Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Contract revenues	$ 708,390	$ 520,894	$ 578,553
Costs of contract revenues	644,349	504,118	516,313
Gross profit	64,041	16,776	62,240
Selling, general and administrative expenses	61,012	53,197	56,640
Amortization of intangible assets	2,640	3,390	4,736
Gain on sale of assets, net	(1,804)	(3,306)	(674)
Goodwill impairment charges		69,483	0
Other gain from continuing operations		(5,448)	0
Operating income (loss)	2,193	(100,540)	1,538
Other (expense) income:
Other income	771	1,692	41
Interest income	353	136	11
Interest expense	(6,808)	(7,943)	(5,731)
Other expense, net	(5,684)	(6,115)	(5,679)
Loss before income taxes	(3,491)	(106,655)	(4,141)
Income tax (benefit) expense	1,868	(12,233)	(4,541)
Net (loss) income	$ (5,359)	$ (94,422)	$ 400
Basic (loss) income per share (in dollars per share)	$ (0.18)	$ (3.31)	$ 0.01
Diluted (loss) income per share (in dollars per share)	$ (0.18)	$ (3.31)	$ 0.01
Shares used to compute (loss) income per share:
Basic (in shares)	29,322,054	28,518,353	28,029,936
Diluted (in shares)	29,322,054	28,518,353	28,354,280