Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss from continuing operations	$ (557,455)	$ (257,824)	$ (210,098)
Other comprehensive income (loss):
Foreign currency translation gain (loss)	19,632	(7,545)	(36,004)
Change in fair value of available for sale securities	(484)	(1,990)	(703)
Total other comprehensive income (loss)	19,148	(9,535)	(36,707)
Comprehensive loss	(538,307)	(267,359)	(246,805)
Less: comprehensive income from continuing operations attributable to non-controlling interest	(22,177)	(3,326)	(8,439)
Comprehensive loss from continuing operations attributable to Iconix Brand Group, Inc.	$ (516,130)	$ (264,033)	$ (238,366)