Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis Classified as Level 3 (Details) - Bank Loans and Other Investments of Consolidated CLO Entities [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 4,058	$ 1,362	$ 1,501	$ 1,547
Paydowns	(6)	(6)	(13)	(12)
Purchases	108		429
Net gains (losses) included in net income	(1)	(218)	37	(397)
Transfers into Level 3	0		2,205
Transfers out of Level 3	(2,228)		(2,228)
Ending balance	$ 1,931	$ 1,138	$ 1,931	$ 1,138