Deposits - Summary of Scheduled Maturities of Time Deposits (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Maturities of Time Deposits [Abstract]
One year or less	$ 138,330	$ 46,325
More than one year to two years	30,789	12,414
More than two years to three years	17,103	9,904
More than three years to four years	7,612	3,980
More than four years to five years	7,224	7,542
More than five years	611	490
Total	$ 201,669	$ 80,655