CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 404,177	$ 351,082	$ 330,802
Operating costs and expenses:
Cost of materials and other	94,103	88,461	84,874
Direct operating expenses (exclusive of depreciation and amortization)	173,629	159,319	156,357
Depreciation and amortization	79,839	71,575	73,986
Cost of sales	347,571	319,355	315,217
Selling, general and administrative expenses	25,829	25,023	25,630
Loss on asset disposals	3,397	390	233
Operating income (loss)	27,380	6,314	(10,278)
Other income (expense):
Interest expense, net	(62,636)	(62,588)	(62,845)
Other income, net	269	6,201	555
Loss before income taxes	(34,987)	(50,073)	(72,568)
Income tax (benefit) expense	(18)	(46)	220
Net loss	$ (34,969)	$ (50,027)	$ (72,788)
Net loss per common unit - basic and diluted (in dollars per unit)	$ (0.31)	$ (0.44)	$ (0.64)
Distributions declared per common unit (in dollars per unit)	$ 0.40	$ 0	$ 0.02
Weighted-average common units outstanding:
Basic and diluted (in units)	113,283	113,283	113,283