QUARTERLY FINANCIAL DATA (UNAUDITED) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 527,428	$ 909,865	$ 473,884	$ 432,965	$ 514,323	$ 812,330	$ 424,010	$ 366,192	$ 2,344,142	$ 2,116,855	$ 1,718,231
Gross profit	178,814	337,057	168,340	154,427	183,490	295,252	148,384	130,133	838,638	757,259	585,009
Net income attributable to G-III (in dollars)	$ 7,964	$ 87,156	$ 12,453	$ 6,760	$ 22,220	$ 80,615	$ 6,236	$ 1,290	$ 114,333	$ 110,361	$ 77,360
Net income per common share
Basic (in dollars per share)	$ 0.17	$ 1.92	$ 0.28	$ 0.15	$ 0.49	$ 1.80	$ 0.15	$ 0.03	$ 2.52	$ 2.55	$ 1.90
Diluted (in dollars per share)	$ 0.17	$ 1.87	$ 0.27	$ 0.15	$ 0.48	$ 1.76	$ 0.14	$ 0.03	$ 2.46	$ 2.48	$ 1.85