Allowance for Loan Losses - Schedule of Loan Modifications (Detail)	3 Months Ended	6 Months Ended
Jun. 30, 2020 USD ($) Loan	Jun. 30, 2021 USD ($) Loan
Financing Receivable Modifications [Line Items]
Loans modified as troubled debt restructuring	$ 0	$ 0
Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified \| Loan		34
Loans modified as troubled debt restructuring		$ 50,436,000
Percent of Loans Outstanding		2.50%
Commercial and Agriculture [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified \| Loan	813
Loans modified as troubled debt restructuring	$ 431,300,000
Commercial and Agriculture [Member] \| Second Modifications [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified \| Loan		34
Loans modified as troubled debt restructuring		$ 50,436,000
Commercial and Agriculture [Member] \| Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified \| Loan		13
Loans modified as troubled debt restructuring		$ 4,222,000
Percent of Loans Outstanding		0.21%
Commercial Real Estate Owner Occupied [Member] \| Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified \| Loan		5
Loans modified as troubled debt restructuring		$ 8,185,000
Percent of Loans Outstanding		0.41%
Commercial Real Estate Non Owner Occupied [Member] \| Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified \| Loan		15
Loans modified as troubled debt restructuring		$ 37,544,000
Percent of Loans Outstanding		1.86%
Real Estate Construction [Member] \| Second Modifications [Member] \| CARES Act [Member]
Financing Receivable Modifications [Line Items]
Number of loans modified \| Loan		1
Loans modified as troubled debt restructuring		$ 485,000
Percent of Loans Outstanding		0.02%

Financing receivable modifications percentage of loans outstanding.

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+ References

No definition available.

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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Amount of financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554

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