Investments (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2014	Oct. 31, 2013
Schedule Of Investments [Line Items]
Investments	$ 624,605	$ 536,323
Total investment securities, trading	381,045	235,524
Equity Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	140,249	117,758
Debt Securities [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	83,824	97,650
Trading Account Assets [Member]
Schedule Of Investments [Line Items]
Total investment securities, trading	381,045	235,524
Short Term Debt Investment [Member] | Trading Account Assets [Member]
Schedule Of Investments [Line Items]
Investments	156,972	20,116
Consolidated Sponsored Funds [Member] | Trading Account Assets [Member]
Schedule Of Investments [Line Items]
Investments	172,413	153,327
Separately Managed Accounts [Member] | Trading Account Assets [Member]
Schedule Of Investments [Line Items]
Investments	51,660	62,081
Available-for-sale Securities [Member]
Schedule Of Investments [Line Items]
Investments	30,167	22,727
Investments in non-consolidated CLO entities [Member]
Schedule Of Investments [Line Items]
Investments	4,033	5,378
Equity Method Investments [Member]
Schedule Of Investments [Line Items]
Investments	206,352	269,683
Cost Method Investments [Member]
Schedule Of Investments [Line Items]
Investments	$ 3,008	$ 3,011