Consolidated Statements of Condition (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Held-to-Maturity, Fair Value (in dollars)	$ 3,679,208	$ 3,687,676
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, authorized shares	500,000,000	500,000,000
Common Stock, issued shares	57,465,782	57,319,352
Common Stock, outstanding shares	44,861,335	44,754,835
Treasury Stock, Shares	12,604,447	12,564,517