SIGNIFICANT ACCOUNTING POLICIES - Reconciliation between Basic and Diluted Net Income per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2020
Basis of Presentation [Abstract]
Net income (loss)	$ 200,101	$ 23,523	$ 143,837
Net income attributable to G-III Apparel Group, Ltd.	$ 200,593	$ 23,545	$ 143,837
Basic net income (loss) per share:
Basic common shares	48,426	48,242	48,209
Net income (loss) per common share (in dollar per shares)	$ 4.14	$ 0.49	$ 2.98
Diluted net income (loss) per share:
Basic common shares	48,426	48,242	48,209
Diluted restricted stock awards and stock options	1,090	539	686
Diluted common shares	49,516	48,781	48,895
Diluted net income (loss) per share (in dollars per share)	$ 4.05	$ 0.48	$ 2.94