Acquisitions - JDS Silver (Details) - JDS Silver Holdings Ltd. shares in Thousands	1 Months Ended
	Oct. 31, 2017 USD ($) shares
Business Acquisition [Line Items]
Shares issued | shares	4,200
Cash	$ 153,194,000
Contingent consideration, liability	47,705,000
Cash consideration	100,000,000
Total purchase price	236,906,000
Assets:
Receivables and other assets	6,828,000
Property, plant, and equipment	29,943,000
Mining properties, net	288,464,000
Total assets acquired	325,235,000
Liabilities:
Accounts payable and accrued liabilities	13,077,000
Asset retirement obligation	6,982,000
Debt and capital lease	20,149,000
Deferred income taxes	48,121,000
Total liabilities assumed	88,329,000
Net assets acquired	236,906,000
Common Stock
Business Acquisition [Line Items]
Common shares issued (value)	$ 36,007,000
Common shares issued (in shares) | shares	4,191,679
Price per common share issued (UDS per share)	$ 8,590