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Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Additional Information (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020 | Dec. 31, 2020
Loans And Leases Receivable Disclosure [Line Items] |  |  |  |  |
Increase (Recaptured) in allowance for loan and lease losses | $ (1,100,000) | $ 10,000,000.0 | $ (5,700,000) | $ 29,300,000 |
Commitments outstanding on troubled debt restructurings | 0 |  | 0 |  | $ 0
Recorded investment in troubled debt restructurings that subsequently defaulted within twelve months | 0 | 0 | 0 | 0 |
Reserve for unfunded commitments | 1,500,000 |  | 1,500,000 |  | $ 1,900,000
Provisions for (credits to) unfunded commitments | 79,000 | 519,000 | 363,000 | 1,200,000 |
Charge-offs or recoveries related to reserve for unfunded commitments |  |  | 0 | 0 |
Acquired Impaired Loans |  |  |  |  |
Loans And Leases Receivable Disclosure [Line Items] |  |  |  |  |
Increase (Recaptured) in allowance for loan and lease losses | 405,000 | 295,000 | 2,200,000 | 2,300,000 |
Individually Evaluated For Impairment |  |  |  |  |
Loans And Leases Receivable Disclosure [Line Items] |  |  |  |  |
Increase (Recaptured) in allowance for loan and lease losses | (1,000,000.0) | 768,000 | 602,000 | 4,100,000 |
Collectively Evaluated For Impairment |  |  |  |  |
Loans And Leases Receivable Disclosure [Line Items] |  |  |  |  |
Increase (Recaptured) in allowance for loan and lease losses | $ (498,000) | $ 8,900,000 | $ (4,200,000) | $ 23,000,000.0 |

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- Definition Charge-offs or recoveries related to the reserve for unfunded commitments. + References No definition available. + Details
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- Definition Provisions for (credits to) unfunded commitments. + References No definition available. + Details
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- Definition Reserve for unfunded commitments. + References No definition available. + Details
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- Definition Troubled debt restructurings, commitments outstanding. + References No definition available. + Details
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- Definition Amount of increase (decrease) of allowance reserve for credit loss. + References No definition available. + Details
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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 + Details
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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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