Allowance for loan losses and credit quality Loan Ratings by Class (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 692,658	$ 670,244
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	513,394	497,260
Satisfactory/Monitor [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	170,919	164,374
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	8,345	8,610
Residential Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	181,957	192,125
Residential Real Estate [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	163,436	174,798
Residential Real Estate [Member] | Satisfactory/Monitor [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	15,218	14,520
Residential Real Estate [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	3,303	2,807
Construction Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	46,708	69,617
Construction Real Estate [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	35,810	47,326
Construction Real Estate [Member] | Satisfactory/Monitor [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	10,360	21,819
Construction Real Estate [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	538	472
Commercial Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	314,048	289,883
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	176,816	168,654
Commercial Real Estate [Member] | Satisfactory/Monitor [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	133,240	117,004
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	3,992	4,225
Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	115,464	47,699
Commercial [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	102,902	35,625
Commercial [Member] | Satisfactory/Monitor [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	12,053	10,974
Commercial [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	509	1,100
Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	3,188	3,562
Consumer [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	3,137	3,499
Consumer [Member] | Satisfactory/Monitor [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	48	57
Consumer [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	3	6
Municipal [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	31,293	67,358
Municipal [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	31,293	67,358
Municipal [Member] | Satisfactory/Monitor [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	0	0
Municipal [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 0	$ 0