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Loans and Allowance for Credit Losses on Loans - Schedule of Accounts, Notes, Loans and Financing Receivable (Detail) - USD ($) $ in Thousands | Sep. 30, 2025 | Jun. 30, 2025 | Dec. 31, 2024 | Sep. 30, 2024 | Jun. 30, 2024 | Dec. 31, 2023
--- | --- | --- | --- | --- | --- | ---
Total loans | $ 433,544 |  | $ 438,967 |  |  |
Allowance for credit losses on loans | (3,517) | $ (3,517) | (3,486) | $ (3,445) | $ (3,451) | $ (3,390)
Net loans | 430,027 |  | 435,481 |  |  |
CRE [Member] |  |  |  |  |  |
Total loans | 87,207 |  | 86,020 |  |  |
Allowance for credit losses on loans | (663) | (654) | (710) | (720) | (745) | (830)
MF [Member] |  |  |  |  |  |
Total loans | 4,701 |  | 5,752 |  |  |
Allowance for credit losses on loans | (47) | (57) | (59) | (60) | (107) | (76)
C+I [Member] |  |  |  |  |  |
Total loans | 24,682 |  | 23,711 |  |  |
Allowance for credit losses on loans | (199) | (202) | (233) | (237) | (234) | (236)
ADL [Member] |  |  |  |  |  |
Total loans | 12,054 |  | 14,946 |  |  |
Allowance for credit losses on loans | (90) | (92) | (87) | (78) | (70) | (105)
RES [Member] |  |  |  |  |  |
Total loans | 271,089 |  | 275,235 |  |  |
Allowance for credit losses on loans | (1,528) | (1,560) | (1,612) | (1,652) | (1,608) | (1,601)
HELOC [Member] |  |  |  |  |  |
Total loans | 21,448 |  | 20,908 |  |  |
Allowance for credit losses on loans | (238) | (237) | (214) | (174) | (171) | (156)
CON [Member] |  |  |  |  |  |
Total loans | 12,363 |  | 12,395 |  |  |
Allowance for credit losses on loans | $ (518) | $ (542) | $ (439) | $ (477) | $ (442) | $ (357)

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