Allowance for Loan Losses (the Allowance) - Roll-forward of allowance by portfolio segment (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	$ 17,767	$ 9,513
Recoveries	10	33
Provision	599	1,552
Balance at end of period	18,376	11,098
Commercial mortgage
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	7,451	3,426
Provision	204	686
Balance at end of period	7,655	4,112
Home equity lines and loans
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	434	342
Recoveries	2	1
Provision	(126)	141
Balance at end of period	310	484
Residential mortgage
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	385	179
Recoveries	2	2
Provision	(73)	38
Balance at end of period	314	219
Construction
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	2,421	2,362
Provision	(110)	19
Balance at end of period	2,311	2,381
Commercial and industrial, including leases
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	5,431	2,684
Recoveries	5	29
Provision	(150)	456
Balance at end of period	5,286	3,169
Small business loans
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	1,259	509
Provision	661	216
Balance at end of period	1,920	725
Consumer
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	4	6
Recoveries	1	1
Provision	(1)	(3)
Balance at end of period	4	4
Leases
Roll-Forward of Allowance for Loan and Lease Losses by Portfolio Segment
Balance at beginning of period	382	5
Provision	194	(1)
Balance at end of period	$ 576	$ 4

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
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-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

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- Definition

Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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-Publisher FASB
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-Topic 942
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