Loans - Risk category of loans by class of loans (Details 8) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Loans	$ 1,027,083	$ 1,009,315
Pass
Financing Receivable, Modifications [Line Items]
Loans	970,522	942,520
Watch
Financing Receivable, Modifications [Line Items]
Loans	35,025	42,621
Substandard
Financing Receivable, Modifications [Line Items]
Loans	21,536	24,174
Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Commercial, financial, and agricultural
Financing Receivable, Modifications [Line Items]
Loans	226,248	210,712
Commercial, financial, and agricultural | Commercial
Financing Receivable, Modifications [Line Items]
Loans	145,442	126,605
Commercial, financial, and agricultural | Commercial | Pass
Financing Receivable, Modifications [Line Items]
Loans	138,570	120,385
Commercial, financial, and agricultural | Commercial | Watch
Financing Receivable, Modifications [Line Items]
Loans	4,992	4,469
Commercial, financial, and agricultural | Commercial | Substandard
Financing Receivable, Modifications [Line Items]
Loans	1,880	1,751
Commercial, financial, and agricultural | Commercial | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Commercial, financial, and agricultural | Financial
Financing Receivable, Modifications [Line Items]
Loans	4,224	4,678
Commercial, financial, and agricultural | Financial | Pass
Financing Receivable, Modifications [Line Items]
Loans	4,224	4,678
Commercial, financial, and agricultural | Financial | Watch
Financing Receivable, Modifications [Line Items]
Loans
Commercial, financial, and agricultural | Financial | Substandard
Financing Receivable, Modifications [Line Items]
Loans
Commercial, financial, and agricultural | Financial | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Commercial, financial, and agricultural | Agricultural
Financing Receivable, Modifications [Line Items]
Loans	10,540	10,894
Commercial, financial, and agricultural | Agricultural | Pass
Financing Receivable, Modifications [Line Items]
Loans	7,639	7,758
Commercial, financial, and agricultural | Agricultural | Watch
Financing Receivable, Modifications [Line Items]
Loans	1,342	2,641
Commercial, financial, and agricultural | Agricultural | Substandard
Financing Receivable, Modifications [Line Items]
Loans	1,559	495
Commercial, financial, and agricultural | Agricultural | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Commercial, financial, and agricultural | Equity lines
Financing Receivable, Modifications [Line Items]
Loans	41,055	40,611
Commercial, financial, and agricultural | Equity lines | Pass
Financing Receivable, Modifications [Line Items]
Loans	39,899	39,576
Commercial, financial, and agricultural | Equity lines | Watch
Financing Receivable, Modifications [Line Items]
Loans	796	691
Commercial, financial, and agricultural | Equity lines | Substandard
Financing Receivable, Modifications [Line Items]
Loans	360	344
Commercial, financial, and agricultural | Equity lines | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Commercial, financial, and agricultural | Other
Financing Receivable, Modifications [Line Items]
Loans	24,987	27,924
Commercial, financial, and agricultural | Other | Pass
Financing Receivable, Modifications [Line Items]
Loans	24,608	27,532
Commercial, financial, and agricultural | Other | Watch
Financing Receivable, Modifications [Line Items]
Loans	320	329
Commercial, financial, and agricultural | Other | Substandard
Financing Receivable, Modifications [Line Items]
Loans	59	63
Commercial, financial, and agricultural | Other | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Commercial real estate
Financing Receivable, Modifications [Line Items]
Loans	370,501	366,566
Commercial real estate | Owner occupied
Financing Receivable, Modifications [Line Items]
Loans	228,041	229,363
Commercial real estate | Owner occupied | Pass
Financing Receivable, Modifications [Line Items]
Loans	209,838	208,370
Commercial real estate | Owner occupied | Watch
Financing Receivable, Modifications [Line Items]
Loans	11,530	14,545
Commercial real estate | Owner occupied | Substandard
Financing Receivable, Modifications [Line Items]
Loans	6,673	6,448
Commercial real estate | Owner occupied | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Commercial real estate | Non Owner occupied
Financing Receivable, Modifications [Line Items]
Loans	142,460	137,203
Commercial real estate | Non Owner occupied | Pass
Financing Receivable, Modifications [Line Items]
Loans	133,026	124,945
Commercial real estate | Non Owner occupied | Watch
Financing Receivable, Modifications [Line Items]
Loans	5,589	5,632
Commercial real estate | Non Owner occupied | Substandard
Financing Receivable, Modifications [Line Items]
Loans	3,845	6,626
Commercial real estate | Non Owner occupied | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Residential real estate
Financing Receivable, Modifications [Line Items]
Loans	245,609	229,161
Residential real estate | Secured by first liens
Financing Receivable, Modifications [Line Items]
Loans	240,790	224,141
Residential real estate | Secured by first liens | Pass
Financing Receivable, Modifications [Line Items]
Loans	231,610	213,167
Residential real estate | Secured by first liens | Watch
Financing Receivable, Modifications [Line Items]
Loans	3,771	6,370
Residential real estate | Secured by first liens | Substandard
Financing Receivable, Modifications [Line Items]
Loans	5,409	4,604
Residential real estate | Secured by first liens | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Residential real estate | Secured by junior liens
Financing Receivable, Modifications [Line Items]
Loans	4,819	5,020
Residential real estate | Secured by junior liens | Pass
Financing Receivable, Modifications [Line Items]
Loans	4,290	4,455
Residential real estate | Secured by junior liens | Watch
Financing Receivable, Modifications [Line Items]
Loans	120	134
Residential real estate | Secured by junior liens | Substandard
Financing Receivable, Modifications [Line Items]
Loans	409	431
Residential real estate | Secured by junior liens | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Acquisition, development and construction
Financing Receivable, Modifications [Line Items]
Loans	164,893	184,292
Acquisition, development and construction | Residential
Financing Receivable, Modifications [Line Items]
Loans	50,788	54,266
Acquisition, development and construction | Residential | Pass
Financing Receivable, Modifications [Line Items]
Loans	50,788	54,168
Acquisition, development and construction | Residential | Watch
Financing Receivable, Modifications [Line Items]
Loans		98
Acquisition, development and construction | Residential | Substandard
Financing Receivable, Modifications [Line Items]
Loans
Acquisition, development and construction | Residential | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Acquisition, development and construction | Other
Financing Receivable, Modifications [Line Items]
Loans	44,740	43,175
Acquisition, development and construction | Other | Pass
Financing Receivable, Modifications [Line Items]
Loans	106,618	119,330
Acquisition, development and construction | Other | Watch
Financing Receivable, Modifications [Line Items]
Loans	6,220	7,354
Acquisition, development and construction | Other | Substandard
Financing Receivable, Modifications [Line Items]
Loans	1,267	3,342
Acquisition, development and construction | Other | Doubtful
Financing Receivable, Modifications [Line Items]
Loans
Consumer
Financing Receivable, Modifications [Line Items]
Loans	19,832	18,584
Consumer | Pass
Financing Receivable, Modifications [Line Items]
Loans	19,412	18,156
Consumer | Watch
Financing Receivable, Modifications [Line Items]
Loans	345	358
Consumer | Substandard
Financing Receivable, Modifications [Line Items]
Loans	75	70
Consumer | Doubtful
Financing Receivable, Modifications [Line Items]
Loans