Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Contract revenues	$ 137,420	$ 140,301		$ 269,924
Costs of contract revenues	122,023	123,355		238,267
Gross profit	15,397	16,946		31,657
Selling, general and administrative expenses	17,528	16,899		32,437
Loss (gain) on sale of assets, net	335	(234)		(606)
Operating (loss) income from operations	(2,466)	281		(174)
Other (expense) income
Other income	11	9		22
Interest income	0	0		1
Interest expense	(1,462)	(1,600)		(3,117)
Other expense, net	(1,451)	(1,591)		(3,094)
Loss before income taxes	(3,917)	(1,310)		(3,268)
Income tax benefit	(1,624)	(502)		(1,252)
Net loss	$ (2,293)	$ (808)	$ (4,101)	$ (2,016)
Basic income (loss) per share (in dollars per share)	$ (0.08)	$ (0.03)		$ (0.07)
Diluted income (loss) per share (in dollars per share)	$ (0.08)	$ (0.03)		$ (0.07)
Shares used to compute loss per share
Basic (in shares)	27,941,814	27,464,683	27,867,090	27,383,748
Diluted (in shares)	27,941,814	27,464,683	27,867,090	27,383,748