LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES - Current, past due, and non-accrual loans by categories of loans and restructured loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 267,435	$ 266,439
Non-accrual	5,441	3,270	$ 3,772	$ 3,751
Total	275,716	271,612
30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,781	1,843
Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	59	60
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	15,469	15,823
Non-accrual	151	185	395	403
Total	15,730	16,112
Consumer | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	110	80
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		24
Residential Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	79,767	79,205
Non-accrual	2,290	2,124	2,342	2,508
Total	82,151	81,926
Residential Real estate | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	94	597
Indirect
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	89,557	83,932
Non-accrual	144	88	180	193
Total	90,278	85,186
Indirect | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	577	1,166
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	11,122	11,203
Non-accrual	48	48
Total	11,176	11,257
Commercial | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6	6
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	4,014	3,188
Non-accrual	318	318	170
Total	4,385	3,536
Construction | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	53	30
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	67,506	73,088
Non-accrual	2,490	507	$ 685	$ 647
Total	71,996	$ 73,595
Commercial Real Estate | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 2,000