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Loans and Allowance for Loan Losses - Troubled Debt Restructurings (Details) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2020 USD ($) loan | Mar. 31, 2019 loan | Sep. 30, 2020 USD ($) loan | Dec. 31, 2019 USD ($)
Troubled debt restructuring |  |  |  |
Number of loans modified as a troubled debt restructuring | loan | 0 |  |  |
Number of loan modifications not considered TDRs, in connection with CARES Act | loan | 552 |  | 552 |
Loan modifications not considered TDRS, in connection with CARES Act | $ | $ 151.4 |  | $ 151.4 |
Maximum |  |  |  |
Troubled debt restructuring |  |  |  |
Typical loan deferral period under the CARES Act |  |  | 90 days |
Interest Rate Below Market Reduction |  |  |  |
Troubled debt restructuring |  |  |  |
Number of loans modified as a troubled debt restructuring | loan |  | 1 |  |
Carrying value of restructured loan | $ |  |  |  | $ 0.2
Specific reserve for loan losses allocated | $ |  |  |  | $ 0.0
Second Deferral |  |  |  |
Troubled debt restructuring |  |  |  |
Number of loan modifications not considered TDRs, in connection with CARES Act | loan | 27 |  | 27 |
Loan modifications not considered TDRS, in connection with CARES Act | $ | $ 16.9 |  | $ 16.9 |
First Deferral |  |  |  |
Troubled debt restructuring |  |  |  |
Number of loan modifications not considered TDRs, in connection with CARES Act | loan | 56 |  | 56 |
Loan modifications not considered TDRS, in connection with CARES Act | $ | $ 12.0 |  | $ 12.0 |

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