Consolidated Financial Information (Parenthetical) (Detail) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended				12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information [Line Items]
Non-cash asset impairment charges			$ 4,100	$ 625,500	$ 438,100
Impairment of equity method investment			$ 16,800				$ 16,848
Net loss on extinguishment of debt							20,939	$ 5,903
Net gains (losses) on sale of trademarks							875	38,104
Gain related to settlement agreement with former management					$ 7,300			7,328
Badgley Mischka Canada and Sharper Image Canada
Quarterly Financial Information [Line Items]
Gain on sale of investments				900
Sharper Image intellectual property and related assets
Quarterly Financial Information [Line Items]
Net gains (losses) on sale of trademarks	$ 28,100							28,113	[1]
Badgley Mischka intellectual property and related assets
Quarterly Financial Information [Line Items]
Net gains (losses) on sale of trademarks		$ 11,800						11,812	[2]
Iconix SE Asia, Ltd.
Quarterly Financial Information [Line Items]
Gain on sale of investments				3,800
Complex Media
Quarterly Financial Information [Line Items]
Gain on sale of investments				$ 2,700		$ 10,200	$ 2,728	$ 10,164

[1] In December 2016, the Company sold the rights to the Sharper Image intellectual property and related assets to 360 Holdings, Inc. for $100.0 million in cash (of which $1.8 million is being held in escrow for the sale of the Sharper Image intellectual property in the Company’s international joint ventures). The Company recognized a gain of $28.1 million as a result of this transaction.

[2] In February 2016, the Company sold its rights to the Badgley Mischka intellectual property and related assets to Titan Industries, Inc. in partnership with the founders, Mark Badgley and James Mischka, and the apparel license MJCLK LLC for $13.8 million in cash. The Company recognized a gain of $11.6 million as a result of this transaction. The $11.6 million gain represented the sale of the Badgley Mischka intellectual property and related assets within the United States, Greater China, Israel and Latin America territories. The Badgley Mischka intellectual property and related assets within other foreign territories is owned by certain of the Company’s joint venture entities and required the Company to negotiate and finalize the sale of the intellectual property with its respective joint venture partners. As a result, in June 2016, the Company recognized an additional gain of approximately $0.2 million upon receipt of cash associated with the sale of the Badgley Mischka intellectual property and related assets which was previously owned by the Iconix Australia joint venture resulting in an aggregate gain on sale of the brand of $11.8 million.