Fair Value - Summary of Assets Measured at Fair Value on Non-recurring Basis (Detail) - Assets Measured at Fair Value on a Non-recurring Basis [Member] - Level 3 [Member] - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Loans Individually Evaluated for Credit Losses [Member] | Commercial Real Estate [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	$ 1,079	$ 617
Loans Individually Evaluated for Credit Losses [Member] | Commercial and Industrial [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	3,239	4,747
Loans Individually Evaluated for Credit Losses [Member] | Residential Real Estate [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	2,347	2,395
Loans Individually Evaluated for Credit Losses [Member] | Agricultural Real Estate [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	2,660	1,253
Loans Individually Evaluated for Credit Losses [Member] | Other [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	2,293	1,871
Other Real Estate Owned | Commercial Real Estate [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	1,263	792
Other Real Estate Owned | Residential Real Estate [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Assets measured at fair value on non-recurring basis	$ 170	$ 170