Annual report pursuant to Section 13 and 15(d)

Revenue Recognition - Narrative (Details)

v3.22.2.2
Revenue Recognition - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2020
Disaggregation of Revenue [Line Items]      
Deferred revenue, revenue recognized $ 103,200 $ 45,900  
Revenue 4,631,018 4,254,485 $ 3,461,537
Cumulative catch-up adjustment to revenue from change in estimates $ 2,500 $ (20,900)  
Cumulative catch-up adjustment to diluted earnings per share from change in estimates (in dollars per share) $ 0.03 $ 0.24  
Performance-based      
Disaggregation of Revenue [Line Items]      
Revenue $ 2,091,608 $ 1,416,562 $ 1,109,153
Performance-based | Future Outcomes | Transferred over Time      
Disaggregation of Revenue [Line Items]      
Revenue 142,400 104,700  
Estimate of fees upon target 55,400 48,700  
Unbilled receivables      
Disaggregation of Revenue [Line Items]      
Unbilled contracts receivable $ 13,100 $ 10,400