Changes in allowance for loan losses - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Residential 1-4 family
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	$ 3,048	$ 2,074	$ 2,393	$ 2,149
Provision	69	175	716	90
Charge-offs	(11)	(31)	(11)	(32)
Recoveries	1	1	9	2
Ending balance	3,107	2,219	3,107	2,219
Acquisition Discount Transfer				10
Residential 5+ multifamily
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	589	495	446	413
Provision	14	(5)	199	77
Charge-offs			(42)
Recoveries
Ending balance	603	490	603	490
Acquisition Discount Transfer
Construction of residential 1-4 family
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	87	79	75	83
Provision	10	4	22
Charge-offs
Recoveries
Ending balance	97	83	97	83
Acquisition Discount Transfer
Home equity lines of credit
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	283	224	197	219
Provision	(8)	(11)	78	(7)
Charge-offs
Recoveries
Ending balance	275	213	275	213
Acquisition Discount Transfer				1
Residential real estate
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	4,007	2,872	3,111	2,864
Provision	85	163	1,015	160
Charge-offs	(11)	(31)	(53)	(32)
Recoveries	1	1	9	2
Ending balance	4,082	3,005	4,082	3,005
Acquisition Discount Transfer				11
Commercial
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	5,160	3,777	3,742	3,048
Provision	317	(149)	1,719	114
Charge-offs	(14)	(20)	(17)	(44)
Recoveries	1		20	2
Ending balance	5,464	3,608	5,464	3,608
Acquisition Discount Transfer				488
Construction of commercial
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	205	127	104	122
Provision	195	23	296	28
Charge-offs
Recoveries
Ending balance	400	150	400	150
Acquisition Discount Transfer
Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	5,365	3,904	3,846	3,170
Provision	512	(126)	2,015	142
Charge-offs	(14)	(20)	(17)	(44)
Recoveries	1		20	2
Ending balance	5,864	3,758	5,864	3,758
Acquisition Discount Transfer				488
Farm land
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	60	47	47	33
Provision	5		18	14
Charge-offs
Recoveries
Ending balance	65	47	65	47
Acquisition Discount Transfer
Vacant land
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	182	89	71	100
Provision	(11)	(14)	100	(25)
Charge-offs
Recoveries
Ending balance	171	75	171	75
Acquisition Discount Transfer
Real estate secured
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	9,614	6,912	7,075	6,167
Provision	591	23	3,148	291
Charge-offs	(25)	(51)	(70)	(76)
Recoveries	2	1	29	4
Ending balance	10,182	6,885	10,182	6,885
Acquisition Discount Transfer				499
Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	1,515	1,176	1,145	1,158
Provision	(44)	74	326	(54)
Charge-offs		(97)		(146)
Recoveries	1	14	1	45
Ending balance	1,472	1,167	1,472	1,167
Acquisition Discount Transfer				164
Municipal
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	36	30	46	12
Provision	5	17	(5)	35
Charge-offs
Recoveries
Ending balance	41	47	41	47
Acquisition Discount Transfer
Consumer
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	74	81	60	56
Provision	40	(26)	72	11
Charge-offs	(41)	(5)	(66)	(29)
Recoveries	7	3	14	15
Ending balance	80	53	80	53
Acquisition Discount Transfer
Unallocated
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	1,132	688	569	438
Provision	94	6	657	256
Charge-offs
Recoveries
Ending balance	1,226	694	1,226	694
Acquisition Discount Transfer
Totals
Financing Receivable, Nonaccrual [Line Items]
Beginning balance	12,371	8,887	8,895	7,831
Provision	686	94	4,198	539
Charge-offs	(66)	(153)	(136)	(251)
Recoveries	10	18	44	64
Ending balance	$ 13,001	$ 8,846	$ 13,001	8,846
Acquisition Discount Transfer				$ 663