Contingencies - Schedule of Contingencies Reserve Balance (Paranthetical) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023		Dec. 31, 2025		Dec. 31, 2024	[1]	Dec. 31, 2022
EPA Notice Letter [Member]
Loss Contingencies [Line Items]
Payment made to settle past cost claims	$ 1,900
New Idria Mercury Mine [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies	$ 13,182	[1]	$ 12,504	[1]	$ 12,425		$ 11,855
Estimated Insurance Recoveries			8,300
New Idria Mercury Mine [Member] | Other Current Liabilities [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies			$ 8,800
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]			Other Accrued Liabilities, Current
New Idria Mercury Mine [Member] | Other Noncurrent Liabilities [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies			$ 3,300
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]			Other Liabilities, Noncurrent
New Idria Mercury Mine [Member] | Accounts Receivable [Member]
Loss Contingencies [Line Items]
Estimated Insurance Recoveries			$ 5,200
New Idria Mercury Mine [Member] | Other Noncurrent Assets [Member]
Loss Contingencies [Line Items]
Estimated Insurance Recoveries			$ 3,100

[1] (1) As of December 31, 2025, Buckhorn has a total ending reserve balance of $12.5 million related to the New Idria Mine, of which $8.8 million is classified in Other current liabilities, $3.3 million in Other liabilities (long-term) and $0.4 million in Accounts payable.