Revenue - Revenue by Contract Relationship (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2024	Sep. 29, 2023	Sep. 27, 2024	Sep. 29, 2023
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,081,656	$ 1,001,507	$ 3,164,403	$ 2,922,819
Prime contractor
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,021,497	945,669	$ 2,972,773	2,740,908
Revenue, percent change	8.00%		8.50%
Subcontractor
Disaggregation of Revenue [Line Items]
Total revenue	$ 60,159	$ 55,838	$ 191,630	$ 181,911
Revenue, percent change	7.70%		5.30%