Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Licensing revenue	$ 46,224	$ 53,165	$ 144,984	$ 173,535
Type of Revenue [Extensible List]	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember	us-gaap:LicenseMember
Selling, general and administrative expenses	$ 30,197	$ 21,509	$ 92,437	$ 73,702
Loss on termination of licenses		2,750	5,650	25,980
Depreciation and amortization	502	592	1,788	1,814
Equity earnings on joint ventures	(967)	(483)	(2,212)	(2,475)
Gain on deconsolidation of joint venture				(3,772)
Gain on sale of trademarks		(875)	(1,268)	(875)
Goodwill impairment		103,877	37,812	103,877
Trademark impairment	4,386	521,653	77,721	521,653
Operating income (loss)	12,106	(595,858)	(66,944)	(546,369)
Other expenses (income):
Interest expense	14,944	16,911	44,320	45,787
Interest income	(89)	(150)	(304)	(417)
Other income	(25,787)	(2,648)	(84,001)	(2,649)
Loss (gain) on extinguishment of debt		1,539	(4,473)	20,939
Foreign currency translation loss (gain)	301	(1,091)	453	2,755
Other (income) expenses – net	(10,631)	14,561	(44,005)	66,415
Income (Loss) from continuing operations before income taxes	22,737	(610,419)	(22,939)	(612,784)
Provision (Benefit) for income taxes	1,026	(29,606)	(128)	(29,220)
Net income (loss) from continuing operations	21,711	(580,813)	(22,811)	(583,564)
Less: Net income (loss) attributable to non-controlling interest from continuing operations	1,487	(30,242)	8,635	(23,857)
Net income (loss) from continuing operations attributable to Iconix Brand Group, Inc.	20,224	(550,571)	(31,446)	(559,707)
Loss from discontinued operations before income taxes		(2,308)		(26,232)
Gain (loss) on sale of Entertainment segment		(228)		104,099
Provision (benefit) for income taxes		(406)		28,555
Net income (loss) from discontinued operations		(2,130)		49,312
Less: Net income attributable to non-controlling interest from discontinued operations				2,943
Net income (loss) from discontinued operations attributable to Iconix Brand Group, Inc.		(2,130)		46,369
Net income (loss) attributable to Iconix Brand Group, Inc.	$ 20,224	$ (552,701)	$ (31,446)	$ (513,338)
Earnings (loss) per share - basic:
Continuing operations	$ 0.20	$ (9.64)	$ (0.62)	$ (9.83)
Discontinued operations		(0.04)		0.81
Earnings (loss) per share - basic	0.20	(9.67)	(0.62)	(9.02)
Earnings (loss) per share - diluted:
Continuing operations	(0.01)	(9.64)	(0.81)	(9.83)
Discontinued operations		(0.04)		0.81
Earnings (loss) per share - diluted	$ (0.01)	$ (9.67)	$ (0.81)	$ (9.02)
Weighted average number of common shares outstanding:
Basic	71,844	57,189	64,577	57,081
Diluted	175,910	57,189	123,096	57,081