LOANS - Changes in allowance for loan losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Residential 1-4 family
Beginning balance	$ 2,149	$ 1,862	$ 1,926
Acquisition Discount Transfer	10
Provision	367	580	100
Charge-offs	(136)	(299)	(197)
Recoveries	3	6	33
Ending balance	2,393	2,149	1,862
Residential 5+ multifamily
Beginning balance	413	155	62
Acquisition Discount Transfer
Provision	33	258	93
Charge-offs
Recoveries
Ending balance	446	413	155
Construction of residential 1-4 family
Beginning balance	83	75	91
Acquisition Discount Transfer
Provision	(8)	8	(16)
Charge-offs
Recoveries
Ending balance	75	83	75
Home equity lines of credit
Beginning balance	219	236	348
Acquisition Discount Transfer	1
Provision	258	(18)	(115)
Charge-offs	(281)		(4)
Recoveries		1	7
Ending balance	197	219	236
Business Activities Loans - Residential real estate
Beginning balance	2,864	2,328	2,427
Acquisition Discount Transfer	11
Provision	650	828	62
Charge-offs	(417)	(299)	(201)
Recoveries	3	7	40
Ending balance	3,111	2,864	2,328
Commercial
Beginning balance	3,048	2,547	1,920
Acquisition Discount Transfer	488
Provision	248	756	836
Charge-offs	(44)	(259)	(453)
Recoveries	2	4	244
Ending balance	3,742	3,048	2,547
Construction of commercial
Beginning balance	122	80	38
Acquisition Discount Transfer
Provision	(18)	42	42
Charge-offs
Recoveries
Ending balance	104	122	80
Commercial real estate
Beginning balance	3,170	2,627	1,958
Acquisition Discount Transfer	488
Provision	230	798	878
Charge-offs	(44)	(259)	(453)
Recoveries	2	4	244
Ending balance	3,846	3,170	2,627
Farm land
Beginning balance	33	32	28
Acquisition Discount Transfer
Provision	14	(6)	45
Charge-offs			(43)
Recoveries		7	2
Ending balance	47	33	32
Vacant land
Beginning balance	100	132	170
Acquisition Discount Transfer
Provision	(29)	(32)	(2)
Charge-offs			(36)
Recoveries
Ending balance	71	100	132
Real estate secured
Beginning balance	6,167	5,119	4,583
Acquisition Discount Transfer	499
Provision	865	1,588	983
Charge-offs	(461)	(558)	(733)
Recoveries	5	18	286
Ending balance	7,075	6,167	5,119
Business Activities Loans - Commercial real estate
Beginning balance	1,158	984	1,079
Acquisition Discount Transfer	164
Provision	(78)	255	(229)
Charge-offs	(145)	(108)	(162)
Recoveries	46	27	296
Ending balance	1,145	1,158	984
Municipal
Beginning balance	12	30	53
Acquisition Discount Transfer
Provision	34	(18)	(23)
Charge-offs
Recoveries
Ending balance	46	12	30
Business Activities Loans - Consumer
Beginning balance	56	80	75
Acquisition Discount Transfer
Provision	3	28	63
Charge-offs	(36)	(81)	(76)
Recoveries	37	29	18
Ending balance	60	56	80
Unallocated
Beginning balance	438	563	337
Acquisition Discount Transfer
Provision	131	(125)	226
Charge-offs
Recoveries
Ending balance	569	438	563
Business Activities Loans - Troubled debt restructurings, total
Beginning balance	7,831	6,776	6,127
Acquisition Discount Transfer	663
Provision	955	1,728	1,020
Charge-offs	(642)	(747)	(971)
Recoveries	88	74	600
Ending balance	$ 8,895	$ 7,831	$ 6,776