Investments (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2012	Oct. 31, 2011
Schedule Of Investments [Line Items]
Investments	$ 486,933	$ 287,735
Total investment securities, trading	190,253	193,209
Equity Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	119,448	107,987
Debt Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	70,805	85,222
Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	190,253	193,209
Corporate Debt Securities [Member] \| Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Investments	0	4,832
Consolidated Sponsored Funds [Member] \| Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Investments	157,405	143,517
Separately Managed Accounts [Member] \| Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Investments	32,848	44,860
Available-for-sale Securities [Member]
Schedule Of Investments [Line Items]
Investments	31,148	39,841
Collateralized Loan Obligations [Member]
Schedule Of Investments [Line Items]
Investments	350	278
Equity Method Investments [Member]
Schedule Of Investments [Line Items]
Investments	257,652	46,900
Cost Method Investments [Member]
Schedule Of Investments [Line Items]
Investments	$ 7,530	$ 7,507

The total of financial instruments that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) or for debt and equity securities formerly categorized as available-for-sale or held-to-maturity which the entity held as of the date it opted to account for such securities at fair value. An enterprise may also categorize such a security as trading without the intent to sell it in the near term assuming the decision to categorize the security as trading occurred at acquisition.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.4)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 29

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Implementation Guide (Q and A)

-Number FAS115

-Paragraph 35

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details