Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 86,062	$ 88,582	$ 137,660	$ 91,873	$ 98,117	$ 79,909	$ 93,197	$ 79,859	$ 404,177	$ 351,082	$ 330,802
Cost of materials and other	22,756	21,617	26,000	23,730	27,263	19,590	19,139	22,469	94,103	88,461	84,874
Direct operating expenses	45,622	47,557	45,630	34,820	37,851	35,334	47,465	38,669	173,629	159,319	156,357
Operating income (loss)	(9,086)	(7,517)	34,544	9,439	7,996	2,529	(790)	(3,421)	27,380	6,314	(10,278)
Net loss	$ (24,882)	$ (22,976)	$ 18,968	$ (6,079)	$ (1,371)	$ (13,146)	$ (16,459)	$ (19,051)	$ (34,969)	$ (50,027)	$ (72,788)
Basic and diluted (loss) income per common unit (in dollars per unit)	$ (0.22)	$ (0.20)	$ 0.17	$ (0.05)	$ (0.01)	$ (0.12)	$ (0.15)	$ (0.17)	$ (0.31)	$ (0.44)	$ (0.64)
Basic and diluted weighted-average common units outstanding (in units)	113,283	113,283	113,283	113,283	113,283	113,283	113,283	113,283	113,283	113,283	113,283