Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Consolidated Statements Of Changes In Shareholders' Equity [Abstract]
Cash dividends declared, per share	$ 0.35	$ 0.34
Exercise of stock options, shares	16,899	5,476
Purchase of common stock for treasury, shares	88,000	270,745