collateral to secure the following obligations: June 30, 2024 December 31, 2023 Workers’ compensation and black lung obligations $ 109,260 $ 104,998 Reclamation-related obligations 727 685 Financial payments and other performance obligations 9,120 10,235 Total restricted cash $ 119,107 $ 115,918
Schedule of Restricted Investments and Deposit Assets	Amounts included in restricted investments provide collateral to secure the following obligations: June 30, 2024 December 31, 2023 Workers’ compensation obligations $ 3,262 $ 2,514 Reclamation-related obligations 33,467 33,173 Financial payments and other performance obligations 5,467 4,910 Total restricted investments (1) $ 42,196 $ 40,597 (1) Classified as long-term trading securities as of June 30, 2024 and December 31, 2023. Amounts included in deposits provide collateral to secure the following obligations: June 30, 2024 December 31, 2023 Workers’ compensation obligations $ 4,500 $ 4,500 Financial payments and other performance obligations — 32 Other operating agreements 847 850 Total deposits 5,347 5,382 Less current portion — (32) Total deposits, net of current portion (1) $ 5,347 $ 5,350 (1) Included within Other non-current assets on the Company’s Condensed Consolidated Balance Sheets.

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2024
Segment Reporting [Abstract]
Schedule of Segment Operating Results and Capital Expenditures	Segment information and reconciliations to consolidated amounts for the three and six months ended June 30, 2024 and 2023 are as follows: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Coal revenues - Met $ 800,130 $ 833,974 $ 1,661,413 $ 1,720,981 Other revenues - Met 3,839 4,564 6,628 9,101 Total revenues - Met $ 803,969 $ 838,538 $ 1,668,041 $ 1,730,082 Coal revenues - All Other — 19,833 — 39,524 Total revenues $ 803,969 $ 858,371 $ 1,668,041 $ 1,769,606 Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Total coal revenues $ 800,130 $ 853,807 $ 1,661,413 $ 1,760,505 Total revenues $ 803,969 $ 858,371 $ 1,668,041 $ 1,769,606 Export coal revenues $ 646,860 $ 616,572 $ 1,348,161 $ 1,294,703 Export coal revenues as % of total coal revenues 81 % 72 % 81 % 74 % Countries with export coal revenue exceeding 10% of total revenues India, Brazil India, Brazil India, Brazil India, Brazil Top customer as % of total revenues 16 % 12 % 16 % 12 % Top 10 customers as % of total revenues 78 % 71 % 78 % 72 % Number of customers exceeding 10% of total revenues 3 2 3 4 As of June 30, 2024 2023 Number of customers exceeding 10% of total trade accounts receivable, net 2 2
Schedule of Reconciliation of Net Income to Adjusted EBITDA	A reconciliation of net income to Adjusted EBITDA for the three and six months ended June 30, 2024 and 2023 is as follows: Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Net income $ 58,909 $ 181,355 $ 185,904 $ 452,126 Interest expense 1,101 1,856 2,187 3,576 Interest income (4,140) (2,754) (8,111) (4,272) Income tax expense 5,278 33,598 19,443 76,009 Depreciation, depletion, and amortization 43,380 32,226 84,081 61,649 Non-cash stock compensation expense 3,535 3,645 6,304 6,679 Accretion on asset retirement obligations 6,257 6,376 12,400 12,753 Amortization of acquired intangibles, net 1,675 2,192 3,350 4,389 Adjusted EBITDA $ 115,995 $ 258,494 $ 305,558 $ 612,909 Adjusted EBITDA - Met $ 115,995 $ 257,887 $ 305,558 $ 607,933 Adjusted EBITDA - All Other — 607 — 4,976 Total Adjusted EBITDA $ 115,995 $ 258,494 $ 305,558 $ 612,909

Revenue - Schedule of Disaggreg

Revenue - Schedule of Disaggregation of Revenue by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 800,130	$ 853,807	$ 1,661,413	$ 1,760,505
Coal
Disaggregation of Revenue [Line Items]
Revenues	800,130	853,807	1,661,413	1,760,505
Coal | Export
Disaggregation of Revenue [Line Items]
Revenues	646,860	616,572	1,348,161	1,294,703
Coal | Domestic
Disaggregation of Revenue [Line Items]
Revenues	153,270	237,235	313,252	465,802
Coal, Met
Disaggregation of Revenue [Line Items]
Revenues	779,991	805,986	1,606,025	1,663,965
Coal, Met | Export
Disaggregation of Revenue [Line Items]
Revenues	634,176	580,328	1,306,915	1,228,260
Coal, Met | Domestic
Disaggregation of Revenue [Line Items]
Revenues	145,815	225,658	299,110	435,705
Coal, Thermal
Disaggregation of Revenue [Line Items]
Revenues	20,139	47,821	55,388	96,540
Coal, Thermal | Export
Disaggregation of Revenue [Line Items]
Revenues	12,684	36,244	41,246	66,443
Coal, Thermal | Domestic
Disaggregation of Revenue [Line Items]
Revenues	$ 7,455	$ 11,577	$ 14,142	$ 30,097

Revenue - Schedule of Performan

Revenue - Schedule of Performance Obligations (Details) $ in Thousands	Jun. 30, 2024 USD ($)
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 59,905
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-07-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 47,905
Estimated coal revenues, satisfaction period	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Estimated coal revenues, satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 12,000
Estimated coal revenues, satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Estimated coal revenues, satisfaction period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Disaggregation of Revenue [Line Items]
Estimated coal revenues	$ 0
Estimated coal revenues, satisfaction period	1 year

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Schedule of Changes to Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 1,573,928	$ 1,429,755
Ending balance	1,643,570	1,566,734
Employee benefit costs
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(40,587)	(12,162)
Other comprehensive income (loss) before reclassifications	(9,442)	(2,825)
Amounts reclassified from accumulated other comprehensive loss	1,709	(904)
Ending balance	$ (48,320)	$ (15,891)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Schedule of Amounts Reclassified (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Employee benefit costs:
Miscellaneous expense, net	$ (3,611)		$ (874)		$ (5,574)	$ (243)
Income tax expense	(5,278)		(33,598)		(19,443)	(76,009)
Net income	58,909	$ 126,995	181,355	$ 270,771	185,904	452,126
Amounts reclassified from accumulated other comprehensive loss | Amortization of net actuarial loss (gain)
Employee benefit costs:
Miscellaneous expense, net	1,232		(535)		2,196	(1,162)
Amounts reclassified from accumulated other comprehensive loss | Employee benefit costs
Employee benefit costs:
Income tax expense	(273)		119		(487)	258
Net income	$ 959		$ (416)		$ 1,709	$ (904)

Net Income Per Share - Narrativ

Net Income Per Share - Narrative (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	26,573	7,441	13,287	3,721

Net Income Per Share - Schedule

Net Income Per Share - Schedule of Net Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Basic
Net income	$ 58,909	$ 126,995	$ 181,355	$ 270,771	$ 185,904	$ 452,126
Weighted average common shares outstanding - basic (in shares)	13,013,684		14,362,072		13,007,905	14,814,099
Net income per common share - basic (in dollars per share)	$ 4.53		$ 12.63		$ 14.29	$ 30.52
Diluted
Weighted average common shares outstanding - basic (in shares)	13,013,684		14,362,072		13,007,905	14,814,099
Dilutive effect of warrants (in shares)	0		135,436		0	146,870
Weighted average common shares outstanding - diluted (in shares)	13,111,010		14,910,633		13,173,803	15,410,994
Net income per common share - diluted (in dollars per share)	$ 4.49		$ 12.16		$ 14.11	$ 29.34
Stock Option
Diluted
Dilutive effect of share-based payment awards (in shares)	0		1,933		0	1,966
Other Stock-Based Instruments
Diluted
Dilutive effect of share-based payment awards (in shares)	97,326		411,192		165,898	448,059

Inventories, net (Details)

Inventories, net (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw coal	$ 47,896	$ 52,508
Saleable coal	111,837	120,000
Materials, supplies and other, net	62,082	58,836
Total inventories, net	$ 221,815	$ 231,344

Capital Stock - Narrative (Deta

Capital Stock - Narrative (Details) - USD ($)	28 Months Ended
	Jun. 30, 2024	Mar. 04, 2022
Equity [Abstract]
Authorized share repurchases		$ 1,500,000,000
Number of shares repurchased (in shares)	6,630,535
Total share repurchase price	$ 1,098,916,000
Value of shares repurchased	1,098,717,000
Shares repurchased, fees	199,000
Stock repurchase program exercise tax	$ 4,652,000

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Wages and benefits	$ 61,962	$ 62,811
Workers’ compensation	10,467	10,482
Black lung	10,687	10,687
Taxes other than income taxes	32,241	31,236
Asset retirement obligations	41,108	38,915
Dividend payable	334	2,342
Freight accrual	16,791	8,461
Other	9,279	12,578
Total accrued expenses and other current liabilities	$ 182,869	$ 177,512

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Debt Disclosure [Abstract]
Notes payable and other	$ 3,910	$ 5,097
Financing leases	4,654	5,277
Total long-term debt	8,564	10,374
Less current portion	(3,263)	(3,582)
Long-term debt, net of current portion	$ 5,301	$ 6,792

Long-Term Debt - ABL Agreement

Long-Term Debt - ABL Agreement (Details) - ABL Facility - USD ($)	Jun. 30, 2024	Dec. 31, 2023	Oct. 27, 2023
Debt Instrument [Line Items]
Amounts borrowed	$ 0	$ 0
Letters of credit outstanding	$ 59,410,000	$ 60,896,000
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 155,000,000
Minimum liquidity threshold			$ 75,000,000

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Total asset retirement obligations at December 31, 2023			$ 205,424
Accretion for the period	$ 6,257	$ 6,376	12,400	$ 12,753
Sites added during the period			5,381
Revisions in estimated cash flows			6,503
Expenditures for the period			(12,786)
Total asset retirement obligations at June 30, 2024	216,922		216,922		$ 205,424
Less current portion	(41,108)		(41,108)		(38,915)
Long-term portion	$ 175,814		$ 175,814		$ 166,509

Fair Value of Financial Instr_3

Fair Value of Financial Instruments and Fair Value Measurements - Schedule of Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Trading securities	$ 42,196	$ 40,597
Quoted Prices in Active Markets (Level 1)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Trading securities	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Trading securities	42,196	40,597
Significant Unobservable Inputs (Level 3)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Trading securities	$ 0	$ 0

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 5,278	$ 33,598	$ 19,443	$ 76,009
Income before income taxes	$ 64,187	$ 214,953	$ 205,347	$ 528,135

Employee Benefit Plans - Compon

Employee Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 6,066	$ 6,028	$ 11,815	$ 11,986
Expected return on plan assets	(4,713)	(5,514)	(10,455)	(10,998)
Amortization of net actuarial loss (gain)	566	228	864	365
Net periodic benefit cost	1,919	742	2,224	1,353
Black Lung
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	601	513	1,202	1,026
Interest cost	1,307	1,165	2,614	2,330
Expected return on plan assets	(13)	(13)	(26)	(26)
Amortization of net actuarial loss (gain)	721	(708)	1,442	(1,416)
Net periodic benefit cost	$ 2,616	$ 957	$ 5,232	$ 1,914

Employee Benefit Plans- Narrati

Employee Benefit Plans- Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Increase in liability for pension obligations	$ 12,135		$ 3,630
Pension
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets ( as a percent )	5.70%	6.20%
Expected minimum required contributions	$ 12,320
Pension | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation ( as percentage )	50%
Pension | Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Target allocation ( as percentage )	50%

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) tonOfCoal in Thousands, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2024 tonOfCoal	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Jan. 31, 2023 USD ($)	Feb. 10, 2022 USD ($)	Feb. 21, 2020 USD ($)	Feb. 20, 2020 USD ($)
Long-term Purchase Commitment [Line Items]
Arrangement, term	3 years
Black Lung
Long-term Purchase Commitment [Line Items]
Collateral for black lung obligations								$ 10,000	$ 65,700	$ 2,600
Surety Bond
Long-term Purchase Commitment [Line Items]
Outstanding surety bonds		$ 179,918		$ 179,918
Reclamation-Related Obligations | Collateral Pledged
Long-term Purchase Commitment [Line Items]
Restricted cash, restricted investments, and deposits		34,194		34,194
ABL Facility
Long-term Purchase Commitment [Line Items]
Letters of credit outstanding		59,410		59,410		$ 60,896
Minimum
Long-term Purchase Commitment [Line Items]
Number of tons of coal allowed to be loaded | tonOfCoal	1,200
Minimum | Black Lung
Long-term Purchase Commitment [Line Items]
Collateral for black lung obligations							$ 80,000
Maximum
Long-term Purchase Commitment [Line Items]
Number of tons of coal allowed to be loaded | tonOfCoal	2,000
Maximum | Black Lung
Long-term Purchase Commitment [Line Items]
Collateral for black lung obligations							$ 100,000
DTA Funding
Long-term Purchase Commitment [Line Items]
Minimum royalty obligations, remainder of fiscal year- 2024		33,000		33,000
Minimum royalty obligations, year one		25,000		25,000
Minimum royalty obligations, year two		25,000		25,000
Minimum royalty obligations, year three		25,000		25,000
Minimum royalty obligations, year four		25,000		25,000
Minimum royalty obligations, year five		25,000		25,000
Minimum royalty obligations, after year five		25,000		25,000
Coal
Long-term Purchase Commitment [Line Items]
Coal royalty expense		$ 37,404	$ 45,523	$ 81,232	$ 97,024

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Restricted Cash Deposits (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Long-term Purchase Commitment [Line Items]
Total restricted cash	$ 119,107	$ 115,918
Workers’ compensation and black lung obligations
Long-term Purchase Commitment [Line Items]
Total restricted cash	109,260	104,998
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total restricted cash	727	685
Financial payments and other performance obligations
Long-term Purchase Commitment [Line Items]
Total restricted cash	$ 9,120	$ 10,235

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Restricted Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Long-term Purchase Commitment [Line Items]
Total restricted investments	$ 42,196	$ 40,597
Workers’ compensation obligations
Long-term Purchase Commitment [Line Items]
Total restricted investments	3,262	2,514
Reclamation-related obligations
Long-term Purchase Commitment [Line Items]
Total restricted investments	33,467	33,173
Financial payments and other performance obligations
Long-term Purchase Commitment [Line Items]
Total restricted investments	$ 5,467	$ 4,910

Commitments and Contingencies_4

Commitments and Contingencies - Schedule of Cash Deposits Held by Third Parties (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Long-term Purchase Commitment [Line Items]
Total deposits	$ 5,347	$ 5,382
Less current portion	0	(32)
Total deposits, net of current portion	5,347	5,350
Workers’ compensation obligations
Long-term Purchase Commitment [Line Items]
Total deposits	4,500	4,500
Financial payments and other performance obligations
Long-term Purchase Commitment [Line Items]
Total deposits	0	32
Other operating agreements
Long-term Purchase Commitment [Line Items]
Total deposits	$ 847	$ 850

Segment Information - Schedule

Segment Information - Schedule of Segment Information and Reconciliations to Consolidated Amounts (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Coal revenues	$ 800,130	$ 853,807	$ 1,661,413	$ 1,760,505
Other revenues	3,839	4,564	6,628	9,101
Total revenues	803,969	858,371	1,668,041	1,769,606
All Other
Segment Reporting Information [Line Items]
Coal revenues	0	19,833	0	39,524
Met | Operating Segments
Segment Reporting Information [Line Items]
Coal revenues	800,130	833,974	1,661,413	1,720,981
Other revenues	3,839	4,564	6,628	9,101
Total revenues	$ 803,969	$ 838,538	$ 1,668,041	$ 1,730,082

Segment Information -Schedule o

Segment Information -Schedule of Reconciliation of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting, Other Significant Reconciling Item [Line Items]
Net income	$ 58,909	$ 181,355	$ 185,904	$ 452,126
Interest expense	1,101	1,856	2,187	3,576
Interest income	(4,140)	(2,754)	(8,111)	(4,272)
Income tax expense	5,278	33,598	19,443	76,009
Depreciation, depletion, and amortization	43,380	32,226	84,081	61,649
Non-cash stock compensation expense	3,535	3,645	6,304	6,679
Accretion on asset retirement obligations	6,257	6,376	12,400	12,753
Amortization of acquired intangibles, net	1,675	2,192	3,350	4,389
Adjusted EBITDA	115,995	258,494	305,558	612,909
Operating Segments | Met
Segment Reporting, Other Significant Reconciling Item [Line Items]
Adjusted EBITDA	115,995	257,887	305,558	607,933
All Other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Adjusted EBITDA	$ 0	$ 607	$ 0	$ 4,976

Segment Information - Schedul_2

Segment Information - Schedule of Revenue from External Customers (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) customer	Jun. 30, 2023 USD ($) customer	Jun. 30, 2024 USD ($) customer	Jun. 30, 2023 USD ($) customer
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 800,130	$ 853,807	$ 1,661,413	$ 1,760,505
Total revenues	803,969	858,371	1,668,041	1,769,606
Export Coal Revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 646,860	$ 616,572	$ 1,348,161	$ 1,294,703
Revenues | Geographic Concentration Risk | Export Coal Revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)	81%	72%	81%	74%
Revenues | Customer Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of customers exceeding 10% of total trade accounts receivable, net | customer	3	2	3	4
Revenues | Customer Concentration Risk | Top Customer
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)	16%	12%	16%	12%
Revenues | Customer Concentration Risk | Top 10 Customers
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)	78%	71%	78%	72%
Accounts Receivable | Customer Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of customers exceeding 10% of total trade accounts receivable, net | customer			2	2