Allowance for Credit Losses and Credit Quality - Average Balance of Nonaccrual Loans and Leases and Interest Income Recognized on Nonaccrual Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	$ 677,601	$ 210,066
Interest Income Recognized	7,932	4,363
Reclassification of previous purchased credit impaired loans	66,860
Commercial
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	513,532	119,431
Interest Income Recognized	5,175	3,544
Impaired Loans With No Valuation Allowance \| Commercial \| Commercial and industrial
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	249,713	68,985
Interest Income Recognized	2,116	1,709
Impaired Loans With No Valuation Allowance \| Commercial \| Commercial real estate
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	171,429	38,383
Interest Income Recognized	3,040	1,784
Impaired Loans With No Valuation Allowance \| Commercial \| Lease financing
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	92,390	12,063
Interest Income Recognized	19	51
Impaired Loans With No Valuation Allowance \| Consumer
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	164,069	90,635
Interest Income Recognized	2,757	819
Impaired Loans With No Valuation Allowance \| Consumer \| Residential mortgage
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	87,093	50,278
Interest Income Recognized	1,304	638
Impaired Loans With No Valuation Allowance \| Consumer \| Home equity
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	71,162	39,505
Interest Income Recognized	1,387	156
Impaired Loans With No Valuation Allowance \| Consumer \| Consumer installment
Financing Receivable, Impaired [Line Items]
Average Loan and Lease Balance	5,814	852
Interest Income Recognized	$ 66	$ 25

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

Amount at purchase price of financing receivable purchased with credit deterioration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 19
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919265-210447

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- Definition

Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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- Definition

Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

+ References

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