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, 2022	Jul. 31, 2021	Jul. 31, 2022	Jul. 31, 2021
Net Income (Loss) per Common Share
Net income attributable to G-III Apparel Group, Ltd.	$ 36,319	$ 19,168	$ 66,953	$ 45,489
Basic net income (loss) per share:
Basic common shares	47,999	48,476	48,007	48,427
Basic net income (loss) per share (in dollars per share)	$ 0.76	$ 0.40	$ 1.39	$ 0.94
Diluted net income (loss) per share:
Basic common shares	47,999	48,476	48,007	48,427
Diluted restricted stock awards and stock options	1,020	1,047	1,054	1,075
Diluted common shares	49,019	49,523	49,061	49,502
Diluted net income (loss) per share (in dollars per share)	$ 0.74	$ 0.39	$ 1.36	$ 0.92