Loans - Company's Recorded Investments in Impaired Loans and the Related Valuation Allowances (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Recorded Investment
Total	$ 32,608	$ 30,291
Unpaid Principal Balance
Total	38,135	35,519
Related Valuation Allowance
Total	2,745	2,402
Construction and Land Development [Member]
Recorded Investment
Impaired Loans with No Related Allowance Recorded	213	223
Impaired Loans with an Allowance Recorded	238	251
Total	451	474
Unpaid Principal Balance
Impaired Loans with No Related Allowance Recorded	497	510
Impaired Loans with an Allowance Recorded	251	264
Total	748	774
Related Valuation Allowance
Impaired Loans with No Related Allowance Recorded	0	0
Impaired Loans with an Allowance Recorded	26	23
Total	26	23
Commercial Real Estate [Member]
Recorded Investment
Impaired Loans with No Related Allowance Recorded	2,777	3,475
Impaired Loans with an Allowance Recorded	4,749	4,780
Total	7,526	8,255
Unpaid Principal Balance
Impaired Loans with No Related Allowance Recorded	4,196	4,873
Impaired Loans with an Allowance Recorded	4,749	4,780
Total	8,945	9,653
Related Valuation Allowance
Impaired Loans with No Related Allowance Recorded	0	0
Impaired Loans with an Allowance Recorded	178	195
Total	178	195
Residential Real Estate [Member]
Recorded Investment
Impaired Loans with No Related Allowance Recorded	14,156	10,272
Impaired Loans with an Allowance Recorded	7,744	8,448
Total	21,900	18,720
Unpaid Principal Balance
Impaired Loans with No Related Allowance Recorded	19,042	15,063
Impaired Loans with an Allowance Recorded	7,932	8,651
Total	26,974	23,714
Related Valuation Allowance
Impaired Loans with No Related Allowance Recorded	0	0
Impaired Loans with an Allowance Recorded	1,094	1,091
Total	1,094	1,091
Commercial And Financial [Member]
Recorded Investment
Impaired Loans with No Related Allowance Recorded	166	19
Impaired Loans with an Allowance Recorded	2,197	2,436
Total	2,363	2,455
Unpaid Principal Balance
Impaired Loans with No Related Allowance Recorded	177	29
Impaired Loans with an Allowance Recorded	878	883
Total	1,055	912
Related Valuation Allowance
Impaired Loans with No Related Allowance Recorded	0	0
Impaired Loans with an Allowance Recorded	1,406	1,050
Total	1,406	1,050
Consumer [Member]
Recorded Investment
Impaired Loans with No Related Allowance Recorded	93	105
Impaired Loans with an Allowance Recorded	275	282
Total	368	387
Unpaid Principal Balance
Impaired Loans with No Related Allowance Recorded	134	180
Impaired Loans with an Allowance Recorded	279	286
Total	413	466
Related Valuation Allowance
Impaired Loans with No Related Allowance Recorded	0	0
Impaired Loans with an Allowance Recorded	41	43
Total	$ 41	$ 43