CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - UNAUDITED (Parenthetical) - $ / shares	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement Of Stockholders Equity [Abstract]
Cash dividends declared per share	$ 0.04	$ 0.04	$ 0.04	$ 0.04	$ 0.04	$ 0.04	$ 0.12	$ 0.12
Treasury stock, shares, acquired	148,035				122,000	220,731	148,035	342,731