Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Summary Of Significant Accounting Policies [Line Items]
Interest bearing amounts held at other financial institutions	$ 82.0	$ 126.1	$ 82.0	$ 126.1
Dilutive effect of common stock issuable upon exercise of options	236,920	348,675	245,043	372,565
Anti-dilutive shares	57,883	48,416	209,245	0