Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020	Sep. 17, 2018
Accounting Policies [Line Items]
Date of incorporation	Apr. 06, 2018
Restricted investments	$ 3,586	$ 2,268
Federal home loan bank stock par value per unit	$ 100	$ 100
Percentage of tax benefit to be realized for recognition in the income statement	50.00%	50.00%
Operating lease right of use assets	$ 4,748	$ 370
Operating lease liabilities	$ 4,748	370
Furniture and Fixtures [Member] | Minimum [Member]
Accounting Policies [Line Items]
Estimated useful lives	3 years
Furniture and Fixtures [Member] | Maximum [Member]
Accounting Policies [Line Items]
Estimated useful lives	10 years
Non Voting Common Stock Warrants [Member]
Accounting Policies [Line Items]
Class of warrants or rights exercise price per share	$ 10
Class of warrants or rights term	10 years
Atlantic Community Bankers Bank (ACBB) [Member]
Accounting Policies [Line Items]
Restricted investments	$ 194	170
Federal Home Loan Bank (FHLB) [Member]
Accounting Policies [Line Items]
Restricted investments	$ 3,392	$ 2,062
Residential loans [Member]
Accounting Policies [Line Items]
Number of days past due for loans to be declared as deliquent		180 days
Consumer loans [Member]
Accounting Policies [Line Items]
Number of days past due for loans to be declared as deliquent		120 days
Stonebridge Bank [Member]
Accounting Policies [Line Items]
Business acquistion percentage of voting interests acquired			100.00%