Consolidated Condensed Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Statement of Financial Position [Abstract]
Securities available-for-sale, amortized cost	$ 846,719	$ 801,147
Securities held-to-maturity, amortized cost	$ 768,076	$ 834,574
Preferred stock, shares authorized	200,000	200,000
Preferred stock, shares issued		100,000
Preferred stock per share liquidation preference	$ 1,000	$ 1,000
Common stock no par value
Common stock shares authorized	20,000,000	20,000,000
Common stock shares issued	16,151,007	16,151,021
Treasury stock shares	745,109	745,109