Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements Of Changes In Shareholders' Equity [Abstract]
Common stock cash dividends, per share, adjusted	$ 0.608	$ 0.564	$ 0.468
Stock dividend, rate	5.00%	5.00%	5.00%
Common stock dividend, shares at fair value	463,193	447,092	422,439
Repurchased stock, in shares	222,594
Issuance and reissuance of stock:
Shares under the dividend reinvestment and stock purchase plan	26,061	19,614	16,553
Shares under the employee stock option plan	10,321	47,164	11,857
Shares of stock-based compensation awards	21,033	29,062	24,431
Shares under employee stock purchase plan	13,127	10,607	10,732