Allowance for Loan Losses - Impaired Loans - Average Recorded Investment and Interest Income Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 1,632	$ 2,859	$ 3,085
Interest Income Recognized	74	116	172
Commercial and Agriculture [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	15	88	367
Interest Income Recognized		4	33
Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	396	520	456
Interest Income Recognized	18	27	32
Commercial Real Estate Non Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	23	243	308
Interest Income Recognized	1	16	20
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	629	1,361	1,271
Interest Income Recognized	31	43	58
Farm Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	569	647	683
Interest Income Recognized	$ 24	$ 26	$ 29

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.

No definition available.

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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