Commitments and Contingencies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Surety Bonds Outstanding	$ 586,400
Letters of credit outstanding	95,300
Cash collateral for surety bond	5,600
Contribution to fund asset retirement obligations	20,000
Long-term asset retirement obligation	40,000	$ 20,000
Asset retirement obligations
Loss Contingencies [Line Items]
Reclamation-related obligations	215,500
Surety Bonds Outstanding	500,300
Letters of credit outstanding	20,000
Cash collateral for surety bond	600
Contribution to fund asset retirement obligations	20,000
Long-term asset retirement obligation	$ 40,000