Investments (Details) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2013	Oct. 31, 2012
Schedule Of Investments [Line Items]
Investments	$ 545,474	$ 486,933
Total investment securities, trading	249,125	190,253
Equity Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	90,222	119,448
Debt Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	148,426	70,805
Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	249,125	190,253
Cash Management Assets [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	10,477
Cash Management Assets [Member] \| Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Investments	10,477
Consolidated Sponsored Funds [Member] \| Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Investments	181,275	157,405
Separately Managed Accounts [Member] \| Categories of Investments, Marketable Securities, Trading Securities [Member]
Schedule Of Investments [Line Items]
Investments	57,373	32,848
Available-for-sale Securities [Member]
Schedule Of Investments [Line Items]
Investments	17,457	31,148
Collateralized Loan Obligations [Member]
Schedule Of Investments [Line Items]
Investments	317	350
Equity Method Investments [Member]
Schedule Of Investments [Line Items]
Investments	271,044	257,652
Cost Method Investments [Member]
Schedule Of Investments [Line Items]
Investments	$ 7,531	$ 7,530

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 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 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 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 5: 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 6: 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.

Reference 7: 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 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

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

+ Details