Document and Entity Information - USD ($)	12 Months Ended
	Jan. 31, 2017	Mar. 31, 2017	Jul. 31, 2016
Document And Entity Information Abstract
Entity Registrant Name	G III APPAREL GROUP LTD /DE/
Entity Central Index Key	0000821002
Trading Symbol	giii
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--01-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock Shares Outstanding		48,640,443
Entity Public Float			$ 1,638,155,776
Document Type	10-K
Document Period End Date	Jan. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY