Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Contract revenues	$ 520,894	$ 578,553	$ 578,236
Costs of contract revenues	499,245	511,663	510,754
Gross profit	21,649	66,890	67,482
Selling, general and administrative expenses	61,460	66,026	64,987
Gain from sale of assets, net	(3,306)	(674)	(1,579)
Goodwill impairment charges	69,483	0	0
Other gain from continuing operations	(5,448)	0	0
Operating (loss) income	(100,540)	1,538	4,074
Other (expense) income:
Gain from sale of assets, net	3,306	674	1,579
Other income	1,692	41	59
Interest income	136	11	3
Interest expense	(7,943)	(5,731)	(6,175)
Other (expense) income, net	(6,115)	(5,679)	(6,113)
Loss before income taxes	(106,655)	(4,141)	(2,039)
Income tax (benefit) expense	(12,233)	(4,541)	1,581
Net (loss) income	$ (94,422)	$ 400	$ (3,620)
Basic income (loss) per share (USD per share)	$ (3.31)	$ 0.01	$ (0.13)
Diluted income (loss) per share (USD per share)	$ (3.31)	$ 0.01	$ (0.13)
Shares used to compute (loss) income per share
Basic (in shares)	28,518,353	28,029,936	27,536,967
Diluted (in shares)	28,518,353	28,354,280	27,536,967