Loans and Allowance for Loan Losses - Performing and Impaired Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 1,374,257	$ 1,323,258
All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,344,421	1,290,464
Purchased Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	29,836	32,794
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	663,694	642,988
Commercial Real Estate [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	647,458	625,085
Commercial Real Estate [Member] | Purchased Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	16,236	17,903
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	299,147	293,457
Consumer Real Estate [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	292,162	286,007
Consumer Real Estate [Member] | Purchased Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,985	7,450
Construction and Land Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	142,704	135,409
Construction and Land Development [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	137,701	130,289
Construction and Land Development [Member] | Purchased Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,003	5,120
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	256,333	238,087
Commercial and Industrial [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	255,684	237,229
Commercial and Industrial [Member] | Purchased Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	649	858
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	12,379	13,317
Consumer and Other [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	11,416	11,854
Consumer and Other [Member] | Purchased Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	963	1,463
Performing [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,341,394	1,287,823
Performing [Member] | Commercial Real Estate [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	646,908	624,638
Performing [Member] | Consumer Real Estate [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	290,556	284,585
Performing [Member] | Construction and Land Development [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	137,154	129,742
Performing [Member] | Commercial and Industrial [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	255,472	237,016
Performing [Member] | Consumer and Other [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	11,304	11,842
Impaired Loans [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,027	2,641
Impaired Loans [Member] | Commercial Real Estate [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	550	447
Impaired Loans [Member] | Consumer Real Estate [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,606	1,422
Impaired Loans [Member] | Construction and Land Development [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	547	547
Impaired Loans [Member] | Commercial and Industrial [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	212	213
Impaired Loans [Member] | Consumer and Other [Member] | All Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 112	$ 12