Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accounting Policies [Abstract]
Interest bearing amounts held at other financial institutions	$ 77.4	$ 28.7	$ 77.4	$ 28.7
Dilutive effect of common stock issuable upon exercise of options	403,367	86,528	407,795	150,946
Anti-dilutive shares	0	540,525	0	371,885