Segments - Reconciliation of Net Income to Gross Margin (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reconciliation Net Income (Loss) to Gross Margin
Total gross margin	$ 113,273	$ 87,416	$ 326,649	$ 275,602
Less:
Selling, general and administrative	26,298	29,108	80,455	81,823
Depreciation and amortization	43,779	47,463	131,565	142,483
Long-lived asset impairment	6,660	7,105	18,323	20,858
Restatement and other charges	396	566	(195)	3,287
Restructuring and other charges	0	422	0	1,245
Interest expense	23,518	22,892	69,402	66,817
Debt extinguishment loss	0	0	2,450	291
Merger-related costs	182	0	9,993	0
Other income, net	(660)	(2,716)	(3,449)	(4,472)
Income (loss) before income taxes	$ 13,100	$ (17,424)	$ 18,105	$ (36,730)