Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Contract revenues	$ 199,507	$ 125,073	$ 508,597	$ 421,682
Costs of contract revenues	178,614	120,247	463,645	382,699
Gross profit	20,893	4,826	44,952	38,983
Selling, general and administrative expenses	14,590	12,412	44,677	40,163
Amortization of intangible assets	662	847	1,980	2,541
Gain on sale of assets, net	(451)	(1,028)	(1,197)	(2,527)
Other gain from continuing operations	0	0	0	(5,448)
Operating income (loss)	6,092	(7,405)	(508)	4,254
Other (expense) income:
Other income	17	1,143	574	1,617
Interest income	75	52	317	100
Interest expense	(1,678)	(3,217)	(4,981)	(5,899)
Other expense, net	(1,586)	(2,022)	(4,090)	(4,182)
Income (loss) before income taxes	4,506	(9,427)	(4,598)	72
Income tax expense (benefit)	467	(3,071)	920	78
Net income (loss)	$ 4,039	$ (6,356)	$ (5,518)	$ (6)
Basic income (loss) per share (in dollars per share)	$ 0.14	$ (0.22)	$ (0.19)
Diluted income (loss) per share (in dollars per share)	$ 0.14	$ (0.22)	$ (0.19)
Shares used to compute (loss) income per share:
Basic (in shares)	29,544,288	28,490,530	29,240,979	28,421,850
Diluted (in shares)	29,547,185	28,490,530	29,240,979	28,421,850