Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of TDR's by Loan Category (Details) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2020 USD ($) Loan	Dec. 31, 2019 USD ($) Loan
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	30	27
Pre-Modification Outstanding Recorded Investment	$ 9,809	$ 12,700
Post-Modification Outstanding Recorded Investment	8,588	10,571
Charge-offs	1,221	2,129
Specific Reserves	$ 3,654	$ 2,166
Accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	11	9
Pre-Modification Outstanding Recorded Investment	$ 2,293	$ 1,771
Post-Modification Outstanding Recorded Investment	2,293	1,771
Specific Reserves	$ 224	$ 341
Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	19	18
Pre-Modification Outstanding Recorded Investment	$ 7,516	$ 10,929
Post-Modification Outstanding Recorded Investment	6,295	8,800
Charge-offs	1,221	2,129
Specific Reserves	$ 3,430	$ 1,825
Commercial Real Estate \| Accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	7	5
Pre-Modification Outstanding Recorded Investment	$ 2,013	$ 1,451
Post-Modification Outstanding Recorded Investment	2,013	1,451
Specific Reserves	$ 104	$ 223
Commercial Real Estate \| Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	6	6
Pre-Modification Outstanding Recorded Investment	$ 2,441	$ 2,777
Post-Modification Outstanding Recorded Investment	2,075	2,600
Charge-offs	366	177
Specific Reserves	$ 427	$ 513
Commercial and Industrial \| Accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	2	2
Pre-Modification Outstanding Recorded Investment	$ 119	$ 129
Post-Modification Outstanding Recorded Investment	119	129
Specific Reserves	$ 120	$ 118
Commercial and Industrial \| Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	12	11
Pre-Modification Outstanding Recorded Investment	$ 4,991	$ 8,048
Post-Modification Outstanding Recorded Investment	4,136	6,096
Charge-offs	855	1,952
Specific Reserves	$ 3,003	$ 1,312
Residential Real Estate \| Accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	2	2
Pre-Modification Outstanding Recorded Investment	$ 161	$ 191
Post-Modification Outstanding Recorded Investment	$ 161	$ 191
Residential Real Estate \| Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans \| Loan	1	1
Pre-Modification Outstanding Recorded Investment	$ 84	$ 104
Post-Modification Outstanding Recorded Investment	$ 84	$ 104

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

+ 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=118936363&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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Reflects the amount of the write-down related to a troubled debt restructuring.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
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