Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Contract revenues	$ 166,620	$ 143,105
Costs of contract revenues	146,862	134,023
Gross profit	19,758	9,082
Selling, general and administrative expenses	15,869	14,975
Amortization of intangible assets	516	658
Gain on sale of assets, net	(992)	(374)
Operating income (loss)	4,365	(6,177)
Other (expense) income:
Other income	97	23
Interest income	40	148
Interest expense	(1,402)	(1,325)
Other expense, net	(1,265)	(1,154)
Loss before income taxes	3,100	(7,331)
Income tax (benefit) expense	377	593
Net (loss) income	$ 2,723	$ (7,924)
Basic (loss) income per share (in dollars per share)	$ 0.09	$ (0.27)
Diluted (loss) income per share (in dollars per share)	$ 0.09	$ (0.27)
Shares used to compute (loss) income per share:
Basic (in shares)	29,653,409	28,927,406
Diluted (in shares)	29,655,557	28,927,406