Variable Interest Entities (Summary of the Amounts Related to VIE that are Consolidated on the Company's Income Statement) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Other income (expense) of consolidated CLO entities:
Gains (losses) and other investment income, net	$ (4,841)	$ 21,794	$ 10,722	$ 27,235
Interest and other expense	(11,647)	(10,821)	(29,043)	(19,157)
Consolidated Securitized CLO Entities [Member]
Other income (expense) of consolidated CLO entities:
Gains (losses) and other investment income, net	(4,841)	17,355	10,722	21,933
Interest and other expense	(11,647)	(9,680)	(29,043)	(17,925)
Net gain (loss) attributable to the Company	$ (16,488)	7,675	$ (18,321)	4,008
Consolidated Warehouse CLO Entities [Member]
Other income (expense) of consolidated CLO entities:
Net gain (loss) attributable to the Company		$ 3,300		$ 4,100