FAIR VALUE - Fair value hierarchy of financial instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Financial assets - Carrying Amount
Cash and cash equivalents	$ 11,497	$ 10,622	$ 16,676	$ 12,371
Loans receivable, net	268,840	262,574
Cash value of life insurance	9,479
Financial liabilities - Carrying Amount
Deposits	334,105	333,246
Long-term debt		10,000
Short-term debt	20,000	10,000
Financial assets - Fair Value
Loans receivable, net	266,254	259,017
Financial liabilities - Fair Value
Deposits	316,619	315,418
Long-term debt		10,257
Short-term debt	20,917	$ 10,188
Fair Value
Financial assets - Fair Value
Cash and cash equivalents	9,479
Loans receivable, net	266,254
Cash value of life insurance	11,497
Financial liabilities - Fair Value
Deposits	20,917
Short-term debt	316,619
Fair Value | Level 1
Financial assets - Fair Value
Cash value of life insurance	11,497
Financial liabilities - Fair Value
Short-term debt	219,478
Fair Value | Level 2
Financial assets - Fair Value
Cash and cash equivalents	9,479
Financial liabilities - Fair Value
Deposits	20,917
Short-term debt	97,141
Fair Value | Level 3
Financial assets - Fair Value
Loans receivable, net	$ 266,254