Note 2 - Cash, Cash Equivalents and Short-term Investments (Tables)
3 Months Ended
Nov. 30, 2012
Schedule of Cash, Cash Equivalents and Short-term Investments [Table Text Block]
                            Balance Sheet Classifications  
                                     
   
Cost
Basis
   
Unrealized
Gain
   
Unrealized
 (Loss)
   
Recorded
Basis
   
Cash and Cash Equivalents
   
Short-term
Investments
 
                                     
Cash
  $ 799,108     $     $     $ 799,108     $ 799,107     $  
Money market mutual funds
    63,327                   63,327       63,327        
Certificates of deposit
    293,200             (690 )     292,510       78,997       213,514  
Available-for-sale securities:
                                               
Bond mutual funds
    20,863             (237 )     20,626             20,626  
Corporate bonds
    21,366       86       (1 )     21,451             21,451  
Total
  $ 1,197,864     $ 86     $ (928 )   $ 1,197,022     $ 941,431     $ 255,591  
                           
Balance Sheet Classifications
 
                                     
   
Cost
Basis
   
Unrealized
Gain
   
Unrealized
(Loss)
   
Recorded
Basis
   
Cash and Cash Equivalents
   
Short-term
Investments
 
                                     
Cash
  $ 932,628     $     $     $ 932,628     $ 932,628     $  
Money market mutual funds
    154,982                   154,982       154,982        
Certificates of deposit
    257,766                   257,766       4,273       253,493  
Available-for-sale securities:
                                               
Bond mutual funds
    20,734             (69 )     20,665             20,665  
Corporate bonds
    22,537       46       (9 )     22,574             22,574  
Total
  $ 1,388,647     $ 46     $ (78 )   $ 1,388,615     $ 1,091,883     $ 296,732  
Realized Gain (Loss) on Investments [Table Text Block]
   
2012
   
2011
 
Proceeds
  $ 1,010     $ 5,617  
Realized gains
  $ 10     $ 1  
Realized losses
  $       $    
Investments Classified by Contractual Maturity Date [Table Text Block]
   
Cost
Basis
   
Estimated
Fair Value
 
Due in one year or less
  $ 12,144     $ 12,161  
Due in one to two years
    9,222       9,290  
Total
  $ 21,366     $ 21,451