Annual report pursuant to Section 13 and 15(d)

Stocks Plans - Additional Information (Detail)

v2.4.0.6
Stocks Plans - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Aug. 31, 2012
Aug. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Class A Common Stock were authorized for issuance 5,400,000  
Shares available for future grants 1,266,053  
Exercise price as percentage of fair market value at grant date 100.00%  
Unrecognized compensation cost related to share-based compensation for stock options and restricted stock outstanding $ 30.6  
Unrecognized compensation cost related to share-based compensation for stock options and restricted stock outstanding, recognition period 3 years 2 months 12 days  
Fair value of shares vested $ 3.3 $ 2.1
Maximum
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options term 10  
After Three Years
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options outstanding, vesting percentage 50.00%  
After Five Years
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Options outstanding, vesting percentage 100.00%  
Performance Shares
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Performance period 3 years  
Performance Shares | Free Cash Flow Conversion Target
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Performance shares, vesting percentage 50.00%  
Performance Shares | Total Shareholders Return
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Performance shares, vesting percentage 50.00%