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Allowance for Credit Losses and Credit Quality of Loans, Summary (Details) - USD ($) $ in Thousands |  | 6 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Aug. 11, 2023 | Jun. 30, 2024 | Dec. 31, 2023 | Mar. 31, 2024 | Jun. 30, 2023 | Mar. 31, 2023 | Dec. 31, 2022
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses |  | $ 120,500 | $ 114,400 | $ 115,300 | $ 100,400 | $ 100,250 |
Percentage of allowance of credit losses |  | 1.22% | 1.19% |  |  |  |
Forecast scenario weighting, baseline |  | 80.00% |  | 70.00% |  |  |
Forecast scenario weighting, downside |  | 20.00% |  | 30.00% |  |  |
Salisbury Bank [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Loans purchased with credit deterioration |  | $ 0 | $ 219,500 |  |  |  |
Allowance for credit losses on loans purchased |  |  | 5,800 |  |  |  |
Allowance for credit losses at acquisition | $ 14,500 |  |  |  |  |  |
Salisbury Bank [Member] | PCD [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses at acquisition | 5,800 |  |  |  |  |  |
Salisbury Bank [Member] | Non-PCD [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses at acquisition | $ 8,800 |  |  |  |  |  |
ASU 2022-02 [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  |  | 100,400 |  | $ 100,152
Loans [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | ASU 2022-02 [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  |  |  |  | (600)
Accrued Interest Receivable [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses |  | 0 | 0 |  |  |  |
AIR on loans |  | $ 36,000 | $ 34,100 |  |  |  |
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] |  | Other Assets | Other Assets |  |  |  |
Residential [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses |  | $ 25,874 | $ 22,070 | $ 23,409 | 15,554 | $ 15,390 |
Amount of loans purchased |  | $ 400 | $ 3,800 |  |  |  |
Premium on loans purchased |  | 7.00% | 7.00% |  |  |  |
Allowance for credit losses on loans purchased |  | $ 4 | $ 31 |  |  |  |
Residential [Member] | ASU 2022-02 [Member] |  |  |  |  |  |  |
Allowance for Credit Losses [Abstract] |  |  |  |  |  |  |
Allowance for credit losses |  |  |  |  | $ 15,554 |  | $ 14,539

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- Definition Percentage of allowance for credit loss to total financing receivable outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph a -Subparagraph (1) -Publisher SEC + Details
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