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Loans and Credit Quality - Narrative (Details) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2020 USD ($) contract financing_commitment | Sep. 30, 2019 contract | Dec. 31, 2019 USD ($) contract
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
PPP loans | $ 1,507,205,000 |  | $ 1,048,456,000
Net nonaccrual loans | 11,047,000 |  | 13,951,000
Total loans classified as troubled debt restructurings | $ 8,476,000 |  | $ 10,100,000
Number of commitments on TDR | financing_commitment | 0 |  |
Charge offs on loans later classified as TDRs | $ 0 |  |
TDR with specific impairment | contract | 0 |  | 0
TDR that subsequently defaulted, number of contracts | contract | 0 | 0 |
Small Business Administration (SBA), CARES Act, Paycheck Protection Program |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Unearned origination fees, net of origination costs | $ 8,800,000 |  |
Commercial |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
PPP loans | 836,178,000 |  | $ 412,690,000
Commercial | Small Business Administration (SBA), CARES Act, Paycheck Protection Program |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
PPP loans | $ 375,600,000 |  |

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- Definition 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 + Details
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