Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Contract revenues	$ 136,843	$ 138,757
Costs of contract revenues	121,021	125,772
Gross profit	15,822	12,985
Selling, general and administrative expenses	15,014	14,979
Gain on sale of assets, net	(813)	(512)
Other gain from continuing operations	5,448	0
Operating income (loss) from operations	7,069	(1,482)
Other (expense) income
Other (expense) income	(2)	10
Interest expense	(1,477)	(1,355)
Other expense, net	(1,479)	(1,345)
Income (loss) before income taxes	5,590	(2,827)
Income tax expense (benefit)	1,489	(1,019)
Net income (loss)	$ 4,101	$ (1,808)
Basic (loss) income per share (in dollars per share)	$ 0.15	$ (0.07)
Diluted (loss) income per share (in dollars per share)	$ 0.14	$ (0.07)
Shares used to compute income (loss) per share:
Basic (in shares)	28,143,791	27,786,087
Diluted (in shares)	28,369,762	27,786,087