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	12 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Beginning of Period Nonaccrual	$ 146,774	$ 54,057
End of Period Nonaccrual	132,413	146,774
Nonaccrual With No Related Allowance	64,628	71,410
Past Due 90+ Days Still Accruing	0	503
Past due	135,324	156,130
Interest income recognized on nonaccrual	352	826
90 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Past due	0	503
Commercial \| Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Beginning of Period Nonaccrual	101,070	25,356
End of Period Nonaccrual	95,074	101,070
Nonaccrual With No Related Allowance	52,460	60,401
Past Due 90+ Days Still Accruing	0	0
Past due	95,074	101,070
Interest income recognized on nonaccrual	61	22
Commercial \| Commercial real estate \| 90 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Past due	0	0
Commercial \| Commercial and industrial
Financing Receivable, Nonaccrual [Line Items]
Beginning of Period Nonaccrual	16,985	10,911
End of Period Nonaccrual	12,416	16,985
Nonaccrual With No Related Allowance	11,425	6,436
Past Due 90+ Days Still Accruing	0	0
Past due	12,416	16,985
Interest income recognized on nonaccrual	43	101
Commercial \| Commercial and industrial \| 90 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Past due	0	0
Commercial \| Commercial construction
Financing Receivable, Nonaccrual [Line Items]
Beginning of Period Nonaccrual	384	737
End of Period Nonaccrual	384	384
Nonaccrual With No Related Allowance	0	285
Past Due 90+ Days Still Accruing	0	0
Past due	384	3,983
Interest income recognized on nonaccrual	0	0
Commercial \| Commercial construction \| 90 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Past due	0	0
Commercial \| Business banking
Financing Receivable, Nonaccrual [Line Items]
Beginning of Period Nonaccrual	17,122	9,863
End of Period Nonaccrual	14,426	17,122
Nonaccrual With No Related Allowance	397	3,890
Past Due 90+ Days Still Accruing	0	371
Past due	15,647	19,486
Interest income recognized on nonaccrual	137	275
Commercial \| Business banking \| 90 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Past due	0	371
Consumer \| Consumer real estate
Financing Receivable, Nonaccrual [Line Items]
Beginning of Period Nonaccrual	11,117	6,063
End of Period Nonaccrual	7,949	11,117
Nonaccrual With No Related Allowance	345	398
Past Due 90+ Days Still Accruing	0	132
Past due	9,498	14,304
Interest income recognized on nonaccrual	110	423
Consumer \| Consumer real estate \| 90 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Past due	0	132
Consumer \| Other consumer
Financing Receivable, Nonaccrual [Line Items]
Beginning of Period Nonaccrual	96	1,127
End of Period Nonaccrual	2,163	96
Nonaccrual With No Related Allowance	0	0
Past Due 90+ Days Still Accruing	0	0
Past due	2,304	302
Interest income recognized on nonaccrual	1	4
Consumer \| Other consumer \| 90 Days Past Due
Financing Receivable, Nonaccrual [Line Items]
Past due	$ 0	$ 0

Amount of interest income on financing receivable on nonaccrual status.

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Amount of financing receivable on nonaccrual status with no allowance for credit loss.

+ References

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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.

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Amount of financing receivable 90 days or more past due and still accruing.

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Amount of financing receivable on nonaccrual status.

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Amount of financing receivable past due.

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