UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Contract revenues	$ 636,624	$ 592,486
Contract costs	556,139	515,533
Gross profit	80,485	76,953
Selling, general and administrative expenses	53,564	49,647
Amortization of intangible assets	2,767	578
Gain on sale of property and equipment	(748)	(683)
Income from operations	24,902	27,411
Other income (expense):
Interest income	8	13
Interest expense	(451)	(475)
Other income (expense), net	(15)	41
Income before provision for income taxes	24,444	26,990
Income tax expense	3,756	7,062
Net income	$ 20,688	$ 19,928
Income per common share:
Basic (in dollars per share)	$ 1.22	$ 1.19
Diluted (in dollars per share)	$ 1.21	$ 1.17
Weighted average number of common shares and potential common shares outstanding:
Basic (in shares)	16,916	16,760
Diluted (in shares)	17,133	17,045
Net income	$ 20,688	$ 19,928
Other comprehensive income:
Foreign currency translation adjustment	1,651	253
Other comprehensive income:	1,651	253
Total comprehensive income	$ 22,339	$ 20,181