Loans, Allowance for Credit Losses and Credit Quality Schedule of Debtor Troubled Debt Restructurings, Subsequent Period (Details)	3 Months Ended
Mar. 31, 2021 USD ($) contract	Mar. 31, 2020 USD ($) contract
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default	$ 0	$ 0
Financing Receivable, Modifications, Number of Contracts \| contract	7	5
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 18,212,000	$ 1,098,000
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 18,212,000	$ 1,106,000
Commercial And Industrial [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Financing Receivable, Modifications, Number of Contracts \| contract	1	2
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 14,148,000	$ 268,000
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 14,148,000	$ 268,000
Commercial Real Estate [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Financing Receivable, Modifications, Number of Contracts \| contract	5	1
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 3,964,000	$ 604,000
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 3,964,000	$ 604,000
Small Business [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Financing Receivable, Modifications, Number of Contracts \| contract	1	1
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 100,000	$ 49,000
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 100,000	$ 25,000
Residential Real Estate [Member]
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Financing Receivable, Modifications, Number of Contracts \| contract		1
Financing Receivable, Troubled Debt Restructuring, Premodification		$ 177,000
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 209,000

Number of financing receivables that have been modified by troubled debt restructurings.

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, after troubled debt restructuring, of modified financing receivable.

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

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Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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