Servicing - Additional Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2024 USD ($) Loan Strata	Dec. 31, 2023 USD ($)
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Valuation allowance	$ 97	$ 7
1-4 Family Real Estate Loans [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Loans serviced for others unpaid principal amount	364,300	367,800
Capitalized servicing rights	3,500	3,500
Fair value of the capitalized servicing rights	$ 4,800	$ 5,500
Number of loans \| Loan	3,677
Number of strata which included loan \| Strata	2
Prepayment rate	6.10%	6.30%
Discount yield	5.98%
Valuation allowance	$ 2
Agricultural Real Estate Loans [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Loans serviced for others unpaid principal amount	141,900	$ 135,800
Capitalized servicing rights	2,200	2,200
Fair value of the capitalized servicing rights	$ 2,700	$ 2,600
Number of loans \| Loan	619
Number of strata which included loan \| Strata	10
Discount yield	8.62%
Valuation allowance	$ 95
Two 1-4 Family Real Estate Strata [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Number of loans \| Loan	82
Ten Agricultural Real Estate Strata [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Number of loans \| Loan	33

Capitalized service right assets.

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- Definition

Capitalized service right assets fair market value.

+ References

No definition available.

+ Details

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- Definition

Loans serviced for others unpaid principal amount.

+ References

No definition available.

+ Details

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- Definition

Number of Loans

+ References

No definition available.

+ Details

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- Definition

Number of strata which included loan.

+ References

No definition available.

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)(5)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481229/860-50-50-4

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- Definition

Discount rate used to estimate the fair value of servicing assets and servicing liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481229/860-50-50-2

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- Definition

Estimated rate of prepayments of principal on servicing assets and servicing liabilities.

+ References

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