Changes in allowance for loan losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance			$ 12,962
Loans and Leases Receivable, Allowance	$ 13,703		13,703
Residential 1-4 family
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	3,063	$ 2,430	2,846	$ 2,646
Allowance for Loan and Lease Losses, Period Increase (Decrease)	232	55	468	264
Allowance for Loan and Lease Losses, Write-offs	9	1	28	10
Allowance for Loan and Lease Loss, Recovery of Bad Debts		3		5
Loans and Leases Receivable, Allowance	3,286	2,377	3,286	2,377
Allowance for Loan and Lease Loss, Recovery of Bad Debts		(3)		(5)
Residential 5+ multifamily
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	820	622	817	686
Allowance for Loan and Lease Losses, Period Increase (Decrease)	337	(77)	571	(141)
Allowance for Loan and Lease Losses, Write-offs			(231)
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	1,157	545	1,157	545
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Construction of residential 1-4 family
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	195	77	186	65
Allowance for Loan and Lease Losses, Period Increase (Decrease)	138	18	147	30
Allowance for Loan and Lease Losses, Write-offs
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	333	95	333	95
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Home equity lines of credit
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	198	195	198	252
Allowance for Loan and Lease Losses, Period Increase (Decrease)	16	(5)	18	(62)
Allowance for Loan and Lease Losses, Write-offs	(9)		(11)
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	205	190	205	190
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Residential real estate
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	4,276	3,324	4,047	3,649
Allowance for Loan and Lease Losses, Period Increase (Decrease)	723	(119)	1,204	(437)
Allowance for Loan and Lease Losses, Write-offs	(18)	(1)	(270)	(10)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		3		5
Loans and Leases Receivable, Allowance	4,981	3,207	4,981	3,207
Allowance for Loan and Lease Loss, Recovery of Bad Debts		(3)		(5)
Commercial
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	5,196	7,080	5,416	6,546
Allowance for Loan and Lease Losses, Period Increase (Decrease)	241	(875)	125	(345)
Allowance for Loan and Lease Losses, Write-offs	(269)		(373)	(6)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	1	7	1	17
Loans and Leases Receivable, Allowance	5,169	6,212	5,169	6,212
Allowance for Loan and Lease Loss, Recovery of Bad Debts	(1)	(7)	(1)	(17)
Construction of commercial
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	1,139	584	1,025	596
Allowance for Loan and Lease Losses, Period Increase (Decrease)	(267)	102	(153)	90
Allowance for Loan and Lease Losses, Write-offs		(18)		(18)
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	872	668	872	668
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Commercial real estate
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	6,335	7,664	6,441	7,142
Allowance for Loan and Lease Losses, Period Increase (Decrease)	(26)	(773)	(28)	(255)
Allowance for Loan and Lease Losses, Write-offs	(269)	(18)	(373)	(24)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	1	7	1	17
Loans and Leases Receivable, Allowance	6,041	6,880	6,041	6,880
Allowance for Loan and Lease Loss, Recovery of Bad Debts	(1)	(7)	(1)	(17)
Farm land
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	19	50	21	59
Allowance for Loan and Lease Losses, Period Increase (Decrease)	8	(18)	6	(27)
Allowance for Loan and Lease Losses, Write-offs
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	27	32	27	32
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Vacant land
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	110	109	95	180
Allowance for Loan and Lease Losses, Period Increase (Decrease)	(2)	(22)	13	(93)
Allowance for Loan and Lease Losses, Write-offs
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	108	87	108	87
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Real estate secured
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	10,740	11,147	10,604	11,030
Allowance for Loan and Lease Losses, Period Increase (Decrease)	703	(932)	1,195	(812)
Allowance for Loan and Lease Losses, Write-offs	(287)	(19)	(643)	(34)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	1	10	1	22
Loans and Leases Receivable, Allowance	11,157	10,206	11,157	10,206
Allowance for Loan and Lease Loss, Recovery of Bad Debts	(1)	(10)	(1)	(22)
Commercial and industrial
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	1,176	1,369	1,364	1,397
Allowance for Loan and Lease Losses, Period Increase (Decrease)	304	(27)	161	(55)
Allowance for Loan and Lease Losses, Write-offs		(131)	(46)	(131)
Allowance for Loan and Lease Loss, Recovery of Bad Debts		45	1	45
Loans and Leases Receivable, Allowance	1,480	1,256	1,480	1,256
Allowance for Loan and Lease Loss, Recovery of Bad Debts		(45)	(1)	(45)
Municipal
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	27	43	31	43
Allowance for Loan and Lease Losses, Period Increase (Decrease)	8	(11)	4	(11)
Allowance for Loan and Lease Losses, Write-offs
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	35	32	35	32
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Consumer
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	105	52	82	77
Allowance for Loan and Lease Losses, Period Increase (Decrease)	51	22	83	20
Allowance for Loan and Lease Losses, Write-offs	(30)	(11)	(45)	(15)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	4	3	10	16
Loans and Leases Receivable, Allowance	130	66	130	66
Allowance for Loan and Lease Loss, Recovery of Bad Debts	(4)	(3)	(10)	(16)
Unallocated
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	867	1,275	881	1,207
Allowance for Loan and Lease Losses, Period Increase (Decrease)	34	(127)	20	(59)
Allowance for Loan and Lease Losses, Write-offs
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Loans and Leases Receivable, Allowance	901	1,148	901	1,148
Allowance for Loan and Lease Loss, Recovery of Bad Debts
Totals
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Allowance	12,915	13,886	12,962	13,754
Allowance for Loan and Lease Losses, Period Increase (Decrease)	1,100	1,075	1,463	917
Allowance for Loan and Lease Losses, Write-offs	(317)	161	734	180
Allowance for Loan and Lease Loss, Recovery of Bad Debts	5	58	12	51
Loans and Leases Receivable, Allowance	13,703	12,708	13,703	12,708
Allowance for Loan and Lease Loss, Recovery of Bad Debts	$ (5)	$ (58)	$ (12)	$ (51)