Loans - Average Recorded Investment - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	$ 15,418	$ 16,506
Interest Income Recognized on an Accrual Basis on Impaired Loans	59	108
Interest Income Recognized on a Cash Basis on Impaired Loans	26	79
Commercial, financial, and agricultural
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	212	533
Interest Income Recognized on an Accrual Basis on Impaired Loans	4	4
Interest Income Recognized on a Cash Basis on Impaired Loans	0	1
Real estate mortgage \| Residential
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	3,258	2,899
Interest Income Recognized on an Accrual Basis on Impaired Loans	22	22
Interest Income Recognized on a Cash Basis on Impaired Loans	16	14
Real estate mortgage \| Commercial
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	11,946	12,829
Interest Income Recognized on an Accrual Basis on Impaired Loans	33	82
Interest Income Recognized on a Cash Basis on Impaired Loans	10	63
Real estate mortgage \| Construction
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	0	245
Interest Income Recognized on an Accrual Basis on Impaired Loans	0	0
Interest Income Recognized on a Cash Basis on Impaired Loans	0	1
Installment loans to individuals
Credit Quality and Related Allowance for Loan Losses
Average Investment in Impaired Loans	2	0
Interest Income Recognized on an Accrual Basis on Impaired Loans	0	0
Interest Income Recognized on a Cash Basis on Impaired Loans	$ 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=49124121&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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