Significant Accounting Policies (Policies)	6 Months Ended
Jul. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation As used in these financial statements, the term “Company” or “G-III” refers to G-III Apparel Group, Ltd. and its subsidiaries. The Company designs, manufactures and markets an extensive range of apparel, including outerwear, dresses, sportswear, swimwear, women’s suits and women’s performance wear, as well as women’s handbags, footwear, small leather goods, cold weather accessories and luggage. The Company also operates retail stores. The Company consolidates the accounts of all its wholly-owned and majority-owned subsidiaries. KL North America BV (“KLNA”) is a Dutch limited liability company that is a joint venture that is 49% owned by the Company. Kingdom Holdings 1 B.V. (“KH1”) is a Dutch limited liability company that is 19% owned by the Company. These investments are accounted for using the equity method of accounting. All material intercompany balances and transactions have been eliminated. Vilebrequin International SA (“Vilebrequin”), a Swiss corporation that is wholly-owned by the Company, KH1 and KLNA report results on a calendar year basis rather than on the January 31 fiscal year basis used by the Company. The Company’s retail stores report results on a 52/53-week fiscal year. The results for the three and six-month periods ended July 31, 2017 are not necessarily indicative of the results expected for the entire fiscal year, given the recent acquisition and integration of Donna Karan International and the seasonal nature of the Company’s business. The accompanying financial statements included herein are unaudited. All adjustments (consisting of only normal recurring adjustments) necessary for a fair presentation of the financial position, results of operations and cash flows for the interim period presented have been reflected. The accompanying financial statements should be read in conjunction with the financial statements and notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended January 31, 2017 filed with the Securities and Exchange Commission (the “SEC”). The Company’s international subsidiaries use different functional currencies, which are the local selling currency. In accordance with the authoritative guidance, operating assets and liabilities of the Company’s foreign operations are translated from foreign currency into U.S. dollars at period-end rates, while income and expenses are translated at the weighted-average exchange rates for the period. The related translation adjustments are reflected as a foreign currency translation adjustment in accumulated other comprehensive income within stockholders’ equity.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Guidance Issued Being Evaluated for Adoption In July 2017, the FASB issued ASU 2017-11, “Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815): (I) Accounting for Certain Financial Instruments with Down Round Features and (II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception.” This standard is effective for fiscal years and interim periods beginning after December 15, 2018. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance. In May 2017, the FASB issued ASU 2017-09, “Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting.” ASU 2017-09 provides clarification on when modification accounting should be used for changes to the terms or conditions of a share-based payment award. This ASU does not change the accounting for modifications but clarifies that modification accounting guidance should only be applied if there is a change to the value, vesting conditions or award classification and would not be required if the changes are considered non-substantive. The amendments of this ASU are effective for reporting periods beginning after December 15, 2017, with early adoption permitted. The adoption of ASU 2017-09 is not expected to have an impact on the Company’s consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, “Intangibles — Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The purpose of ASU 2017-04 is to simplify the subsequent measurement of goodwill by removing the second step of the two-step impairment test. The amendment should be applied on a prospective basis. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019, including interim periods within that year. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company does not expect ASU 2017-04 to have an impact on its consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” The purpose of ASU 2017-01 is to clarify the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within that year. The amendments in ASU 2017-01 should be applied prospectively on or after the effective date. Early adoption is permitted. The Company does not expect ASU 2017-01 to have an impact on its consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory.” The update requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset upon transfer other than inventory, eliminating the current recognition exception. Prior to the update, GAAP prohibited the recognition of current and deferred income taxes for intra-entity asset transfers until the asset was sold to an outside party. The amendments in this update do not include new disclosure requirements; however, existing disclosure requirements might be applicable when accounting for the current and deferred income taxes for an intra-entity transfer of an asset other than inventory. For public business entities, the amendments in this update are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those fiscal years. The Company does not expect ASU 2016-16 to have an impact on its consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” which clarifies guidance with respect to the classification of eight specific cash flow issues. ASU 2016-15 was issued to reduce diversity in practice and prevent financial statement restatements. Cash flow issues include: debt prepayment or debt extinguishment costs, settlement of zero-coupon bonds, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies and bank-owned life insurance policies, distributions received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. ASU 2016-15 is effective for public business entities for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Under the provision, entities must apply the guidance retrospectively to all periods presented but may apply it prospectively if retrospective application would be impracticable. The Company is currently evaluating the provisions of ASU 2016-15. In April 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing.” The guidance clarifies two aspects of Topic 606: (i) identifying performance obligations and (ii) providing licensing implementation guidance, while retaining the related principles for those areas. Topic 606 includes implementation guidance on (a) contracts with customers to transfer goods and services in exchange for consideration and (b) determining whether an entity’s promise to grant a license provides a customer with either a right to use the entity’s intellectual property (which is satisfied at a point in time) or a right to access the entity’s intellectual property (which is satisfied over time). The amendments in this update are intended to render more detailed implementation guidance with the expectation of reducing the degree of judgment necessary to comply with Topic 606. The FASB continues to clarify this guidance and most recently issued ASU 2016-08, “Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” ASU 2016-12, “Narrow-Scope Improvements and Practical Expedients,” and ASU 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers.” These new standards have the same effective date as ASU 2014-09 and will be effective for public entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). The Company has decided to adopt the pronouncement using a modified retrospective approach. The Company currently believes that the adoption of Topic 606 will primarily impact its wholesale operations segment in the timing of recognition of certain adjustments that are currently recorded in net sales along with reclassifications of certain operating expenses such as cooperative advertising, which are currently recorded in selling, general and administrative expenses but will be recorded as an offset to net sales under the new guidance. The Company believes that the retail operations segment will not be materially impacted by the new guidance, as its retail stores do not currently offer significant loyalty programs to their customers. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” The primary difference between the current requirement under GAAP and ASU 2016-02 is the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases. ASU 2016-02 requires that a lessee recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term (other than leases that meet the definition of a short-term lease). The liability will be equal to the present value of lease payments. The asset will be based on the liability, subject to adjustment, such as for initial direct costs. For income statement purposes, the FASB retained a dual model, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense (similar to current operating leases) while finance leases will result in a front-loaded expense pattern (similar to current capital leases). Classification will be based on criteria that are for the most part similar to those applied in current lease accounting. ASU 2016-02 may be adopted using a modified retrospective transition, and provides for certain practical expedients. Transactions will require application of the new guidance at the beginning of the earliest comparative period presented. The guidance is effective for public entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the potential impact of ASU 2016-02 on its consolidated financial statements. Given the Company’s significant number of leases, the Company expects this standard will result in a significant increase to its long-term assets and liabilities but does not expect it to have a material impact on the Consolidated Statements of Income. The Company expects to adopt the new standard in the first quarter of fiscal 2020. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments — Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” This standard (i) modifies how entities measure equity investments and present changes in the fair value of financial liabilities, (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iii) changes presentation and disclosure requirements and (iv) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early application is permitted. The Company does not expect that the adoption of this ASU will have a significant impact on its statement of operations.

Significant Accounting Policies (Policies)

6 Months Ended

Jul. 31, 2017

As used in these financial statements, the term “Company” or “G-III” refers to G-III Apparel Group, Ltd. and its subsidiaries. The Company designs, manufactures and markets an extensive range of apparel, including outerwear, dresses, sportswear, swimwear, women’s suits and women’s performance wear, as well as women’s handbags, footwear, small leather goods, cold weather accessories and luggage. The Company also operates retail stores.

The Company consolidates the accounts of all its wholly-owned and majority-owned subsidiaries. KL North America BV (“KLNA”) is a Dutch limited liability company that is a joint venture that is 49% owned by the Company. Kingdom Holdings 1 B.V. (“KH1”) is a Dutch limited liability company that is 19% owned by the Company. These investments are accounted for using the equity method of accounting. All material intercompany balances and transactions have been eliminated. Vilebrequin International SA (“Vilebrequin”), a Swiss corporation that is wholly-owned by the Company, KH1 and KLNA report results on a calendar year basis rather than on the January 31 fiscal year basis used by the Company. The Company’s retail stores report results on a 52/53-week fiscal year.

The results for the three and six-month periods ended July 31, 2017 are not necessarily indicative of the results expected for the entire fiscal year, given the recent acquisition and integration of Donna Karan International and the seasonal nature of the Company’s business. The accompanying financial statements included herein are unaudited. All adjustments (consisting of only normal recurring adjustments) necessary for a fair presentation of the financial position, results of operations and cash flows for the interim period presented have been reflected.

The accompanying financial statements should be read in conjunction with the financial statements and notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended January 31, 2017 filed with the Securities and Exchange Commission (the “SEC”).

The Company’s international subsidiaries use different functional currencies, which are the local selling currency. In accordance with the authoritative guidance, operating assets and liabilities of the Company’s foreign operations are translated from foreign currency into U.S. dollars at period-end rates, while income and expenses are translated at the weighted-average exchange rates for the period. The related translation adjustments are reflected as a foreign currency translation adjustment in accumulated other comprehensive income within stockholders’ equity.

Recent Accounting Pronouncements

Accounting Guidance Issued Being Evaluated for Adoption

In July 2017, the FASB issued ASU 2017-11, “Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815): (I) Accounting for Certain Financial Instruments with Down Round Features and (II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception.” This standard is effective for fiscal years and interim periods beginning after December 15, 2018. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance.

In May 2017, the FASB issued ASU 2017-09, “Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting.” ASU 2017-09 provides clarification on when modification accounting should be used for changes to the terms or conditions of a share-based payment award. This ASU does not change the accounting for modifications but clarifies that modification accounting guidance should only be applied if there is a change to the value, vesting conditions or award classification and would not be required if the changes are considered non-substantive. The amendments of this ASU are effective for reporting periods beginning after December 15, 2017, with early adoption permitted. The adoption of ASU 2017-09 is not expected to have an impact on the Company’s consolidated financial statements.

In January 2017, the FASB issued ASU 2017-04, “Intangibles — Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The purpose of ASU 2017-04 is to simplify the subsequent measurement of goodwill by removing the second step of the two-step impairment test. The amendment should be applied on a prospective basis. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019, including interim periods within that year. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company does not expect ASU 2017-04 to have an impact on its consolidated financial statements.

In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business.” The purpose of ASU 2017-01 is to clarify the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within that year. The amendments in ASU 2017-01 should be applied prospectively on or after the effective date. Early adoption is permitted. The Company does not expect ASU 2017-01 to have an impact on its consolidated financial statements.

In October 2016, the FASB issued ASU 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory.” The update requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset upon transfer other than inventory, eliminating the current recognition exception. Prior to the update, GAAP prohibited the recognition of current and deferred income taxes for intra-entity asset transfers until the asset was sold to an outside party. The amendments in this update do not include new disclosure requirements; however, existing disclosure requirements might be applicable when accounting for the current and deferred income taxes for an intra-entity transfer of an asset other than inventory. For public business entities, the amendments in this update are effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those fiscal years. The Company does not expect ASU 2016-16 to have an impact on its consolidated financial statements.

In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” which clarifies guidance with respect to the classification of eight specific cash flow issues. ASU 2016-15 was issued to reduce diversity in practice and prevent financial statement restatements. Cash flow issues include: debt prepayment or debt extinguishment costs, settlement of zero-coupon bonds, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies and bank-owned life insurance policies, distributions received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. ASU 2016-15 is effective for public business entities for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Under the provision, entities must apply the guidance retrospectively to all periods presented but may apply it prospectively if retrospective application would be impracticable. The Company is currently evaluating the provisions of ASU 2016-15.

In April 2016, the FASB issued ASU 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing.” The guidance clarifies two aspects of Topic 606: (i) identifying performance obligations and (ii) providing licensing implementation guidance, while retaining the related principles for those areas. Topic 606 includes implementation guidance on (a) contracts with customers to transfer goods and services in exchange for consideration and (b) determining whether an entity’s promise to grant a license provides a customer with either a right to use the entity’s intellectual property (which is satisfied at a point in time) or a right to access the entity’s intellectual property (which is satisfied over time). The amendments in this update are intended to render more detailed implementation guidance with the expectation of reducing the degree of judgment necessary to comply with Topic 606. The FASB continues to clarify this guidance and most recently issued ASU 2016-08, “Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” ASU 2016-12, “Narrow-Scope Improvements and Practical Expedients,” and ASU 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers.” These new standards have the same effective date as ASU 2014-09 and will be effective for public entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). The Company has decided to adopt the pronouncement using a modified retrospective approach. The Company currently believes that the adoption of Topic 606 will primarily impact its wholesale operations segment in the timing of recognition of certain adjustments that are currently recorded in net sales along with reclassifications of certain operating expenses such as cooperative advertising, which are currently recorded in selling, general and administrative expenses but will be recorded as an offset to net sales under the new guidance. The Company believes that the retail operations segment will not be materially impacted by the new guidance, as its retail stores do not currently offer significant loyalty programs to their customers.

In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” The primary difference between the current requirement under GAAP and ASU 2016-02 is the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases. ASU 2016-02 requires that a lessee recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term (other than leases that meet the definition of a short-term lease). The liability will be equal to the present value of lease payments. The asset will be based on the liability, subject to adjustment, such as for initial direct costs. For income statement purposes, the FASB retained a dual model, requiring leases to be classified as either operating or finance. Operating leases will result in straight-line expense (similar to current operating leases) while finance leases will result in a front-loaded expense pattern (similar to current capital leases). Classification will be based on criteria that are for the most part similar to those applied in current lease accounting. ASU 2016-02 may be adopted using a modified retrospective transition, and provides for certain practical expedients. Transactions will require application of the new guidance at the beginning of the earliest comparative period presented. The guidance is effective for public entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the potential impact of ASU 2016-02 on its consolidated financial statements. Given the Company’s significant number of leases, the Company expects this standard will result in a significant increase to its long-term assets and liabilities but does not expect it to have a material impact on the Consolidated Statements of Income. The Company expects to adopt the new standard in the first quarter of fiscal 2020.

In January 2016, the FASB issued ASU 2016-01, “Financial Instruments — Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” This standard (i) modifies how entities measure equity investments and present changes in the fair value of financial liabilities, (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iii) changes presentation and disclosure requirements and (iv) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early application is permitted. The Company does not expect that the adoption of this ASU will have a significant impact on its statement of operations.