Impaired Loans and Allowance for Loan Losses - Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Loan Losses:
Beginning Balance	$ 19,128	$ 17,007	$ 20,068
Provision for Loan Losses	2,411	2,644	(3,486)
Charge-Offs	(1,375)	(3,599)	(2,755)
Recoveries	3,236	3,012	3,244
Net (Charge-Offs) Recoveries	1,861	(587)	489
Ending Balance	23,400	19,128	17,007
Construction and Land Development [Member]
Allowance for Loan Losses:
Beginning Balance	1,151	722	808
Provision for Loan Losses	(158)	1,296	139
Charge-Offs	0	(1,271)	(640)
Recoveries	226	404	415
Net (Charge-Offs) Recoveries	226	(867)	(225)
Ending Balance	1,219	1,151	722
Commercial Real Estate [Member]
Allowance for Loan Losses:
Beginning Balance	6,756	4,528	6,160
Provision for Loan Losses	2,512	2,010	(2,917)
Charge-Offs	(301)	(482)	(398)
Recoveries	306	700	1,683
Net (Charge-Offs) Recoveries	5	218	1,285
Ending Balance	9,273	6,756	4,528
Residential Real Estate [Member]
Allowance for Loan Losses:
Beginning Balance	8,057	9,784	11,659
Provision for Loan Losses	(1,145)	(2,208)	(1,651)
Charge-Offs	(215)	(779)	(1,126)
Recoveries	786	1,260	902
Net (Charge-Offs) Recoveries	571	481	(224)
Ending Balance	7,483	8,057	9,784
Commercial And Financial [Member]
Allowance for Loan Losses:
Beginning Balance	2,042	1,179	710
Provision for Loan Losses	400	1,058	697
Charge-Offs	(615)	(726)	(398)
Recoveries	1,809	531	170
Net (Charge-Offs) Recoveries	1,194	(195)	(228)
Ending Balance	3,636	2,042	1,179
Consumer [Member]
Allowance for Loan Losses:
Beginning Balance	1,122	794	731
Provision for Loan Losses	802	552	182
Charge-Offs	(244)	(341)	(193)
Recoveries	109	117	74
Net (Charge-Offs) Recoveries	(135)	(224)	(119)
Ending Balance	$ 1,789	$ 1,122	$ 794