Quarterly Data (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Data (Unaudited) [Abstract]
Net revenue	$ 48,874	$ 40,771	$ 42,207	$ 38,104	$ 46,895	$ 39,025	$ 42,144	$ 39,400	$ 169,956	$ 167,464	$ 155,528
Income (loss) from operations	21,121	(643)	21,783	14,912	(279,292)	(13,551)	24,244	15,992	57,173	(252,607)	70,136
(Loss) income before income taxes	4,815	(16,247)	6,105	(345)	(294,613)	(28,574)	7,566	1,540	(5,672)	(314,081)	15,788
Net (loss) income	(1,329)	(8,034)	4,689	(304)	(162,220)	(24,732)	4,451	955	(4,978)	(181,546)	6,631
Net income attributable to noncontrolling interest	(863)	(1,581)	(1,102)	(1,960)	(668)	552	(1,921)	(2,135)	(5,506)	(4,172)	(7,452)
Net (loss) income attributable to Sequential Brands Group, Inc. and Subsidiaries	$ (2,192)	$ (9,615)	$ 3,587	$ (2,264)	$ (162,888)	$ (24,180)	$ 2,530	$ (1,180)	$ (10,484)	(185,718)	$ (821)
Basic (loss) earnings per share:
Attributable to Sequential Brands Group, Inc. and Subsidiaries	$ (0.03)	$ (0.15)	$ 0.06	$ (0.04)	$ (2.58)	$ (0.38)	$ 0.04	$ (0.02)
Diluted (loss) earnings per share:
Attributable to Sequential Brands Group, Inc. and Subsidiaries	$ (0.03)	$ (0.15)	$ 0.06	$ (0.04)	$ (2.58)	$ (0.38)	$ 0.04	$ (0.02)
Non-cash positive benefit due to tax reform impact					$ 132,400
Non-cash impairment charges of goodwill					$ 304,100					$ 304,123