Non-operating Income (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Interest and other income	$ 35,150	$ 22,501	$ 11,515
Net gains (losses) on investments and derivatives	(24,319)	(1,901)	(116)
Net foreign currency gains (losses)	(765)	(1,297)	1,012
Gains (losses) and other investment income, net	10,066	19,303	12,411
Interest expense	(23,629)	(27,496)	(29,410)
Loss on extinguishment of debt	0	(5,396)	0
Other income (expense) of consolidated CLO entities:
Interest income	14,883	0	17,975
Net gains on bank loans and other investments and note obligations	1,999	0	6,094
Gains and other investment income, net	16,882	0	24,069
Structuring and closing fees	(4,830)	0	0
Interest expense	(10,456)	0	(13,286)
Interest and other expense	15,286	0	13,286
Total non-operating expense	$ (11,967)	$ (13,589)	$ (6,216)
Hexavest [Member]
Other income (expense) of consolidated CLO entities:
Additional Interest That May Be Purchased By The Company	26.00%	26.00%
Loss recognized on option write-off	$ 6,500