Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement Of Stockholders Equity [Abstract]
Cash dividends declared per share	$ 0.31	$ 0.28	$ 0.91	$ 0.84
Purchase of treasury shares, shares	8,720		16,826