Acquisitions - Lincoln Hill (Details) - Lincoln Hill - USD ($) shares in Thousands	1 Months Ended
	Nov. 30, 2018	Oct. 31, 2017
Business Acquisition [Line Items]
Common shares issued (value)	$ 18,782,000
Transaction advisory fees and other acquisition costs	246,000
Purchase price	19,028,000
Assets:
Prepaid expenses and other	527,000
Mining properties, net	18,501,000
Net assets acquired	$ 19,028,000
Common Stock
Business Acquisition [Line Items]
Common shares issued (in shares)		4,268,703
Price per common share issued (UDS per share)		$ 4,400