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Loans (Tier Risk Rating System) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Nonaccrual [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income on nonaccrual loans	$ 74	$ 210
Nonaccrual [Member] | Agricultural Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Combined increase in nonaccrual loans due to two borrower relationships		15,600
Nonaccrual [Member] | Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Combined increase in nonaccrual loans due to two borrower relationships		$ 4,500
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Repayment period of loan with a reasonable reduction of principal balance		2 years

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Repayment period of loan with reasonable reduction of principal balance.

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Amount of interest income on financing receivable on nonaccrual status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-16

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Amount of increase in financing receivable from purchase. Excludes net investment in lease.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-11

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