LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES - Allowance for Credit Losses (Details)	6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($) borrower	Jun. 30, 2020 USD ($) borrower	Dec. 31, 2020 USD ($)
Financing Receivable, Allowance For Credit Losses [Line Items]
Average loans	$ 244,416,000	$ 284,168,000
Net charge-offs to average loans (annualized)	(0.25%)	0.02%
Number of borrowers | borrower	12	20
Loans charged off	$ 124,000	$ 171,000	$ 392,000
Outstanding commitments	31,800,000	31,800,000
Unfunded commitments
Beginning balance	33,000	37,000	37,000
Reduction of unfunded reserve	(13,000)
Provisions charged to operations		60,000
Ending balance	477,000	$ 97,000	33,000
ASU 2016-13
Unfunded commitments
Beginning balance	$ 457,000
Ending balance			$ 457,000