Revenue from Contracts with Customers Revenue by Contractor Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue by Contractor Type [Line Items]
Revenue	$ 675,545	$ 633,224
Prime contractor
Revenue by Contractor Type [Line Items]
Revenue	623,192	589,074
Subcontractor
Revenue by Contractor Type [Line Items]
Revenue	$ 52,353	$ 44,150