CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
Net revenues	$ 281,098	$ 266,966	$ 517,517	$ 500,961
Material costs	91,399	86,516	169,776	162,872
Personnel costs	91,490	89,554	178,201	175,662
Other operating costs	33,741	30,536	67,296	61,632
General and administrative expenses	29,358	26,523	57,640	52,159
Professional accounting and legal fees	3,247	4,236	5,947	9,082
Depreciation and amortization	8,760	9,272	17,533	18,602
Income from operations	23,103	20,329	21,124	20,952
Interest expense, net	8,481	7,317	17,019	19,580
Loss on extinguishment of debt				16,998
Non-service defined benefit plan expense	173	176	346	352
Income (loss) before income taxes	14,449	12,836	3,759	(15,978)
Provision (benefit) for income taxes	4,414	(92)	675	(6,288)
Net income (loss)	$ 10,035	$ 12,928	$ 3,084	$ (9,690)
Basic and Diluted Per Common Share Data:
Basic income (loss) per share	$ 0.27	$ 0.35	$ 0.08	$ (0.26)
Weighted average shares used to compute basic earnings per common share	37,299,766	36,790,401	37,151,694	36,645,248
Diluted income (loss) per share	$ 0.26	$ 0.35	$ 0.08	$ (0.26)
Weighted average shares used to compute diluted earnings per common share	37,887,559	37,404,360	37,889,586	36,645,248