Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Flows from Operating Activities:
Net Income	$ 286,405	$ 655,892	$ 466,979
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Depreciation, Depletion and Amortization	223,526	241,317	226,878
Stock-Based Compensation	11,350	10,046	7,890
Gain on Sale of Assets	(6,941)	(8,981)	(34,589)
Amortization of Debt Issuance Costs	3,750	5,468	8,314
Loss on Debt Extinguishment	0	2,725	5,623
Deferred Income Taxes	8,820	14,121	49,387
Other Adjustments to Net Income	(2,795)	(3,418)	3,880
Changes in Operating Assets:
Trade and Other Receivables	(2,233)	36,922	(52,577)
Inventories	(8,018)	(21,540)	(3,020)
Other Current Assets	(444)	(4,673)	2,883
Changes in Other Assets	7,936	(11,725)	(26,063)
Changes in Operating Liabilities:
Accounts Payable	4,570	11,449	39,235
Commodity Derivatives, net Liability	0	(15,142)	(37,062)
Other Operating Liabilities	(25,420)	3,063	14,453
Changes in Other Liabilities	(24,116)	(57,575)	(21,221)
Net Cash Provided by Operating Activities	476,390	857,949	650,990
Cash Flows from Investing Activities:
Capital Expenditures	(177,988)	(167,791)	(171,506)
Proceeds from Sales of Assets	7,396	4,255	21,538
Investments in Mining-Related Activities	(4,620)	(7,481)	0
Proceeds from Sales of Short-Term Investments	100,982	122,658	0
Purchases of Short-Term Investments	(66,963)	(200,870)	0
Other Investing Activity	(23,838)	(10,203)	7,790
Net Cash Used in Investing Activities	(165,031)	(259,432)	(142,178)
Cash Flows from Financing Activities:
Payments on Finance Lease Obligations	(10,518)	(25,335)	(24,511)
Payments on Other Debt	(955)	(981)	(840)
Shares Withheld for Taxes	(5,126)	(12,831)	(6,261)
Repurchases of Common Stock	(70,879)	(399,379)	0
Debt Issuance and Financing Fees	0	(2,779)	(7,957)
Payments of Excise Tax on Share Repurchases	(3,747)	0	0
Dividends and Dividend Equivalents Paid	(15,860)	(75,474)	(71,486)
Net Cash Used in Financing Activities	(107,085)	(682,201)	(380,066)
Net Increase (Decrease) in Cash and Cash Equivalents and Restricted Cash	204,274	(83,684)	128,746
Cash and Cash Equivalents and Restricted Cash at Beginning of Period	243,268	326,952	198,206
Cash and Cash Equivalents and Restricted Cash at End of Period	447,542	243,268	326,952
Term Loan A Facility
Cash Flows from Financing Activities:
Payments on Debt	0	0	(41,250)
Term Loan B Facility
Cash Flows from Financing Activities:
Payments on Debt	0	(63,590)	(175,687)
Senior Secured Second Lien Notes due 2025
Cash Flows from Financing Activities:
Payments on Debt	$ 0	$ (101,832)	$ (52,074)