Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Cash Flows from Operating Activities:
Net Income (Loss)	$ (74,235)	$ 255,584
Adjustments to Reconcile Net (Loss) Income to Net Cash Provided by Operating Activities:
Depreciation, Depletion and Amortization	441,825	165,173
Gain on Sale of Assets	(6,159)	(6,960)
Stock-Based Compensation	35,943	9,406
Loss on Debt Extinguishment	11,680	0
Deferred Income Taxes	(49,650)	360
Loss from Equity Method Investments	12,841	905
Other Adjustments to Net (Loss) Income	3,294	(276)
Changes in Operating Assets:
Accounts and Notes Receivable	(35,767)	15,420
Inventories	(4,091)	(28,461)
Other Current Assets	(24,360)	1,844
Changes in Other Assets	26,768	(1,479)
Changes in Operating Liabilities:
Accounts Payable	(63,460)	4,298
Other Operating Liabilities	(14,058)	(8,887)
Payments on Asset Retirement Obligations	(25,094)	(21,379)
Changes in Other Liabilities	(37,035)	(30,468)
Net Cash Provided by Operating Activities	198,442	355,080
Cash Flows from Investing Activities:
Capital Expenditures	(203,304)	(137,148)
Proceeds from Sales of Assets	6,514	7,320
Proceeds from Sales of Short-Term Investments	80,165	44,075
Purchases of Short-Term Investments	(4,802)	(43,265)
Net Cash and Restricted Cash Acquired from Merger	368,726	0
Purchase of Arch Tax-Exempt Bonds	(98,225)	0
Investments in DTA	(10,640)	0
Other Investing Activity	(6,834)	(5,682)
Net Cash Provided by (Used in) Investing Activities	131,600	(134,700)
Cash Flows from Financing Activities:
Payments on Finance Lease Obligations	(8,910)	(8,258)
Proceeds from Long-Term Debt	114,439	0
Payments on Other Debt	(12,412)	(905)
Shares Withheld for Taxes	(14,068)	(5,540)
Repurchases of Common Stock	(202,591)	(70,879)
Debt-Related Financing Fees	(20,477)	0
Payments of Excise Tax on Share Repurchases	(934)	0
Dividends and Dividend Equivalents Paid	(21,050)	(8,451)
Net Cash Used in Financing Activities	(166,003)	(94,033)
Net Increase in Cash and Cash Equivalents and Restricted Cash	164,039	126,347
Cash and Cash Equivalents and Restricted Cash at Beginning of Period	447,542	243,268
Cash and Cash Equivalents and Restricted Cash at End of Period	611,581	369,615
Non-Cash Investing and Financing Activities:
Equipment Financing	91,638	3,248
Equity Issued as Consideration for Merger	$ 2,481,368	$ 0