Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Oct. 31, 2019
Fair Value Measurement [Domain]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	$ 123,465	$ 181,907
Investments held at cost	20,904	20,904
Investments in equity method investees	138,454	139,510
Derivative instruments, assets	2,966	2,075
Assets of consolidated CLO entities: Bank loans and other investments	1,290,583	1,704,270
Total financial assets	2,512,117	2,948,991
Derivative instruments, liabilities	4,165	3,314
Liabilities of consolidated CLO entities: Senior and subordinated note obligations	1,218,216	1,617,095
Total financial liabilities	1,222,381	1,620,409
Fair Value Measurement [Domain] \| Debt and Equity Securities Held in Separately Managed Accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	56,149	55,426
Investment securities	23,363	21,236
Fair Value Measurement [Domain] \| Debt Securities: Short-term [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	280,590	297,845
Fair Value Measurement [Domain] \| Debt Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	351,976	330,966
Fair Value Measurement [Domain] \| Equity Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	211,766	183,106
Fair Value Measurement [Domain] \| Equity Securities: Non-consolidated sponsored funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	10,502	10,329
Fair Value Measurement [Domain] \| Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in non-consolidated CLO entities	1,399	1,417
Investments held at cost	20,904	20,904
Other Assets Not Held at Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	0
Investments held at cost	20,904	20,904
Investments in equity method investees	138,454	139,510
Derivative instruments, assets	0	0
Assets of consolidated CLO entities: Bank loans and other investments	0	0
Total financial assets	160,757	161,831
Derivative instruments, liabilities	0	0
Liabilities of consolidated CLO entities: Senior and subordinated note obligations	0	0
Total financial liabilities	0	0
Other Assets Not Held at Fair Value [Member] \| Debt and Equity Securities Held in Separately Managed Accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Investment securities	0	0
Other Assets Not Held at Fair Value [Member] \| Debt Securities: Short-term [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Other Assets Not Held at Fair Value [Member] \| Debt Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Other Assets Not Held at Fair Value [Member] \| Equity Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	0	0
Other Assets Not Held at Fair Value [Member] \| Equity Securities: Non-consolidated sponsored funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	0	0
Other Assets Not Held at Fair Value [Member] \| Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in non-consolidated CLO entities	1,399	1,417
Level 1 [Member] \| Fair Value Measurement [Domain]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	17,883	24,640
Investments held at cost	0	0
Investments in equity method investees	0	0
Derivative instruments, assets	0	0
Assets of consolidated CLO entities: Bank loans and other investments	0	0
Total financial assets	128,533	126,268
Derivative instruments, liabilities	0	0
Liabilities of consolidated CLO entities: Senior and subordinated note obligations	0	0
Total financial liabilities	0	0
Level 1 [Member] \| Fair Value Measurement [Domain] \| Debt and Equity Securities Held in Separately Managed Accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Investment securities	23,146	21,168
Level 1 [Member] \| Fair Value Measurement [Domain] \| Debt Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Level 1 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	77,572	70,646
Level 1 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Non-consolidated sponsored funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	9,932	9,814
Level 1 [Member] \| Debt Securities: Short-term [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Level 1 [Member] \| Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in non-consolidated CLO entities	0	0
Level 2 [Member] \| Fair Value Measurement [Domain]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	105,582	157,267
Investments held at cost	0	0
Investments in equity method investees	0	0
Derivative instruments, assets	2,966	2,075
Assets of consolidated CLO entities: Bank loans and other investments	1,286,525	1,702,769
Total financial assets	2,218,769	2,659,391
Derivative instruments, liabilities	4,165	3,314
Liabilities of consolidated CLO entities: Senior and subordinated note obligations	1,218,216	1,617,095
Total financial liabilities	1,222,381	1,620,409
Level 2 [Member] \| Fair Value Measurement [Domain] \| Debt and Equity Securities Held in Separately Managed Accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	56,149	55,426
Investment securities	217	68
Level 2 [Member] \| Fair Value Measurement [Domain] \| Debt Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	351,976	330,966
Level 2 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	134,194	112,460
Level 2 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Non-consolidated sponsored funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	570	515
Level 2 [Member] \| Debt Securities: Short-term [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	280,590	297,845
Level 2 [Member] \| Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in non-consolidated CLO entities	0	0
Level 3 [Member] \| Fair Value Measurement [Domain]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	0	0
Investments held at cost	0	0
Investments in equity method investees	0	0
Derivative instruments, assets	0	0
Assets of consolidated CLO entities: Bank loans and other investments	4,058	1,501
Total financial assets	4,058	1,501
Derivative instruments, liabilities	0	0
Liabilities of consolidated CLO entities: Senior and subordinated note obligations	0	0
Total financial liabilities	0	0
Level 3 [Member] \| Fair Value Measurement [Domain] \| Debt and Equity Securities Held in Separately Managed Accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Investment securities	0	0
Level 3 [Member] \| Fair Value Measurement [Domain] \| Debt Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Level 3 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Held by consolidated sponsored funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	0	0
Level 3 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Non-consolidated sponsored funds and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	0	0
Level 3 [Member] \| Debt Securities: Short-term [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	0	0
Level 3 [Member] \| Investments in non-consolidated CLO entities [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investments in non-consolidated CLO entities	$ 0	$ 0

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- Definition

Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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- Definition

Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

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No definition available.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value portion of investments accounted under the equity method.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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Fair value portion of notes payable.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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