COMMITMENTS AND CONTINGENCIES - Textuals (Details) $ in Millions, $ in Millions			1 Months Ended	12 Months Ended
	Mar. 14, 2018 CAD ($)	Mar. 14, 2018 USD ($)	Oct. 27, 2017	Jan. 31, 2019 CAD ($)	Jan. 31, 2019 USD ($)	Jan. 31, 2018 USD ($)	Jan. 31, 2017 USD ($)
Commitment And Contingencies [Line Items]
Rent expense					$ 108.2	$ 110.4	$ 84.7
Advertising expense					87.0	104.8	89.5
CBSA
Commitment And Contingencies [Line Items]
Reassessment period to additional duties			90 days
License Agreements
Commitment And Contingencies [Line Items]
Royalty expense					165.7	154.3	139.0
Advertising expense					46.2	$ 43.4	$ 39.2
G-III Apparel Canada ULC
Commitment And Contingencies [Line Items]
Value of bond issued for prepayments of additional duties	$ 26.9	$ 20.9
Deferred expenses				$ 10.5	$ 8.0