Fair Value Measurements (Details 3) - Nonrecurring - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Total Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		$ 6,610	$ 3,805
Other real estate and foreclosed assets		13,625	15,471
Total Fair Value | Commercial, financial, and agricultural
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		803	248
Total Fair Value | Commercial real estate | Construction
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		42	44
Total Fair Value | Commercial real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		1,308	243
Total Fair Value | Residential real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		4,410	3,170
Total Fair Value | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		47	100
Total Gains (Losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains (losses) on impaired loans	[1]	(20)	(560)
Gains (losses) on other real estate owned and repossessed assets	[1]	15	33
Total Gains (Losses) | Commercial, financial, and agricultural
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains (losses) on impaired loans	[1]	(1)	(359)
Total Gains (Losses) | Commercial real estate | Construction
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains (losses) on impaired loans	[1]	0	0
Total Gains (Losses) | Commercial real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains (losses) on impaired loans	[1]	(4)	(154)
Total Gains (Losses) | Residential real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains (losses) on impaired loans	[1]	(3)	(35)
Total Gains (Losses) | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains (losses) on impaired loans	[1]	(12)	(12)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Other real estate and foreclosed assets		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial, financial, and agricultural
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial real estate | Construction
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Other real estate and foreclosed assets		0	0
Other Observable Inputs (Level 2) | Commercial, financial, and agricultural
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Other Observable Inputs (Level 2) | Commercial real estate | Construction
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Other Observable Inputs (Level 2) | Commercial real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Other Observable Inputs (Level 2) | Residential real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Other Observable Inputs (Level 2) | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		6,610	3,805
Other real estate and foreclosed assets		13,625	15,471
Significant Unobservable Inputs (Level 3) | Commercial, financial, and agricultural
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		803	248
Significant Unobservable Inputs (Level 3) | Commercial real estate | Construction
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		42	44
Significant Unobservable Inputs (Level 3) | Commercial real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		1,308	243
Significant Unobservable Inputs (Level 3) | Residential real estate | Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		4,410	3,170
Significant Unobservable Inputs (Level 3) | Consumer
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans		$ 47	$ 100

[1] Total gains (losses) reported for other real estate and foreclosed assets includes charge-offs, valuation write downs, and net losses taken during the periods reported.