Asset Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2012
Summary of activity in the Velardena Operations ARO
Beginning balance	$ 2,685
Accretion expense	198	$ 200
Ending balance	2,546	2,685
Velardena properties
Asset Retirement and Reclamation Liabilities
Third party estimated closure plan			$ 1,900
Estimated ARO and ARC recorded at the time of the acquisition	3,500
Amortization expense related to the ARC	200
Summary of activity in the Velardena Operations ARO
Beginning balance	2,582	2,467
Changes in estimates, and other	(300)	(85)
Accretion expense	198	200
Ending balance	2,480	2,582
El Quevar Project
Summary of activity in the Velardena Operations ARO
Beginning balance	100
Ending balance	$ 100	$ 100