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	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 291,624	$ 266,439
Non-accrual	2,162	3,270	$ 3,866	$ 3,751
Total	294,981	271,612
30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,167	1,843
Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	28	60
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	14,187	15,823
Non-accrual	334	185	281	403
Total	14,602	16,112
Consumer | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	81	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	81,335	79,205
Non-accrual	933	2,124	2,714	2,508
Total	82,705	81,926
Residential Real estate | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	409	597
Residential Real estate | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	28
Indirect
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	109,380	83,932
Non-accrual	135	88	193	193
Total	110,192	85,186
Indirect | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	677	1,166
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	13,266	11,203
Non-accrual		48	48
Total	13,266	11,257
Commercial | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		6
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,449	3,188
Non-accrual	228	318
Total	2,677	3,536
Construction | Financing Receivables, Equal to Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		30
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	71,007	73,088
Non-accrual	532	507	$ 632	$ 647
Total	$ 71,539	$ 73,595