v3.26.1
Goodwill and Intangibles - Schedule of Carrying Value of Goodwill by Reportable Segment Appearing in Accompanying Consolidated Balance Sheets (Details)
$ in Thousands
 6 Months Ended
Mar. 27, 2026
USD ($)
Goodwill [Roll Forward]  
Balance at the beginning of the period $ 4,780,818
Foreign currency translation adjustments and other (17,556)
Balance at the end of the period 4,763,262
Infrastructure & Advanced Facilities  
Goodwill [Roll Forward]  
Balance at the beginning of the period 3,351,490
Foreign currency translation adjustments and other (2,978)
Balance at the end of the period 3,348,512
PA Consulting  
Goodwill [Roll Forward]  
Balance at the beginning of the period 1,429,328
Foreign currency translation adjustments and other (14,578)
Balance at the end of the period $ 1,414,750