LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES - Non-accrual loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	$ 3,270	$ 3,751
Transfer into non-accrual	2,381	451
Loans paid down/payoffs	(76)	(95)
Loans return to accrual status	(37)	(165)
Loans charged off	(97)	(170)
Balance	5,441	3,772
Consumer
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	185	403
Transfer into non-accrual	38	4
Loans paid down/payoffs	(9)	(12)
Loans charged off	(63)
Balance	151	395
Residential Real estate
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	2,124	2,508
Transfer into non-accrual	183
Loans paid down/payoffs	(17)	(31)
Loans return to accrual status		(132)
Loans charged off		(3)
Balance	2,290	2,342
Indirect
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	88	193
Transfer into non-accrual	160	229
Loans paid down/payoffs	(33)	(42)
Loans return to accrual status	(37)	(33)
Loans charged off	(34)	(167)
Balance	144	180
Commercial
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	48
Balance	48
Construction
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	318
Transfer into non-accrual		170
Balance	318	170
Commercial Real Estate
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	507	647
Transfer into non-accrual	2,000	48
Loans paid down/payoffs	(17)	(10)
Balance	$ 2,490	$ 685