Allowances for Loan Losses - Summary of Allowances for Loan Losses by Loan Class (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	$ 3,152	$ 2,789
Charge-offs	(7)	(339)
Recoveries	231	54
Provision	1,290	648
Ending balance	4,666	3,152
Agriculture Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	23	120
Charge-offs	0	0
Recoveries	0	0
Provision	10	(97)
Ending balance	33	23
Commercial and PPP Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	582	290
Charge-offs	(1)	(24)
Recoveries	32	22
Provision	(30)	294
Ending balance	583	582
Commercial Real Estate Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	799	314
Charge-offs	0	(18)
Recoveries	0	0
Provision	1,663	503
Ending balance	2,462	799
Residential Real Estate Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	1,634	1,702
Charge-offs	(3)	(297)
Recoveries	197	32
Provision	(292)	197
Ending balance	1,536	1,634
Consumer Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	22	35
Charge-offs	(3)	0
Recoveries	2	0
Provision	19	(13)
Ending balance	40	22
Municipal Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	15	18
Charge-offs	0	0
Recoveries	0	0
Provision	(3)	(3)
Ending balance	12	15
Unallocated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning balance	77	310
Charge-offs	0	0
Recoveries	0	0
Provision	(77)	(233)
Ending balance	$ 0	$ 77