FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Balance sheet grouping (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Financial assets:
Available-for-sale, allowance for credit losses	$ 518	$ 518	$ 498	$ 498
Loans, allowance for credit losses	2,001	1,915	$ 1,842	$ 1,804
Carrying Amount
Financial assets:
Cash and cash equivalents	7,206	5,328
Securities available-for-sale	43,031	48,635
Federal Home Loan Bank of New York stock, at cost	3,254	3,272
Federal Reserve Bank stock, at cost	270
Loans, net	233,334	226,030
Accrued interest receivable	1,603	1,479
Financial liabilities:
Deposits	240,853	234,426
Federal Home Loan Bank advances	34,567	35,567
Accrued interest payable	115	120
Advances from borrowers for taxes and insurance	1,938	2,389
Fair Value
Financial assets:
Cash and cash equivalents	7,206	5,328
Securities available-for-sale	43,031	48,635
Federal Home Loan Bank of New York stock, at cost	3,254	3,272
Federal Reserve Bank stock, at cost	270
Loans, net	222,957	213,685
Accrued interest receivable	1,603	1,479
Financial liabilities:
Deposits	230,539	225,763
Federal Home Loan Bank advances	35,987	36,987
Accrued interest payable	115	120
Advances from borrowers for taxes and insurance	1,938	2,389
Level 1
Financial assets:
Cash and cash equivalents	7,206	5,328
Accrued interest receivable	1,603	1,479
Financial liabilities:
Deposits	86,246	85,684
Accrued interest payable	115	120
Advances from borrowers for taxes and insurance	1,938	2,389
Level 2
Financial assets:
Securities available-for-sale	42,883	48,487
Federal Home Loan Bank of New York stock, at cost	3,254	3,272
Federal Reserve Bank stock, at cost	270
Financial liabilities:
Deposits	144,293	140,079
Federal Home Loan Bank advances	35,987	36,987
Level 3 | Carrying Amount
Financial assets:
Securities available-for-sale	148	148
Loans, net	$ 222,957	$ 213,685