Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Contract revenues	$ 194,349	$ 177,633
Revenue, Product and Service [Extensible Enumeration]	us-gaap:ServiceMember	us-gaap:ServiceMember
Costs of contract revenues	$ 161,294	$ 144,557
Cost, Product and Service [Extensible Enumeration]	us-gaap:ServiceMember	us-gaap:ServiceMember
Gross profit	$ 33,055	$ 33,076
General and administrative expenses	14,604	16,322
(Gain) loss on sale of assets—net	(321)	106
Operating income	18,772	16,648
Interest expense—net	(4,025)	(6,586)
Other income (expense)	(405)	141
Income before income taxes	14,342	10,203
Income tax provision	(3,285)	(1,389)
Net income	$ 11,057	$ 8,814
Basic earnings per share	$ 0.17	$ 0.14
Basic weighted average shares	65,847	65,269
Diluted earnings per share	$ 0.17	$ 0.13
Diluted weighted average shares	66,436	66,159