Fair Value Measurements Level 3 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013	Oct. 31, 2013
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Principal repayments of senior note obligations			$ (63,780)	$ (83,742)
Bank Loans And Other Investments Of Consolidated CLO Entity [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurements with unobservable inputs reconciliation recurring basis asset value, beginning of period (asset)	7	2,658	1,245	2,203	2,203
Net gains (losses) on investments and note obligations included in net income	0	57	(186)	21
Sales (asset)			(1,052)
Principal repayments of senior note obligations	0	0	0	0
Transfers into Level 3 (asset)	0	104	0	595
Fair value measurements with unobservable inputs reconciliation recurring basis asset value, end of period (asset)	7	2,819	7	2,819
Change in unrealized (losses) gains included in net income relating to assets and liabilities held (asset)	0	57	(9)	21
Senior And Subordinated Note Obligations And Redeemable Preferred Shares Of Consolidated CLO Entities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value measurements with unobservable inputs reconciliation recurring basis liability value, beginning of period (liability)	665,970	408,924	276,476	443,946	443,946
Issuance of senior and subordinated notes and redeemable preferred shares			421,523
Net gains (losses) on investments and note obligations included in net income	1,026	1,671	(1,135)	5,256
Amortization of original issue discount on senior notes	75	0	75	0
Principal repayments of senior note obligations	(33,912)	(45,135)	(63,780)	(83,742)
Transfers into Level 3 (asset)			0	0
Fair value measurements with unobservable inputs reconciliation recurring basis liability value, end of period (liability)	633,159	365,460	633,159	365,460	276,476
Change in unrealized (losses) gains included in net income relating to assets and liabilities held (liability)	$ 1,026	$ 1,671	$ (1,135)	$ 5,256
Senior and subordinated note obligations prepayment rate			30.00%		30.00%
Senior and subordinated note obligations recovery rate			70.00%		70.00%
Senior and subordinated note obligations and redeemable preferred shares probability of default minimum			1.00%
Senior and subordinated note obligations and redeemable preferred shares probability of default			2.00%		2.00%
Senior and subordinated note obligations minimum discount rate			0.85%		1.05%
Senior and subordinated note obligations maximum discount rate			7.00%		3.75%