Loans and Allowance for Loan Losses (Composition of Nonaccrual Loans by Portfolio Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 252,800	$ 317,970
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	14,574	13,954
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	3,807	4,550
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	40,480	23,665
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	15,087	12,351
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	178,852	263,450
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	152,863	249,037
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 25,989	$ 14,413