v3.23.1
Stock-based compensation expense - Activity Under The Equity Incentive Plans (Details) - $ / shares
shares in Thousands
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2020
Restricted Stock Unit    
Number of Shares    
Non vested shares beginning balance (in shares) 697  
Granted (in shares) 1,430  
Vested/Issued (in shares) (377)  
Forfeited (in shares) (184)  
Non vested shares ending balance (in shares) 1,566  
Weighted average grant date fair value per share    
Weighted average grant date fair value, beginning balance (in dollars per share) $ 73.27  
Granted (in dollars per share) 67.30 $ 38.66
Vested/ Issued (in dollars per share) 72.00  
Forfeited (in dollars per share) 77.23  
Weighted average grant date fair value, ending balance (in dollars per share) $ 67.66  
Performance Stock Unit    
Number of Shares    
Non vested shares beginning balance (in shares) 10  
Granted (in shares) 621  
Vested/Issued (in shares) (14)  
Forfeited (in shares) (88)  
Non vested shares ending balance (in shares) 529  
Weighted average grant date fair value per share    
Weighted average grant date fair value, beginning balance (in dollars per share) $ 128.49  
Granted (in dollars per share) 78.81  
Vested/ Issued (in dollars per share) 34.35  
Forfeited (in dollars per share) 85.40  
Weighted average grant date fair value, ending balance (in dollars per share) $ 79.60