Annual report pursuant to Section 13 and 15(d)

Equity - Narrative (Details)

v3.5.0.2
Equity - Narrative (Details) - USD ($)
 2 Months Ended 12 Months Ended
Nov. 21, 2016
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2014
Aug. 31, 2015
Stock-based compensation          
Shares available for grants (in shares)   1,700,000      
Compensation expense recognized   $ 18,751,000 $ 17,237,000 $ 17,278,000  
Total income tax benefit recognized   7,400,000 7,100,000 7,000,000  
Cash paid to satisfy employees personal tax liability   $ 11,614,000 $ 12,451,000 $ 14,681,000  
Stock repurchase programs, authorized amount         $ 200,000,000
Common shares repurchased   600,000 1,600,000 2,700,000  
Common shares repurchased, cost   $ 31,338,000 $ 82,787,000 $ 113,135,000  
Amount remaining available for future stock repurchases   137,800,000      
Unvested restricted stock units          
Stock-based compensation          
Compensation expense recognized   $ 18,800,000 17,200,000 17,300,000  
Deferred vested award   900,000      
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      
Stock options          
Stock-based compensation          
Award vesting period (in years)   4 years      
Compensation expense recognized   $ 0 $ 0 $ 0  
Award expired period   10 years      
Intrinsic value of outstanding and exercisable stock options at the end of the period   $ 3,600,000      
Stock awards utilized to satisfy employees' personal tax requirements (in shares)   162,016      
Cash paid to satisfy employees personal tax liability   $ 9,300,000      
Subsequent events          
Stock-based compensation          
Common shares repurchased 500,000        
Common shares repurchased, cost $ 24,000,000