Acquisitions - Northern Empire (Details) - Northern Empire Resources Corp. $ in Thousands, shares in Millions	1 Months Ended
	Oct. 31, 2018 USD ($) shares
Business Acquisition [Line Items]
Purchase price	$ 73,593
Fair value of existing investment in Northern Empire	7,257
Assets:
Common shares issued (value)	63,887
Transaction advisory fees and other acquisition costs	2,449
Total assets acquired	111,527
Liabilities:
Total liabilities assumed	37,934
Total assets acquired	$ 73,593
Common Stock
Business Acquisition [Line Items]
Common stock conversion ratio	0.1850
Common shares issued (in shares) | shares	12.1