Income and Mining Taxes - Income and Mining Taxes Paid (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income Tax Paid, Federal, after Refund Received	$ 0	$ 700	$ 0
Income Taxes Paid, Net	178,466	45,100	35,000
South Dakota
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income Tax Paid, State and Local, after Refund Received	15,098	10,800	5,000
All other states
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income Tax Paid, State and Local, after Refund Received	895	0	0
Mexico
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income Tax Paid, Foreign, after Refund Received	161,041	31,700	29,800
Canada
Income Tax Paid, by Individual Jurisdiction [Line Items]
Income Tax Paid, Foreign, after Refund Received	$ 1,432	$ 1,900	$ 200