Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Cash Flows from Operating Activities:
Net Income (Loss)	$ 21,044	$ (69,277)
Adjustments to Reconcile Net Income (Loss) to Net Cash Provided by (Used in) Operating Activities:
Depreciation, Depletion and Amortization	146,295	121,556
Gain on Sale of Assets	(6,765)	(5,817)
Stock-Based Compensation	6,176	36,094
Loss on Debt Extinguishment	0	11,680
Deferred Income Taxes	(294)	(4,193)
Loss from Equity Method Investments	3,951	2,477
Other Adjustments to Net Income (Loss)	1,486	574
Changes in Operating Assets:
Accounts and Notes Receivable	(2,976)	(94,369)
Inventories	6,730	15,382
Other Current Assets	4,230	(21,998)
Changes in Other Assets	2,267	21,774
Changes in Operating Liabilities:
Accounts Payable	(17,436)	(54,048)
Other Operating Liabilities	(17,389)	(35,227)
Payments on Asset Retirement Obligations	(10,413)	(6,182)
Changes in Other Liabilities	(17,506)	(28,064)
Net Cash Provided by (Used in) Operating Activities	119,400	(109,638)
Cash Flows from Investing Activities:
Capital Expenditures	(73,097)	(64,822)
Proceeds from Sales of Assets	9,211	6,003
Proceeds from Sales of Short-Term Investments	0	80,165
Purchases of Short-Term Investments	0	(4,802)
Net Cash and Restricted Cash Acquired from Merger	0	368,726
Purchase of Arch Tax-Exempt Bonds	0	(98,225)
Investments in DTA	(6,847)	(1,496)
Other Investing Activity	(9,102)	(2,538)
Net Cash (Used in) Provided by Investing Activities	(79,835)	283,011
Cash Flows from Financing Activities:
Payments on Finance Lease Obligations	(7,210)	(2,795)
Proceeds from Long-Term Debt Issuance	0	114,439
Payments on Other Debt	(1,713)	(10,831)
Shares Withheld for Taxes	(1,646)	(14,068)
Repurchases of Common Stock	(41,923)	(101,259)
Debt-Related Financing Fees	0	(16,381)
Dividends and Dividend Equivalents Paid	(5,105)	(10,695)
Net Cash Used in Financing Activities	(57,597)	(41,590)
Net (Decrease) Increase in Cash, Cash Equivalents and Restricted Cash	(18,032)	131,783
Cash, Cash Equivalents and Restricted Cash at Beginning of Period	601,162	447,542
Cash, Cash Equivalents and Restricted Cash at End of Period	583,130	579,325
Non-Cash Investing and Financing Activities:
Equipment Financing	80,880	39,150
Equity Issued as Consideration for Merger	$ 0	$ 2,481,368