Troubled Debt Restructuring (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Impaired Financing Receivable And Troubled Debt Restructing [Line Items]
Impaired Financing Receivable, Troubled Debt Restructuring, Still Accruing	$ 170	$ 462
Impaired Financing Receivable, Troubled Debt Restructuring, Nonaccrual	2,191	1,462
Impaired Financing Receivable, Trouble Debt Structuring, Total	2,361	1,924
Impaired Financing Receivable, Troubled Debt Restructuring, Allowance for Credit Losses	36	42
Commercial and Industrial Loans [Member]
Impaired Financing Receivable And Troubled Debt Restructing [Line Items]
Impaired Financing Receivable, Troubled Debt Restructuring, Still Accruing	0	0
Impaired Financing Receivable, Troubled Debt Restructuring, Nonaccrual	30	31
Impaired Financing Receivable, Trouble Debt Structuring, Total	30	31
Impaired Financing Receivable, Troubled Debt Restructuring, Allowance for Credit Losses	30	31
Construction And Land Development Loans [Member]
Impaired Financing Receivable And Troubled Debt Restructing [Line Items]
Impaired Financing Receivable, Troubled Debt Restructuring, Still Accruing	0	0
Impaired Financing Receivable, Troubled Debt Restructuring, Nonaccrual	0	0
Impaired Financing Receivable, Trouble Debt Structuring, Total	0	0
Impaired Financing Receivable, Troubled Debt Restructuring, Allowance for Credit Losses	0	0
Commercial Real Estate Owner Occupied Loans [Member]
Impaired Financing Receivable And Troubled Debt Restructing [Line Items]
Impaired Financing Receivable, Troubled Debt Restructuring, Still Accruing	170	175
Impaired Financing Receivable, Troubled Debt Restructuring, Nonaccrual	0	0
Impaired Financing Receivable, Trouble Debt Structuring, Total	170	175
Impaired Financing Receivable, Troubled Debt Restructuring, Allowance for Credit Losses	6	11
Commercial Real Estate Other Loans [Member]
Impaired Financing Receivable And Troubled Debt Restructing [Line Items]
Impaired Financing Receivable, Troubled Debt Restructuring, Still Accruing	0	287
Impaired Financing Receivable, Troubled Debt Restructuring, Nonaccrual	2,161	1,431
Impaired Financing Receivable, Trouble Debt Structuring, Total	2,161	1,718
Impaired Financing Receivable, Troubled Debt Restructuring, Allowance for Credit Losses	0	0
Commercial Real Estate Loans, Total [Member]
Impaired Financing Receivable And Troubled Debt Restructing [Line Items]
Impaired Financing Receivable, Troubled Debt Restructuring, Still Accruing	170	462
Impaired Financing Receivable, Troubled Debt Restructuring, Nonaccrual	2,161	1,431
Impaired Financing Receivable, Trouble Debt Structuring, Total	2,331	1,893
Impaired Financing Receivable, Troubled Debt Restructuring, Allowance for Credit Losses	$ 6	$ 11