NET INCOME PER COMMON SHARE - Reconciliation between basic and diluted net income per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2025	Jul. 31, 2024	Jul. 31, 2025	Jul. 31, 2024
NET INCOME PER COMMON SHARE
Net income (loss) attributable to G-III Apparel Group, Ltd.	$ 10,939	$ 24,212	$ 18,698	$ 30,014
Basic net income (loss) per share:
Basic common shares	42,777	44,569	43,254	45,022
Basic net income per share (in dollars per share)	$ 0.26	$ 0.54	$ 0.43	$ 0.67
Diluted net income (loss) per share:
Basic common shares	42,777	44,569	43,254	45,022
Dilutive restricted stock unit awards and stock options	1,442	914	1,541	1,083
Diluted common shares	44,219	45,483	44,795	46,105
Diluted net income per share (in dollars per share)	$ 0.25	$ 0.53	$ 0.42	$ 0.65