Variable Interest Entities (Summary of the Amounts Related to VIE that are Consolidated on the Companys Income Statement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Other Income (Expense) Of Consolidated Variable Interest Entity [Abstract]
Gains and other investment income, net	$ 70,272	$ 16,882	$ 0
Interest and other expense	(59,350)	(15,286)	$ 0
Consolidated Securitized CLO Entities [Member]
Other Income (Expense) Of Consolidated Variable Interest Entity [Abstract]
Gains and other investment income, net	66,964	10,264
Interest and other expense	(57,860)	(11,796)
Net gain (loss) attributable to the Company	9,104	(1,532)
Consolidated Warehouse CLO Entities [Member]
Other Income (Expense) Of Consolidated Variable Interest Entity [Abstract]
Gains and other investment income, net	3,308	6,618
Interest and other expense	(1,490)	(3,490)
Net gain (loss) attributable to the Company	$ 1,818	$ 3,128