Unaudited Interim Consolidated Financial Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended													12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Financial Information [Line Items]
Licensing and other revenue	$ 95,513	[1]	$ 92,683	$ 89,293	$ 92,356	$ 87,955		$ 96,887		$ 76,013		$ 71,704		$ 369,845	$ 332,559	$ 232,058
Operating income	51,922		58,954	57,586	60,304	56,070		54,822		49,443		49,380		228,766	209,715	152,565
Net income attributable to Iconix Brand Group, Inc.	$ 27,162	[2]	$ 25,968	$ 41,543	$ 31,432	$ 22,123	[3]	$ 27,409		$ 24,541		$ 24,774		$ 126,105	$ 98,847	$ 75,111
Basic earnings per share	$ 0.37		$ 0.35	$ 0.57	$ 0.43	$ 0.30		$ 0.38		$ 0.34		$ 0.35		$ 1.72	$ 1.37	$ 1.14
Diluted earnings per share	$ 0.36		$ 0.34	$ 0.55	$ 0.42	$ 0.30	[4]	$ 0.37	[4]	$ 0.33	[4]	$ 0.33	[4]	$ 1.67	$ 1.32	$ 1.10

[1] Includes a gain of approximately $5.6 million related to the OP Japan transaction (see Note 3)

[2] Includes a net gain of approximately $6.4 million related to an investment through Iconix China (see Note 3).

[3] Includes a net gain related to specific litigation of $15.7 million (see Notes 8 and 9) and a write down of auction rate securities of $13.0 million in the fourth fiscal quarter of 2010 (see Note 4).

[4] Quarterly earnings per share amounts may not add to full year amounts due to rounding.