Reclamation and Remediation - Narrative (Details) - USD ($)
$ in Thousands
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Undiscounted reclamation liabilities $ 1,833 $ 1,890 $ 2,003
Asset Retirement Obligation 1,279 1,208 $ 1,105
Exploration reclamation liability 3,112 3,098  
Don David Gold Mine      
Undiscounted reclamation liabilities $ 1,800 1,900  
Reclamation and remediation discount rate 8.00%    
Asset Retirement Obligation $ 1,300 $ 1,200  
Back Forty Project      
Exploration reclamation liability $ 600