Fair Value Measurements, Quantitative Information (Details) $ in Thousands	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)
Level 3 [Member] | Commercial Real Estate [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input		0.033	0.0325
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	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	0.0073	0.008	0.0100
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	0.0416	0.064	0.0450
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	0.0258	0.03	0.0281
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	0.0100
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	0.0200
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	0.0128	0.013	0.0138
Level 3 [Member] | Agricultural [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.10	0.043	0.0325
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	0.0325
Level 3 [Member] | Commercial [Member] | Income Approach [Member] | Capitalization Rate [Member]
Quantitative Information [Abstract]
Impaired loans, measurement input	0.10	0.033	0.0325
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	0.0325
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		0.406
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		0.406
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	$ 2,421	$ 5,751	$ 5,658
Other real estate	873	873	873
Nonrecurring [Member] | Commercial Real Estate [Member]
Quantitative Information [Abstract]
Impaired loans		2,588	2,587
Nonrecurring [Member] | Residential 1st Mortgages [Member]
Quantitative Information [Abstract]
Impaired loans	1,599	1,403	1,518
Nonrecurring [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired loans	62	142	66
Nonrecurring [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired loans	400	88	97
Nonrecurring [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired loans	222	1,391	1,390
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	873
Nonrecurring [Member] | Level 3 [Member]
Quantitative Information [Abstract]
Impaired loans	2,421	5,751	5,658
Other real estate	873	873	873
Nonrecurring [Member] | Level 3 [Member] | Commercial Real Estate [Member]
Quantitative Information [Abstract]
Impaired loans		2,588	2,587
Nonrecurring [Member] | Level 3 [Member] | Residential 1st Mortgages [Member]
Quantitative Information [Abstract]
Impaired loans	1,599	1,403	1,518
Nonrecurring [Member] | Level 3 [Member] | Home Equity Lines and Loans [Member]
Quantitative Information [Abstract]
Impaired loans	62	142	66
Nonrecurring [Member] | Level 3 [Member] | Agricultural [Member]
Quantitative Information [Abstract]
Impaired loans	400	88	97
Nonrecurring [Member] | Level 3 [Member] | Commercial [Member]
Quantitative Information [Abstract]
Impaired loans	222	1,391	1,390
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	$ 873