Loans Held for Investment - Schedule of Components of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	$ 761,062	$ 758,065
Undisbursed portion of mortgage loans	(149)	(161)
Net deferred loan costs (fees)	(891)	(1,007)
Less: allowance for credit losses	(6,245)	(6,244)	$ (6,203)
Loans held for investment, net	753,777	750,653
Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	40,134	34,139
Less: allowance for credit losses	(146)	(539)	(1)
Home Equity
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	111,447	106,550
Less: allowance for credit losses	(836)	(1,224)	$ (536)
Residential mortgage loans (1-4 family)
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	278,080	288,781
Residential mortgage loans (1-4 family) | Fixed
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	95,600	98,694
Residential mortgage loans (1-4 family) | Variable
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	142,346	155,948
Residential mortgage loans (1-4 family) | Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	40,134	34,139
Commercial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	347,526	336,044
Commercial loans | Real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	258,175	241,063
Commercial loans | Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	89,351	94,981
Consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	135,456	133,240
Consumer loans | Home Equity
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	111,447	106,550
Consumer loans | Other consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Total loans held for investment	$ 24,009	$ 26,690