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		9 Months Ended
	Oct. 31, 2024	Oct. 31, 2023	Oct. 31, 2024	Oct. 31, 2023
NET INCOME PER COMMON SHARE
Net income attributable to G-III Apparel Group, Ltd.	$ 114,768	$ 127,640	$ 144,782	$ 147,314
Basic net income per share:
Basic common shares	43,885	45,723	44,640	45,904
Basic net income per share (in dollars per share)	$ 2.62	$ 2.79	$ 3.24	$ 3.21
Diluted net income per share:
Basic common shares	43,885	45,723	44,640	45,904
Dilutive restricted stock unit awards and stock options	1,069	837	1,079	1,088
Diluted common shares	44,954	46,560	45,719	46,992
Diluted net income per share (in dollars per share)	$ 2.55	$ 2.74	$ 3.17	$ 3.13