Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Stockholders Equity [Abstract]
Cash dividends declared per common share	$ 0.60	$ 0.60	$ 0.51	$ 0.51	$ 1.20	$ 1.02