Allowance for Credit Losses and Credit Quality - Summary of TDR Modifications (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	$ 63,390	$ 51,758	$ 21,048
Post-modification Investment	62,995	51,528	20,973
Commercial Loan and Lease Portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	46,038	41,344	12,481
Post-modification Investment	45,858	41,344	12,481
Commercial Loan and Lease Portfolio \| Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	4,136	5,347	7,253
Post-modification Investment	3,956	5,347	7,253
Commercial Loan and Lease Portfolio \| Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	41,902	35,997	5,228
Post-modification Investment	41,902	35,997	5,228
Consumer Loan Portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	17,352	10,414	8,567
Post-modification Investment	17,137	10,184	8,492
Consumer Loan Portfolio \| Residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	11,550	6,053	5,333
Post-modification Investment	11,485	5,912	5,259
Consumer Loan Portfolio \| Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	5,269	4,144	2,182
Post-modification Investment	5,210	4,089	2,181
Consumer Loan Portfolio \| Consumer installment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Pre-modification Investment	533	217	1,052
Post-modification Investment	$ 442	$ 183	$ 1,052

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- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ 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

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Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

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