Contingencies - Additional Information (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended	156 Months Ended
	Feb. 14, 2023	Sep. 30, 2024	Dec. 31, 2018	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2016	Sep. 30, 2024	Dec. 31, 2023
Loss Contingencies [Line Items]
Other current liabilities		$ 26,536,000		$ 26,536,000			$ 26,536,000	$ 28,472,000
Other liabilities		19,079,000		19,079,000			19,079,000	$ 12,108,000
EPA Notice Letter [Member]
Loss Contingencies [Line Items]
Payments made					$ 1,900,000
New Idria Mercury Mine [Member]
Loss Contingencies [Line Items]
Financial assurance required to be provided to EPA to secure performance			$ 2,000,000
New Almaden Mine (Formerly Referred to as Guadalupe River Watershed) [Member] | Natural Resource Damage Claim [Member]
Loss Contingencies [Line Items]
Total reserve		4,400,000		4,400,000			4,400,000
Other current liabilities		300,000		300,000			300,000
Other liabilities		4,100,000		4,100,000			4,100,000
Expense recognized		$ 0		0
Revised estimated project cost				$ 9,000,000
New Almaden Mine (Formerly Referred to as Guadalupe River Watershed) [Member] | Natural Resource Damage Claim [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Original estimated project costs						$ 3,300,000
New Almaden Mine (Formerly Referred to as Guadalupe River Watershed) [Member] | Natural Resource Damage Claim [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Original estimated project costs						$ 4,400,000
Scepter Company [Member] | Ms.McCartney [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value	$ 30,000
Pending Litigation [Member] | New Idria Mercury Mine [Member] | EPA Notice Letter [Member]
Loss Contingencies [Line Items]
Payments made							13,200,000
Insurance recoveries							5,800,000
Loss contingency, Loss in period							$ 23,000,000