Loans and Allowance for Credit Losses - Schedule of Allowance for Loan Losses by Portfolio Segment Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Beginning Balance	$ 43,520	$ 45,847	$ 48,365
Provision (reversal) for credit losses	2,546	1,873	125
Initial PCD on Acquired loans	1,000
Loans charged-off	(4,616)	(4,954)	(3,343)
Recoveries	817	754	700
Allowance for Loan Losses, Ending Balance	43,267	43,520	45,847
Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Beginning Balance	13,476	16,731	22,478
Provision (reversal) for credit losses	1,525	(3,330)	(4,554)
Loans charged-off	(97)	(20)	(1,297)
Recoveries	44	95	104
Allowance for Loan Losses, Ending Balance	14,948	13,476	16,731
Commercial and Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Beginning Balance	17,954	14,951	12,248
Provision (reversal) for credit losses	(1,290)	6,703	3,293
Initial PCD on Acquired loans	128
Loans charged-off	(3,185)	(3,791)	(857)
Recoveries	398	91	267
Allowance for Loan Losses, Ending Balance	14,005	17,954	14,951
Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Beginning Balance	7,784	8,608	5,560
Provision (reversal) for credit losses	681	(806)	3,104
Initial PCD on Acquired loans	227
Loans charged-off	(183)	(80)	(99)
Recoveries	44	62	43
Allowance for Loan Losses, Ending Balance	8,553	7,784	8,608
Agricultural Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Beginning Balance	1,718	819	2,235
Provision (reversal) for credit losses	1,464	945	(1,389)
Initial PCD on Acquired loans	330
Loans charged-off	(100)	(54)	(35)
Recoveries	92	8	8
Allowance for Loan Losses, Ending Balance	3,504	1,718	819
Agricultural [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Beginning Balance	995	2,457	3,756
Provision (reversal) for credit losses	(859)	(1,509)	(1,264)
Initial PCD on Acquired loans	306
Loans charged-off	(28)	(108)	(46)
Recoveries	25	155	11
Allowance for Loan Losses, Ending Balance	439	995	2,457
Consumer [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Beginning Balance	1,593	2,281	2,088
Provision (reversal) for credit losses	1,025	(130)	935
Initial PCD on Acquired loans	9
Loans charged-off	(1,023)	(901)	(1,009)
Recoveries	214	343	267
Allowance for Loan Losses, Ending Balance	$ 1,818	$ 1,593	$ 2,281