Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Oct. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 285,986	$ 287,735
Bank loans and other investments	458,392	462,586
Senior and subordinated note obligations	477,096	477,699
Investment Securities, Available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	34,156	39,841
Investment in Non-Consolidated CLO Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	349	278
Investment In Equity Method Investees [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	37,748	46,900
Investments, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7,507	7,507
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	7,002	6,691
Total financial assets	195,123	172,831
Level 1 [Member] | Assets Of Consolidated Collateralized Loan Obligation Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	31,156	15,829
Bank loans and other investments	69	85
Level 1 [Member] | Investment Securities, Trading [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	122,520	102,790
Level 1 [Member] | Investment Securities, Trading [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4,529	11,308
Level 1 [Member] | Investment Securities, Available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	29,847	36,128
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	210,059	360,676
Derivative instruments	316	1,060
Total financial assets	750,103	901,188
Level 2 [Member] | Financial Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	3,435	6,654
Securities sold, not yet purchased	26,018	6,270
Total financial liabilities	32,086	12,924
Level 2 [Member] | Financial Liabilities [Member] | Liabilities Of Consolidated Collateralized Loan Obligation Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior and subordinated note obligations	2,633
Level 2 [Member] | Assets Of Consolidated Collateralized Loan Obligation Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank loans and other investments	456,205	456,591
Level 2 [Member] | Investment Securities, Trading [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	18,191	5,197
Level 2 [Member] | Investment Securities, Trading [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	60,986	73,914
Level 2 [Member] | Investment Securities, Available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4,309	3,713
Level 2 [Member] | Investments, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	37	37
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	2,118	5,910
Level 3 [Member] | Financial Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial liabilities	474,463	477,699
Level 3 [Member] | Financial Liabilities [Member] | Liabilities Of Consolidated Collateralized Loan Obligation Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior and subordinated note obligations	474,463	477,699
Level 3 [Member] | Assets Of Consolidated Collateralized Loan Obligation Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank loans and other investments	2,118	5,910
Other Assets Not Held At Fair Value Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	45,567	54,648
Other Assets Not Held At Fair Value Investments [Member] | Investment in Non-Consolidated CLO Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	349	278
Other Assets Not Held At Fair Value Investments [Member] | Investment In Equity Method Investees [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	37,748	46,900
Other Assets Not Held At Fair Value Investments [Member] | Investments, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7,470	7,470
Total Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	217,061	367,367
Derivative instruments	316	1,060
Total financial assets	992,911	1,134,577
Total Fair Value [Member] | Financial Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	3,435	6,654
Securities sold, not yet purchased	26,018	6,270
Total financial liabilities	506,549	490,623
Total Fair Value [Member] | Financial Liabilities [Member] | Liabilities Of Consolidated Collateralized Loan Obligation Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior and subordinated note obligations	477,096	477,699
Total Fair Value [Member] | Assets Of Consolidated Collateralized Loan Obligation Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	31,156	15,829
Bank loans and other investments	458,392	462,586
Total Fair Value [Member] | Investment Securities, Trading [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	140,711	107,987
Total Fair Value [Member] | Investment Securities, Trading [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	65,515	85,222
Total Fair Value [Member] | Investment Securities, Available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	34,156	39,841
Total Fair Value [Member] | Investment in Non-Consolidated CLO Entity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	349	278
Total Fair Value [Member] | Investment In Equity Method Investees [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	37,748	46,900
Total Fair Value [Member] | Investments, Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 7,507	$ 7,507