Loans - Distribution of Fixed Rate Loans and Variable Rate Loans by Portfolio Segment (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by portfolio segment, Fixed Rate	$ 256,141	$ 267,368
Distribution of variable rate loans by portfolio segment, Variable Rate	277,297	259,071
Agricultural Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by portfolio segment, Fixed Rate	96,221	104,902
Distribution of variable rate loans by portfolio segment, Variable Rate	112,002	112,132
Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by portfolio segment, Fixed Rate	63,014	63,789
Distribution of variable rate loans by portfolio segment, Variable Rate	181,597	154,261
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by portfolio segment, Fixed Rate	733,863	800,127
Distribution of variable rate loans by portfolio segment, Variable Rate	574,737	555,444
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by portfolio segment, Fixed Rate	145,428	147,465
Distribution of variable rate loans by portfolio segment, Variable Rate	192,059	166,940
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by portfolio segment, Fixed Rate	50,849	58,809
Distribution of variable rate loans by portfolio segment, Variable Rate	104	29
Other Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by portfolio segment, Fixed Rate	13,278	13,709
Distribution of variable rate loans by portfolio segment, Variable Rate	$ 9,296	$ 9,424

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

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Amount of loan with fixed rate of interest.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-3

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Amount of loan with variable or adjustable rate of interest.

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