Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends declared (in dollars per share)	$ 0.57	$ 0.53	$ 1.63	$ 1.45
Exercise of stock options (in shares)	3,581	3,986	11,721	29,133
Purchase of treasury shares (in shares)	98,724	7,000	260,674	221,327