Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Consolidated Balance Sheets [Abstract]
Available for sale securities, pledged	$ 420,085,000	$ 418,046,000
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 5	$ 5
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	89,277,398	89,277,398
Treasury stock, shares	587,906	217,755