Loans and Allowance for Loan Losses - Summary of Company considers a loan to have defaulted when it reaches 90 days past due or is transferred to nonaccrual (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2021 USD ($) contract	Mar. 31, 2020 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts \| contract	2	3
Recorded Investment \| $	$ 478	$ 5,948
Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts \| contract	0	2
Recorded Investment \| $	$ 0	$ 4,613
Business banking
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts \| contract	1	0
Recorded Investment \| $	$ 419	$ 0
Consumer home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts \| contract	1	1
Recorded Investment \| $	$ 59	$ 1,335

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

Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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- Definition

Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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