Loans - Average Recorded Investment - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	$ 13,448	$ 19,391	$ 15,136	$ 20,034
Interest Income Recognized on an Accrual Basis on Impaired Loans	168	57	331	175
Interest Income Recognized on a Cash Basis on Impaired Loans	16	157	19	350
Commercial, financial, and agricultural
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	1,543	5,236	1,849	5,269
Interest Income Recognized on an Accrual Basis on Impaired Loans	33	1	34	3
Interest Income Recognized on a Cash Basis on Impaired Loans	14	49	14	131
Real Estate Mortgages \| Residential
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	5,117	5,006	5,535	4,584
Interest Income Recognized on an Accrual Basis on Impaired Loans	63	26	177	81
Interest Income Recognized on a Cash Basis on Impaired Loans	2	76	2	115
Real Estate Mortgages \| Commercial
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	6,587	9,037	7,577	10,053
Interest Income Recognized on an Accrual Basis on Impaired Loans	71	30	118	91
Interest Income Recognized on a Cash Basis on Impaired Loans	0	31	0	100
Real Estate Mortgages \| Construction
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	54	70	60	72
Interest Income Recognized on an Accrual Basis on Impaired Loans	1	0	1	0
Interest Income Recognized on a Cash Basis on Impaired Loans	0	1	0	3
Consumer automobile loans
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	147	37	111	45
Interest Income Recognized on an Accrual Basis on Impaired Loans	0	0	1	0
Interest Income Recognized on a Cash Basis on Impaired Loans	0	0	3	1
Other consumer installment loans
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	0	5	4	11
Interest Income Recognized on an Accrual Basis on Impaired Loans	0	0	0	0
Interest Income Recognized on a Cash Basis on Impaired Loans	$ 0	$ 0	$ 0	$ 0

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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