Segment Reporting (Details) (USD $) In Thousands	3 Months Ended		8 Months Ended	9 Months Ended
	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2010	Aug. 31, 2011
Net revenues, expenses, and total assets by segment
Net revenues	$ 509,282	$ 517,269	$ 1,512,437	$ 1,994,830
Expenses	468,715	443,308	1,239,369	1,639,993
Capital Markets [Member]
Net revenues, expenses, and total assets by segment
Net revenues	506,200	516,500	1,500,600	1,957,300
Expenses	463,700	435,000	1,218,800	1,616,000
Asset Management [Member]
Net revenues, expenses, and total assets by segment
Net revenues	3,100	800	11,800	37,500
Expenses	$ 5,000	$ 8,300	$ 20,600	$ 24,000