Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Contract revenues	$ 165,985	$ 159,767	$ 309,090	$ 296,610
Costs of contract revenues	151,008	140,305	285,031	262,452
Gross profit	14,977	19,462	24,059	34,158
Selling, general and administrative expenses	15,114	14,710	30,087	27,751
Amortization of intangible assets	658	847	1,318	1,694
Gain on sale of assets, net	(372)	(686)	(746)	(1,499)
Other gain from continuing operations	0	0	0	(5,448)
Operating (loss) income from operations	(423)	4,591	(6,600)	11,660
Other (expense) income:
Other income (expense)	534	476	557	474
Interest income	94	47	242	47
Interest expense	(1,978)	(1,205)	(3,303)	(2,682)
Other expense, net	(1,350)	(682)	(2,504)	(2,161)
(Loss) income before income taxes	(1,773)	3,909	(9,104)	9,499
Income tax (benefit) expense	(140)	1,660	453	3,149
Net (loss) income	$ (1,633)	$ 2,249	$ (9,557)	$ 6,350
Basic (loss) income per share (in dollars per share)	$ (0.06)	$ 0.08	$ (0.33)	$ 0.22
Diluted (loss) income per share (in dollars per share)	$ (0.06)	$ 0.08	$ (0.33)	$ 0.22
Shares used to compute (loss) income per share:
Basic (in shares)	29,097,094	28,309,004	29,086,811	28,243,400
Diluted (in shares)	29,097,094	28,544,010	29,086,811	28,474,432