Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Consolidated Statements Of Changes In Shareholders' Equity [Abstract]
Cash dividends declared	$ 0.27	$ 0.24	$ 0.78	$ 0.69
Acquisition of treasury stock, shares			2,605
Treasury shares issued under employee stock purchase plan, shares	381	241	2,944	6,568
Treasury shares issued under dividend reinvestment plan, shares	12,957	5,723	30,966	22,990
Common stock issued under incentive stock option plans, shares	1,600		12,268