Fair Value Measurements, Quantitative Information (Details) $ in Thousands	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)
Level 3 [Member] | Residential 1st Mortgage [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Minimum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0069	0.0072	0.008
Level 3 [Member] | Residential 1st Mortgage [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Maximum [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0406	0.0413	0.042
Level 3 [Member] | Residential 1st Mortgage [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.0257	0.0257	0.026
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	0.011	0.011	0.0022
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	0.013	0.014	0.0142
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	0.0123	0.0125	0.013
Level 3 [Member] | Agricultural [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.10	0.10
Level 3 [Member] | Agricultural [Member] | Income Approach [Member] | Capitalization Rate [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.10	0.10
Level 3 [Member] | Commercial [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.10	0.10
Level 3 [Member] | Commercial [Member] | Income Approach [Member] | Capitalization Rate [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.10	0.10
Level 3 [Member] | Consumer [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input			0.10
Level 3 [Member] | Consumer [Member] | Income Approach [Member] | Capitalization Rate [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input			0.10
Level 3 [Member] | Consumer [Member] | Income Approach [Member] | Adjustment for Difference Between Comparable Sales [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.10
Level 3 [Member] | Consumer [Member] | Income Approach [Member] | Adjustment for Difference Between Comparable Sales [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.10
Level 3 [Member] | Consumer [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.10
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		0.10
Level 3 [Member] | Real Estate Construction [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [Member]
Quantitative Information [Abstract]
Other real estate, measurement input	0.10	0.10	0.10
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, measurement input	0.10	0.10	0.10
Nonrecurring [Member]
Quantitative Information [Abstract]
Impaired loans	$ 1,977	$ 2,396	$ 2,070
Other real estate	873	873	873
Nonrecurring [Member] | Residential 1st Mortgage [Member]
Quantitative Information [Abstract]
Impaired loans	1,576	1,584	1,613
Nonrecurring [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired loans	58	61	63
Nonrecurring [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired loans		400	259
Nonrecurring [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired loans	204	213
Nonrecurring [Member] | Consumer [Member]
Quantitative Information [Abstract]
Impaired loans	139	138	135
Nonrecurring [Member] | Real Estate Construction [Member]
Quantitative Information [Abstract]
Other real estate	873	873	873
Nonrecurring [Member] | Level 3 [Member]
Quantitative Information [Abstract]
Impaired loans	1,977	2,396	2,070
Other real estate	873	873	873
Nonrecurring [Member] | Level 3 [Member] | Residential 1st Mortgage [Member]
Quantitative Information [Abstract]
Impaired loans	1,576	1,584	1,613
Nonrecurring [Member] | Level 3 [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired loans	58	61	63
Nonrecurring [Member] | Level 3 [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired loans		400	259
Nonrecurring [Member] | Level 3 [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired loans	204	213
Nonrecurring [Member] | Level 3 [Member] | Consumer [Member]
Quantitative Information [Abstract]
Impaired loans	139	138	135
Nonrecurring [Member] | Level 3 [Member] | Real Estate Construction [Member]
Quantitative Information [Abstract]
Other real estate	$ 873	$ 873	$ 873