Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Feb. 29, 2012	Nov. 30, 2011
Consolidated Statements of Financial Condition [Abstract]
Securities pledged to creditors	$ 11,614,619	$ 12,452,970
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	209,061,653	197,197,848
Treasury stock, at cost	3,242,869	37,842