Income and Mining Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Deferred tax liabilities:
Property, plant, and equipment	$ 59,006	$ 5,529
Mineral properties	261,588	0
Other long-term liabilities	10,103	0
Deferred tax liabilities, total	330,697	5,529
Deferred tax assets:
Net operating loss carryforwards	288,122	304,244
Deferred Tax Assets, Mineral Properties	0	50,824
Mining Royalty Tax	53,529	8,314
Capital loss carryforwards	17,089	16,910
Asset retirement obligation	58,905	49,306
Accrued expenses	15,323	18,117
Tax credit carryforwards	12,274	13,620
Deferred Tax Assets, Other	0	30,612
Deferred Tax Assets, Gross	445,242	491,947
Valuation allowance	(303,518)	(490,044)
Deferred tax assets, total	141,724	1,903
Net deferred tax liabilities	$ 188,973	$ 3,626