Impact of Adjustments to Redeemable Non-controlling Interest on Earnings Per Share Calculation (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net loss from continuing operations attributable to Iconix Brand Group, Inc.	$ (13,852)	$ 10,602	$ (9,136)	$ 25,228
Accretion of redeemable non-controlling interest	(978)		(2,013)
Net loss attributable to Iconix Brand Group, Inc. after accretion of redeemable non-controlling interest	(14,830)		(11,149)
Net income from discontinued operations attributable to Iconix Brand Group, Inc.	57,493	$ 980	48,498	$ 4,967
Net income attributable to Iconix Brand Group, Inc.	$ 42,663		$ 37,349
Earnings (loss) per share - basic:
Continuing operations	$ (0.26)	$ 0.22	$ (0.20)	$ 0.52
Discontinued operations	1.01	0.02	0.85	0.10
Earnings per share - basic	0.75	0.24	0.65	0.62
Earnings (loss) per share - diluted:
Continuing operations	(0.26)	0.21	(0.19)	0.50
Discontinued operations	1.00	0.02	0.84	0.10
Earnings per share - diluted	$ 0.74	$ 0.23	$ 0.65	$ 0.60
Weighted average number of common shares outstanding:
Basic	57,082	49,035	57,026	48,772
Diluted	57,568	50,675	57,568	50,501