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Commitments and Contingencies (Details) - USD ($) $ in Thousands |  | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Jun. 28, 2018 | Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2012 | Dec. 31, 2017
Operating Leases |  |  |  |  |  |  |
2018 |  | $ 1,106 |  | $ 1,106 |  |  |
2019 |  | 4,198 |  | 4,198 |  |  |
2020 |  | 3,758 |  | 3,758 |  |  |
2021 |  | 2,138 |  | 2,138 |  |  |
2022 |  | 1,330 |  | 1,330 |  |  |
Thereafter |  | 2,904 |  | 2,904 |  |  |
Total |  | 15,400 |  | 15,400 |  |  |
Rent expense |  | 1,100 | $ 997 | 3,500 | $ 3,000 |  |
Visa Inc. |  |  |  |  |  |  |
Litigation Matters |  |  |  |  |  |  |
Settlement agreement amount |  |  |  |  |  | $ 4,000,000 |
Litigation escrow deposit | $ 600,000 |  |  |  |  |  |
Balance of escrow account for legal settlements |  | 1,500,000 |  | 1,500,000 |  |  |
Visa Inc. | Pending due to reversal |  |  |  |  |  |  |
Litigation Matters |  |  |  |  |  |  |
Settlements reached by percentage of sales volume of merchants who opted out in Visa litigation, percent |  |  |  |  |  |  | 51.00%
Loan commitments and standby letters of credit, unused |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet |  | 483,328 |  | 483,328 |  |  | $ 453,202
Loan commitments and standby letters of credit, unused | Interest payable and other liabilities |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Allowance for off balance sheet commitments |  | 958 |  | 958 |  |  | 958
Commercial lines of credit |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet |  | 228,932 |  | 228,932 |  |  | 224,370
Revolving home equity lines |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet |  | 189,353 |  | 189,353 |  |  | 177,678
Undisbursed construction loans |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet |  | 51,624 |  | 51,624 |  |  | 35,322
Personal and other lines of credit |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet |  | 10,783 |  | 10,783 |  |  | 11,758
Standby letters of credit |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |
Loan commitments and standby letters of credit, off-balance sheet |  | $ 2,636 |  | $ 2,636 |  |  | $ 4,074

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