Consolidated Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2014	[1]	Sep. 30, 2014	[1]	Jun. 30, 2014	[1]	Mar. 31, 2014	[1]	Dec. 31, 2013	[2]	Sep. 30, 2013	[2]	Jun. 30, 2013	[2]	Mar. 31, 2013	[2]	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Licensing revenue	$ 94,822		$ 91,612		$ 96,071		$ 111,652		$ 88,265		$ 99,135		$ 105,356		$ 105,062		$ 207,723	$ 210,418	$ 299,334	$ 309,553	$ 394,157	$ 398,047	$ 341,685
Other revenue	7,151		18,680		16,038		3,971		14,999		8,040		9,769				20,009	9,769	38,690	17,809	45,840	32,579	12,133
Operating income	50,317		63,414		68,254		67,859		58,191		61,470		71,514		66,236		136,113	137,750	199,527	199,220	249,844	257,411	215,450
Net income attributable to Iconix Brand Group, Inc.	$ 24,279		$ 33,684		$ 31,162		$ 59,718		$ 26,146		$ 28,997		$ 38,716		$ 34,189		$ 90,880	$ 72,905	$ 124,564	$ 101,902	$ 148,843	$ 128,048	$ 109,408
Basic earnings per share	$ 0.51		$ 0.70		$ 0.64		$ 1.21		$ 0.51		$ 0.54		$ 0.69		$ 0.53		$ 1.85	$ 1.21	$ 2.56	$ 1.76	$ 3.07	$ 2.28	$ 1.57
Diluted earnings per share	$ 0.45		$ 0.58		$ 0.53		$ 1.03		$ 0.44		$ 0.50		$ 0.66		$ 0.51		$ 1.56	$ 1.16	$ 2.14	$ 1.67	$ 2.59	$ 2.11	$ 1.52

[1] FY 2014 (Restated): Other revenue includes a net gain of approximately $4.0 million related to the Iconix LC Partners U.S. transaction in the first quarter, a net gain of approximately $8.3 million and $18.7 million related to additional Iconix SE Asia transactions in the second and third quarter, respectively, a net gain of $7.8 million on the sale of the "sharperimage.com" domain name and certain categories under the Sharper Image trademark in the second quarter, and net gain of $7.2 million related to the Iconix Middle East transaction in the fourth quarter. See Note 3 for a description of these transactions. Included in net income attributable to Iconix Brand Group, Inc is a non-cash pre-tax re-measurement gain of approximately $37.9 million related to the purchase of the remaining interest in Iconix Latin America in the first quarter.

[2] FY 2013 (Restated): Other revenue includes a net gain of approximately $9.8 million related to the Iconix Canada transaction in the second quarter, a net gain of approximately $5.1 million related to the Iconix Australia transaction in the third quarter, and net gains of $2.7 million, $2.3 million, and $10.0 million related to the Iconix SE Asia, Iconix Israel and Umbro Korea transactions, respectively, in the fourth quarter. See Note 3 for a description of these transactions.