Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Assets
Securities held to maturity fair value	$ 61,535	$ 72,198
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	2,500,000	2,500,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	50,000,000
Common stock, shares issued (in shares)	39,305,131	38,035,539
Common stock in treasury, at cost (in shares)	5,529,781	4,878,829