Contingencies - Schedule of Contingencies Reserve Balance (Parenthetical) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022		Sep. 30, 2023		Sep. 30, 2022		Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
EPA Notice Letter [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies revision in estimates			$ 1,900
New Idria Mercury Mine [Member]
Loss Contingencies [Line Items]
Amount of insurance refunds	$ 300				$ 400
Reserve balance	$ 10,530	[1]	11,200	[1]	$ 10,530	[1]	$ 12,082	$ 11,855	$ 9,153	$ 8,213
Estimated Insurance Recoveries			6,200
New Idria Mercury Mine [Member] | Other Current Liabilities [Member]
Loss Contingencies [Line Items]
Reserve balance			7,700
New Idria Mercury Mine [Member] | Other Liabilities [Member]
Loss Contingencies [Line Items]
Reserve balance			3,500
New Idria Mercury Mine [Member] | Accounts Receivable [Member]
Loss Contingencies [Line Items]
Estimated Insurance Recoveries			3,200
New Idria Mercury Mine [Member] | Other Noncurrent Assets [Member]
Loss Contingencies [Line Items]
Estimated Insurance Recoveries			$ 3,000

[1] (2) As of September 30, 2023, Buckhorn has a total ending reserve balance of $11.2 million related to the New Idria Mine, of which $7.7 million is classified in Other current liabilities and $3.5 million in Other liabilities (long-term).