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Loans, Allowance for Credit Losses and Credit Quality - Financing Receivable Past Due (Details) $ in Thousands | Mar. 31, 2023 USD ($) loan | Dec. 31, 2022 USD ($) loan | Mar. 31, 2022 USD ($)
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Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan |  | 421 |  | 481 |  |
Total loans |  | $ 13,947,952 | [1] | $ 13,928,675 |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan |  | 33 |  | 35 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan |  | 50 |  | 46 |  |
Number Of Financing Receivables Total Past Due | loan |  | 504 |  | 562 |  |
Total |  | $ 13,947,952 |  | $ 13,928,675 | $ 13,580,027 |
Financing Receivable, 90 Days or More Past Due, Still Accruing |  | 23 |  | 0 |  |
Financing receivable, net deferred costs |  | 5,500 |  | 5,000 |  |
Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 5,233 |  | 5,934 |  |
Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 921 |  | 6,560 |  |
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 31,848 |  | 29,426 |  |
Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 38,002 |  | 41,920 |  |
Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | $ 13,909,950 |  | $ 13,886,755 |  |
Commercial And Industrial [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan |  | 5 |  | 3 |  |
Total loans |  | $ 1,649,882 | [1] | $ 1,635,103 |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan |  | 1 |  | 1 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan |  | 2 |  | 3 |  |
Number Of Financing Receivables Total Past Due | loan |  | 8 |  | 7 |  |
Total |  | $ 1,649,882 |  | $ 1,635,103 | 1,566,192 | [1]
Financing Receivable, 90 Days or More Past Due, Still Accruing |  | 0 |  | 0 |  |
Commercial And Industrial [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 339 |  | 49 |  |
Commercial And Industrial [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 69 |  | 175 |  |
Commercial And Industrial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 23,472 |  | 23,726 |  |
Commercial And Industrial [Member] | Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 23,880 |  | 23,950 |  |
Commercial And Industrial [Member] | Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | $ 1,626,002 |  | $ 1,611,153 |  |
Commercial Real Estate [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan |  | 4 |  | 7 |  |
Total loans |  | $ 7,820,094 | [1] | $ 7,760,230 |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan |  | 0 |  | 5 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan |  | 3 |  | 3 |  |
Number Of Financing Receivables Total Past Due | loan |  | 7 |  | 15 |  |
Total |  | $ 7,820,094 |  | $ 7,760,230 | 7,897,616 | [1]
Financing Receivable, 90 Days or More Past Due, Still Accruing |  | 0 |  | 0 |  |
Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 785 |  | 2,052 |  |
Commercial Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 0 |  | 4,971 |  |
Commercial Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 4,846 |  | 2,977 |  |
Commercial Real Estate [Member] | Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 5,631 |  | 10,000 |  |
Commercial Real Estate [Member] | Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | $ 7,814,463 |  | $ 7,750,230 |  |
Construction Loans [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan |  | 0 |  | 0 |  |
Total loans |  | $ 1,046,310 | [1] | $ 1,154,413 |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan |  | 0 |  | 0 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan |  | 0 |  | 0 |  |
Number Of Financing Receivables Total Past Due | loan |  | 0 |  | 0 |  |
Total |  | $ 1,046,310 |  | $ 1,154,413 | 1,153,945 | [1]
Financing Receivable, 90 Days or More Past Due, Still Accruing |  | 0 |  | 0 |  |
Construction Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 0 |  | 0 |  |
Construction Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 0 |  | 0 |  |
Construction Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 0 |  | 0 |  |
Construction Loans [Member] | Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 0 |  | 0 |  |
Construction Loans [Member] | Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | $ 1,046,310 |  | $ 1,154,413 |  |
Small Business [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan |  | 9 |  | 12 |  |
Total loans |  | $ 225,866 | [1] | $ 219,102 |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan |  | 4 |  | 3 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan |  | 6 |  | 3 |  |
Number Of Financing Receivables Total Past Due | loan |  | 19 |  | 18 |  |
Total |  | $ 225,866 |  | $ 219,102 | 200,405 | [1]
Financing Receivable, 90 Days or More Past Due, Still Accruing |  | 0 |  | 0 |  |
Small Business [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 114 |  | 111 |  |
Small Business [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 116 |  | 25 |  |
Small Business [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 140 |  | 5 |  |
Small Business [Member] | Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 370 |  | 141 |  |
Small Business [Member] | Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | $ 225,496 |  | $ 218,961 |  |
Residential Real Estate [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan |  | 11 |  | 8 |  |
Total loans |  | $ 2,095,644 | [1] | $ 2,035,524 |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan |  | 5 |  | 8 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan |  | 15 |  | 16 |  |
Number Of Financing Receivables Total Past Due | loan |  | 31 |  | 32 |  |
Total |  | $ 2,095,644 |  | $ 2,035,524 | 1,706,045 | [1]
Financing Receivable, 90 Days or More Past Due, Still Accruing |  | 0 |  | 0 |  |
Residential Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 2,202 |  | 1,654 |  |
Residential Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 579 |  | 1,105 |  |
Residential Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 2,002 |  | 1,725 |  |
Residential Real Estate [Member] | Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 4,783 |  | 4,484 |  |
Residential Real Estate [Member] | Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | $ 2,090,861 |  | $ 2,031,040 |  |
Home Equity Loan [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan |  | 18 |  | 19 |  |
Total loans | [1] | $ 1,090,755 |  |  |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan |  | 3 |  | 3 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan |  | 18 |  | 17 |  |
Number Of Financing Receivables Total Past Due | loan |  | 39 |  | 39 |  |
Total |  | $ 1,090,755 |  | $ 1,088,750 | $ 1,025,815 | [1]
Financing Receivable, 90 Days or More Past Due, Still Accruing |  | 23 |  | 0 |  |
Home Equity Loan [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 1,440 |  | 1,647 |  |
Home Equity Loan [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 81 |  | 201 |  |
Home Equity Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 1,343 |  | 965 |  |
Home Equity Loan [Member] | Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | 2,864 |  | 2,813 |  |
Home Equity Loan [Member] | Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans |  | $ 1,087,891 |  | $ 1,085,937 |  |
Consumer - Other [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Number Of Financing Receivables Thirty To Fifty Nine Days Past Due | loan | [2] | 374 |  | 432 |  |
Total loans |  | $ 19,401 |  | $ 35,553 |  |
Number of Financing Receivables Sixty to Eighty Nine Days Past Due | loan | [2] | 20 |  | 15 |  |
Number Of Financing Receivables Equal To Greater Than Ninety Days | loan | [2] | 6 |  | 4 |  |
Number Of Financing Receivables Total Past Due | loan | [2] | 400 |  | 451 |  |
Total | [2] | $ 19,401 |  | $ 35,553 |  |
Financing Receivable, 90 Days or More Past Due, Still Accruing | [2] | 0 |  | 0 |  |
Consumer - Other [Member] | Financial Asset, 30 to 59 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans | [2] | 353 |  | 421 |  |
Consumer - Other [Member] | Financial Asset, 60 to 89 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans | [2] | 76 |  | 83 |  |
Consumer - Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans | [2] | 45 |  | 28 |  |
Consumer - Other [Member] | Financial Asset, Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans | [2] | 474 |  | 532 |  |
Consumer - Other [Member] | Financial Asset, Not Past Due |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |
Total loans | [2] | $ 18,927 |  | $ 35,021 |  |
[1] | Loan origination dates in the tables above reflect the original origination date, or the date of a material modification of a previously originated loan.
[2] | Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances. (2)The amount of net deferred costs on originated loans included in the ending balance was $5.5 million and $5.0 million at March 31, 2023 and December 31, 2022, respectively.

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