Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements Of Changes In Shareholders' Equity [Abstract]
Common stock dividends, per share	$ 1.095	$ 1.045	$ 1.04
Issuance of common stock, shares		82,021	800,000
Issuance of preferred stock, shares			18,751
Purchase of preferred stock shares and warrants, shares		18,751
Stock options exercised, shares	78,035	57,141	22,775
Purchase of treasury stock, shares	22,087	10,000	5,571