Credit Quality of Loans and Allowance for Loan Losses - Troubled Debt Restructurings (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) contract	Sep. 30, 2014 contract	Sep. 30, 2015 USD ($) contract	Sep. 30, 2014 USD ($) contract	Dec. 31, 2014 USD ($)
Financing Receivable, Modifications [Line Items]
Current	$ 18,000		$ 18,000		$ 176,000
Past Due Greater Than 30 Days	150,000		150,000		0
Nonaccrual TDRs	21,324,000		21,324,000		234,000
Total TDRs	$ 21,492,000		$ 21,492,000		410,000
Pre-modified contracts identified as TDRs (contracts) | contract	0	0	1	1
Number of TDR defaulted (contracts) | contract	1	0	1	0
TDRs defaulted, amount	$ 21,100,000		$ 21,100,000
Pre-modification balance identified as TDR			21,400,000	$ 1,200,000
Commitments to lend additional funds	0		0
Commercial, financial and agricultural
Financing Receivable, Modifications [Line Items]
Current	18,000		18,000		21,000
Past Due Greater Than 30 Days	0		0		0
Nonaccrual TDRs	21,324,000		21,324,000		234,000
Total TDRs	21,342,000		21,342,000		255,000
Real estate – commercial
Financing Receivable, Modifications [Line Items]
Current	0		0		155,000
Past Due Greater Than 30 Days	150,000		150,000		0
Nonaccrual TDRs	0		0		0
Total TDRs	$ 150,000		$ 150,000		$ 155,000