Credit Quality of Loans and Allowance for Loan Losses - Troubled Debt Restructurings (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) contract	Mar. 31, 2015 contract	Dec. 31, 2015 USD ($)
Financing Receivable, Modifications [Line Items]
Current	$ 1,732,000		$ 16,000
Past Due Greater Than 30 Days	3,943,000		148,000
Nonaccrual TDRs	20,708,000		20,865,000
Total TDRs	$ 26,383,000		21,029,000
Pre-modified contracts identified as TDRs (contracts) | contract	1	0
Number of TDR defaulted (contracts) | contract	1	0
TDRs defaulted, amount	$ 5,500,000
Pre-modification balance identified as TDR	5,500,000
Commitments to lend additional funds	0
Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Current	16,000		16,000
Past Due Greater Than 30 Days	3,943,000		0
Nonaccrual TDRs	20,708,000		20,865,000
Total TDRs	24,667,000		20,881,000
Real estate – commercial
Financing Receivable, Modifications [Line Items]
Current	1,716,000		0
Past Due Greater Than 30 Days	0		148,000
Nonaccrual TDRs	0		0
Total TDRs	$ 1,716,000		$ 148,000