Consolidated Statements of Changes in Shareholders' Equity Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends declared (in dollars per share)	$ 0.53	$ 0.46	$ 1.06	$ 0.92
Exercise of stock options (in shares)	2,502	17,760	8,140	25,147
Purchase of treasury shares (in shares)	107,210	10,000	161,950	214,327