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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, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans | [1] | $ 6,427 | $ 5,155 | $ 11,248 | $ 16,375 |
Commercial real estate |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans | [1] | 6,090 | 0 | 6,090 | 0 |
Commercial and industrial |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans | [1] | 0 | 5,034 | 4,529 | 10,845 |
Residential mortgage |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans | [1] | 115 | 41 | 163 | 196 |
Home equity |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans | [1] | 214 | 73 | 457 | 621 |
Installment and other consumer |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans | [1] | $ 9 | $ 7 | 9 | $ 23 |
Performing TDRs |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 20,690 |  | $ 16,786
Performing TDRs | Commercial real estate |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3,519 |  | 2,054
Performing TDRs | Commercial and industrial |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 9,671 |  | 7,026
Performing TDRs | Commercial construction |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 1,913 |  | 1,912
Performing TDRs | Residential mortgage |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 1,997 |  | 2,214
Performing TDRs | Home equity |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3,577 |  | 3,568
Performing TDRs | Installment and other consumer |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 13 |  | 12
Nonperforming TDRs |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 9,944 |  | 11,088
Nonperforming TDRs | Commercial real estate |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 5,600 |  | 1,139
Nonperforming TDRs | Commercial and industrial |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 980 |  | 6,646
Nonperforming TDRs | Commercial construction |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 406 |  | 406
Nonperforming TDRs | Residential mortgage |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 1,497 |  | 1,543
Nonperforming TDRs | Home equity |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 1,458 |  | 1,349
Nonperforming TDRs | Installment and other consumer |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3 |  | 5
Total TDRs |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 30,634 |  | 27,874
Total TDRs | Commercial real estate |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 9,119 |  | 3,193
Total TDRs | Commercial and industrial |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 10,651 |  | 13,672
Total TDRs | Commercial construction |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 2,319 |  | 2,318
Total TDRs | Residential mortgage |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3,494 |  | 3,757
Total TDRs | Home equity |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 5,035 |  | 4,917
Total TDRs | Installment and other consumer |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | $ 16 |  | $ 17
[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.

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