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Allowance for Credit Losses (Non-accrual Basis By Loan Class) (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total | $ 19,822,000 | $ 4,886,000 | $ 15,791,000
Reduced interest income on non-accrual loans | 694,000 | 340,000 | $ 1,119,000
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] |  |  |
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total | 1,189,000 | 1,901,000 |
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] |  |  |
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total | 439,000 | 1,208,000 |
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member] |  |  |
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total | 134,000 | 165,000 |
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development |  |  |
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total | 17,496,000 | 938,000 |
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] |  |  |
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total | 526,000 | 670,000 |
Real estate - mortgage | Domestic | Residential Junior Lien |  |  |
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total | $ 38,000 |  |
Consumer | Domestic |  |  |
Loan loss allowances, financing receivable past due |  |  |
Non-accrual loans, total |  | $ 4,000 |

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