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Loans and Loans Held for Sale - Summary of Restructured Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019 | Dec. 31, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans | [1],[2] | $ 1,304 | $ 6,427 | $ 7,853 |  | $ 11,248 |
Commercial real estate |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans | [1] | 0 | 6,090 | 2,210 |  | 6,090 |
Commercial and industrial |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans | [1] | 102 | 0 | 2,170 |  | 4,529 |
Commercial construction |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans | [1] | 701 | 0 | 2,572 |  | 0 |
Residential Mortgage |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans | [1] | 310 | 115 | 337 |  | 163 |
Home equity |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans | [1] | $ 191 | 213 | 564 |  | 457 |
Installment and other consumer |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans | [1] |  | $ 9 |  |  | $ 9 |
Performing TDRs |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 15,536 | [3] |  | $ 36,960
Performing TDRs | Commercial real estate |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 25 |  |  | 22,233
Performing TDRs | Commercial and industrial |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 4,388 |  |  | 6,909
Performing TDRs | Commercial construction |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 3,997 |  |  | 1,425
Performing TDRs | Business banking |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 1,488 |  |  |
Performing TDRs | Consumer real estate |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 5,635 |  |  |
Performing TDRs | Residential Mortgage |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 2,013
Performing TDRs | Home equity |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 4,371
Performing TDRs | Other consumer |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 3 |  |  |
Performing TDRs | Installment and other consumer |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 9
Nonperforming TDRs |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 31,755 | [3] |  | 8,912
Nonperforming TDRs | Commercial real estate |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 27,100 |  |  | 6,713
Nonperforming TDRs | Commercial and industrial |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 2,068 |  |  | 695
Nonperforming TDRs | Commercial construction |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 0 |  |  | 0
Nonperforming TDRs | Business banking |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 349 |  |  |
Nonperforming TDRs | Consumer real estate |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 2,238 |  |  |
Nonperforming TDRs | Residential Mortgage |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 822
Nonperforming TDRs | Home equity |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 678
Nonperforming TDRs | Other consumer |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 0 |  |  |
Nonperforming TDRs | Installment and other consumer |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 4
Total TDRs |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 47,291 | [3] |  | 45,872
Total TDRs | Commercial real estate |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 27,125 |  |  | 28,946
Total TDRs | Commercial and industrial |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 6,456 |  |  | 7,604
Total TDRs | Commercial construction |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 3,997 |  |  | 1,425
Total TDRs | Business banking |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 1,837 |  |  |
Total TDRs | Consumer real estate |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | 7,873 |  |  |
Total TDRs | Residential Mortgage |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 2,835
Total TDRs | Home equity |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | 5,049
Total TDRs | Other consumer |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  | $ 3 |  |  |
Total TDRs | Installment and other consumer |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |  |
Restructured loans |  |  |  |  |  |  | $ 13
[1] | Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
[2] | Refer to Note 1, Basis of Presentation for details of reclassification of our portfolio segments related to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instrument.
[3] | Refer to Note 1, Basis of Presentation for details of reclassification of our portfolio segments related to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.

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