Loans - Troubled Debt Restructurings (Details)	3 Months Ended
	Mar. 31, 2017 USD ($) contract	Mar. 31, 2016 USD ($) contract	Dec. 31, 2016 USD ($)
Financing Receivable, Modifications [Line Items]
Current	$ 1,995,000		$ 12,000
Past Due Greater Than 30 Days	0		140,000
Nonaccrual TDRs	22,672,000		25,139,000
Total TDRs	$ 24,667,000		25,291,000
Pre-modified contracts identified as TDRs (contracts) | contract	1	1
Number of TDR defaulted (contracts) | contract	0	1
TDRs defaulted, amount		$ 5,500,000
Pre-modification balance identified as TDR	$ 2,000,000	$ 5,500,000
Commitments to lend additional funds	0
Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Current	1,995,000		12,000
Past Due Greater Than 30 Days	0		0
Nonaccrual TDRs	21,864,000		24,331,000
Total TDRs	23,859,000		24,343,000
Real estate – commercial
Financing Receivable, Modifications [Line Items]
Current	0		0
Past Due Greater Than 30 Days	0		140,000
Nonaccrual TDRs	808,000		808,000
Total TDRs	$ 808,000		$ 948,000