Allowance For Doubtful Accounts For Trade Accounts Receivable
 12 Months Ended
Oct. 31, 2012
Allowance For Doubtful Accounts For Trade Accounts Receivable [Abstract]  
Allowance For Doubtful Accounts For Trade Accounts Receivable

(2) Allowance for Doubtful Accounts for Trade Accounts Receivable

A summary of changes in the allowance for doubtful accounts for trade accounts receivable for the years ended October 31, 2012, 2011 and 2010 follows:

          Years ended October 31,    
    2012     2011     2010  
 
Balance at beginning of year $ 145,616   $ 120,450   $ 108,913  
Bad debt expense (recovery)   (10,327 )   40,231     29,798  
Losses charged to allowance   (43,141 )   (15,065 )   (18,261 )
 
Balance at end of year $ 92,148   $ 145,616   $ 120,450