FAIR VALUE (Tables)	9 Months Ended
FAIR VALUE (Tables)	Sep. 30, 2025
FAIR VALUE [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis [Table Text Block]	Assets and liabilities measured at fair value on a recurring basis are summarized below as of the indicated dates: As of September 30, 2025 As of December 31, 2024 Fair Value Measurements Using Fair Value Measurements Using Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (In thousands) Assets: Available-for-sale debt securities: U.S. Treasury securities $ 496,803 $ - $ - $ 496,803 $ 59,189 $ - $ - $ 59,189 Noncallable U.S. agencies debt securities - 646,783 - 646,783 - 533,296 - 533,296 Callable U.S. agencies debt securities - 612,631 - 612,631 - 1,307,035 - 1,307,035 MBS - 2,836,675 3,332 (1) 2,840,007 - 2,658,967 4,195 (1) 2,663,162 Puerto Rico government obligation - - 1,579 1,579 - - 1,620 1,620 Other investments - - 500 500 - - 1,000 1,000 Equity securities 5,009 - - 5,009 4,886 - - 4,886 Derivative assets - 332 - 332 - 318 - 318 Liabilities: Derivative liabilities - 264 - 264 - 150 - 150 (1) Related to private label MBS.
Fair Value of Assets and Liabilities Measured on Recurring Basis [Table Text Block]	The table below presents a reconciliation of the beginning and ending balances of all assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the quarters and nine-month periods ended September 30, 2025 and 2024: Quarter Ended September 30, Nine-Month Period Ended September 30, 2025 2024 2025 2024 Level 3 Instruments Only Securities Available for Sale (1) Securities Available for Sale (1) Securities Available for Sale (1) Securities Available for Sale (1) (In thousands) Beginning balance $ 5,857 $ 7,099 $ 6,815 $ 6,200 Total (losses) gains: Included in other comprehensive income (unrealized) (72) 178 219 592 Included in earnings (unrealized) (2) (146) 36 (138) 45 Purchases - - - 1,000 Principal repayments and amortization (3) (228) (425) (1,485) (949) Ending balance $ 5,411 $ 6,888 $ 5,411 $ 6,888 ___________________ (1) Amounts mostly related to private label MBS. (2) Changes in unrealized (losses) gains included in earnings were recognized within provision for credit losses – expense and relate to assets still held as of the reporting date. (3) For the nine-month period ended September 30, 2025 include a $ 0.5 million repayment of a matured debt security.
Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) [Table Text Block]	The tables below present quantitative information for significant assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) as of the indicated dates: September 30, 2025 Fair Value Valuation Technique Unobservable Input Range Weighted Average Minimum Maximum (Dollars in thousands) Available-for-sale debt securities: Private label MBS $ 3,332 Discounted cash flows Discount rate 16.0% 16.0% 16.0% Prepayment rate 1.6% 8.1% 3.4% Projected cumulative loss rate 0.1% 11.7% 5.8% Puerto Rico government obligation $ 1,579 Discounted cash flows Discount rate 11.3% 11.3% 11.3% Projected cumulative loss rate 24.3% 24.3% 24.3% December 31, 2024 Fair Value Valuation Technique Unobservable Input Range Weighted Average Minimum Maximum (Dollars in thousands) Available-for-sale debt securities: Private label MBS $ 4,195 Discounted cash flows Discount rate 16.6% 16.6% 16.6% Prepayment rate 0.0% 5.7% 3.2% Projected cumulative loss rate 0.1% 10.1% 4.9% Puerto Rico government obligation $ 1,620 Discounted cash flows Discount rate 11.5% 11.5% 11.5% Projected cumulative loss rate 23.9% 23.9% 23.9%
Impairment of Valuation Adjustments were Recorded for Assets Recognized at Fair Value [Table Text Block]	For the quarter and nine-month period ended September 30, 2025, the Corporation recorded losses or valuation adjustments for assets recognized at fair value on a non-recurring basis and still held at September 30, 2025, as shown in the following table: Carrying value as of September 30, 2025 Related to losses recorded for the Quarter Ended September 30, 2025 Related to losses recorded for the Nine-Month Period Ended September 30, 2025 Losses recorded for the Quarter Ended September 30, 2025 Losses recorded for the Nine-Month Period Ended September 30, 2025 (In thousands) Level 3: Loans receivable (1) $ 250 $ 9,214 $ (12) $ (630) OREO (2) (3) 211 387 (1) (5) (1) Consists mainly of collateral dependent commercial and construction loans. The Corporation generally measured losses based on the fair value of the collateral. The Corporation derived the fair values from external appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the collateral (e.g., absorption rates), which are not market observable. There were no adjustments applied on appraisals for the quarter ended September 30, 2025. The adjustment applied on appraisals was of 22 % for the nine-month period ended September 30, 2025. (2) The Corporation derived the fair values from appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the properties (e.g., absorption rates and net operating income of income producing properties), which are not market observable. Losses were related to market valuation adjustments after the transfer of the loans to the OREO portfolio. The adjustments applied on appraisals ranged from 3 % to 24 % for the quarter and nine-month period ended September 30, 2025. (3) Excludes the aforementioned $ 2.8 million adjustment in connection with ongoing litigation involving a commercial OREO property in the Virgin Islands region. See Note 19 – “Regulatory Matters, Commitments and Contingencies” for further details. For the quarter and nine-month period ended September 30, 2024, the Corporation recorded losses or valuation adjustments for assets recognized at fair value on a non-recurring basis and still held at September 30, 2024, as shown in the following table: Carrying value as of September 30, 2024 Related to losses recorded for the Quarter Ended September 30, 2024 Related to losses recorded for the Nine-Month Period Ended September 30, 2024 Losses recorded for the Quarter Ended September 30, 2024 Losses recorded for the Nine-Month Period Ended September 30, 2024 (In thousands) Level 3: Loans receivable (1) $ 5,910 $ 22,204 $ (386) $ (1,441) OREO (2) 752 1,437 (33) (108) Level 2: (1) Consists mainly of collateral dependent commercial and construction loans. The Corporation generally measured losses based on the fair value of the collateral. The Corporation derived the fair values from external appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the collateral (e.g., absorption rates), which are not market observable. There were no adjustments applied on appraisals for the quarter ended September 30, 2024. The adjustments applied on appraisals were of 4 % for the nine-month period ended September 30, 2024. (2) The Corporation derived the fair values from appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the properties (e.g., absorption rates and net operating income of income producing properties), which are not market observable. Losses were related to market valuation adjustments after the transfer of the loans to the OREO portfolio. The adjustments applied ranged from 2 % to 44 % for the quarter and nine-month period ended September 30, 2024.
Estimated Fair Value and Carrying Value of Financial Instruments [Table Text Block]	The following tables present the carrying value, estimated fair value and estimated fair value level of the hierarchy of financial instruments as of the indicated dates: Total Carrying Amount in Statement of Financial Condition as of September 30, 2025 Fair Value Estimate as of September 30, 2025 Level 1 Level 2 Level 3 (In thousands) Assets: Cash and due from banks and money market investments (amortized cost) $ 899,570 $ 899,570 $ 899,570 $ - $ - Available-for-sale debt securities (fair value) 4,598,303 4,598,303 496,803 4,096,089 5,411 Held-to-maturity debt securities: Held-to-maturity debt securities (amortized cost) 273,363 Less: ACL on held-to-maturity debt securities (698) Held-to-maturity debt securities, net of ACL $ 272,665 269,253 - 184,070 85,183 Equity securities (amortized cost) 39,381 39,381 - 39,381 (1) - Other equity securities (fair value) 5,009 5,009 5,009 - - Loans held for sale (lower of cost or market) 12,546 12,793 - 12,793 - Loans held for investment: Loans held for investment (amortized cost) 13,048,684 Less: ACL for loans and finance leases (246,990) Loans held for investment, net of ACL $ 12,801,694 12,700,160 - - 12,700,160 MSRs (amortized cost) 23,659 41,710 - - 41,710 Derivative assets (fair value) (2) 332 332 - 332 - Liabilities: Deposits (amortized cost) $ 16,861,047 $ 16,864,154 $ - $ 16,864,154 $ - Long-term advances from the FHLB (amortized cost) 290,000 292,473 - 292,473 - Derivative liabilities (fair value) (2) 264 264 - 264 - (1) Includes FHLB stock with a carrying value of $ 24.7 million, which is considered restricted. (2) Includes interest rate swap agreements, forward contracts, and interest rate lock commitments. Total Carrying Amount in Statement of Financial Condition as of December 31, 2024 Fair Value Estimate as of December 31, 2024 Level 1 Level 2 Level 3 (In thousands) Assets: Cash and due from banks and money market investments (amortized cost) $ 1,159,415 $ 1,159,415 $ 1,159,415 $ - $ - Available-for-sale debt securities (fair value) 4,565,302 4,565,302 59,189 4,499,298 6,815 Held-to-maturity debt securities: Held-to-maturity debt securities (amortized cost) 317,786 Less: ACL on held-to-maturity debt securities (802) Held-to-maturity debt securities, net of ACL $ 316,984 308,040 - 212,432 95,608 Equity securities (amortized cost) 47,132 47,132 - 47,132 (1) - Other equity securities (fair value) 4,886 4,886 4,886 - - Loans held for sale (lower of cost or market) 15,276 15,276 - 15,276 - Loans held for investment: Loans held for investment (amortized cost) 12,746,556 Less: ACL for loans and finance leases (243,942) Loans held for investment, net of ACL $ 12,502,614 12,406,405 - - 12,406,405 MSRs (amortized cost) 25,019 43,046 - - 43,046 Derivative assets (fair value) (2) 318 318 - 318 - Liabilities: Deposits (amortized cost) $ 16,871,298 $ 16,872,963 $ - $ 16,872,963 $ - Long-term advances from the FHLB (amortized cost) 500,000 500,128 - 500,128 - Junior subordinated debentures (amortized cost) 61,700 61,752 - - 61,752 Derivative liabilities (fair value) (2) 150 150 - 150 - (1) Includes FHLB stock with a carrying value of $ 34.0 million, which is considered restricted. (2) Includes interest rate swap agreements, forward contracts, and interest rate lock commitments.

Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset.