CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
Net revenues	$ 233,434	$ 281,098	$ 467,173	$ 517,517
Material costs	69,972	91,399	147,213	169,776
Personnel costs	73,822	91,490	163,007	178,201
Other operating costs	8,277	33,741	44,163	67,296
General and administrative expenses	31,874	29,358	60,247	57,640
Professional accounting and legal fees	1,749	3,247	5,145	5,947
Depreciation and amortization	8,879	8,760	17,710	17,533
Income from operations	38,861	23,103	29,688	21,124
Interest expense, net	8,636	8,481	16,906	17,019
Non-service defined benefit plan expense	158	173	316	346
Income from operations	30,067	14,449	12,466	3,759
(Benefit) provision for income taxes	(987)	4,414	(2,840)	675
Net income	$ 31,054	$ 10,035	$ 15,306	$ 3,084
Basic and Diluted Per Common Share Data:
Basic income per share	$ 0.82	$ 0.27	$ 0.41	$ 0.08
Weighted average shares used to compute basic earnings per common share	37,958,408	37,299,766	37,749,930	37,151,694
Diluted income per share	$ 0.81	$ 0.26	$ 0.40	$ 0.08
Weighted average shares used to compute diluted earnings per common share	38,325,872	37,887,559	38,424,334	37,889,586