Fair Value Measurements (Tables)
 6 Months Ended
Apr. 30, 2013
Fair Value Measurements Disclosure Table [Abstract]  
Summary of the assets and liabilites measured at fair value on a recurring basis and their assigned levels within the hierarchy.
April 30, 2013              
(in thousands)    Level 1 Level 2 Level 3 Other Assets Not Held at Fair Value  Total
                
Financial assets:              
Cash equivalents   $ 10,222$ 126,947$ -$ -$ 137,169
Investments:              
Investment securities, trading – debt  37,846  60,379   -  -  98,225
Investment securities, trading – equity  124,808  61,988   -  -  186,796
Investment securities, available-for-sale  14,686  5,084  -  -  19,770
Investment in non-consolidated CLO            
entity(1)  -  -  -  314  314
Investments in equity method investees(2)  -  -  -  229,422  229,422
Investments, other(3)  -  61  -  7,470  7,531
Derivative instruments     -  1,174  -  -  1,174
Assets of consolidated CLO entity:            
Cash equivalents     59,485  -  -  -  59,485
Bank loans and other investments -  316,502  2,819  -  319,321
Total financial assets   $ 247,047$ 572,135$ 2,819$ 237,206$ 1,059,207

Financial liabilities:              
Derivative instruments $ -$ 6,453$ -$ -$ 6,453
Securities sold, not yet purchased  -  1,603  -  -  1,603
Liabilities of consolidated CLO entity:            
Senior and subordinated note obligations -  2,667  365,460  -  368,127
Total financial liabilities   $ -$ 10,723$ 365,460$ -$ 376,183

October 31, 2012              
(in thousands)    Level 1 Level 2 Level 3 Other Assets Not Held at Fair Value  Total
                
Financial assets:              
Cash equivalents   $ 16,390$ 139,469$ -$ -$ 155,859
Investments:              
Investment securities, trading – debt  4,512  66,293   -  -  70,805
Investment securities, trading – equity  87,991  31,457   -  -  119,448
Investment securities, available-for-sale  26,736  4,412  -  -  31,148
Investment in non-consolidated CLO            
entity(1)  -  -  -  350  350
Investments in equity method investees(2)  -  -  -  257,652  257,652
Investments, other(3)  -  60  -  7,470  7,530
Derivative instruments     -  2,229  -  -  2,229
Assets of consolidated CLO entity:            
Cash equivalents     34,561  -  -  -  34,561
Bank loans and other investments 98  428,282  2,203  -  430,583
Total financial assets   $ 170,288$ 672,202$ 2,203$ 265,472$ 1,110,165
                
Financial liabilities:              
Derivative instruments $ -$ 788$ -$ -$ 788
Securities sold, not yet purchased  -  26,142  -  -  26,142
Liabilities of consolidated CLO entity:            
Senior and subordinated note obligations -  2,659  443,946  -  446,605
Total financial liabilities   $ -$ 29,589$ 443,946$ -$ 473,535
(1)The Company’s investment in this CLO entity is measured at fair value on a non-recurring basis using Level 3 inputs. 
 The investment is carried at amortized cost unless facts and circumstances indicate that the investment has been  
 impaired, at which time the investment is written down to fair value. There was no re-measurement of this asset during  
 the six month period ended April 30, 2013 or the twelve month period ended October 31, 2012. 
(2)Investments in equity method investees are not measured at fair value in accordance with GAAP.
(3)Investments, other include investments carried at cost that are not measured at fair value in accordance with GAAP.
Summary of fair value transfers between level 1 and level 2
     Three Months Ended April 30,  Six Months Ended April 30,
(in thousands)  2013 2012  2013 2012
Transfers from Level 1 into Level 2(1) $ 120$ - $ 120$ 7,204
Transfers from Level 2 into Level 1(2)   137  2,620   1,743  -
             
(1) Transfers from Level 1 into Level 2 primarily represent debt and equity securities that were valued based on prices of similar
 securities because unadjusted quoted market prices were not available in the current period.
(2) Transfers from Level 2 into Level 1 primarily represent debt and equity securities due to the availability of unadjusted quoted
 market prices in active markets.
Summary of the changes in Level 3 assets and liabilities measured at fair value on a recurring basis
    Three Months Ended  Three Months Ended
    April 30, 2013  April 30, 2012
(in thousands) Bank loans and other investments of consolidated CLO entity  Senior and subordinated note obligations of consolidated CLO entity  Bank loans and other investments of consolidated CLO entity  Senior and subordinated note obligations of consolidated CLO entity
              
Beginning balance$ 2,658 $ 408,924 $ 4,728 $ 480,345
Net gains (losses) on investments and            
 note obligations included in net           
 income(1)  57   1,671   (9)   5,301
Principal paydown 0   (45,135)  0   -
Transfers into Level 3(2)  104   -   15   -
Transfers out of Level 3(3)  -   -   (2,584)   (2,584)
Ending balance$ 2,819 $ 365,460 $ 2,150 $ 483,062
Change in unrealized (losses) gains          
 included in net income relating to            
 assets and liabilities held$ 57 $ 1,671 $ (9) $ 5,301

    Six Months Ended  Six Months Ended
    April 30, 2013  April 30, 2012
(in thousands) Bank loans and other investments of consolidated CLO entity  Senior and subordinated note obligations of consolidated CLO entity  Bank loans and other investments of consolidated CLO entity  Senior and subordinated note obligations of consolidated CLO entity
              
Beginning balance$ 2,203 $ 443,946 $ 5,910 $ 477,699
Net gains (losses) on investments and            
 note obligations included in net           
 income(1)  21   5,256   (49)   7,947
Principal paydown 0   (83,742)  0   -
Transfers into Level 3(2)  595   -   15   -
Transfers out of Level 3(3)  -   -   (3,726)   (2,584)
Ending balance$ 2,819 $ 365,460 $ 2,150 $ 483,062
Change in unrealized (losses) gains          
 included in net income relating to            
 assets and liabilities held$ 21 $ 5,256 $ (49) $ 7,947
(1)Substantially all net gains and losses on investments and note obligations attributable to the assets and borrowings of the Company's
  consolidated CLO entity are allocated to non-controlling and other beneficial interests on the Company's Consolidated Statements of Income.
(2)Transfers into Level 3 were the result of a reduction in the availability of significant observable inputs used in determining the fair value
  of a second lien term loan. Fair value was determined utilizing a discounted cash flow analysis.
(3)Transfers out of Level 3 into Level 2 were due to an increase in the observability of the inputs used in determining the fair value of certain
  instruments.
Summary of quantitative information about Level 3 fair value measurements
 April 30, 2013   Valuation  Unobservable  
 ($ in thousands) Fair Value  Technique Inputs(1) Range
          
 Liabilities of consolidated CLO entity:        
          
       Prepayment rate 30 percent
       Recovery rate 70 percent
 Senior and subordinated     Default rate 200 bps
  note obligations$ 365,460 Income approach Discount rate 105-450 bps
          

 October 31, 2012   Valuation  Unobservable  
 ($ in thousands) Fair Value  Technique Inputs(1) Range
          
 Liabilities of consolidated CLO entity:        
          
       Prepayment rate 30 percent
       Recovery rate 70 percent
 Senior and subordinated     Default rate 200 bps
  note obligations$ 443,946 Income approach Discount rate 135-700 bps
(1) Discount rate refers to spread over LIBOR. Lower spreads relate to the more senior tranches in the CLO note structure;
 higher spreads relate to the less senior tranches. The default rate refers to the constant annual default rate. Prepayment rate
 is the rate at which the underlying collateral is expected to repay principal. Recovery rate is the expected recovery of defaulted
 amounts received through asset sale or recovery through bankruptcy restructuring or other settlement processes.