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Summary of Significant Accounting Policies - Summary of impact of the adoption (Detail) - USD ($) $ in Thousands | Jun. 30, 2023 | Mar. 31, 2023 | Jan. 01, 2023 | Dec. 31, 2022 | Jun. 30, 2022 | Mar. 31, 2022 | Dec. 31, 2021
--- | --- | --- | --- | --- | --- | --- | ---
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | $ 3,319 | $ 3,287 |  | $ 3,581 | $ 3,644 | $ 3,642 | $ 3,590
Liabilities [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on OBS credit exposures | 323,000 |  |  | 18,000 |  |  |
ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | $ 3,286 |  |  |  |
Liabilities [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on OBS credit exposures |  |  | 308 |  |  |  |
ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 3,581 |  |  |  |
Liabilities [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on OBS credit exposures |  |  | 18 |  |  |  |
ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | (295) | (295) |  |  |
Liabilities [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on OBS credit exposures |  |  | 290 |  |  |  |
CRE [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | 806 | 725 |  | 942 | 1,019 | 894 | 833
CRE [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 788 |  |  |  |
CRE [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 942 |  |  |  |
CRE [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | (154) | (154) |  |  |
MF [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | 49 | 49 |  | 54 | 57 | 78 | 80
MF [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 55 |  |  |  |
MF [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 54 |  |  |  |
MF [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 1 | 1 |  |  |
C+I [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | 277 | 281 |  | 184 | 208 | 218 | 194
C+I [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 273 |  |  |  |
C+I [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 184 |  |  |  |
C+I [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 89 | 89 |  |  |
ADL [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | 70 | 96 |  | 138 | 110 | 116 | 178
ADL [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 120 |  |  |  |
ADL [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 138 |  |  |  |
ADL [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | (18) | (18) |  |  |
RES [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | 1,910 | 1,904 |  | 2,048 | 2,025 | 2,188 | 2,139
RES [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 1,847 |  |  |  |
RES [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 2,048 |  |  |  |
RES [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | (201) | (201) |  |  |
HELOC [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | 85 | 88 |  | 81 | 87 | 62 | 63
HELOC [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 88 |  |  |  |
HELOC [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 81 |  |  |  |
HELOC [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 7 | 7 |  |  |
CON [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | 109 | 119 |  | 100 | 111 | $ 86 | 75
CON [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 114 |  |  |  |
CON [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 100 |  |  |  |
CON [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 14 | 14 |  |  |
Unallocated [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans | $ 13 | $ 25 |  | 34 | $ 27 |  | $ 28
Unallocated [Member] | ASU 2016-13 [Member] | As reported under ASC 326 [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 1 |  |  |  |
Unallocated [Member] | ASU 2016-13 [Member] | Pre-ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | 34 |  |  |  |
Unallocated [Member] | ASU 2016-13 [Member] | Impact of ASC 326 Adoption [Member] |  |  |  |  |  |  |
Assets [Abstract] |  |  |  |  |  |  |
Allowance for credit losses on loans |  |  | $ (33) | $ (33) |  |  |

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