Non-operating income (expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Non-operating income (expense)
Interest and other income	$ 9,116	$ 4,643
Net losses on investments and derivatives	(5,545)	(3,936)
Net foreign currency losses	(973)	(213)
Gains and other investment income, net	2,598	494
Interest expense	(5,907)	(7,347)
Other income (expense) of consolidated CLO entity:
Interest income	823	0
Net gains on bank loans	894	0
Gains and other investment income, net	1,717	0
Interest expense	(94)	0
Total non-operating expense	$ (1,686)	$ (6,853)