Adjustment Previously Reported Condensed Consolidated Statements of Income and Comprehensive Income (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Licensing revenue	$ 93,797	$ 111,652
Total revenue	93,797	115,623
Selling, general and administrative expenses	41,208	47,764
Operating income	52,589	67,859
Income before taxes	93,117	88,319
Provision for income taxes	26,365	25,527
Net income	66,752	62,792
Net income attributable to Iconix Brand Group, Inc.	$ 63,685	$ 59,718
Earnings per share:
Basic	$ 1.32	$ 1.21
Diluted	$ 1.23	$ 1.03
Comprehensive income	$ 28,521	$ 62,504
Comprehensive income attributable to Iconix Brand Group, Inc.	25,454	59,430
Other Comprehensive Income (Loss)
Earnings per share:
Comprehensive income	28,521	62,504
Comprehensive income attributable to Iconix Brand Group, Inc.	25,454	59,430
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Licensing revenue	95,387	112,167
Total revenue	95,387	116,138
Selling, general and administrative expenses	44,155	48,202
Operating income	51,232	67,936
Income before taxes	91,817	88,396
Provision for income taxes	25,910	22,554
Net income	65,907	62,842
Net income attributable to Iconix Brand Group, Inc.	$ 62,840	$ 59,768
Earnings per share:
Basic	$ 1.30	$ 1.21
Diluted	$ 1.21	$ 1.03
As Previously Reported | Other Comprehensive Income (Loss)
Earnings per share:
Comprehensive income	$ 27,668	$ 62,554
Comprehensive income attributable to Iconix Brand Group, Inc.	24,601	59,480
Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Licensing revenue	(1,590)	(515)
Total revenue	(1,590)	(515)
Selling, general and administrative expenses	(2,947)	(438)
Operating income	1,357	(77)
Income before taxes	1,300	(77)
Provision for income taxes	455	(27)
Net income	845	(50)
Net income attributable to Iconix Brand Group, Inc.	$ 845	$ (50)
Earnings per share:
Basic	$ 0.02	$ 0.00
Diluted	$ 0.02	$ 0.00
Adjustments | Other Comprehensive Income (Loss)
Earnings per share:
Comprehensive income	$ 853	$ (50)
Comprehensive income attributable to Iconix Brand Group, Inc.	$ 853	$ (50)