Revenue (Impact of Adoption of ASC 606) (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
Net revenue									$ 169,956	$ 167,464	$ 155,528
Operating expenses									87,767	79,443	85,392
Impairment charges									17,899	340,628
Loss on sale of assets									7,117
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
Other expense (income)									693	1,583	3,810
Interest expense, net									62,152	59,891	50,538
(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
(Benefit from) provision for income taxes									(694)	(132,535)	9,157
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 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)
Loss per share attributable to Sequential Brands Group, Inc. and Subsidiaries:
Basic	$ (0.03)	$ (0.15)	$ 0.06	$ (0.04)	$ (2.58)	$ (0.38)	$ 0.04	$ (0.02)
Diluted	$ (0.03)	$ (0.15)	$ 0.06	$ (0.04)	$ (2.58)	$ (0.38)	$ 0.04	$ (0.02)
Basic and diluted (in dollars per share)									$ (0.16)	$ (2.95)	$ (0.01)
Weighted-average common shares outstanding:
Basic and diluted ( in shares)									63,700,081	62,861,743	61,912,410
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Net revenue									$ (3,553)
Operating expenses									226
Income (loss) from operations									(3,779)
(Loss) income before income taxes									(3,779)
(Benefit from) provision for income taxes									(869)
Net (loss) income									(2,910)
Net income attributable to noncontrolling interest									177
Net loss attributable to Sequential Brands Group, Inc. and Subsidiaries									$ (2,733)
Loss per share attributable to Sequential Brands Group, Inc. and Subsidiaries:
Basic and diluted (in dollars per share)									$ (0.04)
Weighted-average common shares outstanding:
Basic and diluted ( in shares)									63,700,081
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Net revenue									$ 173,509
Operating expenses									87,541
Impairment charges									17,899
Loss on sale of assets									7,117
Income (loss) from operations									60,952
Other expense (income)									693
Interest expense, net									62,152
(Loss) income before income taxes									(1,893)
(Benefit from) provision for income taxes									175
Net (loss) income									(2,068)
Net income attributable to noncontrolling interest									(5,683)
Net loss attributable to Sequential Brands Group, Inc. and Subsidiaries									$ (7,751)
Loss per share attributable to Sequential Brands Group, Inc. and Subsidiaries:
Basic and diluted (in dollars per share)									$ (0.12)
Weighted-average common shares outstanding:
Basic and diluted ( in shares)									63,700,081