Loans - Summary of Activities in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Allowance for Loan Losses
Balance at beginning of year	$ 26,352	$ 24,680	$ 25,826	$ 25,024	$ 25,024
Provision for (recovery of) credit losses - loans	661	605	1,472	316	944
Charge Offs	(132)	(85)	(467)	(277)	(480)
Recoveries	96	70	146	207	338
Balance at ending of year	26,977	25,270	26,977	25,270	25,826
Consumer Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	3,683	3,285	3,543	3,581	3,581
Provision for (recovery of) credit losses - loans	(31)	(82)	108	(372)	(31)
Charge Offs		(3)		(13)	(13)
Recoveries	1	1	2	5	6
Balance at ending of year	3,653	3,201	3,653	3,201	3,543
Agricultural Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	771	1,171	895	312	312
Provision for (recovery of) credit losses - loans	(33)	(245)	(157)	614	583
Balance at ending of year	738	926	738	926	895
Agricultural [Member]
Allowance for Loan Losses
Balance at beginning of year	306	377	285	336	336
Provision for (recovery of) credit losses - loans	27	(92)	39	(51)	(52)
Recoveries	1		10		1
Balance at ending of year	334	285	334	285	285
Commercial Real Estate [Member]
Allowance for Loan Losses
Balance at beginning of year	16,907	15,953	16,560	17,400	17,400
Provision for (recovery of) credit losses - loans	431	365	775	(1,085)	(834)
Charge Offs					(15)
Recoveries	16	1	19	4	9
Balance at ending of year	17,354	16,319	17,354	16,319	16,560
Commercial and Industrial [Member]
Allowance for Loan Losses
Balance at beginning of year	3,165	2,248	2,969	1,766	1,766
Provision for (recovery of) credit losses - loans	205	514	420	1,031	1,176
Charge Offs			(25)	(101)	(106)
Recoveries	6	39	12	105	133
Balance at ending of year	3,376	2,801	3,376	2,801	2,969
Consumer [Member]
Allowance for Loan Losses
Balance at beginning of year	952	1,162	1,012	1,302	1,302
Provision for (recovery of) credit losses - loans	53	63	272	(60)	(133)
Charge Offs	(132)	(82)	(442)	(163)	(346)
Recoveries	72	29	103	93	189
Balance at ending of year	945	1,172	945	1,172	1,012
Other [Member]
Allowance for Loan Losses
Balance at beginning of year	568	484	562	327	327
Provision for (recovery of) credit losses - loans	9	82	15	239	235
Balance at ending of year	$ 577	$ 566	$ 577	$ 566	$ 562

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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