Equity method investment - Financail information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 29, 2020	Feb. 29, 2020	Feb. 28, 2019
Summarizes on Equity Method Investment
Share of loss on equity investment		$ (178)	$ 0
February 29, 2020, equity method investment	$ 175,822	175,822
Summarized Financial Information, Income Statement
Amortization		42	37
General and administrative expense		651	$ 492
Ambler Metals LLC
Schedule of Equity Method Investments [Line Items]
Operating loss	400
Summarizes on Equity Method Investment
February 11, 2020, fair value ascribed to Ambler Metals interest	176,000
Share of loss on equity investment	(178)
February 29, 2020, equity method investment	175,822	175,822
Summarized Financial Information, Balance Sheet
Current assets: Cash, deposits and prepaid expenses	145,049	145,049
Non - current assets: Property, equipment and mineral properties	31,454	31,454
Current liabilities: Accounts payable and accrued liabilities	(517)	(517)
Non - current liabilities: Lease obligation	(91)	(91)
Net assets	175,895	$ 175,895
Summarized Financial Information, Income Statement
Amortization	12
Mineral properties expense	167
General and administrative expense	219
Interest income	(43)
Comprehensive loss	$ 355