Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Operating revenues, net	$ 674,423	$ 579,545	$ 634,098
Expenses:
Direct expenses	631,807	546,699	592,550
Selling, general and administrative expenses	66,685	53,817	44,418
Total operating expenses	698,492	600,516	636,968
Loss (gain) on disposition of assets, net	753	298	(3,350)
Impairments of assets	109,024	368	407
Equity in loss (profit) of unconsolidated affiliate	(188)	385	(151)
Operating (loss) income	(133,658)	(22,022)	224
Interest expense	33,981	32,183	30,644
Other income, net	(179)	(2,764)	(3,271)
Total expenses	33,802	29,419	27,373
(Loss) earnings before income taxes	(167,460)	(51,441)	(27,149)
Income tax (benefit) expense	(25,946)	(58,973)	(469)
Net earnings (loss)	$ (141,514)	$ 7,532	$ (26,680)
Earnings (loss) per share:
Basic (USD per share)	$ (8.95)	$ 0.48	$ (1.70)
Diluted (USD per share)	$ (8.95)	$ 0.48	$ (1.70)
Weighted average shares outstanding:
Basic (shares)	15,818	15,762	15,663
Diluted (shares)	15,818	15,762	15,663