CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)
Net revenues	$ 266,966	$ 263,386	$ 500,961	$ 497,067
Material costs	86,516	83,657	162,872	158,062
Personnel costs	89,554	87,831	175,662	175,786
Other operating costs	30,536	31,861	61,632	64,550
General and administrative expenses	26,523	25,227	52,159	50,613
Professional accounting and legal fees	4,236	8,521	9,082	21,171
Depreciation and amortization	9,272	9,825	18,602	19,962
Income from operations	20,329	16,464	20,952	6,923
Interest expense, net	7,317	14,091	19,580	28,100
Loss on extinguishment of debt			16,998
Non-service defined benefit plan expense	176	184	352	368
Income (loss) before income taxes	12,836	2,189	(15,978)	(21,545)
(Benefit) provision for income taxes	(92)	552	(6,288)	(5,448)
Net income (loss)	12,928	1,637	(9,690)	(16,097)
Other comprehensive income (loss):
Unrealized gain on cash flow hedges (net of tax provision of $710 and $8 for the three and six months ended June 30, 2018, respectively)	2,314		24
Unrealized gain (loss) on defined benefit plan (net of tax benefit of $0 and $0 for the three months and $105 and $0 for the six months ended June 30, 2018 and 2017, respectively)	26	(17)	(266)	(34)
Total other comprehensive income (loss)	2,340	(17)	(242)	(34)
Comprehensive income (loss)	$ 15,268	$ 1,620	$ (9,932)	$ (16,131)
Per share data:
Basic earnings (loss) per share (in dollars per share)	$ 0.35	$ 0.05	$ (0.26)	$ (0.44)
Weighted average shares outstanding - basic	36,790,401	36,286,528	36,645,248	36,187,340
Diluted earnings (loss) per share (in dollars per share)	$ 0.35	$ 0.04	$ (0.26)	$ (0.44)
Weighted average shares outstanding - diluted	37,404,360	36,543,740	36,645,248	36,187,340