Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement
Contract revenues	$ 709,942	$ 708,390	$ 520,894
Costs of contract revenues	625,239	644,349	504,118
Gross profit	84,703	64,041	16,776
Selling, general and administrative expenses	65,091	61,012	53,197
Amortization of intangible assets	2,070	2,640	3,390
Gain on disposal of assets, net	(9,044)	(1,804)	(3,306)
Goodwill impairment charges		0	69,483
Other gain from continuing operations		0	(5,448)
Operating income (loss)	26,586	2,193	(100,540)
Other (expense) income:
Other income	347	771	1,692
Interest income	183	353	136
Interest expense	(4,920)	(6,808)	(7,943)
Other expense, net	(4,390)	(5,684)	(6,115)
Income (loss) before income taxes	22,196	(3,491)	(106,655)
Income tax expense	1,976	1,868	(12,233)
Net income (loss)	$ 20,220	$ (5,359)	$ (94,422)
Basic earnings (loss) per share (in dollars per share)	$ 0.67	$ (0.18)	$ (3.31)
Diluted earnings (loss) per share (in dollars per share)	$ 0.67	$ (0.18)	$ (3.31)
Shares used to compute income (loss) per share:
Basic (in shares)	30,122,362	29,322,054	28,518,353
Diluted (in shares)	30,122,362	29,322,054	28,518,353