Document and Entity Information - USD ($)	12 Months Ended
	Jan. 31, 2019	Mar. 25, 2019	Jul. 31, 2018
Document And Entity Information Abstract
Entity Registrant Name	G III APPAREL GROUP LTD /DE/
Entity Central Index Key	0000821002
Trading Symbol	giii
Current Fiscal Year End Date	--01-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 2,069,366,515
Entity Common Stock Shares Outstanding		48,708,410
Document Type	10-K
Document Period End Date	Jan. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY