Mineral properties and development costs - Mineral property expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Feb. 29, 2020	Feb. 28, 2019
Mineral property expense	$ 1,545	$ 1,535
Alaska, USA [Member]
Community	137	118
Drilling		0
Engineering	723	357
Environmental	99	165
Geochemistry and geophysics	12	165
Land and permitting	134	120
Project support	249	226
Other income		(1)
Wages and benefits	191	385
Mineral property expense	$ 1,545	$ 1,535