Consolidated Statements Of Changes In Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Stockholders' Equity [Abstract]
Cash dividends declared (in dollars per share)	$ 0.46	$ 0.44
Exercise of stock options (in shares)	7,388	1,250
Stock issued during period (in shares)	0	440,604
Purchase of treasury shares (in shares)	204,327	0