Quarterly report pursuant to Section 13 or 15(d)

Supplemental disclosures (Details)

v3.7.0.1
Supplemental disclosures (Details) - USD ($)
shares in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Sep. 30, 2016
Sep. 30, 2015
Aug. 31, 2015
Income Taxes Paid, Net [Abstract]              
Income taxes paid     $ 65,500,000 $ 79,500,000      
Cash and Cash Equivalents [Abstract]              
Cash and cash equivalents $ 104,378,000 $ 50,609,000 104,378,000 50,609,000 $ 66,199,000 $ 74,672,000  
Foreign currency translation adjustments 5,936,000 $ (9,354,000) 1,865,000 (11,979,000)      
Payments for Repurchase of Equity [Abstract]              
Stock repurchase programs, authorized amount             $ 200,000,000
Repurchases of common stock     28,858,000 $ 31,336,000      
Amount remaining available for future stock repurchases 109,300,000   $ 109,300,000        
Restricted Stock Units (RSUs)              
Employee Benefits and Share-based Compensation, Noncash [Abstract]              
Granted (in shares)     400        
Vesting period     5 years        
Common Stock              
Payments for Repurchase of Equity [Abstract]              
Common shares repurchased     558 587      
Repurchases of common stock     $ 28,900,000 $ 31,300,000      
Non-U.S.              
Cash and Cash Equivalents [Abstract]              
Cash and cash equivalents 101,100,000   101,100,000        
United Kingdom              
Restructuring Charges [Abstract]              
Restructuring charges     2,200,000        
Mutual Fund              
Retirement Benefits [Abstract]              
Investments in mutual funds $ 14,500,000   $ 14,500,000