Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Apr. 30, 2020	Oct. 31, 2019
Fair Value Measurement [Domain]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	$ 22,473	$ 181,907
Investments held at cost	20,928	20,904
Investments in non-consolidated CLO entities	1,380	1,417
Investments in equity method investees	133,061	139,510
Derivative instruments, assets	10,787	2,075
Assets of consolidated CLO entities: Bank loans and other investments	1,135,609	1,704,270
Total financial assets	1,803,948	2,948,991
Derivative instruments, liabilities	4,793	3,314
Liabilities of consolidated CLO entities: Senior and subordinated note obligations	1,088,574	1,617,095
Total financial liabilities	1,093,367	1,620,409
Fair Value Measurement [Domain] \| Debt Securities: Short-term [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	16,427	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	209,427	330,966
Fair Value Measurement [Domain] \| Debt Securities: Held in separately managed accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	53,627	55,426
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	165,262	183,106
Fair Value Measurement [Domain] \| Equity Securities: Held in separately managed accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	21,065	21,236
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	13,902	10,329
Investments held at cost	20,928	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	20,928	20,904
Investments in non-consolidated CLO entities	1,380	1,417
Investments in equity method investees	133,061	139,510
Derivative instruments, assets	0	0
Assets of consolidated CLO entities: Bank loans and other investments	0	0
Total financial assets	155,369	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 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] \| Debt Securities: Held in separately managed accounts [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: 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: Held in separately managed accounts [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
Level 1 [Member] \| Fair Value Measurement [Domain]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	19,473	24,640
Investments held at cost	0	0
Investments in non-consolidated CLO entities	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	129,242	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 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] \| Debt Securities: Held in separately managed accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	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	75,514	70,646
Level 1 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Held in separately managed accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	20,869	21,168
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	13,386	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 2 [Member] \| Fair Value Measurement [Domain]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash equivalents	3,000	157,267
Investments held at cost	0	0
Investments in non-consolidated CLO entities	0
Investments in equity method investees	0	0
Derivative instruments, assets	10,787	2,075
Assets of consolidated CLO entities: Bank loans and other investments	1,133,678	1,702,769
Total financial assets	1,517,406	2,659,391
Derivative instruments, liabilities	4,793	3,314
Liabilities of consolidated CLO entities: Senior and subordinated note obligations	1,088,574	1,617,095
Total financial liabilities	1,093,367	1,620,409
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	209,427	330,966
Level 2 [Member] \| Fair Value Measurement [Domain] \| Debt Securities: Held in separately managed accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	53,627	55,426
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	89,748	112,460
Level 2 [Member] \| Fair Value Measurement [Domain] \| Equity Securities: Held in separately managed accounts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities	196	68
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	516	515
Level 2 [Member] \| Debt Securities: Short-term [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Investment securities, trading	16,427	297,845
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 non-consolidated CLO entities	0
Investments in equity method investees	0	0
Derivative instruments, assets	0	0
Assets of consolidated CLO entities: Bank loans and other investments	1,931	1,501
Total financial assets	1,931	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 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] \| Debt Securities: Held in separately managed accounts [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: 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: Held in separately managed accounts [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

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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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- Definition

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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- Definition

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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