Asset Retirement and Reclamation Liabilities (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2012	Mar. 31, 2012
Asset retirement and reclamation liabilities (Note 12)	$ 2,839	$ 3,166	$ 2,839
Summary of activity in the Velardena Operations ARO
ARO, Beginning balance		2,839
Accretion expense		249	225
ARO, Ending balance	2,839	3,166	2,839
Velardena Properties
Asset retirement and reclamation liabilities (Note 12)	2,825	3,156	2,825	$ 1,900	$ 3,500
Summary of activity in the Velardena Operations ARO
ARO, Beginning balance		2,825	2,660
Changes in estimates, and other	200	82	(60)
Accretion expense		249	225
ARO, Ending balance	$ 2,825	$ 3,156	$ 2,825