Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Available-for-sale securities encumbered	$ 254,190	$ 309,816
Estimated fair value of securities held-to-maturity	2,309	3,771
Held-to-maturity securities encumbered	$ 0	$ 0
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	46,904,286	46,904,286
Common stock, shares outstanding	41,486,819	40,518,591
Treasury stock, shares	5,417,467	5,114,020