Allowance for Credit Losses - Summary of Allowances for Loan Losses by Loan Class (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	$ 4,666	$ 3,152
Charge-offs		0
Recoveries		11
Provision for credit losses	293	280
Ending balance	10,526	3,443
Agriculture Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	33	23
Charge-offs		0
Recoveries		0
Provision for credit losses		(3)
Ending balance		20
Commercial and PPP Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	583	582
Charge-offs		0
Recoveries		2
Provision for credit losses		1
Ending balance		585
Commercial Real Estate Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	2,462	799
Charge-offs		0
Recoveries		0
Provision for credit losses		271
Ending balance		1,070
Residential Real Estate Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	1,536	1,634
Charge-offs		0
Recoveries		7
Provision for credit losses		87
Ending balance		1,728
Consumer Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	40	22
Charge-offs		0
Recoveries		2
Provision for credit losses		(11)
Ending balance		13
Municipal Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	12	15
Charge-offs		0
Recoveries		0
Provision for credit losses		0
Ending balance		15
Unallocated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	$ 0	77
Charge-offs		0
Recoveries		0
Provision for credit losses		(65)
Ending balance		$ 12