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Summary of Significant Accounting Policies (Details) - USD ($) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023 | Aug. 08, 2023 | Mar. 01, 2022
Summary of Significant Accounting Policies Textuals |  |  |  |  |
Corporate Hedging | From time to time, the Company may utilize various types of derivative instruments to manage its exposure to risks in the normal course of business, including (1) foreign currency exchange rate risk and the variability of cash flows associated with forecasted Australian dollar expenditures made in its Australian mining platform and (2) price risk of fluctuating coal prices related to forecasted sales or purchases of coal, or changes in the fair value of a fixed price physical sales contract. These risk management activities are actively monitored for compliance with the Company’s risk management policies. On a limited basis, the Company engages in the direct and brokered trading of coal and freight-related contracts. Except those contracts for which the Company has elected to apply a normal purchases and normal sales exception, all derivative coal trading contracts are accounted for at fair value. |  |  |  |
Income tax provision | $ 8,800,000 | $ 108,800,000 | $ 308,800,000 |  |
Accounts receivable, payment term | 30 days |  |  |  |
Interest costs capitalized | $ 8,000,000.0 | 5,800,000 | 0 |  |
Royalty Expense | $ 311,500,000 | 370,000,000.0 | 448,300,000 |  |
Lease term | 10 years |  |  |  |
Minimum annual production of federal coal mining leases on original amount | 1.00% |  |  |  |
Monthly federal royalties payable from sale using surface mining methods | 12.50% |  |  |  |
Monthly federal royalties payable of production using underground mining methods | 8.00% |  |  |  |
Equity method investment | $ 0 | 0 | 0 |  |
Restructuring charges for voluntary and involuntary workforce reductions | 9,500,000 | 4,400,000 | 3,300,000 |  |
Restructuring charges | 1,100,000 |  |  |  |
Foreign Currency Remeasurement Gains (Losses) | 22,400,000 | (32,300,000) | 5,300,000 |  |
Foreign currency translation adjustment | 3,100,000 | (4,300,000) | 900,000 |  |
Asset impairment charges related to long-lived assets | 0 | $ 0 | $ 0 |  |
Patriot Federal Black Lung, Payment for Settlement |  |  |  | $ 72,000,000.0 |
Patriot Federal Black Lung, Settlement Fees |  |  |  | 4,200,000 |
Patriot Federal Black Lung, Gain (Loss) Due to Settlement |  |  |  | $ 3,900,000 |
Duration fees | 20,800,000 |  |  |  |
Commitment fees | $ 25,900,000 |  |  |  |
OBBBA federal coal royalty rate | 7.00% |  |  |  |
Letter of Credit |  |  |  |  |
Summary of Significant Accounting Policies Textuals |  |  |  |  |
Stated interest rate | 0.75% |  |  |  |
Senior Notes | 3.250% Convertible Senior Notes due March 2028 |  |  |  |  |
Summary of Significant Accounting Policies Textuals |  |  |  |  |
Stated interest rate | 3.25% |  |  |  |
Debt principal amount |  |  |  |  | $ 320,000,000.0
Middlemount |  |  |  |  |
Summary of Significant Accounting Policies Textuals |  |  |  |  |
Ownership percentage of equity method investment | 50.00% |  |  |  |
Minimum | Machinery and equipment | Buildings and improvements |  |  |  |  |
Summary of Significant Accounting Policies Textuals |  |  |  |  |
Useful life | 1 year |  |  |  |
Maximum | Land and coal interests |  |  |  |  |
Summary of Significant Accounting Policies Textuals |  |  |  |  |
Useful life | 31 years |  |  |  |
Maximum | Machinery and equipment | Buildings and improvements |  |  |  |  |
Summary of Significant Accounting Policies Textuals |  |  |  |  |
Useful life | 31 years |  |  |  |

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