CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) (Unaudited) (USD $)	Jun. 30, 2011	Sep. 30, 2010
CONDENSED CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Unaudited) - Parenthetical [Abstract]
Preferred stock; par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock; shares authorized (in shares)	10,000,000	10,000,000
Preferred stock; shares issued (in shares)	0	0
Preferred stock; shares outstanding (in shares)	0	0
Common stock; par value (in dollars per share)	$ 0.01	$ 0.01
Common stock; shares authorized (in shares)	350,000,000	350,000,000
Common stock; shares issued (in shares)	130,370,735	128,620,429
Shares exchangeable into common stock (in shares)	0	243,048
Treasury stock, shares (in shares)	3,798,214	3,918,492