Deposits - Summary of Deposit Accounts (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Deposits [Abstract]
Demand, noninterest-bearing	$ 175,609	$ 66,573
Demand, interest-bearing	217,857	158,708
Money market and savings	207,460	69,188
Time deposits, $250,000 and over	55,844	33,853
Time deposits, other	145,825	46,802
Total deposits	$ 802,595	$ 375,124
Demand, noninterest-bearing	21.88%	17.75%
Demand, interest-bearing	27.14%	42.31%
Money market and savings	25.85%	18.44%
Time deposits, $250,000 and over	6.96%	9.02%
Time deposits, other	18.17%	12.48%
Total deposits	100.00%	100.00%