Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements Of Changes In Shareholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Declared	$ 0.93	$ 0.82	$ 0.74
Acquisition of treasury stock, shares		34,048
Treasury shares issued under stock option plan, shares	6,827	907	4,794
Treasury shares issued under dividend reinvestment plan, shares	30,375	45,068
Common stock issued under dividend reinvestment plan, shares		25,230	52,755
Common stock issued under stock option plans, shares	750	3,800