Loans and Allowance for Loan Losses - Summary of Company's Loans by Risk Rating (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 584,800	$ 549,837
Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	334,838	298,574
Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	235,463	237,645
Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	9,007	8,180
Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	5,492	5,438
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	199,255	197,423
Commercial Real Estate Loans [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	187,745	186,774
Commercial Real Estate Loans [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	7,967	7,106
Commercial Real Estate Loans [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	3,543	3,543
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	15,478	17,242
Commercial and Industrial [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	15,174	16,910
Commercial and Industrial [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	304	332
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	7,267	7,552
Consumer [Member] | Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	7,267	7,552
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	271,755	236,364
One-to-Four Family [Member] | Residential Real Estate [Member] | Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	269,450	234,225
One-to-Four Family [Member] | Residential Real Estate [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	356	361
One-to-Four Family [Member] | Residential Real Estate [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	1,949	1,778
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	58,501	57,295
Second Mortgages and HELOC [Member] | Residential Real Estate [Member] | Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	58,121	56,797
Second Mortgages and HELOC [Member] | Residential Real Estate [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	380	381
Second Mortgages and HELOC [Member] | Residential Real Estate [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans		117
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	32,544	33,961
Construction [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 32,544	$ 33,961