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 ($)	Apr. 26, 2011 USD ($)	Jun. 03, 2010 USD ($)	Dec. 29, 2008 USD ($)	Nov. 07, 2007 USD ($)	Apr. 30, 2015 USD ($)	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 ($)	May 31, 2011 USD ($)	Jan. 31, 2011 USD ($)	Jul. 31, 2010 USD ($)	Jun. 30, 2010 USD ($)	Mar. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	May 31, 2009 USD ($) shares	Sep. 30, 2008 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jul. 06, 2015	Jun. 30, 2013 INR (₨)	Sep. 30, 2009 USD ($)	Mar. 31, 2009
Schedule of Investments [Line Items]
Purchase price Percentage of Agreed value		120.00%																	120.00%																120.00%		120.00%
Royalty revenue																																			$ 7,284,000	$ 6,264,000	$ 22,600,000	$ 16,812,000
Gain on re-measurement of initial equity investment																																					49,990,000	28,897,000
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																		6 months
Put/Call option commencement date																			Sep. 17, 2019																		Jan. 13, 2019
Eight-Year Put/Call Options
Schedule of Investments [Line Items]
Put/Call option period																			6 months																		6 months
Put/Call option commencement date																			Sep. 17, 2022																		Jan. 13, 2022
Iconix Middle East
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment		50.00%								50.00%																									50.00%		50.00%		50.00%
Agreed price for sale of interest in a subsidiary										$ 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																									$ 12,300,000		$ 12,300,000		12,500,000
Committed amount receivable period										24 months
Payment made to subsidiary for diligence and Market analysis										$ 3,100,000																											$ 3,100,000
Purchase price Percentage of Agreed value		120.00%																																	120.00%		120.00%
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
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
Payment received upon sale interest in subsidiary																																							800,000
Receivable for investments sold		$ 2,400,000													$ 3,200,000																				$ 2,400,000		$ 2,400,000
Number of equal annual installments | Installment															4
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																																					$ 4,000,000
Multiplier on put and call options																																					5
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																	1,000,000		$ 1,000,000
Committed amount receivable period																		36 months
Percentage of equity interest subject to call option																		5.00%
Price for sale of interest in a subsidiary																		$ 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 Southeast Asia
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														$ 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																17,700,000		$ 17,700,000
Committed amount receivable period																			24 months
Purchase price Percentage of Agreed value																			120.00%
Price for sale of interest in a subsidiary																			$ 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		$ 21,500,000
Payment received upon sale interest in subsidiary												$ 4,300,000
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
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 Canada
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																						$ 17,800,000
Payment received upon sale interest in subsidiary																						8,900,000
Receivable for investments sold		5,700,000																				$ 8,900,000													5,700,000		$ 5,700,000
Committed amount receivable period																						5 years
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%
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
Decrease in accounts receivable										$ 5,800,000																													$ 5,800,000
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 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
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 Lifestyle India Private Limited
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment																						50.00%																				50.00%
Receivable for investments sold																						$ 4,000,000
Price for sale of interest in a subsidiary																						6,000,000
Net gain recognized on sale of interest in subsidiary																						2,300,000
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								$ 15,700,000
Equity interest acquired								100.00%
Goodwill		9,600,000																																	9,600,000		9,600,000
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		38,870,000																																	38,870,000		38,870,000
Gain on re-measurement of initial equity investment																																					49,990,000
Strawberry Shortcake
Schedule of Investments [Line Items]
Business acquisition purchase price, cash paid								$ 105,000,000
Goodwill		35,400,000																																	35,400,000		35,400,000
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		$ 14,700,000																																	14,700,000		$ 14,700,000
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
B B C Ice Cream Limited Liability Company
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired							50.00%
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
Cost method of accounting | Variable Interest Entity, Not Primary Beneficiary
Schedule of Investments [Line Items]
Percentage of interest sold in equity method investment																																									16.60%
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%
Cash collateral deposited under the terms of the entity's financing agreements																	$ 11,800,000
Cash collateral released and distributed to the Scion members																														$ 3,300,000
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
LF Centennial Limited | Iconix Southeast Asia
Schedule of Investments [Line Items]
Cost of brand strategy services																			$ 500,000
Number of installments | Installment																			4
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
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																				₨ 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		$ 38,900,000																																	$ 38,900,000		$ 38,900,000
American Greetings Corporation | Strawberry Shortcake
Schedule of Investments [Line Items]
Business acquisition purchase price, cash paid								$ 95,000,000
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%
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%
Goodwill																$ 1,100,000
Percentage of interest sold in equity method investment					50.00%
Agreed price for sale of interest in a subsidiary					$ 6,000,000
Payment received upon sale interest in subsidiary					1,000,000
Receivable for investments sold					$ 5,000,000
Committed amount receivable period					30 months
Gain on re-measurement of initial equity investment																$ 34,748,000
Iconix Europe
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																	50.00%
Equity interest acquired																	51.00%
Percentage of minority interest in subsidiary										49.00%																													49.00%
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											$ 1,000,000				$ 3,000,000
Business acquisition, percentage of voting interests acquired during the period																	1.00%
Preferred profit distribution to the Company																	$ 3,000,000
Hydraulic IP Holdings
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired										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%
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]
Business acquisition purchase price, cash paid																							39,614,000
Goodwill																							$ 7,100,000
Percentage of minority interest in subsidiary																							49.00%
Receivable for investments sold																							$ 12,700,000
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Notes Receivable																							$ 36,900,000
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 B B C L L C | B B C Ice Cream Limited Liability Company
Schedule of Investments [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired																										50.00%
Business acquisition purchase price, cash paid																										$ 3,500,000
Reliance Brands Limited | Equity method of accounting
Schedule of Investments [Line Items]
Additional amount agreed to be contributed as working capital																						$ 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 | Other Liabilities-Current
Schedule of Investments [Line Items]
Amount to be paid to seller		$ 2,000,000																																	$ 2,000,000		2,000,000
MG Icon | Equity method of accounting | Minimum
Schedule of Investments [Line Items]
Preferred profit distribution to the Company																																					$ 23,000,000
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%

[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.