Credit Quality of Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	$ 48,784	$ 75,283
Current	1,187,185	1,208,799
Total Loans	1,235,969	1,284,082
Recorded Investment, 90 days past due and Accruing	402	268
Commercial, financial and agricultural
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	29,817	34,624
Current	417,665	424,950
Total Loans	447,482	459,574
Recorded Investment, 90 days past due and Accruing	384	96
Real estate - construction
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	3,101	3,021
Current	86,987	97,938
Total Loans	90,088	100,959
Recorded Investment, 90 days past due and Accruing	0	0
Real estate – commercial
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	11,553	32,498
Current	461,493	448,657
Total Loans	473,046	481,155
Recorded Investment, 90 days past due and Accruing	0	140
Real estate - residential
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	3,393	3,716
Current	152,283	154,156
Total Loans	155,676	157,872
Recorded Investment, 90 days past due and Accruing	0	16
Installment loans to individuals
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	796	1,330
Current	62,352	81,330
Total Loans	63,148	82,660
Recorded Investment, 90 days past due and Accruing	18	16
Lease financing receivable
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	33	0
Current	727	1,095
Total Loans	760	1,095
Recorded Investment, 90 days past due and Accruing	0	0
Other loans
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	91	94
Current	5,678	673
Total Loans	5,769	767
Recorded Investment, 90 days past due and Accruing	0	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	7,270	12,870
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial, financial and agricultural
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	2,144	2,297
Financing Receivables, 30 to 59 Days Past Due [Member] | Real estate - construction
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	335	2,613
Financing Receivables, 30 to 59 Days Past Due [Member] | Real estate – commercial
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	1,804	5,159
Financing Receivables, 30 to 59 Days Past Due [Member] | Real estate - residential
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	2,467	1,956
Financing Receivables, 30 to 59 Days Past Due [Member] | Installment loans to individuals
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	408	756
Financing Receivables, 30 to 59 Days Past Due [Member] | Lease financing receivable
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	33	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Other loans
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	79	89
Financing Receivables, 60 to 89 Days Past Due [Member]
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	1,075	3,480
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial, financial and agricultural
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	512	902
Financing Receivables, 60 to 89 Days Past Due [Member] | Real estate - construction
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	350	399
Financing Receivables, 60 to 89 Days Past Due [Member] | Real estate – commercial
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	0	1,931
Financing Receivables, 60 to 89 Days Past Due [Member] | Real estate - residential
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	28	207
Financing Receivables, 60 to 89 Days Past Due [Member] | Installment loans to individuals
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	173	36
Financing Receivables, 60 to 89 Days Past Due [Member] | Lease financing receivable
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Other loans
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	12	5
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	40,439	58,933
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial, financial and agricultural
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	27,161	31,425
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real estate - construction
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	2,416	9
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real estate – commercial
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	9,749	25,408
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real estate - residential
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	898	1,553
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Installment loans to individuals
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	215	538
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Lease financing receivable
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Other loans
Age Analysis of Past Due Loans by Class of Loans [Abstract]
Total Past Due	$ 0	$ 0