Recent Accounting Pronouncements (Detail Textuals) $ / shares in Units, $ in Millions	6 Months Ended
Jul. 31, 2016 USD ($) $ / shares
Accounting Changes And Error Corrections [Abstract]
Recognition of excess tax benefits on adoption of ASU 2016-09 \| $	$ 2.4
Recognition of excess tax benefits per diluted share on adoption of ASU 2016-09 \| $ / shares	$ 0.05

Represents effect of new accounting pronouncement or change in accounting principle effect of change on tax expenses benefit per diluted share.

No definition available.

Name:	giii_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnTaxExpensesBenefitPerDilutedShare
Namespace Prefix:	giii_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration