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
	Aug. 31, 2024	May 31, 2024	Feb. 29, 2024	Aug. 31, 2023	May 31, 2023	Feb. 28, 2023	Aug. 31, 2024	Nov. 30, 2023
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	$ 30	$ 30	$ 30	$ 20	$ 35	$ 4
Number of shares, issued	160,567,514						160,567,514	155,559,334
Common Stock [Member]
Class of Stock [Line Items]
Private Placement, net of share issue cost, Number of shares					5,854,545
Private Placement, net of share issue cost, Ascribed value					$ 3,115
Restricted share units, Number of shares	326,020	353,347	3,633,065	248,092	213,463	2,346,366	4,312,432
Restricted share units, Ascribed value							$ 2,112
NovaGold deferred share units conversion, Number of shares				1,130
NovaGold deferred share units conversion, Ascribed value				$ 3
Services settled by common shares, Number of shares	54,706	66,511	64,368	40,816	63,533	7,793	185,585
Services settled by common shares, Ascribed value	$ 30	$ 30	$ 30	$ 20	$ 35	$ 4	$ 90
Joint venture equity contribution (note 3(a)), Number of shares			143,507			143,505	143,507
Joint venture equity contribution (note 3(a)), Ascribed value	$ 112						$ 112
Ending balance, Number of shares outstanding	160,567,514						160,567,514	155,925,990
Beginning balance, Number of shares			155,925,990				155,925,990
Ending balance, Ascribed value	$ 190,200						$ 190,200	$ 187,886
Beginning balance, Ascribed value			$ 187,886				$ 187,886
Contributed surplus.
Class of Stock [Line Items]
NovaGold deferred share units conversion, Ascribed value				$ (3)