Loans and Allowance for Credit Losses - Schedule of Loans Evaluated for Impairment (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable Impaired [Line Items]
Individually evaluated for credit losses	$ 5,315		$ 4,765
Collectively evaluated for credit losses	38,172		38,755
Total Allowance for Loan Losses	43,487	$ 44,449	43,520	$ 44,544	$ 45,103	$ 45,847
Individually evaluated for credit losses	30,012		27,963
Collectively evaluated for credit losses	3,424,395		3,304,938
Total Loans	3,454,407		3,332,901
Commercial Real Estate [Member]
Financing Receivable Impaired [Line Items]
Individually evaluated for credit losses	853		582
Collectively evaluated for credit losses	13,639		12,894
Total Allowance for Loan Losses	14,492	13,582	13,476	16,652	16,611	16,731
Individually evaluated for credit losses	7,158		6,031
Collectively evaluated for credit losses	1,786,386		1,753,824
Total Loans	1,793,544		1,759,855
Commercial and Industrial [Member]
Financing Receivable Impaired [Line Items]
Individually evaluated for credit losses	2,153		1,644
Collectively evaluated for credit losses	14,254		16,310
Total Allowance for Loan Losses	16,407	17,651	17,954	15,194	15,620	14,951
Individually evaluated for credit losses	7,143		5,498
Collectively evaluated for credit losses	656,575		592,829
Total Loans	663,718		598,327
Residential Real Estate [Member]
Financing Receivable Impaired [Line Items]
Individually evaluated for credit losses	1,205		1,113
Collectively evaluated for credit losses	6,861		6,671
Total Allowance for Loan Losses	8,066	8,319	7,784	8,855	8,751	8,608
Individually evaluated for credit losses	5,127		7,495
Collectively evaluated for credit losses	567,396		548,833
Total Loans	572,523		556,328
Agricultural Real Estate [Member]
Financing Receivable Impaired [Line Items]
Individually evaluated for credit losses	652		674
Collectively evaluated for credit losses	1,602		1,044
Total Allowance for Loan Losses	2,254	1,688	1,718	583	586	819
Individually evaluated for credit losses	7,058		4,672
Collectively evaluated for credit losses	212,168		191,442
Total Loans	219,226		196,114
Agricultural [Member]
Financing Receivable Impaired [Line Items]
Individually evaluated for credit losses	250		598
Collectively evaluated for credit losses	272		397
Total Allowance for Loan Losses	522	1,612	995	1,289	1,547	2,457
Individually evaluated for credit losses	2,611		3,598
Collectively evaluated for credit losses	101,731		114,989
Total Loans	104,342		118,587
Consumer [Member]
Financing Receivable Impaired [Line Items]
Individually evaluated for credit losses	202		154
Collectively evaluated for credit losses	1,544		1,439
Total Allowance for Loan Losses	1,746	$ 1,597	1,593	$ 1,971	$ 1,988	$ 2,281
Individually evaluated for credit losses	915		669
Collectively evaluated for credit losses	100,139		103,021
Total Loans	$ 101,054		$ 103,690