Loans - Summary of Activities in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Allowance for Loan Losses
Balance at beginning of year	$ 20,313
Provision for credit losses-Loans	817	$ 580	$ 4,600
Charge Offs	(122)	(94)	(827)
Recoveries	62	43	298
Balance at ending of year	24,634		20,313
Consumer Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	998
Provision for credit losses-Loans	(256)	30	121
Recoveries	7	5	20
Balance at ending of year	3,623		998
Agricultural Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	349
Provision for credit losses-Loans	26	(434)	(691)
Balance at ending of year	209		349
Agricultural [Member]
Allowance for Loan Losses
Balance at beginning of year	751
Provision for credit losses-Loans	(35)	135	35
Recoveries			7
Balance at ending of year	66		751
Commercial Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	11,924
Provision for credit losses-Loans	661	441	2,785
Recoveries	2	2	9
Balance at ending of year	16,088		11,924
Commercial and Industrial [Member]
Allowance for Loan Losses
Balance at beginning of year	5,382
Provision for credit losses-Loans	191	216	1,860
Charge Offs		(6)	(418)
Recoveries	6	9	93
Balance at ending of year	3,414		5,382
Consumer [Member]
Allowance for Loan Losses
Balance at beginning of year	909
Provision for credit losses-Loans	230	59	506
Charge Offs	(122)	(88)	(409)
Recoveries	47	$ 27	169
Balance at ending of year	1,234		909
Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan Losses
Balance at beginning of year	$ 3,564
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13 [Member]
Balance at ending of year			3,564
Cumulative Effect, Period of Adoption, Adjustment [Member] | Consumer Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	$ 2,874
Balance at ending of year			2,874
Cumulative Effect, Period of Adoption, Adjustment [Member] | Agricultural Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	(166)
Balance at ending of year			(166)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Agricultural [Member]
Allowance for Loan Losses
Balance at beginning of year	(650)
Balance at ending of year			(650)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Commercial Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	3,501
Balance at ending of year			3,501
Cumulative Effect, Period of Adoption, Adjustment [Member] | Commercial and Industrial [Member]
Allowance for Loan Losses
Balance at beginning of year	(2,165)
Balance at ending of year			(2,165)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Consumer [Member]
Allowance for Loan Losses
Balance at beginning of year	$ 170
Balance at ending of year			$ 170