Consolidated Entities, Joint Ventures and Investments - Additional Information (Detail) ₨ in Millions			1 Months Ended																				3 Months Ended						6 Months Ended	12 Months Ended
	Dec. 02, 2020 USD ($)	Apr. 26, 2011 USD ($)	Mar. 31, 2021 USD ($)	Feb. 28, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jul. 31, 2019 USD ($)	Jul. 31, 2018 USD ($)	Apr. 30, 2018	Oct. 31, 2016 USD ($)	Jul. 31, 2016 USD ($)	Feb. 28, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Jan. 31, 2014 USD ($)	Oct. 31, 2013 USD ($)	Jul. 31, 2013 USD ($)	Feb. 28, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2012 USD ($)	Mar. 31, 2010 USD ($)	May 31, 2009 USD ($) shares	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) Multiplier	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) Multiplier	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jun. 30, 2018	Jun. 30, 2017 USD ($)	Nov. 30, 2013 USD ($)	Sep. 30, 2013 USD ($)	Jun. 30, 2012 INR (₨)	Dec. 31, 2009
Schedule Of Investments [Line Items]
Payments to acquire ownership interest																														$ 2,750,000
Payment received upon sale interest in subsidiary																														2,750,000
Redeemable non-controlling interest																							$ 24,321,000		$ 33,069,000					$ 24,321,000	$ 33,069,000
Type of Revenue [Extensible List]																														us-gaap:LicenseMember	us-gaap:LicenseMember
Additional equity interest acquisition date																																		2017-02
Investment impairment																														$ 19,607,000	$ 26,613,000
Noncontrolling interest																							26,604,000		27,913,000					26,604,000	27,913,000
Impairment of equity method investment																							2,400,000	$ 17,200,000
Distributions from equity investments																														3,928,000	2,681,000
Lee Cooper And Umbro Brands
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid																																			$ 3,500,000
Percentage of interest sold in equity method investment																																			70.00%
Business acquisition total purchase price																																			$ 24,700,000
Company purchased the Umbro China and Lee Cooper brands																																			24,700,000
Note receivable																																			9,400,000
Adjustments to additional paid in capital of excess purchase price over non-controlling interest																														2,200,000
Lee Cooper And Umbro Brands | Accounts Payable And Accrued Liabilities
Schedule Of Investments [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities																																			5,200,000
Lee Cooper And Umbro Brands | Other Noncurrent Liabilities
Schedule Of Investments [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities																																			5,400,000
Hong Kong MH Umbro International Co. Limited
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid										$ 25,000,000
Business acquisition completion period										4 years
Equity ownership percentage										50.00%
LiNing
Schedule Of Investments [Line Items]
Equity Interest Acquisition Commencement Date									Jun. 30, 2020
Equity Interest Sale Cash Consideration On Commencement Date									$ 5,400,000
Alberta ULC
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid																		$ 76,500,000
Ownership interest acquired																		51.00%
Modern Amusement
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid																			$ 5,000,000
Ownership interest acquired																			51.00%
Hardy Way
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid																						$ 9,000,000
Ownership interest acquired		85.00%																				50.00%
Business acquisition total purchase price		$ 62,000,000																				$ 17,000,000
Business acquisition purchase price, common stock issued, shares | shares																						58,868
Business acquisition purchase price, common stock issued, value																						$ 8,000,000
Hardy Way | Addition capital
Schedule Of Investments [Line Items]
Business acquisition purchase price, common stock issued, value																						$ 1,000,000
Umbro China Limited | Hong Kong MH Umbro International Co. Limited
Schedule Of Investments [Line Items]
Proceeds from sale of interest										$ 2,500,000
Percentage of interest sold										5.00%
Noncontrolling interest																							$ 1,800,000							$ 1,800,000
Reliance Brands Limited
Schedule Of Investments [Line Items]
Additional amount agreed to be contributed as working capital																				$ 500,000																						₨ 25
MG Icon
Schedule Of Investments [Line Items]
Payments to acquire ownership interest																					$ 4,000,000
Ownership interest acquired																					50.00%
Business acquisition total purchase price																					$ 20,000,000
Business consideration payable																					$ 3,000,000
Distributions from equity investments																												$ 23,000,000
Administrative Manager
Schedule Of Investments [Line Items]
Percentage of gross revenue paid monthly as services fee																																				5.00%
Local Manager
Schedule Of Investments [Line Items]
Percentage of gross revenue paid monthly as services fee																																				15.00%
Minimum | LiNing
Schedule Of Investments [Line Items]
Aggregate percentage of interest in newly registered company in Hong Kong									30.00%
Minimum | MG Icon
Schedule Of Investments [Line Items]
Preferred profit distribution to the Company																																$ 23,000,000
Maximum | Hong Kong MH Umbro International Co. Limited
Schedule Of Investments [Line Items]
Aggregate percentage of interest in newly registered company in Hong Kong										50.00%
Maximum | LiNing
Schedule Of Investments [Line Items]
Aggregate percentage of interest in newly registered company in Hong Kong									50.00%
Aggregate Cash Consideration Payment Increase									$ 8,600,000
Pony International, LLC.
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid											$ 37,000,000
Ownership interest acquired											75.00%
Percentage of minority interest in subsidiary											25.00%
Pony International, LLC. | Subsequent Event
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid				$ 2,000,000
Ownership interest acquired				25.00%
Iconix Europe
Schedule Of Investments [Line Items]
Percentage of minority interest in subsidiary															49.00%
Hydraulic IP Holdings
Schedule Of Investments [Line Items]
Business acquisition purchase price, cash paid												$ 6,000,000
Ownership interest acquired												51.00%																								51.00%
Top On International Group, LLC
Schedule Of Investments [Line Items]
Percentage of minority interest in subsidiary												49.00%																								49.00%
Hydraulic IP Holdings LLC | Variable Interest Entity, Primary Beneficiary
Schedule Of Investments [Line Items]
Percentage of company ownership								51.00%
Ownership interest acquired								49.00%
Ownership interest								100.00%
I Brands International L L C
Schedule Of Investments [Line Items]
Percentage of company ownership																							15.00%							15.00%
Investment impairment																																$ 2,500,000
Buffalo International Unlimited Liability Corporation
Schedule Of Investments [Line Items]
Percentage of minority interest in subsidiary																		49.00%
Umbro China Limited
Schedule Of Investments [Line Items]
Percentage of company ownership						100.00%
Payment received upon sale interest in subsidiary																														$ 62,500,000
Gain on sale of interest in subsidiary																														59,600,000
Umbro China Limited | Hong Kong MH Umbro International Co. Limited
Schedule Of Investments [Line Items]
Payments to acquire ownership interest						$ 1,300,000
Ownership interest acquired						5.00%
Danskin China Limited | Li Ning Sports (Hong Kong) Company Ltd
Schedule Of Investments [Line Items]
Percentage of equity ownership interest sold																													10.00%
Sale of ownership interest																													$ 1,600,000
Danskin China Limited | Subsequent Event | Li Ning Sports (Hong Kong) Company Ltd
Schedule Of Investments [Line Items]
Percentage of equity ownership interest sold			10.00%
Sale of ownership interest			$ 1,800,000
Starter China Limited
Schedule Of Investments [Line Items]
Payment received upon sale interest in subsidiary					$ 16,000,000																									16,000,000
Gain on sale of interest in subsidiary																														14,500,000
Starter China Limited | Photosynthesis Holdings, Co. Ltd
Schedule Of Investments [Line Items]
Gain on sale of interest in subsidiary																														$ 14,500,000
Additional percentage of ownership interest sold																											10.00%
Description of completed date of sale																														Company completed the sale of Starter China in September, 2020
Starter China Limited | Photosynthesis Holdings, Co. Ltd | Sale Agreement Over Three-Year Period from January 15, 2020
Schedule Of Investments [Line Items]
Cash consideration from sale of equity interest																											$ 20,000,000
Starter China Limited | Photosynthesis Holdings, Co. Ltd | Sale Agreement Over Three-Year Period from January 16, 2022
Schedule Of Investments [Line Items]
Cash consideration from sale of equity interest																											$ 2,700,000
Percentage of royalty received as consideration																											2.50%
Starter China Limited | Minimum | Photosynthesis Holdings, Co. Ltd
Schedule Of Investments [Line Items]
Percentage of minority interest in subsidiary																											50.00%
Starter China Limited | Maximum | Photosynthesis Holdings, Co. Ltd
Schedule Of Investments [Line Items]
Percentage of minority interest in subsidiary																											60.00%
Lee Cooper China Limited | POS Lee Cooper HK Co. Ltd | Share Purchase Agreement
Schedule Of Investments [Line Items]
Business acquisition total purchase price	$ 16,000,000
Lee Cooper China Limited | Minimum | POS Lee Cooper HK Co. Ltd
Schedule Of Investments [Line Items]
Percentage of minority interest in subsidiary																																						50.00%
Iconix Australia
Schedule Of Investments [Line Items]
Percentage of company ownership							55.00%
Business acquisition purchase price, cash paid							$ 700,000
Ownership interest acquired							5.00%
Percentage of minority interest in subsidiary							45.00%
Redeemable non-controlling interest																							$ 3,000,000							$ 3,000,000
Cash payment for acquisition of assets							$ 5,900,000
Iconix China Holdings Limited
Schedule Of Investments [Line Items]
Additional amount agreed to be contributed as working capital																				2,000,000																						₨ 100
Marcy Media Holdings
Schedule Of Investments [Line Items]
Payment received upon sale interest in subsidiary																									15,000,000
Percentage of minority interest in subsidiary																	5.00%
Cash payment for acquisition of assets																	$ 32,000,000
Impairment charge																										$ 17,000,000
Iconix Lifestyle India Private Limited
Schedule Of Investments [Line Items]
Payment received upon sale interest in subsidiary																				$ 2,000,000
Percentage of interest sold in equity method investment																				50.00%																						50.00%
Receivable for investments sold																				$ 4,000,000
Committed amount receivable period																				48 months
Price for sale of interest in a subsidiary																				$ 6,000,000
Net gain recognized on sale of interest in subsidiary																																					$ 2,300,000
Iconix Lifestyle India Private Limited | Note Receivable
Schedule Of Investments [Line Items]
Receivable for investments sold																							1,000,000							1,000,000
Iconix Middle East
Schedule Of Investments [Line Items]
Payment received upon sale interest in subsidiary												$ 6,300,000
Percentage of interest sold in equity method investment												50.00%																								50.00%
Agreed price for sale of interest in a subsidiary												$ 18,800,000																								$ 18,800,000
Receivable for investments sold												$ 12,500,000																								12,500,000
Committed amount receivable period												24 months
Redeemable non-controlling interest																							$ 13,100,000							$ 13,100,000
Agreement Percentage																							120.00%							120.00%
Payment made to subsidiary for diligence and Market analysis																																				$ 3,100,000
Percentage of additional equity interest to be acquired by exercising call right																																		5.00%
Equity method investment cash Consideration																																		$ 1,800,000
Increased ownership percentage																																		55.00%
Iconix Middle East | Five-Year Put/Call Options
Schedule Of Investments [Line Items]
Put/Call option period																														6 months
Put/Call option commencement date																														Jul. 01, 2022
Multiplier on put and call options | Multiplier																														5.5
Iconix Middle East | Five-Year Put/Call Options | Minimum
Schedule Of Investments [Line Items]
Royalty revenue																														$ 12,000,000
Type of Revenue [Extensible List]																														Royalty
Iconix Middle East | Eight-Year Put/Call Options
Schedule Of Investments [Line Items]
Put/Call option period																														6 months
Put/Call option commencement date																														Jul. 01, 2022
Multiplier on put and call options | Multiplier																														5.5
Iconix Middle East | Eight-Year Put/Call Options | Minimum
Schedule Of Investments [Line Items]
Royalty revenue																														$ 12,000,000
Type of Revenue [Extensible List]																														Royalty
Iconix Israel
Schedule Of Investments [Line Items]
Percentage of interest sold in equity method investment																																								50.00%
Price for sale of interest in a subsidiary																																								$ 3,300,000
Iconix Europe
Schedule Of Investments [Line Items]
Payment received upon sale interest in subsidiary															$ 1,500,000															$ 4,000,000
Ownership interest acquired															1.00%
Percentage of interest sold in equity method investment																																											50.00%
Redeemable non-controlling interest																							$ 8,200,000							$ 8,200,000
Agreement Percentage																																	120.00%
Equity interest acquired															51.00%
Business Combination, Bargain Purchase, Revenue Recognized, Amount															$ 1,500,000
Preferred profit distribution to the Company															$ 3,000,000
Iconix Europe | Five-Year Put/Call Options
Schedule Of Investments [Line Items]
Put/Call option period																														6 months
Put/Call option commencement date																														Jul. 01, 2022
Multiplier on put and call options | Multiplier																																5.5
Iconix Europe | Eight-Year Put/Call Options
Schedule Of Investments [Line Items]
Put/Call option period																														6 months
Put/Call option commencement date																														Jul. 01, 2022
Multiplier on put and call options | Multiplier																														5.5
Iconix Australia
Schedule Of Investments [Line Items]
Percentage of interest sold in equity method investment																																									50.00%
Price for sale of interest in a subsidiary																																									$ 7,200,000
Gain on sale of interest in subsidiary																																					$ 4,100,000
Iconix SE Asia, Ltd.
Schedule Of Investments [Line Items]
Payment received upon sale interest in subsidiary														$ 4,000,000		$ 7,500,000
Percentage of interest sold in equity method investment																50.00%
Agreed price for sale of interest in a subsidiary														$ 15,900,000
Receivable for investments sold																$ 4,500,000
Committed amount receivable period																24 months
Agreement Percentage																120.00%
Price for sale of interest in a subsidiary																$ 12,000,000
Marketing costs incurred																																			5,400,000
Contractual value of option																							$ 19,500,000							$ 19,500,000
Pre-tax gain on deconsolidation of entity																																	$ 3,800,000
Iconix SE Asia, Ltd. | Level 3
Schedule Of Investments [Line Items]
Equity-method investment at fair value																																							$ 17,400,000
Iconix SE Asia, Ltd. | Lee Cooper And Umbro Brands
Schedule Of Investments [Line Items]
Payment received upon sale interest in subsidiary													$ 4,300,000
Agreed price for sale of interest in a subsidiary													21,500,000
Guaranteed minimum distributions													$ 5,100,000
Iconix SE Asia, Ltd. | Administrative Manager
Schedule Of Investments [Line Items]
Percentage of gross revenue paid monthly as services fee																																5.00%
Iconix SE Asia, Ltd. | Local Manager
Schedule Of Investments [Line Items]
Percentage of gross revenue paid monthly as services fee																																15.00%
Iconix SE Asia, Ltd. | Minimum | Guarantee of Business Revenue
Schedule Of Investments [Line Items]
Guaranteed minimum distributions																																			$ 2,500,000
Iconix SE Asia, Ltd. | Five-Year Put/Call Options
Schedule Of Investments [Line Items]
Put/Call option period																6 months
Put/Call option commencement date																Jul. 01, 2022
Iconix SE Asia, Ltd. | Five-Year Put/Call Options | Europe
Schedule Of Investments [Line Items]
Multiplier on put and call options | Multiplier																																5.5
Iconix SE Asia, Ltd. | Five-Year Put/Call Options | Minimum | Europe
Schedule Of Investments [Line Items]
Agreed Value																																$ 7,600,000
Iconix SE Asia, Ltd. | Eight-Year Put/Call Options
Schedule Of Investments [Line Items]
Put/Call option period																6 months
Put/Call option commencement date																Jul. 01, 2022
Iconix SE Asia, Ltd. | Eight-Year Put/Call Options | Europe
Schedule Of Investments [Line Items]
Multiplier on put and call options | Multiplier																																5.5
Iconix SE Asia, Ltd. | Eight-Year Put/Call Options | Minimum | Europe
Schedule Of Investments [Line Items]
Agreed Value																																$ 7,600,000
Global Brands Group Asia Limited
Schedule Of Investments [Line Items]
Ownership interest acquired																																			50.00%
MG Icon
Schedule Of Investments [Line Items]
Payments to acquire ownership interest																									2,600,000						2,600,000
Investment impairment																									$ 9,600,000						$ 9,600,000