Net Income per Common Share - Reconciliation between basic and diluted net income per share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Apr. 30, 2014	Apr. 30, 2013
Earnings Per Share [Abstract]
Net income attributable to G-III	$ 1,290	$ 1,118
Basic net income per share:
Basic common shares	20,488	20,161
Basic net income per share (in dollars per share)	$ 0.06	$ 0.06
Diluted net income per share:
Basic common shares	20,488	20,161
Stock options and restricted stock awards	534	241
Diluted common shares	21,022	20,402
Diluted net income per share (in dollars per share)	$ 0.06	$ 0.05