LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES - Allowance for Credit Losses (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($) borrower	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) borrower
Financing Receivable, Allowance For Credit Losses [Line Items]
Average loans	$ 175,914,000	$ 184,787,000
Net charge-offs to average loans (annualized)	0.66%	(0.09%)
Number of borrowers | borrower	6		3
Loans charged off	$ 314,000	$ 8,000	$ 203,000
Outstanding commitments	34,600,000
Term Loans by Origination Year
2022	13,000
2021	299,000		47,000
2020			43,000
2019			27,000
Prior	2,000		86,000
Total	314,000	8,000	203,000
Unfunded commitments
Beginning balance	473,000	477,000	477,000
Reduction of unfunded reserve	(15,000)
Provisions charged to operations	39,000	5,000
Ending balance	$ 497,000	$ 482,000	473,000
Real Estate Loan | Single-family Residential
Financing Receivable, Allowance For Credit Losses [Line Items]
Number of borrowers | borrower	1
Commercial and Industrial | Commercial and Industrial
Financing Receivable, Allowance For Credit Losses [Line Items]
Loans charged off	$ 299,000
Term Loans by Origination Year
2021	299,000
Total	299,000
Consumer Loans | Consumer
Financing Receivable, Allowance For Credit Losses [Line Items]
Loans charged off	13,000		79,000
Term Loans by Origination Year
2022	13,000
Prior			79,000
Total	13,000		79,000
Consumer Loans | Automobile
Financing Receivable, Allowance For Credit Losses [Line Items]
Loans charged off	2,000		124,000
Term Loans by Origination Year
2021			47,000
2020			43,000
2019			27,000
Prior	2,000		7,000
Total	$ 2,000		$ 124,000