Document and Entity Information - shares	9 Months Ended
	Oct. 31, 2017	Dec. 01, 2017
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 Common Stock Shares Outstanding		49,080,953
Document Type	10-Q
Document Period End Date	Oct. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3