Non-operating income (expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Interest and other income	$ 5,420	$ 11,534	$ 14,756	$ 21,354
Net gains (losses) on investments and derivatives	(56,241)	3,716	(49,241)	69
Net foreign currency losses	309	(44)	63	(384)
Gains (losses) and other investment income, net	(50,512)	15,206	(34,422)	21,039
Interest expense	(6,364)	(5,888)	(12,252)	(12,019)
Other income (expense) of consolidated CLO entities:
Interest income	16,480	15,059	41,385	26,809
Net gains (losses) on bank loans and other investments and note obligations	(21,321)	6,735	(30,663)	426
Gains (losses) and other investment income, net	(4,841)	21,794	10,722	27,235
Structuring and closing fees	(43)	(18)	(279)	(119)
Interest expense	(11,604)	(10,803)	(28,764)	(19,038)
Interest and other expense	(11,647)	(10,821)	(29,043)	(19,157)
Total non-operating income (expense)	$ (73,364)	$ 20,291	$ (64,995)	$ 17,098