LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES - Summary of recorded investment amount and related allowance for losses of impaired loans (Details)	6 Months Ended
	Jun. 30, 2019 USD ($) borrower loan	Jun. 30, 2019 USD ($) loan	Jun. 30, 2018 borrower	Dec. 31, 2018 USD ($)
Financing Receivable, Impaired [Line Items]
Loans outstanding	$ 800,000	$ 800,000
Number of borrowers	39	1	25
Amount of troubled debt restructured loans, outstanding	$ 42,341	$ 42,341
Amount of troubled debt restructured loans, specific reserve	16,318	16,318
30-89 Days Past Due
Financing Receivable, Impaired [Line Items]
Loans outstanding	577,000	577,000		$ 1,726,000
30-89 Days Past Due | Substandard
Financing Receivable, Impaired [Line Items]
Loans outstanding	$ 800,000	$ 800,000
Consumer
Financing Receivable, Impaired [Line Items]
Number of loans | loan	2	2
Number of borrowers | borrower	2
Amount of consumer and indirect loans, outstanding	$ 83,121	$ 83,121
Amount of consumer and indirect loans, specific reserves	16,448	16,448
Consumer | 30-89 Days Past Due
Financing Receivable, Impaired [Line Items]
Loans outstanding	55,000	55,000		216,000
Commercial | 30-89 Days Past Due
Financing Receivable, Impaired [Line Items]
Loans outstanding				$ 86,000
Commercial | 30-89 Days Past Due | Substandard
Financing Receivable, Impaired [Line Items]
Loans outstanding	199,000	199,000
Commercial Real Estate | 30-89 Days Past Due | Substandard
Financing Receivable, Impaired [Line Items]
Loans outstanding	$ 563,000	$ 563,000