Non-operating income (expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Interest and other income	$ 43,665	$ 35,150	$ 22,501
Net gain (losses) on investments and derivatives	8,255	(24,319)	(1,901)
Net foreign currency losses	(880)	(765)	(1,297)
Gains and other investment income, net	51,040	10,066	19,303
Interest expense	(23,795)	(23,629)	(27,496)
Loss on extinguishment of debt	0	0	(5,396)
Other income (expense) of consolidated collateralized loan obligation (CLO) entities:
Interest income	74,512	14,883	0
Net gains (losses) on bank loans and other investments note obligations	(4,240)	1,999	0
Gains and other investment income, net	70,272	16,882	0
Structuring and closing fees	(6,337)	(4,830)	0
Interest expense	(53,013)	(10,456)	0
Interest and other expense	(59,350)	(15,286)	0
Total non-operating income (expense)	$ 38,167	$ (11,967)	$ (13,589)
Hexavest [Member]
Gains (losses) on investment
Additional interest that may be purchased by the Company		26.00%
Loss recognized on determination not to acquire addition ownership percentage		$ 6,500