SECURITIES - Summary of amortized cost of securities held to maturity and their estimated fair value (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 27,107	$ 33,174
Gross Unrecognized Gains	5	0
Gross Unrecognized Losses	(1,484)	(3,179)
Estimated Fair Value	25,628	29,995
Securities held for investment, allowance	(91)	(98)
Securities held-to-maturity	27,016	33,076
Asset-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	8,507	14,574
Gross Unrecognized Gains	0	0
Gross Unrecognized Losses	(472)	(993)
Estimated Fair Value	8,035	13,581
Corporate Bonds
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	18,600	18,600
Gross Unrecognized Gains	5	0
Gross Unrecognized Losses	(1,012)	(2,186)
Estimated Fair Value	$ 17,593	$ 16,414

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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+ Details

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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+ Details

Blue Foundry Bancorp 10-K