INVESTMENT SECURITIES (Tables)	12 Months Ended
INVESTMENT SECURITIES (Tables)	Dec. 31, 2021
Other Than Temporary Impairment Credit Losses Recognized In Earnings [Line Items]
Significant Assumptions in Valuation of Private Label MBS [Table Text Block]	The tables below present qualitative information for significant assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) as of December 31, 2021 and 2020: December 31, 2021 Fair Value Valuation Technique Unobservable Input Range Weighted Average (Dollars in thousands) Minimum Maximum Investment securities available-for-sale: Private label MBS $ 7,234 Discounted cash flows Discount rate 12.9% 12.9% 12.9% Prepayment rate 7.6% 24.9% 15.2% Projected Cumulative Loss Rate 0.2% 15.7% 7.6% Puerto Rico government obligations $ 2,850 Discounted cash flows Discount rate 7.9% 7.9% 7.9% Projected Cumulative Loss Rate 8.6% 8.6% 8.6% December 31, 2020 Fair Value Valuation Technique Unobservable Input Range Weighted Average (Dollars in thousands) Minimum Maximum Investment securities available-for-sale: Private label MBS $ 8,428 Discounted cash flows Discount rate 12.2% 12.2% 12.2% Prepayment rate 1.2% 18.8% 12.1% Projected Cumulative Loss Rate 2.6% 22.3% 10.2% Puerto Rico government obligations $ 2,899 Discounted cash flows Discount rate 7.9% 7.9% 7.9% Projected Cumulative Loss Rate 12.4% 12.4% 12.4%
Debt Securities, Available-for-sale, Allowance for Credit Loss [Table Text Block]	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 debt securities available-for-sale $ 797 $ 308 $ 1,105 Year Ended December 31, 2020 Private label MBS Puerto Rico Government Obligations Total (In thousands) Beginning balance $ - $ - $ - Provision for credit losses 1,333 308 1,641 Net charge-offs (331) - (331) ACL on debt securities available-for-sale $ 1,002 $ 308 $ 1,310
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Table Text Block]	Puerto Rico Municipal Bonds Year Ended December 31, 2021 December 31, 2020 (In thousands) Beginning Balance $ 8,845 $ - Impact of adopting ASC 326 - 8,134 Initial allowance on PCD debt securities - 1,269 Provision for credit losses - (benefit) (274) (558) $ 8,571 $ 8,845
Debt Securities, Held-to-maturity, Credit Quality Indicator [Table Text Block]	Held to Maturity Puerto Rico Municipal Bonds December 31, December 31 (In thousands) 2021 2020 Risk Ratings: Pass $ 178,133 $ 189,488 Criticized: Special Mention - - Substandard - - Doubtful - - Loss - - Total $ 178,133 $ 189,488
Held-to-maturity Securities [Member]
Other Than Temporary Impairment Credit Losses Recognized In Earnings [Line Items]
Investments Classified by Contractual Maturity Date [Table Text Block]	The amortized cost, gross unrecognized gains and losses, estimated fair value, ACL, weighted-average yield and contractual maturities of investment securities held to maturity as of December 31, 2021 and December 31, 2020 were as follows December 31, 2021 Amortized cost Fair value Gross Unrecognized Weighted- (Dollars in thousands) Gains Losses ACL average yield% Puerto Rico municipal bonds: Due within one year $ 2,995 $ 5 $ - $ 3,000 $ 70 5.39 After 1 to 5 years 14,785 526 156 15,155 347 2.35 After 5 to 10 years 90,584 1,555 3,139 89,000 3,258 4.25 After 10 years 69,769 - 9,777 59,992 4,896 4.06 Total investment securities held to maturity $ 178,133 $ 2,086 $ 13,072 $ 167,147 $ 8,571 4.04 December 31, 2020 Amortized cost Fair value Gross Unrecognized Weighted- (Dollars in thousands) Gains Losses ACL average yield% Puerto Rico municipal bonds: Due within one year $ 556 $ 7 $ - $ 563 $ - 5.41 After 1 to 5 years 17,297 561 305 17,553 576 3.00 After 5 to 10 years 88,394 1,388 3,146 86,636 4,401 4.66 After 10 years 83,241 - 14,187 69,054 3,868 3.57 Total investment securities held to maturity $ 189,488 $ 1,956 $ 17,638 $ 173,806 $ 8,845 4.03
Schedule of Unrealized Loss on Investments [Table Text Block]	The following tables show the Corporation’s held-to-maturity investments’ fair value and gross unrecognized losses, aggregated by investment category and length of time that individual securities had been in a continuous unrecognized loss position, as of December 31, 2021 and December 31, 2020, including debt securities for which an ACL was recorded: As of December 31, 2021 Less than 12 months 12 months or more Total Unrecognized Unrecognized Unrecognized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) Debt securities: Puerto Rico municipal bonds $ - $ - $ 140,732 $ 13,072 $ 140,732 $ 13,072 As of December 31, 2020 Less than 12 months 12 months or more Total Unrecognized Unrecognized Unrecognized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) Debt securities: Puerto Rico municipal bonds $ 28,252 $ 1,611 $ 116,216 $ 16,027 $ 144,468 $ 17,638
Available-for-sale Securities [Member]
Other Than Temporary Impairment Credit Losses Recognized In Earnings [Line Items]
Investments Classified by Contractual Maturity Date [Table Text Block]	The amortized cost, gross unrealized gains and losses recorded in OCI, ACL, estimated fair value, and weighted-average yield of investment securities available for sale by contractual maturities as of December 31, 2021 were as follows: December 31, 2021 Amortized cost Gross ACL Fair value Unrealized Weighted- Gains Losses average yield% (Dollars in thousands) U.S. Treasury securities: After 1 to 5 years $ 149,660 $ 59 $ 1,233 $ - $ 148,486 0.68 U.S. government-sponsored agencies' obligations: After 1 to 5 years 1,877,181 240 29,555 - 1,847,866 0.60 After 5 to 10 years 403,785 175 10,856 - 393,104 0.90 After 10 years 15,788 224 - - 16,012 0.63 Puerto Rico government obligations: After 10 years (1) 3,574 - 416 308 2,850 - United States and Puerto Rico government obligations 2,449,988 698 42,060 308 2,408,318 0.67 MBS: FHLMC certificates: After 1 to 5 years 2,811 119 - - 2,930 2.65 After 5 to 10 years 193,234 2,419 1,122 - 194,531 1.29 After 10 years 1,240,964 3,748 23,503 - 1,221,209 1.18 1,437,009 6,286 24,625 - 1,418,670 1.20 GNMA certificates: Due within one year 2 - - - 2 1.32 After 1 to 5 years 16,714 572 - - 17,286 2.90 After 5 to 10 years 27,271 80 139 - 27,212 0.51 After 10 years 338,927 7,091 2,174 - 343,844 1.45 382,914 7,743 2,313 - 388,344 1.45 FNMA certificates: Due within one year 4,975 21 - - 4,996 2.03 After 1 to 5 years 21,337 424 - - 21,761 2.87 After 5 to 10 years 298,771 4,387 1,917 - 301,241 1.41 After 10 years 1,389,381 8,953 21,747 - 1,376,587 1.21 1,714,464 13,785 23,664 - 1,704,585 1.27 Collateralized mortgage obligations issued or guaranteed by the FHLMC FNMA and GNMA: After 1 to 5 years 24,007 1 778 - 23,230 1.31 After 5 to 10 years 14,316 97 - - 14,413 0.76 After 10 years 500,811 290 13,134 - 487,967 1.23 539,134 388 13,912 - 525,610 1.22 Private label: After 10 years 9,994 - 1,963 797 7,234 2.21 Total MBS 4,083,515 28,202 66,477 797 4,044,443 1.26 Other Due within one year 500 - - - 500 0.72 After 1 to 5 years 500 - - - 500 0.84 1,000 - - - 1,000 0.78 Total investment securities available for sale $ 6,534,503 $ 28,900 $ 108,537 $ 1,105 $ 6,453,761 1.03 (1) 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. During the second quarter of 2021, the Corporation placed this instrument in nonaccrual status based on this delinquency status of the underlying second mortgage loans collateral. December 31, 2020 Amortized cost Gross ACL Fair value Unrealized Weighted- Gains Losses average yield% (Dollars in thousands) U.S. Treasury securities: Due within one year $ 7,498 $ 9 $ - $ - $ 7,507 1.65 U.S. government-sponsored agencies' obligations: Due within one year 24,413 273 - - 24,686 1.95 After 1 to 5 years 691,668 911 290 - 692,289 0.57 After 5 to 10 years 441,454 821 347 - 441,928 0.83 After 10 years 21,413 - 149 - 21,264 0.65 Puerto Rico government obligations: After 10 years (1) 3,987 - 780 308 2,899 6.97 United States and Puerto Rico government obligations 1,190,433 2,014 1,566 308 1,190,573 0.72 MBS: FHLMC certificates: After 1 to 5 years 75 8 - - 83 4.86 After 5 to 10 years 60,773 2,850 - - 63,623 2.15 After 10 years 1,070,984 15,340 159 - 1,086,165 1.38 1,131,832 18,198 159 - 1,149,871 1.42 GNMA certificates: Due within one year 1 - - - 1 1.93 After 1 to 5 years 26,918 1,080 - - 27,998 2.91 After 5 to 10 years 40,727 128 69 - 40,786 0.42 After 10 years 614,584 16,271 148 - 630,707 1.27 682,230 17,479 217 - 699,492 1.29 FNMA certificates: After 1 to 5 years 24,812 891 - - 25,703 2.81 After 5 to 10 years 110,832 5,783 - - 116,615 2.13 After 10 years 1,154,707 23,459 203 - 1,177,963 1.53 1,290,351 30,133 203 - 1,320,281 1.61 Collateralized mortgage obligations issued or guaranteed by the FHLMC, FNMA and GNMA: After 1 to 5 years 538 - 1 - 537 0.81 After 5 to 10 years 18,438 152 - - 18,590 0.80 After 10 years 258,069 1,019 491 - 258,597 1.56 277,045 1,171 492 - 277,724 1.51 Private label: After 10 years 12,310 - 2,880 1,002 8,428 2.25 Total MBS 3,393,768 66,981 3,951 1,002 3,455,796 1.47 Other After 1 to 5 years 650 - - - 650 2.94 Total investment securities available for sale $ 4,584,851 $ 68,995 $ 5,517 1,310 $ 4,647,019 1.28 (1) 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. The aggregate amortized cost and approximate market value of investment securities available for sale as of December 31, 2021 by contractual maturity are shown below: Amortized Cost Fair Value (Dollars in thousands) United States and Puerto Rico government obligations, and other debt securities: Within 1 year $ 500 $ 500 After 1 to 5 years 2,027,341 1,996,852 After 5 to 10 years 403,785 393,104 After 10 years 19,362 18,862 2,450,988 2,409,318 MBS and collateralized mortgage obligations (1) 4,083,515 4,044,443 Total investment securities available for sale $ 6,534,503 $ 6,453,761 (1) The expected maturities of MBS and collateralized mortgage obligations may differ from their contractual maturities because they may be subject to prepayments.
Schedule of Unrealized Loss on Investments [Table Text Block]	The following tables show the fair value and gross unrealized losses of the Corporation’s available-for-sale investment securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, as of December 31, 2021 and December 31, 2020. The tables also include debt securities for which an ACL was recorded. As of December 31, 2021 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) Debt securities: Puerto Rico-government obligations $ - $ - $ 2,850 $ 416 $ 2,850 $ 416 U.S. Treasury and U.S. government agencies’ obligations 1,717,340 25,401 606,179 16,243 2,323,519 41,644 MBS: FNMA 1,237,701 19,843 112,559 3,821 1,350,260 23,664 FHLMC 986,345 16,144 221,896 8,481 1,208,241 24,625 GNMA 194,271 1,329 41,233 984 235,504 2,313 Collateralized mortgage obligations issued or guaranteed by the FHLMC, FNMA and GNMA 466,004 13,552 16,656 360 482,660 13,912 Private label MBS - - 7,234 1,963 7,234 1,963 $ 4,601,661 $ 76,269 $ 1,008,607 $ 32,268 $ 5,610,268 $ 108,537 As of December 31, 2020 Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair Value Losses Fair Value Losses Fair Value Losses (In thousands) Debt securities: Puerto Rico-government obligations $ - $ - $ 2,899 $ 780 $ 2,899 $ 780 U.S. Treasury and U.S. government agencies’ obligations 425,155 621 23,377 165 448,532 786 MBS: FNMA 93,509 203 - - 93,509 203 FHLMC 89,292 159 - - 89,292 159 GNMA 70,504 217 - - 70,504 217 Collateralized mortgage obligations issued or guaranteed by the FHLMC, FNMA and GNMA 104,500 410 9,761 82 114,261 492 Private label MBS - - 8,428 2,880 8,428 2,880 $ 782,960 $ 1,610 $ 44,465 $ 3,907 $ 827,425 $ 5,517
Significant Assumptions in Valuation of Private Label MBS [Table Text Block]	As of As of December 31, 2021 December 31, 2020 Weighted Range Weighted Range Average Minimum Maximum Average Minimum Maximum Discount rate 12.9% 12.9% 12.9% 12.2% 12.2% 12.2% Prepayment rate 15.2% 7.6% 24.9% 12.1% 1.2% 18.8% Projected Cumulative Loss Rate 7.6% 0.2% 15.7% 10.2% 2.6% 22.3%
OTTI Losses on Debt Securities [Table Text Block]	During the year ended December 31, 2019, the Corporation recorded OTTI losses on available-for-sale debt securities as follows: 2019 (In thousands) Total OTTI losses $ (557) Portion of OTTI recognized in OCI 60 Net impairment losses recognized in earnings (1) $ (497) (1) Prior to the adoption of CECL on January 1, 2020, credit-related impairment recognized in earnings was reported as part of net gain (loss) on investment securities in the consolidated statements of income rather than as a provision for credit losses.