Loans and Allowance for Loan Losses (Schedule of Nonaccrual Loans by Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans	$ 1,064	$ 393
Commercial real estate [Member] | Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans	391	393
Commercial real estate [Member] | Agricultural Sector [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans
Commercial real estate [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans
Consumer Real Estate [Member] | 1-4 Family Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans	515
Consumer Real Estate [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans	138
Consumer Real Estate [Member] | Home equity lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans
Commercial and Industrial Sector [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans
Commercial and Industrial Sector [Member] | Tax-free loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans
Commercial and Industrial Sector [Member] | Agriculture loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual Loans	$ 20