DEBT SECURITIES - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Investments [Line Items]
Investments purchased, classified as available-for-sale debt securities	$ 266,198,000	$ 5,458,000	$ 512,327,000
Fair value	4,565,302,000	5,229,984,000
Gross Unrealized Losses	559,768,000	633,049,000
Available-for-sale, allowance for credit losses	521,000	511,000
Allowance for credit losses, Held-to-Maturity securities	802,000	2,197,000
Provision for credit loss expense	(1,445,000)	(6,069,000)	(719,000)
Debt Securities, Held-to-maturity	317,786,000	354,178,000
Accrued interest receivable on loans and investments	71,881,000	77,716,000
Interest income on available for sale debt securities	71,700,000	78,300,000	86,100,000
Interest income, held to maturity securities	17,100,000	20,900,000	15,500,000
Held to maturity securities classified as cash and cash equivalents	0	0
Past Due [Member]
Schedule Of Investments [Line Items]
Debt Securities, Held-to-maturity	0	0
Puerto Rico government obligations [Member]
Schedule Of Investments [Line Items]
Available-for-sale, allowance for credit losses	300,000	400,000
Residential MBS [Member]
Schedule Of Investments [Line Items]
Investments purchased, classified as available-for-sale debt securities	224,500,000
Fair value	2,481,253,000	2,633,161,000
Gross Unrealized Losses	440,826,000	436,055,000
Available-for-sale, allowance for credit losses	176,000	116,000
Allowance for credit losses, Held-to-Maturity securities	0	0
Debt Securities, Held-to-maturity	129,319,000	146,468,000
Residential MBS [Member] | Private label [Member]
Schedule Of Investments [Line Items]
Fair value	4,195,000
Gross Unrealized Losses	1,715,000
Available-for-sale, allowance for credit losses	$ 176,000	100,000
Debt Instrument Variable Interest Rate Type Extensible Enumeration	SOFR [Member]
Spread on variable rate	0.26161%
Debt Instrument Description Of Variable Rate Basis	3-month CME Term SOFR
Residential MBS [Member] | Private label [Member] | FICO Score, Greater than 700 [Member] | LTV Less than 80 Percent [Member]
Schedule Of Investments [Line Items]
Loan To Value Coverage Percentage	80.00%
Residential MBS [Member] | Private label [Member] | SOFR [Member]
Schedule Of Investments [Line Items]
Spread on variable rate	0.26161%
MBS And Government Obligations Held By International Banking Entities [Member]
Schedule Of Investments [Line Items]
Interest income on available for sale debt securities	$ 36,200,000	39,100,000	40,700,000
Interest income, held to maturity securities	16,800,000	20,500,000	15,400,000
Commercial MBS [Member]
Schedule Of Investments [Line Items]
Investments purchased, classified as available-for-sale debt securities	40,700,000
Fair value	181,909,000	151,618,000
Gross Unrealized Losses	41,097,000	38,620,000
Available-for-sale, allowance for credit losses	0	0
Allowance for credit losses, Held-to-Maturity securities	0	0
Debt Securities, Held-to-maturity	96,025,000	100,670,000
Available-for-Sale Securities [Member]
Schedule Of Investments [Line Items]
Available-for-sale, allowance for credit losses	521,000	511,000	458,000	$ 1,105,000
Provision For Other Credit Losses Previous Expected Credit Losses	50,000	(20,000)	434,000
Charge-offs	(60,000)	(33,000)	213,000
Accrued interest receivable on loans and investments	9,600,000	10,600,000
Available-for-Sale Securities [Member] | Puerto Rico government obligations [Member]
Schedule Of Investments [Line Items]
Available-for-sale, allowance for credit losses	345,000	395,000	375,000	308,000
Provision For Other Credit Losses Previous Expected Credit Losses	50,000	(20,000)	(67,000)
Charge-offs	0	0	0
Available-for-Sale Securities [Member] | Residential MBS [Member] | Private label [Member]
Schedule Of Investments [Line Items]
Available-for-sale, allowance for credit losses	176,000	116,000	83,000	$ 797,000
Provision For Other Credit Losses Previous Expected Credit Losses	0	0	501,000
Charge-offs	(60,000)	(33,000)	$ 213,000
Held-to-Maturity Securities [Member]
Schedule Of Investments [Line Items]
Accrued interest receivable on loans and investments	$ 4,100,000	$ 4,800,000