Condensed Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Treasury stock, at cost, shares of Class A common stock	19,041,000	18,041,000
Class A Common Stock [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	197,924,000	141,955,000
Common stock, shares outstanding	178,883,000	123,914,000
Class B Common Stock [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	34,848,000	34,848,000
Common stock, shares outstanding	34,848,000	34,848,000