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Allowance for Loan Losses and Credit Quality of Loans, Troubled Debt Restructurings (Details) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2016 USD ($) Contract | Mar. 31, 2015 USD ($) Contract
Financing Receivable, Modifications [Line Items] |  |
Period of sustained repayment performance for nonperforming TDRs to be returned to performing status | 6 months |
Home Equity [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 12 | 20
Pre-modification outstanding recorded investment | $ | $ 1.0 | $ 1.3
Number of TDR loans with subsequent default | Contract |  | 5
Outstanding recorded investment on TDR loans with subsequent default | $ |  | $ 0.4
Residential Real Estate Mortgages [Member] |  |
Financing Receivable, Modifications [Line Items] |  |
Number of contracts | Contract | 4 | 9
Pre-modification outstanding recorded investment | $ | $ 0.5 | $ 0.8
Number of TDR loans with subsequent default | Contract | 1 |
Outstanding recorded investment on TDR loans with subsequent default | $ | $ 0.2 |

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- Definition Number of financing receivables that have been modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953676-111524 + Details
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- Definition Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953682-111524 + Details
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