Fair Value Measurements, Quantitative Information (Details) $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Level 3 [Member] | Commercial Real Estate [Member] | Income Approach [Member] | Capitalization Rate [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0330	0.0325
Level 3 [Member] | Residential 1st Mortgages [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Minimum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0080	0.01
Level 3 [Member] | Residential 1st Mortgages [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Maximum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0640	0.04
Level 3 [Member] | Residential 1st Mortgages [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0300	0.03
Level 3 [Member] | Home Equity Lines and Loans [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Minimum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0100	0.01
Level 3 [Member] | Home Equity Lines and Loans [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Maximum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0200	0.02
Level 3 [Member] | Home Equity Lines and Loans [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0130	0.02
Level 3 [Member] | Agricultural [Member] | Income Approach [Member] | Capitalization Rate [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0430
Level 3 [Member] | Commercial [Member] | Income Approach [Member] | Capitalization Rate [Member] | Minimum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.0295
Level 3 [Member] | Commercial [Member] | Income Approach [Member] | Capitalization Rate [Member] | Maximum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.0870
Level 3 [Member] | Commercial [Member] | Income Approach [Member] | Capitalization Rate [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0330	0.0340
Level 3 [Member] | Consumer [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.4060
Level 3 [Member] | Real Estate Construction [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Other Real Estate Owned, Measurement Input	0.1000	0.1
Nonrecurring [Member]
Quantitative Information [Abstract]
Impaired Loans	$ 5,751	$ 5,732
Other Real Estate	873	873
Nonrecurring [Member] | Commercial Real Estate [Member]
Quantitative Information [Abstract]
Impaired Loans	2,588	2,658
Nonrecurring [Member] | Residential 1st Mortgages [Member]
Quantitative Information [Abstract]
Impaired Loans	1,403	1,550
Nonrecurring [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired Loans	142	70
Nonrecurring [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired Loans	88
Nonrecurring [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired Loans	1,391	1,454
Nonrecurring [Member] | Consumer [Member]
Quantitative Information [Abstract]
Impaired Loans	139
Nonrecurring [Member] | Real Estate Construction [Member]
Quantitative Information [Abstract]
Other Real Estate	873	873
Nonrecurring [Member] | Level 3 [Member]
Quantitative Information [Abstract]
Impaired Loans	5,751	5,732
Other Real Estate	873	873
Nonrecurring [Member] | Level 3 [Member] | Commercial Real Estate [Member]
Quantitative Information [Abstract]
Impaired Loans	2,588	2,658
Nonrecurring [Member] | Level 3 [Member] | Residential 1st Mortgages [Member]
Quantitative Information [Abstract]
Impaired Loans	1,403	1,550
Nonrecurring [Member] | Level 3 [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired Loans	142	70
Nonrecurring [Member] | Level 3 [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired Loans	88
Nonrecurring [Member] | Level 3 [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired Loans	1,391	1,454
Nonrecurring [Member] | Level 3 [Member] | Consumer [Member]
Quantitative Information [Abstract]
Impaired Loans	139
Nonrecurring [Member] | Level 3 [Member] | Real Estate Construction [Member]
Quantitative Information [Abstract]
Other Real Estate	$ 873	$ 873