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Allowance for Loan Losses and Credit Quality of Loans, Troubled Debt Restructurings (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 USD ($) Contract | Dec. 31, 2016 USD ($) Contract
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 42 | 41
Pre-modification outstanding recorded investment | $ 6,115 | $ 2,970
Post-modification outstanding recorded investment | $ 6,116 | $ 2,586
Number of TDR loans with subsequent default | Contract | 57 | 53
Outstanding recorded investment on TDR loans with subsequent default | $ 3,515 | $ 4,688
Commercial Loans [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 4 |
Pre-modification outstanding recorded investment | $ 3,685 |
Post-modification outstanding recorded investment | $ 3,620 |
Number of TDR loans with subsequent default | Contract | 2 | 3
Outstanding recorded investment on TDR loans with subsequent default | $ 474 | $ 1,809
Commercial Loans [Member] | Commercial [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 1 |
Pre-modification outstanding recorded investment | $ 3,300 |
Post-modification outstanding recorded investment | $ 3,239 |
Number of TDR loans with subsequent default | Contract | 1 | 1
Outstanding recorded investment on TDR loans with subsequent default | $ 145 | $ 169
Commercial Loans [Member] | Commercial Real Estate [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of TDR loans with subsequent default | Contract | 0 | 1
Outstanding recorded investment on TDR loans with subsequent default | $ 0 | $ 1,573
Commercial Loans [Member] | Business Banking [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 3 |
Pre-modification outstanding recorded investment | $ 385 |
Post-modification outstanding recorded investment | $ 381 |
Number of TDR loans with subsequent default | Contract | 1 | 1
Outstanding recorded investment on TDR loans with subsequent default | $ 329 | $ 67
Consumer Loans [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 23 | 28
Pre-modification outstanding recorded investment | $ 976 | $ 1,886
Post-modification outstanding recorded investment | $ 1,022 | $ 1,743
Number of TDR loans with subsequent default | Contract | 36 | 34
Outstanding recorded investment on TDR loans with subsequent default | $ 1,739 | $ 1,770
Consumer Loans [Member] | Indirect [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 8 |
Pre-modification outstanding recorded investment | $ 145 |
Post-modification outstanding recorded investment | $ 143 |
Number of TDR loans with subsequent default | Contract | 2 | 0
Outstanding recorded investment on TDR loans with subsequent default | $ 19 | $ 0
Consumer Loans [Member] | Home Equity [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 13 | 28
Pre-modification outstanding recorded investment | $ 552 | $ 1,886
Post-modification outstanding recorded investment | $ 600 | $ 1,743
Number of TDR loans with subsequent default | Contract | 34 | 34
Outstanding recorded investment on TDR loans with subsequent default | $ 1,720 | $ 1,770
Consumer Loans [Member] | Direct [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 2 |
Pre-modification outstanding recorded investment | $ 279 |
Post-modification outstanding recorded investment | $ 279 |
Residential Real Estate Mortgages [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 15 | 13
Pre-modification outstanding recorded investment | $ 1,454 | $ 1,084
Post-modification outstanding recorded investment | $ 1,474 | $ 843
Number of TDR loans with subsequent default | Contract | 19 | 16
Outstanding recorded investment on TDR loans with subsequent default | $ 1,302 | $ 1,109

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