Loans - Contractual Aging of Recorded Investment in Past Due Loans by Portfolio Classification of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans after net deferred loan fees and costs	$ 2,356,387	$ 1,857,419
Recorded Investment > 90 Days and Accruing	0	0
30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	3,197	749
60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	674	131
Greater Than 90 Days [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	2,154	575
Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	6,025	1,455
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	2,350,362	1,855,964
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans after net deferred loan fees and costs	494,423	395,805
Consumer Real Estate [Member] | 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,536	228
Consumer Real Estate [Member] | 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	635
Consumer Real Estate [Member] | Greater Than 90 Days [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	90	246
Consumer Real Estate [Member] | Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	2,261	474
Consumer Real Estate [Member] | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	492,162	395,331
Agricultural Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans after net deferred loan fees and costs	220,514	198,033
Agricultural Real Estate [Member] | 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	118	436
Agricultural Real Estate [Member] | 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	2
Agricultural Real Estate [Member] | Greater Than 90 Days [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,550
Agricultural Real Estate [Member] | Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,670	436
Agricultural Real Estate [Member] | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	218,844	197,597
Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans after net deferred loan fees and costs	128,926	118,504
Agricultural [Member] | 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	433
Agricultural [Member] | Greater Than 90 Days [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	152
Agricultural [Member] | Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	585
Agricultural [Member] | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	128,341	118,504
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans after net deferred loan fees and costs	1,150,511	847,110
Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	74
Commercial Real Estate [Member] | Greater Than 90 Days [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	180	180
Commercial Real Estate [Member] | Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	254	180
Commercial Real Estate [Member] | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,150,257	846,930
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans after net deferred loan fees and costs	272,119	240,138
Commercial and Industrial [Member] | 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	953	21
Commercial and Industrial [Member] | 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due		131
Commercial and Industrial [Member] | Greater Than 90 Days [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	182	149
Commercial and Industrial [Member] | Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	1,135	301
Commercial and Industrial [Member] | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	270,984	239,837
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans after net deferred loan fees and costs	89,894	57,829
Consumer [Member] | 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	83	64
Consumer [Member] | 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	37
Consumer [Member] | Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	120	64
Consumer [Member] | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Past Due	$ 89,774	$ 57,765