Document and Entity Information - shares	3 Months Ended
	Apr. 30, 2019	Jun. 05, 2019
Document And Entity Information Abstract
Entity Registrant Name	G III APPAREL GROUP LTD /DE/
Entity Central Index Key	0000821002
Current Fiscal Year End Date	--01-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock Shares Outstanding		48,939,190
Document Type	10-Q
Document Period End Date	Apr. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1