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Commitments and Contingent Liabilities - Additional Information (Details) - USD ($) | 1 Months Ended | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2018 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Commitments And Contingencies Liabilities [Line Items] |  |  |  |  |
Rental expenses |  |  | $ 5,800,000 | $ 5,500,000 | $ 4,600,000
Sublease income |  |  | 752,000 | 723,000 | 702,000
Minimum rental to be received in future on subleases |  |  | $ 1,200,000 |  |
Sublease contract maturity year |  |  | 2025 |  |
Data processing |  |  | $ 13,733,000 | $ 18,242,000 | $ 9,539,000
Fixed rate loan commitments maturity year |  |  | 2043 |  |
Variable rate loan commitments maturity year |  |  | 2048 |  |
Maximum |  |  |  |  |
Commitments And Contingencies Liabilities [Line Items] |  |  |  |  |
Commitments to make loans period |  |  | 90 days |  |
Loan commitments fixed interest rate |  |  | 19.50% |  |
Loan commitments variable interest rate |  |  | 10.00% |  |
Minimum |  |  |  |  |
Commitments And Contingencies Liabilities [Line Items] |  |  |  |  |
Loan commitments fixed interest rate |  |  | 2.50% |  |
Loan commitments variable interest rate |  |  | 2.75% |  |
Contract termination |  |  |  |  |
Commitments And Contingencies Liabilities [Line Items] |  |  |  |  |
Data processing | $ 8,100,000 | $ 8,100,000 |  |  |
Remaining data processing cost balance |  |  | $ 0 |  |

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