Allowance for loan losses and credit quality New Troubled Debt Restructured Loans (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019 USD ($) loans	Sep. 30, 2018 USD ($) loans	Sep. 30, 2019 USD ($) loans	Sep. 30, 2018 USD ($) loans
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
New TDRs, Number of Loans \| loans	0	1	1	2
New TDRs, Pre-Modification Outstanding Recorded Investment	$ 0	$ 80	$ 77	$ 176
New TDRs, Post-Modification Outstanding Recorded Investment	$ 0	$ 81	$ 79	$ 179
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
New TDRs, Number of Loans \| loans		0		1
New TDRs, Pre-Modification Outstanding Recorded Investment		$ 0		$ 204
New TDRs, Post-Modification Outstanding Recorded Investment		$ 0		$ 204
Commercial [Member]
Financing Receivable, Modifications [Line Items]
New TDRs, Number of Loans \| loans		1		2
New TDRs, Pre-Modification Outstanding Recorded Investment		$ 18		$ 31
New TDRs, Post-Modification Outstanding Recorded Investment		$ 18		$ 31

Number of financing receivables that have been modified by troubled debt restructurings during the reporting period.

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

+ Details

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- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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