Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Operating revenues, net	$ 168,787	$ 150,167	$ 498,400	$ 431,209
Expenses:
Direct expenses	160,200	136,786	471,509	400,250
Selling, general and administrative expenses	16,255	11,401	46,199	38,691
Total operating expenses	176,455	148,187	517,708	438,941
(Gain) loss on disposal of assets	0	(4)	708	3
Equity in (gain) loss of unconsolidated affiliates, net	(118)	(438)	(162)	1,556
Operating (loss) income	(7,550)	2,422	(19,854)	(9,291)
Interest expense	8,357	8,027	24,894	24,305
Other income – net	(1,845)	(706)	(436)	(2,474)
Total expenses	6,512	7,321	24,458	21,831
Loss before income taxes	(14,062)	(4,899)	(44,312)	(31,122)
Income tax benefit	(2,531)	(1,622)	(8,705)	(9,324)
Net loss	$ (11,531)	$ (3,277)	$ (35,607)	$ (21,798)
Weighted average shares outstanding:
Basic (shares)	15,816	15,799	15,811	15,750
Diluted (shares)	15,816	15,799	15,811	15,750
Net loss per share:
Basic (in USD per share)	$ (0.73)	$ (0.21)	$ (2.25)	$ (1.38)
Diluted (in USD per share)	$ (0.73)	$ (0.21)	$ (2.25)	$ (1.38)