Loans - Average Recorded Investment - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	$ 20,677	$ 14,787
Interest Income Recognized on an Accrual Basis on Impaired Loans	60	113
Interest Income Recognized on a Cash Basis on Impaired Loans	93	28
Commercial, financial, and agricultural
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	5,302	1,259
Interest Income Recognized on an Accrual Basis on Impaired Loans	1	17
Interest Income Recognized on a Cash Basis on Impaired Loans	38	0
Real Estate Mortgages \| Residential
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	4,163	4,098
Interest Income Recognized on an Accrual Basis on Impaired Loans	28	38
Interest Income Recognized on a Cash Basis on Impaired Loans	17	11
Real Estate Mortgages \| Commercial
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	11,069	9,430
Interest Income Recognized on an Accrual Basis on Impaired Loans	31	58
Interest Income Recognized on a Cash Basis on Impaired Loans	36	17
Real Estate Mortgages \| Construction
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	73	0
Interest Income Recognized on an Accrual Basis on Impaired Loans	0	0
Interest Income Recognized on a Cash Basis on Impaired Loans	1	0
Consumer automobile loans
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	52	0
Interest Income Recognized on an Accrual Basis on Impaired Loans	0	0
Interest Income Recognized on a Cash Basis on Impaired Loans	1	0
Other consumer installment loans
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	18	0
Interest Income Recognized on an Accrual Basis on Impaired Loans	0	0
Interest Income Recognized on a Cash Basis on Impaired Loans	$ 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=84173941&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=84173941&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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