Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Contract revenues	$ 578,236	$ 466,498	$ 385,818
Costs of contract revenues	510,754	426,316	341,224
Gross profit	67,482	40,182	44,594
Selling, general and administrative expenses	64,987	47,715	34,691
Gain (Loss) on Disposition of Assets	(1,579)	466	(359)
Operating income (loss)	4,074	(7,999)	10,262
Other (expense) income:
(Gain) loss from sale of assets, net	1,579	(466)	359
Other income	59	536	467
Interest income	3	32	17
Interest expense	(6,175)	(3,148)	(694)
Other (expense) income, net	(6,113)	(2,580)	(210)
(Loss) income before income taxes	(2,039)	(10,579)	10,052
Income tax expense (benefit)	1,581	(2,519)	3,175
Net (loss) income	$ (3,620)	$ (8,060)	$ 6,877
Basic income (loss) per share (USD per share)	$ (0.13)	$ (0.29)	$ 0.25
Diluted income (loss) per share (USD per share)	$ (0.13)	$ (0.29)	$ 0.25
Shares used to compute (loss) income per share
Basic (in shares)	27,536,967	27,366,528	27,421,441
Diluted (in shares)	27,536,967	27,366,528	27,787,613