ASSET RETIREMENT AND ENVIRONMENTAL REMEDIATION OBLIGATIONS - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Dec. 31, 2025
Asset Retirement Obligation and Accrual for Environmental Loss Contingencies [Roll Forward]
Obligations at beginning of period	$ 336,768
Liabilities settled	(7,038)
Accretion expense	951
Change in estimate	4,233
Total obligations at end of period	334,914
Less current obligations at end of period	(143,798)
Long-term obligations at end of period	$ 191,116	$ 200,267

Asset Retirement Obligation And Accrual For Environmental Loss Contingencies

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Asset Retirement Obligation And Accrual For Environmental Loss Contingencies, Accretion Expense

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Asset Retirement Obligation And Accrual For Environmental Loss Contingencies, Current

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Asset Retirement Obligation And Accrual For Environmental Loss Contingencies, Liabilities Settled

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Asset Retirement Obligation And Accrual For Environmental Loss Contingencies, Noncurrent

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Asset Retirement Obligation And Accrual For Environmental Loss Contingencies, Revision Of Estimate

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Asset Retirement Obligation And Accrual For Environmental Loss Contingencies, Roll Forward Analysis

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