Fair Value Measurements, Assets or Liabilities Measured at Fair Value on a Non-recurring Basis (Details) - Nonrecurring [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	$ 5,789	$ 5,732	$ 4,665
Other Real Estate	873	873	873
Total Assets Measured at Fair Value On a Non-Recurring Basis	6,662	6,605	5,538
Commercial Real Estate [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	2,660	2,658	2,608
Residential 1st Mortgage [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	1,540	1,550	475
Home Equity Lines and Loans [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	69	70	74
Agricultural [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	102
Commercial [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	1,418	1,454	1,508
Real Estate Construction [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Other Real Estate	873	873	873
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Other Real Estate	0	0	0
Total Assets Measured at Fair Value On a Non-Recurring Basis	0	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial Real Estate [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Residential 1st Mortgage [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Home Equity Lines and Loans [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Agricultural [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Real Estate Construction [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Other Real Estate	0	0	0
Other Observable Inputs (Level 2) [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Other Real Estate	0	0	0
Total Assets Measured at Fair Value On a Non-Recurring Basis	0	0	0
Other Observable Inputs (Level 2) [Member] | Commercial Real Estate [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Other Observable Inputs (Level 2) [Member] | Residential 1st Mortgage [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Other Observable Inputs (Level 2) [Member] | Home Equity Lines and Loans [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Other Observable Inputs (Level 2) [Member] | Agricultural [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0
Other Observable Inputs (Level 2) [Member] | Commercial [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	0	0	0
Other Observable Inputs (Level 2) [Member] | Real Estate Construction [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Other Real Estate	0	0	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	5,789	5,732	4,665
Other Real Estate	873	873	873
Total Assets Measured at Fair Value On a Non-Recurring Basis	6,662	6,605	5,538
Significant Unobservable Inputs (Level 3) [Member] | Commercial Real Estate [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	2,660	2,658	2,608
Significant Unobservable Inputs (Level 3) [Member] | Residential 1st Mortgage [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	1,540	1,550	475
Significant Unobservable Inputs (Level 3) [Member] | Home Equity Lines and Loans [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	69	70	74
Significant Unobservable Inputs (Level 3) [Member] | Agricultural [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	102
Significant Unobservable Inputs (Level 3) [Member] | Commercial [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Impaired Loans	1,418	1,454	1,508
Significant Unobservable Inputs (Level 3) [Member] | Real Estate Construction [Member]
Fair Value on Non-recurring Basis by Fair Value Hierarchy [Abstract]
Other Real Estate	$ 873	$ 873	$ 873