Loans and allowance for loan losses (Details 1) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 735,865	$ 677,006	$ 620,591
Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	720,373	660,090
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	7,154	7,805
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	4,508	6,163
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	3,830	2,948
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	239,163	223,030	220,697
Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	13,357	12,870
Commercial real estate | Construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	13,357	12,870
Commercial real estate | Construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Commercial real estate | Construction | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Commercial real estate | Construction | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Commercial real estate | Non-residential
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	207,027	197,499
Commercial real estate | Non-residential | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	197,330	186,020
Commercial real estate | Non-residential | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	6,495	6,840
Commercial real estate | Non-residential | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	3,202	4,639
Commercial real estate | Non-residential | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Commercial real estate | Multifamily
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	18,779	12,661
Commercial real estate | Multifamily | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	18,394	12,261
Commercial real estate | Multifamily | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Commercial real estate | Multifamily | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	385	400
Commercial real estate | Multifamily | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	39,959	43,534	43,736
Residential real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	37,263	41,249
Residential real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Residential real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Residential real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	2,696	2,285
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	89,473	83,203	75,612
Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	87,853	81,111
Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	659	965
Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	921	1,124
Commercial and industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	40	3
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	28,903	30,095	30,329
Consumer | Indirect automobile
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	338,367	297,144	$ 250,217
Consumer | Indirect automobile | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	337,777	296,692
Consumer | Indirect automobile | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Consumer | Indirect automobile | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Consumer | Indirect automobile | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	590	452
Consumer | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	18,591	19,269
Consumer | Home equity | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	18,127	19,071
Consumer | Home equity | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Consumer | Home equity | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Consumer | Home equity | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	464	198
Consumer | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	10,312	10,826
Consumer | Other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	10,272	10,816
Consumer | Other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Consumer | Other consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Consumer | Other consumer | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 40	$ 10