Non-operating income (expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2012	Apr. 30, 2011
Non-operating income (expense)
Interest and other income	$ 1,956	$ 3,720	$ 3,693	$ 5,783
Net gains on investments and derivatives	1,250	9,358	7,680	8,612
Net foreign currency losses	(410)	(586)	(400)	(583)
Gains and other investment income, net	2,796	12,492	10,973	13,812
Interest expense	(8,412)	(8,412)	(16,825)	(16,825)
Other income (expense) of consolidated CLO entity:
Interest income	5,668	5,356	11,212	10,576
Net gains (losses) on bank loans, other investments and note obligations	3,227	(18,340)	7,963	(21,725)
Gains (losses) and other investment income, net	8,895	(12,984)	19,175	(11,149)
Interest expense	(4,134)	(4,033)	(8,445)	(5,547)
Total non-operating (expense) income	$ (855)	$ (12,937)	$ 4,878	$ (19,709)