Investments (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2012	Oct. 31, 2011
Schedule Of Investments [Line Items]
Investments	$ 295,862	$ 287,735
Corporate Debt Securities [Member] | Debt Securities [Member]
Schedule Of Investments [Line Items]
Investments	0	4,832
Consolidated Funds [Member] | Equity Securities [Member]
Schedule Of Investments [Line Items]
Investments	107,638	74,434
Consolidated Funds [Member] | Debt Securities [Member]
Schedule Of Investments [Line Items]
Investments	55,523	69,083
Separately Managed Accounts [Member] | Equity Securities [Member]
Schedule Of Investments [Line Items]
Investments	39,964	33,553
Separately Managed Accounts [Member] | Debt Securities [Member]
Schedule Of Investments [Line Items]
Investments	21,212	11,307
Sponsored Funds [Member]
Schedule Of Investments [Line Items]
Investments	37,323	39,841
CLO Entity [Member]
Schedule Of Investments [Line Items]
Investments	449	278
Investments In Affiliates [Member]
Schedule Of Investments [Line Items]
Investments	26,246	46,900
Other Investments [Member]
Schedule Of Investments [Line Items]
Investments	$ 7,507	$ 7,507