CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION
Marketable securities available-for-sale, amortized cost (in dollars)	$ 1,008,975	$ 1,022,078
Marketable securities held-to-maturity, fair value (in dollars)	$ 120,933	$ 124,061
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	94,464,430	94,243,713