DEBT SECURITIES (Tables)	12 Months Ended
DEBT SECURITIES (Tables)	Dec. 31, 2023
Marketable Securities [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Table Text Block]	Year Ended December 31, 2023 Private label MBS Puerto Rico Government Obligations Total (In thousands) Beginning balance $ 83 $ 375 $ 458 Provision for credit losses - expense - 20 20 Net recoveries 33 - 33 ACL on available-for-sale debt securities $ 116 $ 395 $ 511 Year Ended December 31, 2022 Private label MBS Puerto Rico Government Obligations Total (In thousands) Beginning balance $ 797 $ 308 $ 1,105 Provision for credit losses - (benefit) expense (501) 67 (434) Net charge-offs (213) - (213) ACL on available-for-sale debt securities $ 83 $ 375 $ 458 Year Ended December 31, 2021 Private label MBS Puerto Rico Government Obligations Total (In thousands) Beginning balance $ 1,002 $ 308 $ 1,310 Provision for credit losses - benefit (136) - (136) Net charge-offs (69) - (69) ACL on available-for-sale debt securities $ 797 $ 308 $ 1,105
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Table Text Block]	Puerto Rico Municipal Bonds Year Ended December 31, 2023 2022 2021 (In thousands) Beginning Balance $ 8,286 $ 8,571 $ 8,845 Provision for credit losses - benefit (6,089) (285) (274) ACL on held-to-maturity debt securities $ 2,197 $ 8,286 $ 8,571
Held-to-maturity Securities [Member]
Marketable Securities [Line Items]
Investments Classified by Contractual Maturity Date [Table Text Block]	December 31, 2023 Amortized cost (1) (2) Gross Unrecognized Fair value Weighted- Gains Losses ACL average yield% (Dollars in thousands) Puerto Rico municipal bonds: Due within one year $ 3,165 $ 8 $ 38 $ 3,135 $ 50 9.30 After 1 to 5 years 51,230 994 710 51,514 1,266 7.78 After 5 to 10 years 36,050 3,540 210 39,380 604 7.13 After 10 years 16,595 269 - 16,864 277 8.87 Total Puerto Rico municipal bonds 107,040 4,811 958 110,893 2,197 7.78 MBS: Residential MBS: FHLMC certificates: After 5 to 10 years 16,469 - 556 15,913 - 3.03 After 10 years 18,324 - 714 17,610 - 4.32 34,793 - 1,270 33,523 - 3.71 GNMA certificates: After 10 years 16,265 - 789 15,476 - 3.32 FNMA certificates: After 10 years 67,271 - 2,486 64,785 - 4.18 CMOs issued or guaranteed by FHLMC, FNMA, and GNMA: After 10 years 28,139 - 1,274 26,865 - 3.49 Total Residential MBS 146,468 - 5,819 140,649 - 3.84 Commercial MBS: After 1 to 5 years 9,444 - 297 9,147 - 3.48 After 10 years 91,226 - 5,783 85,443 - 3.15 Total Commercial MBS 100,670 - 6,080 94,590 - 3.18 Total MBS 247,138 - 11,899 235,239 - 3.57 Total held-to-maturity debt securities $ 354,178 $ 4,811 $ 12,857 $ 346,132 $ 2,197 4.84 (1) Excludes accrued interest receivable on held-to-maturity debt securities that totaled $ 4.8 million as of December 31, 2023 reported as part of accrued interest receivable on loans and investment securities in the consolidated statements of financial condition, and excluded from the estimate of credit losses. (2) Includes $ 126.6 million (fair value - $ 125.9 million) that serves as collateral for the uninsured portion of government deposits. The secured parties are not permitted to sell or repledge the collateral. December 31, 2022 Amortized cost (1) (2) Gross Unrecognized Fair value Weighted- Gains Losses ACL average yield% (Dollars in thousands) Puerto Rico municipal bonds: Due within one year $ 1,202 $ - $ 15 $ 1,187 $ 2 5.20 After 1 to 5 years 42,530 886 1,076 42,340 656 6.34 After 5 to 10 years 55,956 3,182 360 58,778 3,243 6.29 After 10 years 66,022 - 1,318 64,704 4,385 7.10 Total held-to-maturity debt securities 165,710 4,068 2,769 167,009 8,286 6.62 MBS: Residential MBS: FHLMC certificates: After 5 to 10 years 21,443 - 746 20,697 - 3.03 After 10 years 19,362 - 888 18,474 - 4.21 40,805 - 1,634 39,171 - 3.59 GNMA certificates: After 10 years 19,131 - 943 18,188 - 3.35 FNMA certificates: After 10 years 72,347 - 3,155 69,192 - 4.14 CMOs issued or guaranteed by FHLMC, FNMA, and GNMA: After 10 years 34,456 - 1,424 33,032 - 3.49 Total Residential MBS 166,739 - 7,156 159,583 - 3.78 Commercial MBS: After 1 to 5 years 9,621 - 396 9,225 - 3.48 After 10 years 95,467 - 4,169 91,298 - 3.15 Total Commercial MBS 105,088 - 4,565 100,523 - 3.18 Total MBS 271,827 - 11,721 260,106 - 3.55 Total held-to-maturity debt securities $ 437,537 $ 4,068 $ 14,490 $ 427,115 $ 8,286 4.71 (1) Excludes accrued interest receivable on held-to-maturity debt securities that totaled $ 5.5 million as of December 31, 2022 reported as part of accrued interest receivable on loans and investment securities in the consolidated statements of financial condition, and excluded from the estimate of credit losses. (2) Includes $ 190.1 million (fair value - $ 189.4 million) that serves as collateral for the uninsured portion of government deposits. The secured parties are not permitted to sell or repledge the collateral.
Schedule of Unrealized Loss on Investments [Table Text Block]	As of December 31, 2023 Less than 12 months 12 months or more Total Unrecognized Unrecognized Unrecognized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) Puerto Rico municipal bonds $ - $ - $ 34,682 $ 958 $ 34,682 $ 958 MBS: Residential MBS: FHLMC certificates - - 33,523 1,270 33,523 1,270 GNMA certificates - - 15,476 789 15,476 789 FNMA certificates - - 64,785 2,486 64,785 2,486 CMOs issued or guaranteed by FHLMC, FNMA, and GNMA - - 26,865 1,274 26,865 1,274 Commercial MBS - - 94,590 6,080 94,590 6,080 Total held-to-maturity debt securities $ - $ - $ 269,921 $ 12,857 $ 269,921 $ 12,857 As of December 31, 2022 Less than 12 months 12 months or more Total Unrecognized Unrecognized Unrecognized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) Puerto Rico municipal bonds $ - $ - $ 98,797 $ 2,769 $ 98,797 $ 2,769 MBS: Residential MBS: FHLMC certificates 39,171 1,634 - - 39,171 1,634 GNMA certificates 18,188 943 - - 18,188 943 FNMA certificates 69,192 3,155 - - 69,192 3,155 CMOs issued or guaranteed by FHLMC, FNMA, and GNMA 33,032 1,424 - - 33,032 1,424 Commercial MBS 100,523 4,565 - - 100,523 4,565 Total held-to-maturity debt securities $ 260,106 $ 11,721 $ 98,797 $ 2,769 $ 358,903 $ 14,490
Available-for-sale Securities [Member]
Marketable Securities [Line Items]
Investments Classified by Contractual Maturity Date [Table Text Block]	December 31, 2023 Amortized cost (1) Gross ACL Fair value (2) Unrealized Weighted- Gains Losses average yield% (Dollars in thousands) U.S. Treasury securities: Due within one year $ 80,314 $ - $ 2,144 $ - $ 78,170 0.66 After 1 to 5 years 60,239 - 3,016 - 57,223 0.75 U.S. GSEs obligations: Due within one year 542,847 - 15,832 - 527,015 0.77 After 1 to 5 years 1,899,620 49 135,347 - 1,764,322 0.86 After 5 to 10 years 8,850 - 687 - 8,163 2.64 After 10 years 8,891 8 2 - 8,897 5.49 Puerto Rico government obligations: After 10 years (3) 3,156 - 1,346 395 1,415 - United States and Puerto Rico government obligations 2,603,917 57 158,374 395 2,445,205 0.85 MBS: Residential MBS: FHLMC certificates: After 1 to 5 years 19,561 - 868 - 18,693 2.06 After 5 to 10 years 153,308 - 12,721 - 140,587 1.55 After 10 years 991,060 15 161,197 - 829,878 1.41 1,163,929 15 174,786 - 989,158 1.44 GNMA certificates: Due within one year 254 - 3 - 251 3.27 After 1 to 5 years 16,882 - 872 - 16,010 1.19 After 5 to 10 years 27,916 8 2,247 - 25,677 1.62 After 10 years 206,254 87 22,786 - 183,555 2.57 251,306 95 25,908 - 225,493 2.38 FNMA certificates: After 1 to 5 years 32,489 - 1,423 - 31,066 2.11 After 5 to 10 years 293,492 - 23,146 - 270,346 1.70 After 10 years 1,047,298 83 156,344 - 891,037 1.37 1,373,279 83 180,913 - 1,192,449 1.46 Collateralized mortgage obligations (“CMOs”) issued or guaranteed by the FHLMC, FNMA, and GNMA: After 10 years 273,539 - 52,263 - 221,276 1.54 Private label: After 10 years 7,086 - 2,185 116 4,785 7.66 Total Residential MBS 3,069,139 193 436,055 116 2,633,161 1.55 Commercial MBS: After 1 to 5 years 45,022 - 6,898 - 38,124 2.17 After 5 to 10 years 22,386 - 2,685 - 19,701 2.16 After 10 years 122,830 - 29,037 - 93,793 1.36 Total Commercial MBS 190,238 - 38,620 - 151,618 1.64 Total MBS 3,259,377 193 474,675 116 2,784,779 1.55 Total available-for-sale debt securities $ 5,863,294 $ 250 $ 633,049 $ 511 $ 5,229,984 1.24 (1) Excludes accrued interest receivable on available-for-sale debt securities that totaled $ 10.6 million as of December 31, 2023 reported as part of accrued interest receivable on loans and investment securities in the consolidated statements of financial condition, and excluded from the estimate of credit losses. (2) Includes $ 477.9 million (amortized cost - $ 527.2 million) that was pledged at the FHLB as collateral for borrowings and letters of credit as well as $ 2.8 billion (amortized cost - $ 3.2 billion) pledged as collateral for the uninsured portion of government deposits. The secured parties are not permitted to sell or repledge the collateral. (3) Consists of a residential pass-through MBS issued by the PRHFA that is collateralized by certain second mortgages originated under a program launched by the Puerto Rico government in 2010 and is in nonaccrual status based on the delinquency status of the underlying second mortgage loans collateral. December 31, 2022 Amortized cost (1) Gross ACL Fair value (2) Unrealized Weighted- Gains Losses average yield% (Dollars in thousands) U.S. Treasury securities: Due within one year $ 7,493 $ - $ 309 $ - $ 7,184 0.22 After 1 to 5 years 141,366 - 9,675 - 131,691 0.70 U.S. GSEs’ obligations: Due within one year 129,018 - 4,036 - 124,982 0.32 After 1 to 5 years 2,395,273 22 227,724 - 2,167,571 0.83 After 5 to 10 years 56,251 13 7,670 - 48,594 1.54 After 10 years 12,170 36 - - 12,206 4.62 Puerto Rico government obligations: After 10 years (3) 3,331 - 755 375 2,201 - United States and Puerto Rico government obligations 2,744,902 71 250,169 375 2,494,429 0.83 MBS: Residential MBS: FHLMC certificates: After 1 to 5 years 4,235 - 169 - 4,066 2.33 After 5 to 10 years 201,072 - 18,709 - 182,363 1.55 After 10 years 1,092,289 - 186,558 - 905,731 1.38 1,297,596 - 205,436 - 1,092,160 1.41 GNMA certificates: Due within one year 5 - - - 5 1.73 After 1 to 5 years 15,508 - 622 - 14,886 2.00 After 5 to 10 years 45,322 1 3,809 - 41,514 1.31 After 10 years 232,632 51 27,169 - 205,514 2.47 293,467 52 31,600 - 261,919 2.27 FNMA certificates: After 1 to 5 years 9,685 - 521 - 9,164 1.76 After 5 to 10 years 358,346 - 31,620 - 326,726 1.68 After 10 years 1,186,635 124 186,757 - 1,000,002 1.38 1,554,666 124 218,898 - 1,335,892 1.45 CMOs issued or guaranteed by the FHLMC, FNMA, and GNMA: After 10 years 302,232 - 56,539 - 245,693 1.44 Private label: After 10 years 7,903 - 2,026 83 5,794 6.83 Total Residential MBS 3,455,864 176 514,499 83 2,941,458 1.52 Commercial MBS: After 1 to 5 years 30,578 - 4,463 - 26,115 2.43 After 5 to 10 years 44,889 - 5,603 - 39,286 1.89 After 10 years 121,464 - 23,732 - 97,732 1.23 Total Commercial MBS 196,931 - 33,798 - 163,133 1.56 Total MBS 3,652,795 176 548,297 83 3,104,591 1.52 Other Due within one year 500 - - - 500 0.84 Total available-for-sale debt securities $ 6,398,197 $ 247 $ 798,466 $ 458 $ 5,599,520 1.22 (1) Excludes accrued interest receivable on available-for-sale debt securities that totaled $ 11.1 million as of December 31, 2022 reported as part of accrued interest receivable on loans and investment securities in the consolidated statements of financial condition, and excluded from the estimate of credit losses. (2) Includes $ 250.6 million (amortized cost - $ 286.5 million) that was pledged at the FHLB as collateral for borrowings and letters of credit as well as $ 2.4 billion (amortized cost - $ 2.8 billion) pledged as collateral for the uninsured portion of government deposits. The secured parties are not permitted to sell or repledge the collateral. (3) Consists of a residential pass-through MBS issued by the PRHFA that is collateralized by certain second mortgages originated under a program launched by the Puerto Rico government in 2010 and is in nonaccrual status based on the delinquency status of the underlying second mortgage loans collateral.
Schedule of Unrealized Loss on Investments [Table Text Block]	As of December 31, 2023 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) U.S. Treasury and U.S. GSEs’ obligations $ 2,544 $ 2 $ 2,428,784 $ 157,026 $ 2,431,328 $ 157,028 Puerto Rico government obligations - - 1,415 1,346 (1) 1,415 1,346 MBS: Residential MBS: FHLMC 9 - 988,092 174,786 988,101 174,786 GNMA 12,257 100 202,390 25,808 214,647 25,908 FNMA - - 1,183,275 180,913 1,183,275 180,913 CMOs issued or guaranteed by the FHLMC, FNMA, and GNMA - - 221,276 52,263 221,276 52,263 Private label - - 4,785 2,185 (1) 4,785 2,185 Commercial MBS 11,370 18 140,248 38,602 151,618 38,620 $ 26,180 $ 120 $ 5,170,265 $ 632,929 $ 5,196,445 $ 633,049 (1) Unrealized losses do not include the credit loss component recorded as part of the ACL. As of December 31, 2023, the PRHFA bond and private label MBS had an ACL of $ 0.4 million and $ 0.1 million, respectively. As of December 31, 2022 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) U.S. Treasury and U.S. GSEs’ obligations $ 298,313 $ 18,057 $ 2,174,724 $ 231,357 $ 2,473,037 $ 249,414 Puerto Rico government obligations - - 2,201 755 (1) 2,201 755 MBS: Residential MBS: FHLMC 260,524 45,424 831,637 160,012 1,092,161 205,436 GNMA 74,829 3,433 179,854 28,167 254,683 31,600 FNMA 405,977 49,479 920,200 169,419 1,326,177 218,898 CMOs issued or guaranteed by the FHLMC, FNMA, and GNMA 45,370 6,735 200,323 49,804 245,693 56,539 Private label - - 5,794 2,026 (1) 5,794 2,026 Commercial MBS 30,179 2,215 132,953 31,583 163,132 33,798 $ 1,115,192 $ 125,343 $ 4,447,686 $ 673,123 $ 5,562,878 $ 798,466 (1) Unrealized losses do not include the credit loss component recorded as part of the ACL. As of December 31, 2022, the PRHFA bond and private label MBS had an ACL of $ 0.4 million and $ 0.1 million, respectively.