Asset Retirement Obligation and Reclamation Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2012	Mar. 31, 2012
Asset retirement and reclamation liabilities	$ 2,434,000	$ 2,434,000
Summary of activity in the Velardena Operations ARO
ARO, Beginning balance	2,434,000
Accretion expense	196,000	193,000
ARO, Ending balance	2,495,000	2,434,000
Velardena properties
Asset retirement and reclamation liabilities	2,380,000	2,480,000	$ 1,900,000	$ 3,500,000
Amortization expense related to the ARC	4,000
Summary of activity in the Velardena Operations ARO
ARO, Beginning balance	2,380,000	2,480,000
Changes in estimates, and other	(128,000)	(293,000)
Accretion expense	196,000	193,000
ARO, Ending balance	2,448,000	2,380,000
El Quevar Project
ARO arising in the period	$ 50,000	$ 50,000