Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Allowance for loan losses and credit quality Allocation of the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	$ 76		$ 196
Collectively evaluated for impairment	7,615		5,926
Total allocated	7,691	$ 6,888	6,122	$ 5,808	$ 5,676	$ 5,739
Residential real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	33		39
Collectively evaluated for impairment	1,567		1,353
Total allocated	1,600	1,590	1,392	1,409	1,396	1,368
Construction real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	669		774
Total allocated	669	594	774	689	646	617
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	36		149
Collectively evaluated for impairment	4,109		3,029
Total allocated	4,145	3,832	3,178	3,167	3,011	2,933
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	7		8
Collectively evaluated for impairment	485		386
Total allocated	492	491	394	326	313	354
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	17		23
Total allocated	17	23	23	25	23	23
Municipal
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	212		76
Total allocated	212	79	76	78	33	82
Unallocated
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for impairment	0		0
Collectively evaluated for impairment	556		285
Total allocated	$ 556	$ 279	$ 285	$ 114	$ 254	$ 362