v3.26.1
Reportable Segments - Summary of Financial Information of Reportable Segments (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2025
Jun. 28, 2026
Jun. 29, 2025
Dec. 29, 2024
Jun. 28, 2026
Jun. 29, 2025
Segment Reporting [Line Items]            
Total consolidated revenue   $ 1,308,555 $ 1,369,816   $ 3,739,374 $ 4,112,490
Total consolidated subcontractor costs   (199,996) (216,800)   (544,007) (658,439)
Other segment items   (930,177) (966,186)   (2,719,743) (2,957,388)
Segment operating income   157,925 164,986   430,442 227,114
Reconciliation of profit (segment operating income):            
Other non-operating income   0 0   12,361 0
Legal contingency costs   0 0 $ (115,000) 0 (115,000)
Impairment of goodwill $ 0 0 0   0 (92,416)
Contingent consideration – fair value adjustments   (77) 58   7,429 2,355
Interest expense, net   (7,158) (8,288)   (23,124) (23,996)
Other corporate expenses   (20,380) (21,902)   (52,611) (64,488)
Income before income tax expense   150,767 156,698   419,679 203,118
Depreciation expense related to property and equipment   5,700 5,400   16,900 16,100
Amortization expense for intangible assets   9,000 8,300   26,200 27,600
Stock-based compensation expense   9,800 8,800   27,400 25,800
GSG            
Segment Reporting [Line Items]            
Other segment items   (391,500) (472,942)   (1,135,795) (1,512,925)
Reconciliation of profit (segment operating income):            
Depreciation expense related to property and equipment   800 800   2,400 2,600
Income (loss) from equity method investments   0 0      
CIG            
Segment Reporting [Line Items]            
Other segment items   (538,677) (493,244)   (1,583,948) (1,444,463)
Reconciliation of profit (segment operating income):            
Depreciation expense related to property and equipment   4,800 4,500   14,200 13,300
Operating Segments Excluding Intersegment Elimination            
Segment Reporting [Line Items]            
Total consolidated revenue   1,308,555 1,369,816   3,739,374 4,112,490
Total consolidated subcontractor costs   (199,996) (216,800)   (544,007) (658,439)
Operating Segments Excluding Intersegment Elimination | GSG            
Segment Reporting [Line Items]            
Total consolidated revenue   590,567 703,108   1,655,408 2,180,734
Total consolidated subcontractor costs   (113,777) (126,971)   (293,748) (387,977)
Operating Segments Excluding Intersegment Elimination | CIG            
Segment Reporting [Line Items]            
Total consolidated revenue   717,988 666,708   2,083,966 1,931,756
Total consolidated subcontractor costs   (86,219) (89,829)   (250,259) (270,462)
Intersegment Eliminations            
Segment Reporting [Line Items]            
Total consolidated revenue   (18,123) (16,083)   (52,462) (46,222)
Total consolidated subcontractor costs   (18,123) (16,083)   (52,462) (46,222)
Intersegment Eliminations | GSG            
Segment Reporting [Line Items]            
Total consolidated revenue   (7,835) (6,303)   (27,852) (18,902)
Total consolidated subcontractor costs   (10,288) (9,780)   (24,610) (27,320)
Intersegment Eliminations | CIG            
Segment Reporting [Line Items]            
Total consolidated revenue   (10,288) (9,780)   (24,610) (27,320)
Total consolidated subcontractor costs   (7,835) (6,303)   (27,852) (18,902)
Operating Segments            
Segment Reporting [Line Items]            
Total consolidated revenue   1,326,678 1,385,899   3,791,836 4,158,712
Total consolidated subcontractor costs   (218,119) (232,883)   (596,469) (704,661)
Segment operating income   178,382 186,830   475,624 496,663
Operating Segments | GSG            
Segment Reporting [Line Items]            
Total consolidated revenue   598,402 709,411   1,683,260 2,199,636
Total consolidated subcontractor costs   (124,065) (136,751)   (318,358) (415,297)
Segment operating income   82,837 99,718   229,107 271,414
Operating Segments | CIG            
Segment Reporting [Line Items]            
Total consolidated revenue   728,276 676,488   2,108,576 1,959,076
Total consolidated subcontractor costs   (94,054) (96,132)   (278,111) (289,364)
Segment operating income   95,545 87,112   246,517 225,249
Corporate            
Reconciliation of profit (segment operating income):            
Amortization expense for intangible assets   9,000 8,300   26,200 27,600
Stock-based compensation expense   $ 5,900 $ 5,000   $ 16,700 $ 14,900