Consolidated Financial Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Licensing revenue	$ 102,161	[1]	$ 95,070	[1]	$ 97,542	[1]	$ 112,167	[1]	$ 88,265	[2]	$ 99,364	[2]	$ 105,356	[2]	$ 105,062	[2]	$ 406,940	$ 398,047	$ 341,685
Other revenue	10,251	[1]	18,680	[1]	21,401	[1]	3,971	[1]	16,999	[2]	7,811	[2]	9,769	[2]			54,303	34,579	12,133
Operating income	49,687	[1]	63,560	[1]	74,650	[1]	67,936	[1]	58,191	[2]	61,470	[2]	71,514	[2]	66,236	[2]	255,833	257,411	215,450
Net income attributable to Iconix Brand Group, Inc.	$ 23,870	[1]	$ 33,779	[1]	$ 35,319	[1]	$ 59,768	[1]	$ 26,146	[2]	$ 28,997	[2]	$ 38,716	[2]	$ 34,189	[2]	$ 152,736	$ 128,048	$ 109,408
Basic earnings per share	$ 0.50	[1]	$ 0.70	[1]	$ 0.73	[1]	$ 1.21	[1]	$ 0.51	[2]	$ 0.54	[2]	$ 0.69	[2]	$ 0.53	[2]	$ 3.15	$ 2.28	$ 1.57
Diluted earnings per share	$ 0.44	[1]	$ 0.58	[1]	$ 0.60	[1]	$ 1.03	[1]	$ 0.44	[2]	$ 0.50	[2]	$ 0.66	[2]	$ 0.51	[2]	$ 2.66	$ 2.11	$ 1.52

[1] FY 2014: 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 $13.6 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 $10.3 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 remeasurement 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: 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 $4.7 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.