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Allowance for Credit Losses - Loans on Nonaccrual Status and Loans Past Due 90 Days or More and Still Accruing (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2021 | Sep. 30, 2021 | Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items] |  |  |
Beginning of Period Nonaccrual |  | $ 146,774 | $ 54,057
End of Period Nonaccrual | $ 111,312 | 111,312 | 146,774
Nonaccrual With No Related Allowance | 65,145 | 65,145 | 71,410
Past Due 90+ Days Still Accruing |  |  | 503
Interest income recognized on nonaccrual | 642 | 1,383 | 826
Commercial |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |
Non - performing | 1,700 | 1,700 |
Commercial | Commercial real estate |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |
Beginning of Period Nonaccrual |  | 101,070 | 25,356
End of Period Nonaccrual | 54,797 | 54,797 | 101,070
Nonaccrual With No Related Allowance | 47,730 | 47,730 | 60,401
Past Due 90+ Days Still Accruing |  |  | 0
Interest income recognized on nonaccrual | 493 | 556 | 22
Commercial | Commercial and industrial |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |
Beginning of Period Nonaccrual |  | 16,985 | 10,911
End of Period Nonaccrual | 33,909 | 33,909 | 16,985
Nonaccrual With No Related Allowance | 12,566 | 12,566 | 6,436
Past Due 90+ Days Still Accruing |  |  | 0
Interest income recognized on nonaccrual | 6 | 88 | 101
Commercial | Commercial construction |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |
Beginning of Period Nonaccrual |  | 384 | 737
End of Period Nonaccrual | 4,053 | 4,053 | 384
Nonaccrual With No Related Allowance | 3,357 | 3,357 | 285
Past Due 90+ Days Still Accruing |  |  | 0
Interest income recognized on nonaccrual | 0 | 0 | 0
Commercial | Business banking |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |
Beginning of Period Nonaccrual |  | 17,122 | 9,863
End of Period Nonaccrual | 10,221 | 10,221 | 17,122
Nonaccrual With No Related Allowance | 1,492 | 1,492 | 3,890
Past Due 90+ Days Still Accruing |  |  | 371
Interest income recognized on nonaccrual | 57 | 333 | 275
Consumer | Consumer real estate |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |
Beginning of Period Nonaccrual |  | 11,117 | 6,063
End of Period Nonaccrual | 8,143 | 8,143 | 11,117
Nonaccrual With No Related Allowance | 0 | 0 | 398
Past Due 90+ Days Still Accruing |  |  | 132
Interest income recognized on nonaccrual | 86 | 405 | 423
Consumer | Other consumer |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |
Beginning of Period Nonaccrual |  | 96 | 1,127
End of Period Nonaccrual | 189 | 189 | 96
Nonaccrual With No Related Allowance | 0 | 0 | 0
Past Due 90+ Days Still Accruing |  |  | 0
Interest income recognized on nonaccrual | $ 0 | $ 1 | $ 4

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