Mineral Properties - Guadalupe (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jun. 30, 2020	Sep. 30, 2020	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Mineral properties, Net		$ 2,146		$ 2,146	$ 2,146	$ 2,146
Deferred option gain		2,960		2,960	2,960
Gain (Loss) On Disposal Of Mineral Property Interests, Net				2,568	2,568
Guadalupe De Los Reyes, Mexico | Option Agreement Two
Property, Plant and Equipment [Line Items]
Payments Received In Lieu Of Grant Of Royalty And Back-In Rights		2,100
Aggregate Payments Received To Date Of Sale Price Of Gold Project					4,500
Mineral properties, Net		0		0	0
Deferred option gain		2,892		$ 2,892	$ 2,892
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Subsequent Event [Member]
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project	$ 1,500
Guadalupe De Los Reyes, Mexico | Option Agreement Two | Scenario, Plan
Property, Plant and Equipment [Line Items]
Gain (Loss) On Disposal Of Mineral Property Interests, Net			$ 2,892,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-09-30 | Guadalupe De Los Reyes, Mexico | Option Agreement Two
Property, Plant and Equipment [Line Items]
Sale price of gold/silver project		1,500
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-31 | Guadalupe De Los Reyes, Mexico | Option Agreement Two
Property, Plant and Equipment [Line Items]
Payments Received In Lieu Of Grant Of Royalty And Back-In Rights		1,100,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-31 | Guadalupe De Los Reyes, Mexico | Option Agreement Two
Property, Plant and Equipment [Line Items]
Payments Received In Lieu Of Grant Of Royalty And Back-In Rights		$ 1