Annual report pursuant to Section 13 and 15(d)

Revenue Recognition - Narrative (Details)

v3.19.3
Revenue Recognition - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Disaggregation of Revenue [Line Items]    
Deferred revenue, revenue recognized $ 39.4  
Cumulative catch-up adjustment to revenue from change in estimates (10.9)  
Contractual retainage provisions 11.5 $ 13.4
Performance-based | Transferred over Time    
Disaggregation of Revenue [Line Items]    
Unbilled accounts receivable 47.0  
Future Outcomes | Performance-based | Transferred over Time    
Disaggregation of Revenue [Line Items]    
Deferred revenue, revenue recognized 91.3  
Average Effective Rate | Performance-based | Transferred over Time    
Disaggregation of Revenue [Line Items]    
Deferred revenue, revenue recognized $ 144.0