Commitments and Contingencies (Details) $ in Thousands, T in Millions		12 Months Ended
	May 29, 2020 USD ($)	Dec. 31, 2021 USD ($) T	Dec. 31, 2020 USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
Royalty payment, percentage of net profit		4.00%
Royalty payment, annual advance		$ 120
Royalty payment, additional incremental payment		$ 120
Royalty payment, annual tons mined threshold | T		5.0
Royalty payment, maximum lease payments		$ 7,600
Payments to acquire royalty interests in mining properties		3,000
Proceeds from sale of royalty to Sprott	$ 30,000	$ 0	$ 30,000
Smelter royalty obligation, percentage	1.50%
Royalty obligation, metal price discount rate		5.00%
Royalty obligation
Unrecorded Unconditional Purchase Obligation [Line Items]
Royalty obligation, fair value		$ 154,000	$ 148,400
Other assets, noncurrent
Unrecorded Unconditional Purchase Obligation [Line Items]
Payments to acquire royalty interests in mining properties		$ 600