Fair Value Measurements, Quantitative Information (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Level 3 [Member] | Commercial Real Estate [Member] | Income Approach [Member] | Capitalization Rate [Member] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.033
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	0.0072	0.008
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	0.0413	0.064
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	0.0257	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	0.011	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	0.014	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	0.0125	0.013
Level 3 [Member] | Agricultural [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	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	0.043
Level 3 [Member] | Commercial [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	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	0.033
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] | Weighted Average [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.406
Level 3 [Member] | Real Estate Construction [Member] | Sales Comparison Approach [Member] | Adjustment for Difference Between Comparable Sales [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] | Weighted Average [Member]
Quantitative Information [Abstract]
Other Real Estate Owned, Measurement Input	0.10	0.10
Nonrecurring [Member]
Quantitative Information [Abstract]
Impaired Loans	$ 2,396	$ 5,751
Other Real Estate	873	873
Nonrecurring [Member] | Commercial Real Estate [Member]
Quantitative Information [Abstract]
Impaired Loans		2,588
Nonrecurring [Member] | Residential 1st Mortgages [Member]
Quantitative Information [Abstract]
Impaired Loans	1,584	1,403
Nonrecurring [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired Loans	61	142
Nonrecurring [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired Loans	400	88
Nonrecurring [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired Loans	213	1,391
Nonrecurring [Member] | Consumer [Member]
Quantitative Information [Abstract]
Impaired Loans	138	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	2,396	5,751
Other Real Estate	873	873
Nonrecurring [Member] | Level 3 [Member] | Commercial Real Estate [Member]
Quantitative Information [Abstract]
Impaired Loans		2,588
Nonrecurring [Member] | Level 3 [Member] | Residential 1st Mortgages [Member]
Quantitative Information [Abstract]
Impaired Loans	1,584	1,403
Nonrecurring [Member] | Level 3 [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired Loans	61	142
Nonrecurring [Member] | Level 3 [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired Loans	400	88
Nonrecurring [Member] | Level 3 [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired Loans	213	1,391
Nonrecurring [Member] | Level 3 [Member] | Consumer [Member]
Quantitative Information [Abstract]
Impaired Loans	138	139
Nonrecurring [Member] | Level 3 [Member] | Real Estate Construction [Member]
Quantitative Information [Abstract]
Other Real Estate	$ 873	$ 873