EMPLOYEE BENEFIT PLANS - Textuals (Details) - USD ($) $ in Millions	12 Months Ended
Jan. 31, 2024	Jan. 31, 2023	Jan. 31, 2022
EMPLOYEE BENEFIT PLANS [Abstract]
Non-discretionary matching contribution	100.00%
Percentage of employee's compensation matched by employer	3.00%
Employer matching percentage of employee contributions	50.00%
Percentage of additional employee's compensation matched by employer	2.00%
Defined contribution plan, matching contributions	$ 4.3	$ 4.0	$ 0.3

Represents defined contribution plan additional maximum annual contributions per employee percent.

No definition available.

Name:	giii_DefinedContributionPlanAdditionalMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	giii_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage Of Employer Contribution To Match Participant Contribution In Defined Contribution Plan

No definition available.

Name:	giii_PercentageOfEmployerContributionToMatchParticipantContributionInDefinedContributionPlan
Namespace Prefix:	giii_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage employer matches of the employee's percentage contribution matched.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration