CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Securities held-to-maturity, fair value (in dollars)	$ 65,659	$ 50,964
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, par value per share	$ 0	$ 0
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	26,333,368	26,322,147
Common stock, shares outstanding	26,333,368	26,322,147
Series C convertible perpetual preferred stock
Preferred stock, shares issued	21,004	21,004
Preferred stock, shares outstanding	21,004	21,004
Preferred stock, liquidation preference (in dollars)	$ 21,004	$ 21,004