Discontinued Operations - Summary of Financial Results of Entertainment Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other expenses (income):
(Loss) Income from operations of discontinued operations before income taxes	$ (2,308)	$ 3,231	$ (26,232)	$ 13,857
Gain (loss) on sale of Entertainment segment	(228)		104,099
Provision (benefit) for income taxes	(406)	497	28,555	3,074
Net income (loss) from discontinued operations	(2,130)	2,734	49,312	10,783
Less: Net income attributable to non-controlling interest from discontinued operations		1,698	2,943	4,778
Net income (loss) from discontinued operations attributable to Iconix Brand Group, Inc.	(2,130)	1,036	46,369	6,005
Operating Segments | Entertainment
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Licensing revenue		30,487	53,129	84,977
Selling, general and administrative expenses		20,761	34,542	57,281
Depreciation and amortization		139	303	408
Operating income		9,587	18,284	27,288
Other expenses (income):
Interest expense		6,543	12,973	14,726
Interest income		(189)	(180)	(548)
Loss on extinguishment of debt	2,308		31,554
Foreign currency translation loss (gain)		2	169	(747)
Other expenses – net	2,308	6,356	44,516	13,431
(Loss) Income from operations of discontinued operations before income taxes	(2,308)	3,231	(26,232)	13,857
Gain (loss) on sale of Entertainment segment	(228)		104,099
Provision (benefit) for income taxes	(406)	497	28,555	3,074
Net income (loss) from discontinued operations	(2,130)	2,734	49,312	10,783
Less: Net income attributable to non-controlling interest from discontinued operations		1,698	2,943	4,778
Net income (loss) from discontinued operations attributable to Iconix Brand Group, Inc.	$ (2,130)	$ 1,036	$ 46,369	$ 6,005