Annual report pursuant to Section 13 and 15(d)

Revenue recognition - Narrative (Details)

v3.20.2
Revenue recognition - Narrative (Details) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Disaggregation of Revenue [Line Items]    
Deferred revenue, revenue recognized $ 54,600 $ 39,900
Accounts receivable — unbilled 163,332 123,884
Cumulative catch-up adjustment to revenue from change in estimates (9,200) (10,900)
Unbilled receivables 12,300 11,500
Future Outcomes | Performance-based | Transferred over Time    
Disaggregation of Revenue [Line Items]    
Deferred revenue, revenue recognized 45,000  
Accounts receivable — unbilled $ 24,800 $ 47,000