v3.26.1
Revenue and Contract Balances - Summary of Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Jun. 28, 2026
Jun. 29, 2025
Jun. 28, 2026
Jun. 29, 2025
Disaggregation of Revenue [Line Items]        
Revenue $ 1,308,555 $ 1,369,816 $ 3,739,374 $ 4,112,490
Fixed-price        
Disaggregation of Revenue [Line Items]        
Revenue 634,872 633,508 1,794,387 1,678,280
Time-and-materials        
Disaggregation of Revenue [Line Items]        
Revenue 549,062 595,082 1,614,318 1,799,288
Cost-plus        
Disaggregation of Revenue [Line Items]        
Revenue 124,621 141,226 330,669 634,922
U.S. federal government        
Disaggregation of Revenue [Line Items]        
Revenue 338,855 452,629 923,573 1,367,899
U.S. state and local government        
Disaggregation of Revenue [Line Items]        
Revenue 174,382 189,181 522,349 599,606
U.S. commercial        
Disaggregation of Revenue [Line Items]        
Revenue 235,255 221,351 667,450 666,027
International        
Disaggregation of Revenue [Line Items]        
Revenue $ 560,063 $ 506,655 $ 1,626,002 $ 1,478,958