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Commitments and Contingent Liabilities (Tables) | 12 Months Ended
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Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract] |
Summary of Financial Instruments with Off-Balance-Sheet Risks | The amounts of financial instruments with off-balance-sheet risk are as follows:
|  | December 31, |
|  | 2019 |  |  | 2018 |
|  | (Dollars in thousands) |
Loan commitments |  | $ | 1,618,001 |  |  | $ | 1,232,996 |
Stand-by letters of credit |  |  | 64,702 |  |  |  | 56,096 |

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