LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses (Details)	9 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($) borrower	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) borrower
Financing Receivable, Allowance For Credit Losses [Line Items]
Average loans	$ 181,234,000	$ 197,199,000
Net charge-offs to average loans (annualized)	0.05%	0.00%
Number of borrowers | borrower	6		14
Loans charged off	$ 136,000	$ 151,000	$ 392,000
Outstanding commitments	30,600,000	30,500,000
Term Loans by Origination Year
2021	30,000
2020	19,000
Prior	87,000
Total	136,000	151,000	392,000
Unfunded commitments
Beginning balance	477,000	371,000	371,000
Reduction of unfunded reserve	(52,000)	(76,000)
Provisions charged to operations	23,000	174,000
Ending balance	448,000	$ 469,000	477,000
Consumer
Financing Receivable, Allowance For Credit Losses [Line Items]
Loans charged off	79,000
Term Loans by Origination Year
Prior	79,000
Total	79,000
Consumer | Consumer Loans
Financing Receivable, Allowance For Credit Losses [Line Items]
Loans charged off			14,000
Term Loans by Origination Year
Total			14,000
Automobile
Financing Receivable, Allowance For Credit Losses [Line Items]
Loans charged off	57,000
Term Loans by Origination Year
2021	30,000
2020	19,000
Prior	8,000
Total	57,000
Automobile | Consumer Loans
Financing Receivable, Allowance For Credit Losses [Line Items]
Loans charged off	136,000		169,000
Term Loans by Origination Year
Total	$ 136,000		$ 169,000