Investment Securities, Trading (Details) (USD $)
3 Months Ended 6 Months Ended
Apr. 30, 2013
Number
Apr. 30, 2012
Number
Apr. 30, 2013
Number
Apr. 30, 2012
Number
Oct. 31, 2012
Schedule Of Trading Securities And Other Trading Assets [Line Items]          
Total investment securities, trading $ 285,021,000   $ 285,021,000   $ 190,253,000
Trading securities net unrealized gain 6,400,000 1,000,000 15,900,000 6,800,000  
Number of seeded sponsored funds 9 13 9 13  
Number of seeded separately managed accounts 14 3 14 3  
Equity Securities [Member]
         
Schedule Of Trading Securities And Other Trading Assets [Line Items]          
Total investment securities, trading 186,796,000   186,796,000   119,448,000
Debt Securities [Member]
         
Schedule Of Trading Securities And Other Trading Assets [Line Items]          
Total investment securities, trading $ 98,225,000   $ 98,225,000   $ 70,805,000