Loans and Allowance for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	$ 1,811	$ 1,764
Total Past Due and NonAccrual	4,762	5,269
Current Loans	1,339,659	1,285,195
Total loans	1,374,257	1,323,258
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	6	128
Total Past Due and NonAccrual	1,210	1,373
Current Loans	646,248	623,712
Total loans	663,694	642,988
Consumer Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	1,085	991
Total Past Due and NonAccrual	1,673	1,987
Current Loans	290,489	284,020
Total loans	299,147	293,457
Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	547	547
Total Past Due and NonAccrual	1,119	938
Current Loans	136,582	129,351
Total loans	142,704	135,409
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	83	85
Total Past Due and NonAccrual	536	502
Current Loans	255,148	236,727
Total loans	256,333	238,087
Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	90	13
Total Past Due and NonAccrual	224	469
Current Loans	11,192	11,385
Total loans	12,379	13,317
Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	29,836	32,794
Purchased Credit Impaired Loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	16,236	17,903
Purchased Credit Impaired Loans [Member] | Consumer Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	6,985	7,450
Purchased Credit Impaired Loans [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	5,003	5,120
Purchased Credit Impaired Loans [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	649	858
Purchased Credit Impaired Loans [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	963	1,463
30-89 Days Past Due and Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	2,153	1,996
30-89 Days Past Due and Accruing [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	1,039	517
30-89 Days Past Due and Accruing [Member] | Consumer Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	458	963
30-89 Days Past Due and Accruing [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	238	65
30-89 Days Past Due and Accruing [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	315	286
30-89 Days Past Due and Accruing [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	103	165
Past Due 90 Days or More and Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	798	1,509
Past Due 90 Days or More and Accruing [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	165	728
Past Due 90 Days or More and Accruing [Member] | Consumer Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	130	33
Past Due 90 Days or More and Accruing [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	334	326
Past Due 90 Days or More and Accruing [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	138	131
Past Due 90 Days or More and Accruing [Member] | Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded investment, past due	$ 31	$ 291