Property, Plant and Equipment, Net (Details)			1 Months Ended					3 Months Ended		9 Months Ended
	May 02, 2017 USD ($)	Mar. 31, 2017 USD ($)	Oct. 31, 2017 USD ($)	May 31, 2017 USD ($)	Oct. 31, 2016 USD ($)	Aug. 31, 2016 USD ($) item	Apr. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Property, plant and equipment
Property, plant and equipment, gross								$ 34,109,000		$ 34,109,000		$ 34,751,000
Less: Accumulated depreciation & amortization								(25,540,000)		(25,540,000)		(25,516,000)
Property, plant and equipment, net								8,569,000		8,569,000		9,235,000
Payments to acquire property								5,000	$ 15,000	5,000	$ 36,000
Proceeds from sale of assets										750,000	898,000
Related party receivable												643,000
Gain on sale of equipment										605,000	$ 1,522,000
Mineral properties
Property, plant and equipment
Property, plant and equipment, gross								9,352,000		9,352,000		9,352,000
Exploration properties
Property, plant and equipment
Property, plant and equipment, gross								2,518,000		2,518,000		2,518,000
Royalty properties
Property, plant and equipment
Property, plant and equipment, gross								200,000		200,000		200,000
Buildings
Property, plant and equipment
Property, plant and equipment, gross								4,221,000		4,221,000		4,386,000
Mining equipment and machinery
Property, plant and equipment
Property, plant and equipment, gross								15,996,000		15,996,000		16,351,000
Other furniture and equipment
Property, plant and equipment
Property, plant and equipment, gross								957,000		957,000		952,000
Asset retirement cost
Property, plant and equipment
Property, plant and equipment, gross								865,000		865,000		$ 992,000
Velardena properties | Sale, not discontinued operations | Sale of Equipment
Property, plant and equipment
Gain on sale of equipment										105,000
Celaya | Electrum
Property, plant and equipment
Payments to acquire property									$ 200,000
Interest in joint venture									60.00%		60.00%
Exploration expenditures in first three year of the agreement									$ 2,500,000
Exploration expenditures in second three year of the agreement									$ 2,500,000
Additional interest in joint venture (as a percent)									20.00%		20.00%
Net profit interest									10.00%		10.00%
Celaya | Electrum | Minimum
Property, plant and equipment
Earn-in obligation									$ 500,000
Celaya | Electrum | Maximum
Property, plant and equipment
Interest in joint venture									80.00%		80.00%
Zacatecas Properties | Santacruz | Sale, not discontinued operations
Property, plant and equipment
Proceeds from sale of assets			$ 150,000	$ 300,000	$ 200,000		$ 200,000
Total consideration							$ 1,500,000
Due 18 months after signing agreement			$ 150,000
Due 24 months after signing agreement								$ 500,000		$ 500,000
Minera Inde | Sale, not discontinued operations | Sale of Equipment
Property, plant and equipment
Sale of mining equipments						$ 687,000
Proceeds from sale of assets	$ 750,000	$ 100,000
Net book value of disposals		$ 185,000
Sales price received (as a percent)						10.00%
Interest rate on receivable (as a percent)		10.00%				10.00%
Minera Inde | Velardena properties | Sale, not discontinued operations | Sale of Equipment
Property, plant and equipment
Number of haul trucks sold | item						2
Number of scoop trams sold | item						2
Sale of mining equipments						$ 687,000
Proceeds from sale of assets	$ 750,000	$ 100,000				$ 69,000
Net book value of disposals		$ 185,000
Sales price received (as a percent)						10.00%
Related party receivable						$ 618,000
Interest rate on receivable (as a percent)						10.00%