Annual report [Section 13 and 15(d), not S-K Item 405]

Goodwill And Intangible Assets - Schedule of Goodwill (Details)

v3.25.3
Goodwill And Intangible Assets - Schedule of Goodwill (Details) - USD ($)
$ in Thousands
 12 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2023
Goodwill [Roll Forward]      
Balance at the beginning of the period $ 1,782,871 $ 1,779,215  
Divestitures   (364)  
Foreign currency translation (776) 4,020  
Balance at the end of the period 1,782,095 1,782,871 $ 1,779,215
Goodwill, impairment charges 0 0 0
U.S. Federal Services      
Goodwill [Roll Forward]      
Balance at the beginning of the period 1,559,863 1,559,863  
Divestitures   0  
Foreign currency translation 0 0  
Balance at the end of the period 1,559,863 1,559,863 1,559,863
U.S. Services      
Goodwill [Roll Forward]      
Balance at the beginning of the period 164,472 164,472  
Divestitures   0  
Foreign currency translation 0 0  
Balance at the end of the period 164,472 164,472 164,472
Outside the US      
Goodwill [Roll Forward]      
Balance at the beginning of the period 58,536 54,880  
Divestitures   (364)  
Foreign currency translation (776) 4,020  
Balance at the end of the period $ 57,760 $ 58,536 $ 54,880