Loans and Allowance for Credit Losses - Schedule of Aging of Recorded Investment in Past Due Loans by Segment and Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable Recorded Investment Past Due [Line Items]
Greater Than 90 Days Past Due Still On Accrual	$ 74	$ 279
Nonaccrual	26,552	25,026
Total loans	3,454,407	3,332,901
30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	8,717	7,645
60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	4,271	3,770
Loans Not Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	3,414,793	3,296,181
Commercial Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater Than 90 Days Past Due Still On Accrual	74	189
Nonaccrual	6,899	5,447
Total loans	1,793,544	1,759,855
Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	2,789	2,397
Commercial Real Estate [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	1,386	198
Commercial Real Estate [Member] | Loans Not Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	1,782,396	1,751,624
Commercial and Industrial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater Than 90 Days Past Due Still On Accrual		71
Nonaccrual	6,436	5,041
Total loans	663,718	598,327
Commercial and Industrial [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	1,225	1,853
Commercial and Industrial [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	987	2,713
Commercial and Industrial [Member] | Loans Not Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	655,070	588,649
Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Nonaccrual	4,772	7,251
Total loans	572,523	556,328
Residential Real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	1,426	1,444
Residential Real Estate [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	669	676
Residential Real Estate [Member] | Loans Not Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	565,656	546,957
Agricultural Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Nonaccrual	6,430	4,214
Total loans	219,226	196,114
Agricultural Real Estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	1,716	949
Agricultural Real Estate [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater Than 90 Days Past Due Still On Accrual	721
Agricultural Real Estate [Member] | Loans Not Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	210,359	190,951
Agricultural [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater Than 90 Days Past Due Still On Accrual		19
Nonaccrual	1,217	2,470
Total loans	104,342	118,587
Agricultural [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	1,024	559
Agricultural [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Greater Than 90 Days Past Due Still On Accrual	296	65
Agricultural [Member] | Loans Not Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	101,805	115,474
Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Nonaccrual	798	603
Total loans	101,054	103,690
Consumer [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	537	443
Consumer [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	212	118
Consumer [Member] | Loans Not Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Financing Receivables, Past Due	$ 99,507	$ 102,526