Goodwill and Trademarks and Other Intangibles, net - Additional Information (Detail)		3 Months Ended				12 Months Ended
	Oct. 15, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2019 USD ($) Segment	Dec. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Intangible Assets By Major Class [Line Items]
Goodwill		$ 26,099,000	$ 26,099,000			$ 26,099,000	$ 26,099,000		$ 63,882,000
Number of reportable segments | Segment						4
Impairment of goodwill		0	0		$ 37,800,000	$ 0	37,812,000
Impairment of intangible assets, indefinite-lived						65,587,000	136,417,000
Trademarks and other intangibles, net		274,084,000	337,700,000			274,084,000	337,700,000
Amortization expense for intangible assets						65,000	258,000
Projects amortization expenses, 2022		0				0
Projects amortization expenses, 2023		0				0
Projects amortization expenses, 2024		0				0
Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of the definite-lived trademarks						0	0
Trademarks
Intangible Assets By Major Class [Line Items]
Trademarks and other intangibles, net			12,300,000				12,300,000
Operating Segments | Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived			58,700,000			65,600,000
Women's
Intangible Assets By Major Class [Line Items]
Goodwill									37,812,000
Impairment of goodwill					37,800,000		37,812,000
Women's | Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived	$ 0		32,700,000	$ 4,400,000	$ 73,300,000
Women's | Joe Boxer Trademark
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived			6,800,000
Women's | Operating Segments | Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived			55,100,000			35,300,000
Men's | Operating Segments | Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived			100,000			800,000
Home | Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived			2,700,000
Home | Operating Segments | Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived			2,700,000			17,800,000
International
Intangible Assets By Major Class [Line Items]
Goodwill		26,099,000	26,099,000			26,099,000	$ 26,099,000		$ 26,070,000
International | Operating Segments | Trademarks
Intangible Assets By Major Class [Line Items]
Impairment of intangible assets, indefinite-lived			$ 800,000			11,700,000
Iconix Australia
Intangible Assets By Major Class [Line Items]
Ownership interest acquired			5.00%				5.00%	5.00%
Goodwill								$ 29,000
Iconix Australia | International
Intangible Assets By Major Class [Line Items]
Ownership interest acquired			5.00%				5.00%
Maximum
Intangible Assets By Major Class [Line Items]
Projects amortization expenses, 2020		100,000				100,000
Projects amortization expenses, 2021		$ 100,000				$ 100,000
Maximum | Iconix Australia
Intangible Assets By Major Class [Line Items]
Goodwill								$ 100,000