Investments (Tables)
12 Months Ended
Oct. 31, 2011
Investments Table [Abstract]  
Summary of investments
 (in thousands)2011  2010
  Corporate debt securities$ 4,832  $ 4,732
  Consolidated funds:      
  Debt securities  69,083    111,585
  Equity securities  74,434    88,184
  Separately managed accounts:      
  Debt securities  11,307    3,666
  Equity securities  33,553    28,692
  Sponsored funds  39,841    37,541
  CLO entities  278    1,391
  Investments in affiliates  46,900    51,111
  Other investments  7,507    7,507
 Total investments$ 287,735  $ 334,409
Summary of investments classified as trading securities
  2011     
  (in thousands)CostFair Value
   Debt securities$ 83,852 $ 85,222
   Equity securities  105,230   107,987
  Total investments$ 189,082 $ 193,209
        
  2010     
  (in thousands)CostFair Value
   Debt securities$ 119,159 $ 119,983
   Equity securities  111,814   116,876
  Total investments$ 230,973 $ 236,859
Summary of investments classified as available-for-sale securities
 2011    Gross Unrealized   
 (in thousands)Cost Gains Losses Fair Value
  Sponsored funds$ 34,368 $ 5,518 $(45) $ 39,841

 2010    Gross Unrealized   
 (in thousands)Cost Gains Losses Fair Value
  Sponsored funds$ 34,300 $ 3,655 $(414) $ 37,541
Summary of realized gains and losses upon disposition of sponsored funds classified as available-for-sale
 (in thousands)201120102009
 Gains$ 3,212$ 3,108$ 1,959
 Losses  (2,626)  (60)  (397)
 Net realized gains $ 586$ 3,048$ 1,562