Allowance for loan losses and credit quality New Troubled Debt Restructure Loans (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) loans	Dec. 31, 2018 USD ($) loans
Residential Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
New Troubled Debt Restructured Loans, Number of Loans \| loans	1	3
New Troubled Debt Restructured Loans, Pre-Modification Recorded Investment	$ 77	$ 190
New Troubled Debt Restructured Loans, Post-Modification Recorded Investment	$ 79	$ 193
Construction Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
New Troubled Debt Restructured Loans, Number of Loans \| loans	0	1
New Troubled Debt Restructured Loans, Pre-Modification Recorded Investment	$ 0	$ 44
New Troubled Debt Restructured Loans, Post-Modification Recorded Investment	$ 0	$ 44
Commercial Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
New Troubled Debt Restructured Loans, Number of Loans \| loans	0	1
New Troubled Debt Restructured Loans, Pre-Modification Recorded Investment	$ 0	$ 204
New Troubled Debt Restructured Loans, Post-Modification Recorded Investment	$ 0	$ 204
Commercial [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
New Troubled Debt Restructured Loans, Number of Loans \| loans	1	2
New Troubled Debt Restructured Loans, Pre-Modification Recorded Investment	$ 15	$ 31
New Troubled Debt Restructured Loans, Post-Modification Recorded Investment	$ 15	$ 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

Amount, after troubled debt restructuring, of modified financing receivable.

+ 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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- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

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