Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investment securities available for sale, amortized cost	$ 320,030	$ 311,747
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	16,527,323	16,390,608
Common stock, shares outstanding	13,551,438	13,412,690
Common stock in treasury, shares	2,975,885	2,977,918