Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash dividends per share	$ 1.25	$ 1.24	$ 1.21
Common stock options exercised, shares	100,302	7,510
Common Stock [Member]
Grant of restricted stock, shares	52,825	52,700
Forfeiture of restricted stock, shares	1,664	840
Common stock options exercised, shares	100,302	7,510	4.0447
Treasury Stock [Member]
Purchase of treasury stock, shares	1,596	455	0.0676
Distribution of treasury stock for deferred compensation plan, shares	3,827	4,710	0.3069