Annual report pursuant to Section 13 and 15(d)

Stock compensation (Details)

v2.4.0.8
Stock compensation (Details) (USD $)
 12 Months Ended
Sep. 30, 2014
Sep. 30, 2013
Sep. 30, 2012
Stock-based compensation      
Shares available for grants 2,400,000    
Information pertaining to stock options vested and exercised      
Total income tax benefit recognized $ 7,000,000 $ 5,200,000 $ 4,300,000
Cash paid to satisfy employees personal tax liability 14,681,000 8,868,000 4,464,000
Unvested restricted stock units
      
Stock-based compensation      
Compensation expense recognized 17,300,000 14,600,000 12,100,000
Summary of RSU activity      
Non-vested shares outstanding at the beginning of the period 2,418,954    
Granted (in shares) 451,741    
Vested (in shares) (946,478)    
Forfeited (in shares) (39,316)    
Non-vested shares outstanding at the end of the period 1,884,901 2,418,954  
Weighted-Average Grant-Date Fair value      
Non-vested shares outstanding at the beginning of the period (in dollars per share) $ 17.47    
Granted (in dollars per share) $ 46.49 $ 30.66 $ 21.00
Vested (in dollars per share) $ 17.46    
Forfeited (in dollars per share) $ 22.90    
Non-vested shares outstanding at the end of the period (in dollars per share) $ 24.32 $ 17.47  
Total fair value 38,700,000 40,800,000 25,000,000
Total unrecognized compensation cost related to unvested RSUs 31,800,000    
Unrecognized compensation cost period expected to be realized 4 years    
Weighted Average Exercise Price      
Weighted average remaining life 1 year 7 months 6 days    
RSUs awarded in 2009 and after
      
Stock-based compensation      
Award vesting period 5 years    
Stock options
      
Stock-based compensation      
Award vesting period 4 years    
Award expired period 10 years    
Summary of stock option activity      
Outstanding at the beginning of the period (in shares) 421,464    
Exercised (in shares) (161,020)    
Expired (in shares) (444)    
Outstanding and exercisable at the end of the period (in shares) 260,000 421,464  
Weighted Average Exercise Price      
Outstanding at the beginning of the period (in dollars per share) $ 8.85    
Exercised (in dollars per share) $ 8.60    
Expired (in dollars per share) $ 10.22    
Outstanding and exercisable at the end of the period (in dollars per share) $ 9.00 $ 8.85  
Intrinsic value of outstanding and exercisable stock options at the end of the period 8,100,000    
Weighted average remaining life 1 year 10 months 24 days    
Information pertaining to stock options vested and exercised      
Aggregate intrinsic value of all stock options exercised 5,698,000 7,081,000 10,920,000
Net cash proceeds from exercise of stock options 1,362,000 2,168,000 6,441,000
Stock awards utilized to satisfy employees' personal tax requirements (in shares) 349,353    
Cash paid to satisfy employees personal tax liability $ 14,200,000