Asset Retirement and Reclamation Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2012
Asset retirement and reclamation liabilities	$ 2,979
Summary of activity in the Velardena Operations ARO
ARO, Beginning balance	2,839
Accretion expense	59	$ 55
ARO, Ending balance	2,979
Velardena properties
Asset retirement and reclamation liabilities	2,966	2,655	$ 1,900
Summary of activity in the Velardena Operations ARO
ARO, Beginning balance	2,825	2,660
Changes in estimates, and other	82	(60)
Accretion expense	59	55
ARO, Ending balance	$ 2,966	$ 2,655