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Loans - Schedule of Loans Renegotiated in Troubled Debt Restructurings (Details) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2018 USD ($) note | Sep. 30, 2017 USD ($) | Sep. 30, 2018 USD ($) note | Sep. 30, 2017 USD ($) | Dec. 31, 2017 USD ($)
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | note | 3 |  | 5 |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | $ 3,900,000 |  | $ 4,100,000 |  |
Loans renegotiated in troubled debt restructurings | 30,300,000 |  | 30,300,000 |  | $ 44,500,000
Loans renegotiated in troubled debt restructurings, non-accrual loans | 24,400,000 |  | 24,400,000 |  | 31,900,000
Loans renegotiated in troubled debt restructurings, accrual loans | 5,900,000 |  | 5,900,000 |  | $ 12,600,000
Charge-offs directly related to modifying troubled debt restructurings | 0 | $ 0 | 0 | $ 0 |
Balance of defaulted loans under trouble debt restructurings |  |  | 0 |  |
Commitments to lend additional funds | $ 0 |  | $ 0 |  |
Commercial |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Number of Contracts | note | 3 |  | 5 |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | $ 3,900,000 |  | $ 4,100,000 |  |
Interest Only Period Concession [Member] |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | 3,400,000 |  | 3,600,000 |  |
Interest Only Period Concession [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | 3,400,000 |  | 3,600,000 |  |
Extended Maturity [Member] |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | 0 |  | 0 |  |
Extended Maturity [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | 0 |  | 0 |  |
Contractual Interest Rate Reduction [Member] |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | 0 |  | 0 |  |
Contractual Interest Rate Reduction [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | 0 |  | 0 |  |
Other Concession [Member] |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | 500,000 |  | 500,000 |  |
Other Concession [Member] | Commercial |  |  |  |  |
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |  |
Financing Receivable, Modifications, Post-Modification Recorded Investment | $ 500,000 |  | $ 500,000 |  |

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