Allowance for loan losses and credit quality Allocation of Investment in Loans, by Impairment Methodology (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	$ 5,264	$ 5,241
Collectively evaluated for impairment	760,786	665,003
Total	766,050	670,244
Residential real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	1,805	1,515
Collectively evaluated for impairment	181,130	190,610
Total	182,935	192,125
Construction real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	212	223
Collectively evaluated for impairment	49,456	69,394
Total	49,668	69,617
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	3,018	3,204
Collectively evaluated for impairment	314,967	286,679
Total	317,985	289,883
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	229	299
Collectively evaluated for impairment	114,639	47,400
Total	114,868	47,699
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	2,833	3,562
Total	2,833	3,562
Municipal
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	97,761	67,358
Total	$ 97,761	$ 67,358

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount, before allowance for credit loss, of financing receivable.

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