Share capital - Authorized unlimited common shares, no par value (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended						9 Months Ended	12 Months Ended
	Apr. 25, 2023	Aug. 31, 2023	May 31, 2023	Feb. 28, 2023	Aug. 31, 2022	May 31, 2022	Feb. 28, 2022	Aug. 31, 2023	Nov. 30, 2022
Class of Stock [Line Items]
Unlimited common shares authorized								Unlimited	Unlimited
Common Stock, No Par Value		$ 0						$ 0	$ 0
Private Placement, net of share issue cost, Ascribed value			$ 3,115
Services settled by common shares, Ascribed value		$ 20	$ 35	$ 4
Share capital
Class of Stock [Line Items]
Exercise of options, Number of shares						50,000	31,674
Private Placement, net of share issue cost, Number of shares	5,854,545		5,854,545					5,854,545
Private Placement, net of share issue cost, Ascribed value			$ 3,115					$ 3,115
Restricted share units, Number of shares		248,092	213,463	2,346,366	244,216	110,000	391,332	2,807,921
Restricted share units, Ascribed value								$ 1,780
Deferred share units, Number of shares								415,056
Deferred share units, Ascribed value								$ 468
NovaGold deferred share units conversion, Number of shares		1,130						1,130
NovaGold deferred share units conversion, Ascribed value		$ 3						$ 3
Services settled by common shares, Number of shares		40,816	63,533	7,793				112,142
Services settled by common shares, Ascribed value		$ 20	$ 35	$ 4				$ 60
Joint venture equity contribution (note 3(b)), Number of shares				143,505			31,469	143,505
Joint venture equity contribution (note 3(b)), Ascribed value		$ 111						$ 111
Ending balance, Number of shares outstanding		155,559,334						155,559,334	146,225,035
Beginning balance, Number of shares				146,225,035				146,225,035
Ending balance, Ascribed value		$ 187,715						$ 187,715	$ 182,178
Beginning balance, Ascribed value				$ 182,178				$ 182,178
Contributed surplus.
Class of Stock [Line Items]
NovaGold deferred share units conversion, Ascribed value		$ (3)