Acquisitions, Joint Ventures and Investments - Additional Information (Detail) ₨ in Millions														1 Months Ended																									3 Months Ended	9 Months Ended		12 Months Ended
		Sep. 30, 2015 USD ($)	Jul. 06, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2014 USD ($)	Nov. 30, 2013 USD ($)	Oct. 31, 2013 USD ($)	Sep. 30, 2013 USD ($)	Jun. 30, 2013 USD ($)	Apr. 26, 2011 USD ($)	Jun. 03, 2010 USD ($)	Dec. 31, 2009 USD ($)	Nov. 07, 2007 USD ($)	Mar. 31, 2015 USD ($)	Feb. 28, 2015 USD ($)	Dec. 31, 2014 USD ($)	Oct. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jul. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($) Installment	Feb. 28, 2014 USD ($)	Jan. 31, 2014 USD ($)	Nov. 30, 2013 USD ($)	Oct. 31, 2013 USD ($) Installment	Sep. 30, 2013 USD ($)	Jul. 31, 2013 USD ($)	Jun. 30, 2013 USD ($)	Feb. 28, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2012 USD ($)	May. 31, 2012 USD ($)	May. 31, 2011 USD ($)	Jul. 31, 2010 USD ($)	Jun. 30, 2010 USD ($)	Mar. 31, 2010 USD ($)	May. 31, 2009 USD ($) shares	Sep. 30, 2008 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jun. 30, 2013 INR (₨)	Sep. 30, 2009 USD ($)	Mar. 31, 2009
Schedule of Investments [Line Items]
Cash payment for acquisition of assets																																									$ 2,500,000
Additional paid-in capital		$ 974,552,000		$ 948,714,000												$ 948,714,000																							$ 974,552,000	$ 974,552,000		$ 948,714,000
Purchase price Percentage of Agreed value							120.00%																		120.00%
Note receivable	[1]	$ 5,000,000																																					5,000,000	$ 5,000,000
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%
Five-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option period																									6 months
Put/Call option commencement date																									Sep. 17, 2019
Eight-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option period																									6 months
Put/Call option commencement date																									Sep. 17, 2022
Iconix Europe
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																							1.00%
Equity interest acquired																							51.00%
Percentage of interest sold in equity method investment												50.00%
Agreed price for sale of interest in a subsidiary												$ 4,000,000
Payment received upon sale interest in subsidiary																							$ 1,500,000
Scion
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired			50.00%
Business acquisition purchase price, cash paid			$ 6,000,000
Equity interest acquired			100.00%
Decrease in restricted cash																			$ 8,500,000
Allowance for doubtful accounts receivable				2,700,000												2,700,000																										2,700,000
Decrease in accounts receivable				$ 5,800,000												5,800,000																										5,800,000
Additional paid-in capital			$ 800,000
Iconix Middle East
Schedule of Investments [Line Items]
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																										18,800,000
Payment received upon sale interest in subsidiary																6,300,000
Receivable for investments sold		$ 12,300,000		$ 12,500,000												$ 12,500,000																							$ 12,300,000	$ 12,300,000		12,500,000
Committed amount receivable period																24 months
Gain on sale of interest in subsidiary																																										10,300,000
Purchase price Percentage of Agreed value		120.00%																																					120.00%	120.00%
Payment made to subsidiary for diligence and Market analysis																																								$ 3,100,000
Iconix Middle East | Two Year Call Option
Schedule of Investments [Line Items]
Call option period																6 months
Call option commencement date																Dec. 19, 2016
Payment for the purchased call option																$ 1,800,000
Iconix Middle East | Five-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option period																																								6 months
Put/Call option commencement date																																								Dec. 19, 2019
Multiplier on put and call options																																								5.5
Iconix Middle East | Eight-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option period																																								6 months
Put/Call option commencement date																																								Dec. 19, 2022
Multiplier on put and call options																																								5.5
Iconix Middle East | Maximum | Two Year Call Option
Schedule of Investments [Line Items]
Percentage of equity interest subject to call option																5.00%
Iconix Middle East | Minimum | Five-Year Put/Call Options
Schedule of Investments [Line Items]
Royalty revenue																																								$ 12,000,000
Iconix Middle East | Minimum | Eight-Year Put/Call Options
Schedule of Investments [Line Items]
Royalty revenue																																								12,000,000
Iconix Middle East | Other assets - current
Schedule of Investments [Line Items]
Receivable for investments sold		$ 6,300,000																																					$ 6,300,000	6,300,000
Iconix Middle East | Other Assets
Schedule of Investments [Line Items]
Receivable for investments sold		6,000,000																																					6,000,000	6,000,000
LC Partners U.S. LLC
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment					50.00%
Agreed price for sale of interest in a subsidiary					$ 4,000,000																$ 4,000,000
Payment received upon sale interest in subsidiary																																										800,000
Receivable for investments sold		2,400,000			$ 3,200,000																$ 3,200,000																		2,400,000	2,400,000
Number of equal annual installments | Installment																					4
Net gain recognized on sale of interest in subsidiary																																								$ 4,000,000
Equity method investment put option value multiplier times net wholesale sales																																								0.10
LC Partners U.S. LLC | Put Option
Schedule of Investments [Line Items]
Payment for the purchased call option																																								$ 4,000
Multiplier on put and call options																																								5
LC Partners U.S. LLC | Other assets - current
Schedule of Investments [Line Items]
Receivable for investments sold		800,000																																					800,000	$ 800,000
LC Partners U.S. LLC | Other Assets
Schedule of Investments [Line Items]
Receivable for investments sold		1,600,000																																					1,600,000	1,600,000
Iconix Southeast Asia
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment							50.00%
Agreed price for sale of interest in a subsidiary																				$ 15,900,000
Payment received upon sale interest in subsidiary																				$ 4,000,000					$ 7,500,000
Receivable for investments sold		17,700,000					$ 4,500,000																		$ 4,500,000														17,700,000	17,700,000
Committed amount receivable period																									24 months
Gain on sale of interest in subsidiary																																										8,300,000	$ 2,700,000
Purchase price Percentage of Agreed value							120.00%																		120.00%
Price for sale of interest in a subsidiary							$ 12,000,000																		$ 12,000,000
Business acquisition transaction costs																																											2,000,000
Marketing costs incurred																																										5,400,000
Consulting costs																																											2,000,000
Iconix Southeast Asia | Lee Cooper And Umbro Brands
Schedule of Investments [Line Items]
Agreed price for sale of interest in a subsidiary																		$ 21,500,000																							$ 21,500,000
Payment received upon sale interest in subsidiary																		$ 4,300,000
Gain on sale of interest in subsidiary																																										$ 18,700,000
Guaranteed minimum distributions		5,100,000																																					5,100,000	$ 5,100,000
Iconix Southeast Asia | Administrative Manager
Schedule of Investments [Line Items]
Percentage of gross revenue paid monthly as services fee																																								5.00%
Iconix Southeast Asia | Local Manager
Schedule of Investments [Line Items]
Percentage of gross revenue paid monthly as services fee																																								15.00%
Iconix Southeast Asia | Two Year Call Option
Schedule of Investments [Line Items]
Call option period																									6 months
Call option commencement date																									Oct. 01, 2015
Payment for the purchased call option																																								$ 38,400,000
Iconix Southeast Asia | Two Year Call Option | Multiplier Rate One
Schedule of Investments [Line Items]
Multiplier on put and call options																																								0.10
Iconix Southeast Asia | Two Year Call Option | Multiplier Rate Two
Schedule of Investments [Line Items]
Multiplier on put and call options																																								1.15
Iconix Southeast Asia | Five-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option period																									6 months
Put/Call option commencement date																									Oct. 01, 2018
Iconix Southeast Asia | Five-Year Put/Call Options | Europe
Schedule of Investments [Line Items]
Multiplier on put and call options																																								5.5
Iconix Southeast Asia | Eight-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option period																									6 months
Put/Call option commencement date																									Oct. 01, 2021
Iconix Southeast Asia | Eight-Year Put/Call Options | Europe
Schedule of Investments [Line Items]
Multiplier on put and call options																																								5.5
Iconix Southeast Asia | Maximum | Two Year Call Option
Schedule of Investments [Line Items]
Percentage of equity interest subject to call option																									5.00%
Iconix Southeast Asia | Minimum | Guarantee of Business Revenue
Schedule of Investments [Line Items]
Guaranteed minimum distributions		2,500,000																																					2,500,000	$ 2,500,000
Iconix Southeast Asia | Minimum | Five-Year Put/Call Options
Schedule of Investments [Line Items]
Agreed Value		15,500,000																																					15,500,000	15,500,000
Iconix Southeast Asia | Minimum | Five-Year Put/Call Options | Europe
Schedule of Investments [Line Items]
Agreed Value		7,600,000																																					7,600,000	7,600,000
Iconix Southeast Asia | Minimum | Eight-Year Put/Call Options | Europe
Schedule of Investments [Line Items]
Agreed Value		7,600,000																																					7,600,000	7,600,000
Iconix Southeast Asia | Other assets - current
Schedule of Investments [Line Items]
Receivable for investments sold		8,200,000																																					8,200,000	8,200,000
Iconix Southeast Asia | Other Assets
Schedule of Investments [Line Items]
Receivable for investments sold		9,500,000																																					9,500,000	9,500,000
Iconix Israel
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment						50.00%
Payment received upon sale interest in subsidiary																								$ 1,000,000
Receivable for investments sold		1,000,000				$ 2,300,000																		$ 2,300,000															1,000,000	$ 1,000,000
Committed amount receivable period																								36 months
Gain on sale of interest in subsidiary																																											2,300,000
Percentage of equity interest subject to call option																								5.00%
Price for sale of interest in a subsidiary						$ 3,300,000																		$ 3,300,000
Iconix Israel | Call Option | Multiplier Rate One
Schedule of Investments [Line Items]
Multiplier on put and call options																																								0.05
Iconix Israel | Call Option | Multiplier Rate Two
Schedule of Investments [Line Items]
Multiplier on put and call options																																								6.5
Iconix Israel | Other assets - current
Schedule of Investments [Line Items]
Receivable for investments sold		800,000																																					800,000	$ 800,000
Iconix Israel | Other Assets
Schedule of Investments [Line Items]
Receivable for investments sold		200,000																																					200,000	$ 200,000
Iconix Australia
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment								50.00%
Gain on sale of interest in subsidiary																																											$ 5,100,000
Price for sale of interest in a subsidiary								$ 7,200,000																		$ 7,200,000
Iconix Australia | Two Year Call Option
Schedule of Investments [Line Items]
Call option period																										6 months
Call option commencement date																										Sep. 17, 2015
Multiplier on put and call options																																								6.5
Iconix Australia | Five-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option commencement date																										Sep. 17, 2017
Iconix Australia | Four Year Put And Call Option
Schedule of Investments [Line Items]
Multiplier on put and call options																																								5
Iconix Australia | Maximum | Two Year Call Option
Schedule of Investments [Line Items]
Percentage of equity interest subject to call option																										5.00%
Iconix Canada
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment									50.00%
Agreed price for sale of interest in a subsidiary									$ 17,800,000																			$ 17,800,000
Payment received upon sale interest in subsidiary																												8,900,000
Receivable for investments sold		5,700,000							$ 8,900,000																			$ 8,900,000											5,700,000	$ 5,700,000
Committed amount receivable period																												5 years
Net gain recognized on sale of interest in subsidiary																												$ 9,800,000
Option to purchase Encumbered Canadian Assets description																																								Ico Brands has an option to purchase the Encumbered Canadian Assets for one dollar within one year following the earlier of (i) January 15, 2020 and (ii) the later of (a) the release of such assets from the Company’s securitization and (b) Ico Brands receipt of notice of such release.
Option to purchase Encumbered Canadian Assets price		1
Liquidated damages obligation		4,900,000																																					4,900,000	$ 4,900,000
Iconix Canada | Guarantee of Business Revenue
Schedule of Investments [Line Items]
Royalty revenue																												2,700,000
Iconix Canada | Call Option
Schedule of Investments [Line Items]
Percentage of equity interest subject to call option																																								5.00%
Payment for the purchased call option																																								$ 1,500,000
Multiplier on put and call options																																								5.5
Percentage of amount obtained for options																																								5.00%
Iconix Canada | Other assets - current
Schedule of Investments [Line Items]
Receivable for investments sold		2,900,000																																					2,900,000	$ 2,900,000
Iconix Canada | Other Assets
Schedule of Investments [Line Items]
Receivable for investments sold		2,800,000																																					2,800,000	2,800,000
Iconix Lifestyle India Private Limited
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment									50.00%
Receivable for investments sold									$ 4,000,000																			4,000,000
Net gain recognized on sale of interest in subsidiary																												5,600,000
Price for sale of interest in a subsidiary									6,000,000																			6,000,000
Note receivable		1,900,000																																					1,900,000	1,900,000
Iconix Lifestyle India Private Limited | Other assets - current
Schedule of Investments [Line Items]
Note receivable		1,000,000																																					1,000,000	1,000,000
Iconix Lifestyle India Private Limited | Other Assets
Schedule of Investments [Line Items]
Note receivable		900,000																																					900,000	900,000
Iconix China
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired														50.00%
Business acquisition total purchase price														$ 57,400,000
Business acquisition purchase price, cash paid														40,400,000
Business acquisition purchase price, common stock issued, value														$ 15,703,000
Equity interest acquired														100.00%
Goodwill		5,900,000																																					5,900,000	5,900,000
Revenues																																							300,000	300,000
Selling, general and administrative expenses period increase																																							600,000	1,200,000
Other income period increase																																								600,000
Equity interests aggregate fair value		42,659,000																																					42,659,000	42,659,000
Strawberry Shortcake
Schedule of Investments [Line Items]
Business acquisition purchase price, cash paid														$ 105,000,000
Goodwill		500,000																																					500,000	500,000
Revenues																																							2,600,000	$ 6,100,000
Quarterly installment period																																								2 years
Strawberry Shortcake | Notes Receivable
Schedule of Investments [Line Items]
Notes receivable principal amount														10,000,000
Pony International, LLC.
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired															75.00%
Business acquisition purchase price, cash paid															$ 37,000,000
Goodwill		$ 300,000																																					300,000	$ 300,000
Revenues																																							$ 700,000	$ 1,800,000
Percentage of minority interest in subsidiary															25.00%
Artful Dodger | Scion
Schedule of Investments [Line Items]
Business acquisition purchase price, cash paid													$ 15,000,000
BBC Ice Cream LLC
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired			50.00%
Artful Holdings LLC
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired			100.00%
Equity method of accounting | Iconix Lifestyle India Private Limited
Schedule of Investments [Line Items]
Payment received upon sale interest in subsidiary																												$ 2,000,000
Committed amount receivable period																												48 months
Equity method of accounting | Iconix China
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		50.00%																																					50.00%	50.00%
Cost method of accounting | Scion | Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																																														16.60%
Percentage of interest sold in equity method investment			16.60%
Cash collateral released and distributed to the Scion members																																			$ 3,300,000
Cash collateral deposited under the terms of the entity's financing agreements																							$ 11,800,000
Novel | Iconix China
Schedule of Investments [Line Items]
Business acquisition purchase price, cash paid														40,400,000
Offset of accounts receivable														$ 1,269,000
Novel | Equity method of accounting
Schedule of Investments [Line Items]
Committed contribution to joint venture																																						$ 20,000,000							$ 9,000,000
Cash payment for acquisition of assets																															$ 2,000,000		$ 3,000,000	$ 4,000,000				8,000,000
Beagle Scout LLC | Peanuts Worldwide
Schedule of Investments [Line Items]
Cash payment for acquisition of assets											$ 34,000,000
Percentage of minority interest in subsidiary											20.00%
Notes loaned to subsidiary											$ 17,500,000
Notes receivable, annual interest rate											6.00%
Notes receivable, minimum principal annual installments											$ 2,200,000
Notes receivable, maturity date											Jun. 03, 2015
LF Centennial Limited | Iconix Southeast Asia
Schedule of Investments [Line Items]
Cost of brand strategy services																									$ 500,000
Number of installments | Installment																									4
Parent Company | Equity method of accounting
Schedule of Investments [Line Items]
Committed contribution to joint venture																																						5,000,000
Cash payment for acquisition of assets																																						$ 2,000,000
Additional amount agreed to be contributed as working capital									2,000,000																			$ 2,000,000																₨ 100
Investments Associated with Iconix China Acquisition
Schedule of Investments [Line Items]
Equity interest acquired		100.00%																																					100.00%	100.00%
Equity interests aggregate fair value		$ 42,700,000																																					$ 42,700,000	$ 42,700,000
Iconix Latin America
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																						50.00%
Business acquisition purchase price, cash paid																						$ 42,000,000
Equity interest acquired																						100.00%
Hydraulic IP Holdings
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired				51.00%												51.00%																										51.00%
Business acquisition purchase price, cash paid																$ 6,000,000
Hydraulic IP Holdings | Top On International Group, LLC
Schedule of Investments [Line Items]
Percentage of minority interest in subsidiary				49.00%												49.00%																										49.00%
NGX LLC
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																	51.00%
Business acquisition purchase price, cash paid																	$ 6,000,000
NGX LLC | NGO LLC
Schedule of Investments [Line Items]
Percentage of minority interest in subsidiary																	49.00%
Alberta ULC
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																													51.00%
Business acquisition purchase price, cash paid																													$ 76,500,000
Buffalo Brand
Schedule of Investments [Line Items]
Percentage of minority interest in subsidiary																													49.00%
Modern Amusement | Equity method of accounting
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																														51.00%
Business acquisition purchase price, cash paid																														$ 5,000,000
Icon Entertainment LLC | Peanuts Worldwide
Schedule of Investments [Line Items]
Cash payment for acquisition of assets											$ 141,000,000
Business Acquisition, Percentage of Voting Interests Acquired											80.00%
Business acquisition purchase price, cash paid											$ 172,100,000
Hardy Way
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired										85.00%
Business acquisition total purchase price										$ 62,000,000
Hardy Way | Equity method of accounting
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																																					50.00%
Business acquisition total purchase price																																					$ 17,000,000
Business acquisition purchase price, cash paid																																					9,000,000
Business acquisition purchase price, common stock issued, value																																					$ 8,000,000
Business acquisition purchase price, common stock issued, shares | shares																																					588,688
Hardy Way | Equity method of accounting | Addition capital
Schedule of Investments [Line Items]
Business acquisition purchase price, common stock issued, value																																					$ 1,000,000
Scion BBC LLC | BBC Ice Cream LLC
Schedule of Investments [Line Items]
Business acquisition purchase price, cash paid																																$ 3,500,000
Equity interest acquired																																50.00%
Iconix Brands | Call Option
Schedule of Investments [Line Items]
Percentage of equity interest subject to call option																																								5.00%
Payment for the purchased call option																																								$ 600,000
Multiplier on put and call options																																								5.5
Percentage of amount obtained for options																																								5.00%
Reliance Brands Limited | Equity method of accounting
Schedule of Investments [Line Items]
Additional amount agreed to be contributed as working capital									$ 500,000																			$ 500,000																₨ 25
MG Icon | Equity method of accounting
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																																				50.00%
Business acquisition total purchase price																																				$ 20,000,000
Acquisition of interest in MG Icon																																				4,000,000				$ 21,000,000
Amount to be paid to seller																																				$ 3,000,000
MG Icon | Equity method of accounting | Minimum
Schedule of Investments [Line Items]
Preferred profit distribution to the Company																																								23,000,000
MG Icon | Equity method of accounting | Other Liabilities-Current
Schedule of Investments [Line Items]
Amount to be paid to seller		$ 2,000,000																																					$ 2,000,000	$ 2,000,000
Marcy Media Holdings
Schedule of Investments [Line Items]
Cash payment for acquisition of assets																											$ 32,000,000
Percentage of minority interest in subsidiary																											5.00%
Complex Media Inc.
Schedule of Investments [Line Items]
Cash payment for acquisition of assets																										$ 25,000,000
Percentage of minority interest in subsidiary								14.40%																		14.40%

[1] The Note receivable in connection with Strawberry Shortcake acquisition represents amounts due from AG in respect of non-compete payments pursuant to a License Agreement entered into with AG simultaneously with the closing of the transaction.