Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2014	Oct. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 624,605	$ 536,323
Bank loans and other investments	147,116	685,681
Senior and subordinated note obligations	151,982	279,127
Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	30,167	22,727
Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4,033	5,378
Equity Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	206,352	269,683
Cost Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	3,008	3,011
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	19,599	104,261
Total financial assets	149,199	219,982
Level 1 [Member] | Assets Of Consolidated Collateralized Loan Obligation Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	8,697	29,970
Level 1 [Member] | Trading Account Assets [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	86,504	61,615
Level 1 [Member] | Trading Account Assets [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	10,799	7,053
Level 1 [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	23,600	17,083
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	60,312	2,900
Derivative instruments	4,416	334
Total financial assets	501,413	860,230
Level 2 [Member] | Financial Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	2,618	8,412
Securities sold, not yet purchased	981	687
Total financial liabilities	6,271	11,750
Level 2 [Member] | Financial Liabilities [Member] | Liabilities Of Consolidated Collateralized Loan Obligation Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior and subordinated note obligations	2,672	2,651
Level 2 [Member] | Assets Of Consolidated Collateralized Loan Obligation Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank loans and other investments	146,315	684,436
Level 2 [Member] | Trading Account Assets [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	53,745	56,143
Level 2 [Member] | Trading Account Assets [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	73,025	90,597
Level 2 [Member] | Trading Account Assets [Member] | Short Term Debt Investment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	156,972	20,116
Level 2 [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	6,567	5,644
Level 2 [Member] | Cost Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	61	60
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	801	1,245
Level 3 [Member] | Financial Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial liabilities	149,310	276,476
Level 3 [Member] | Financial Liabilities [Member] | Liabilities Of Consolidated Collateralized Loan Obligation Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior and subordinated note obligations	149,310	276,476
Level 3 [Member] | Assets Of Consolidated Collateralized Loan Obligation Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank loans and other investments	801	1,245
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	213,332	278,012
Other Assets Not Held At Fair Value Investments [Member] | Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4,033	5,378
Other Assets Not Held At Fair Value Investments [Member] | Equity Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	206,352	269,683
Other Assets Not Held At Fair Value Investments [Member] | Cost Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	2,947	2,951
Total Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	79,911	107,161
Derivative instruments	4,416	334
Total financial assets	864,745	1,359,469
Total Fair Value [Member] | Financial Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	2,618	8,412
Securities sold, not yet purchased	981	687
Total financial liabilities	155,581	288,226
Total Fair Value [Member] | Financial Liabilities [Member] | Liabilities Of Consolidated Collateralized Loan Obligation Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior and subordinated note obligations	151,982	279,127
Total Fair Value [Member] | Assets Of Consolidated Collateralized Loan Obligation Entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	8,697	29,970
Bank loans and other investments	147,116	685,681
Total Fair Value [Member] | Trading Account Assets [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	140,249	117,758
Total Fair Value [Member] | Trading Account Assets [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	83,824	97,650
Total Fair Value [Member] | Trading Account Assets [Member] | Short Term Debt Investment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	156,972	20,116
Total Fair Value [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	30,167	22,727
Total Fair Value [Member] | Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4,033	5,378
Total Fair Value [Member] | Equity Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	206,352	269,683
Total Fair Value [Member] | Cost Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 3,008	$ 3,011