Commitments and Contigencies (Details Textual)	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($) t milestone	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Oct. 02, 2014 USD ($)
Business Acquisition [Line Items]
Palmarejo Gold Stream Agreement, Deferred Revenue Unamortized Balance	$ 11,600,000	$ 11,600,000
Silvertip acquisition contingent consideration	49,817,000	$ 49,817,000		$ 25,000,000
Palmarejo gold production royalty
Business Acquisition [Line Items]
Production to be sold, percent						50.00%
Price per ounce under agreement						$ 800
Aggregate deposit to be received						$ 22,000,000.0
JDS Silver Holdings Ltd.
Business Acquisition [Line Items]
Silvertip acquisition contingent consideration					$ 50,000,000.0
Long-term Purchase Commitment, Milestones | milestone		2
JDS Silver Holdings Ltd. | First Milestone
Business Acquisition [Line Items]
Silvertip acquisition contingent consideration					25,000,000.0
Sustained minim and milling per day (in tones) | t		1,000
JDS Silver Holdings Ltd. | Second Milestone
Business Acquisition [Line Items]
Silvertip acquisition contingent consideration					25,000,000.0
Maximum payment					$ 25,000,000.0
Tonnes of Resource Added | t		3,700,000
Amount of resource required (in tonnes) | t		300,000
Commitment amount per resource amount reached		$ 5,000,000.0
Minimum Resource Tonnes Milestone | t		2,500,000
Silvertip [Member] | Permit Contingent Consideration
Business Acquisition [Line Items]
Contingent consideration, liability	25,000,000.0	$ 25,000,000.0
Silvertip [Member] | Resource Contingent Consideration
Business Acquisition [Line Items]
Contingent consideration, liability	24,800,000	24,800,000
Kensington
Business Acquisition [Line Items]
Revenue liability	10,600,000	$ 10,600,000	$ 25,000,000.0
Revenue recognized	$ 14,700,000