Annual report pursuant to Section 13 and 15(d)

Equity - Narrative (Details)

v3.19.3
Equity - Narrative (Details) - USD ($)
$ / shares in Units, shares in Millions
12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2017
Jun. 30, 2018
Stock-based compensation        
Shares available for grants (in shares) 0.9      
Total income tax benefit recognized $ 9,900,000 $ 8,700,000 $ 15,000,000.0  
Liability related to forfeitures for tax payments $ 10,614,000 $ 8,733,000 $ 8,724,000  
Stock repurchase programs, authorized amount       $ 200,000,000
Common shares repurchased 0.7 1.1 0.6  
Common shares repurchased, cost $ 46,797,000 $ 67,572,000 $ 28,863,000  
Amount remaining available for future stock repurchases $ 146,000,000.0      
RSUs awarded in 2009 and after | Minimum        
Stock-based compensation        
Award vesting period (in years) 1 year      
RSUs awarded in 2009 and after | Maximum        
Stock-based compensation        
Award vesting period (in years) 5 years      
Restricted stock units (RSU)        
Stock-based compensation        
Share-based compensation expense $ 20,800,000 $ 20,200,000 $ 21,400,000  
Deferred vested award (in shares) 0.6      
Granted (in dollars per share) $ 66.96 $ 64.33 $ 53.63  
Total fair value $ 27,400,000 $ 30,300,000 $ 24,900,000  
Unrecognized compensation cost $ 38,800,000      
Unrecognized compensation costs, period for recognition 4 years      
Weighted average life (in years) 1 year 6 months      
Stock options        
Stock-based compensation        
Award vesting period (in years) 4 years      
Share-based compensation expense $ 0 0 0  
Award expired period 10 years      
Liability related to forfeitures for tax payments $ 10,600,000 $ 8,700,000 $ 8,700,000