Fair Value - Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Details) - Individually Analyzed Loans - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Commercial and Industrial Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	$ 2,699	$ 1,858
Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	6,877	10,040
Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	1,841	2,970
Consumer Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	9	8
Home Equity Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	363	368
Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	537	718
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial and Industrial Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Consumer Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Home Equity Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Significant Other Observable Inputs (Level 2) | Commercial and Industrial Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Significant Other Observable Inputs (Level 2) | Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Significant Other Observable Inputs (Level 2) | Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Significant Other Observable Inputs (Level 2) | Consumer Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Significant Other Observable Inputs (Level 2) | Home Equity Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Significant Other Observable Inputs (Level 2) | Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	0	0
Significant Unobservable  Inputs (Level 3) | Commercial and Industrial Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	2,699	1,858
Significant Unobservable  Inputs (Level 3) | Commercial Real Estate Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	6,877	10,040
Significant Unobservable  Inputs (Level 3) | Agricultural Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	1,841	2,970
Significant Unobservable  Inputs (Level 3) | Consumer Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	9	8
Significant Unobservable  Inputs (Level 3) | Home Equity Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	363	368
Significant Unobservable  Inputs (Level 3) | Residential Mortgage Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets	$ 537	$ 718