Loans and allowance for loan losses (Details 4) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Allowance for loan losses:
Beginning balance	$ 7,183	$ 5,620	$ 6,646	$ 5,457	$ 5,457
Provision (credit) for loan losses	780	525	1,560	1,050	2,100
Loans charged-off	(440)	(381)	(946)	(1,084)	(2,013)
Recoveries	335	175	598	516	1,102
Ending balance	7,858	5,939	7,858	5,939	6,646
Allowance for loan losses:
Ending balance: Individually evaluated for impairment	121	61	121	61	50
Ending balance: Collectively evaluated for impairment	7,737	5,878	7,737	5,878	6,596
Loan receivables:
Ending balance	735,865	620,591	735,865	620,591	677,006
Ending balance: Individually evaluated for impairment	6,150	10,166	6,150	10,166	5,749
Ending balance: Collectively evaluated for impairment	729,715	610,425	729,715	610,425	671,257
Commercial Real Estate
Allowance for loan losses:
Beginning balance	1,159	897	1,080	1,305	1,305
Provision (credit) for loan losses	93	50	172	(55)	(45)
Loans charged-off	0	0	0	(303)	(303)
Recoveries	0	0	0	0	123
Ending balance	1,252	947	1,252	947	1,080
Allowance for loan losses:
Ending balance: Individually evaluated for impairment	0	0	0	0	0
Ending balance: Collectively evaluated for impairment	1,252	947	1,252	947	1,080
Loan receivables:
Ending balance	239,163	220,697	239,163	220,697	223,030
Ending balance: Individually evaluated for impairment	2,054	5,874	2,054	5,874	2,507
Ending balance: Collectively evaluated for impairment	237,109	214,823	237,109	214,823	220,523
Residential real estate
Allowance for loan losses:
Beginning balance	286	462	320	455	455
Provision (credit) for loan losses	17	49	(18)	55	(140)
Loans charged-off	0	0	0	0	0
Recoveries	2	2	3	3	5
Ending balance	305	513	305	513	320
Allowance for loan losses:
Ending balance: Individually evaluated for impairment	0	0	0	0	0
Ending balance: Collectively evaluated for impairment	305	513	305	513	320
Loan receivables:
Ending balance	39,959	43,736	39,959	43,736	43,534
Ending balance: Individually evaluated for impairment	2,696	2,483	2,696	2,483	2,285
Ending balance: Collectively evaluated for impairment	37,263	41,253	37,263	41,253	41,249
Commercial and industrial
Allowance for loan losses:
Beginning balance	1,575	950	1,542	879	879
Provision (credit) for loan losses	327	131	364	118	578
Loans charged-off	(7)	(9)	(12)	(28)	(37)
Recoveries	0	10	1	113	122
Ending balance	1,895	1,082	1,895	1,082	1,542
Allowance for loan losses:
Ending balance: Individually evaluated for impairment	41	0	41	0	0
Ending balance: Collectively evaluated for impairment	1,854	1,082	1,854	1,082	1,542
Loan receivables:
Ending balance	89,473	75,612	89,473	75,612	83,203
Ending balance: Individually evaluated for impairment	307	1,211	307	1,211	297
Ending balance: Collectively evaluated for impairment	89,166	74,401	89,166	74,401	82,906
Consumer
Allowance for loan losses:
Beginning balance	783	734	789	668	668
Provision (credit) for loan losses	14	48	10	115	168
Loans charged-off	(9)	(10)	(15)	(18)	(66)
Recoveries	12	4	16	11	19
Ending balance	800	776	800	776	789
Allowance for loan losses:
Ending balance: Individually evaluated for impairment	11	0	11	0	0
Ending balance: Collectively evaluated for impairment	789	776	789	776	789
Loan receivables:
Ending balance	28,903	30,329	28,903	30,329	30,095
Ending balance: Individually evaluated for impairment	503	273	503	273	208
Ending balance: Collectively evaluated for impairment	28,400	30,056	28,400	30,056	29,887
Consumer \| Indirect
Allowance for loan losses:
Beginning balance	3,380	2,577	2,915	2,150	2,150
Provision (credit) for loan losses	329	247	1,032	817	1,539
Loans charged-off	(424)	(362)	(919)	(735)	(1,607)
Recoveries	321	159	578	389	833
Ending balance	3,606	2,621	3,606	2,621	2,915
Allowance for loan losses:
Ending balance: Individually evaluated for impairment	69	61	69	61	50
Ending balance: Collectively evaluated for impairment	3,537	2,560	3,537	2,560	2,865
Loan receivables:
Ending balance	338,367	250,217	338,367	250,217	297,144
Ending balance: Individually evaluated for impairment	590	325	590	325	452
Ending balance: Collectively evaluated for impairment	$ 337,777	$ 249,892	$ 337,777	$ 249,892	$ 296,692

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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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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The balance of financing receivables that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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