LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES - Summary of allowance for credit losses (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Troubled debt restructured loans	$ 237,000	$ 248,000
Non-accrual and 90+ days past due and still accruing loans to average loans	1.51%	0.76%
Allowance for credit losses to non-accrual and 90 days or more and still accruing loans	54.30%	128.70%
Commercial
Financing Receivable, Impaired [Line Items]
Troubled debt restructured loans	$ 195,000
Consumer
Financing Receivable, Impaired [Line Items]
Troubled debt restructured loans	$ 42,000