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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

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LOANS HELD FOR INVESTMENT - Loan Portfolio Held for Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Jun. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 13,048,684		$ 12,746,556
ACL for loans and finance leases	(246,990)	$ (248,578)	(243,942)	$ (246,996)	$ (254,532)	$ (261,843)
Loans held for investment, net	12,801,694		12,502,614
Puerto Rico and Virgin Islands regions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10,549,215		10,451,606
Florida region [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,499,469		2,294,950
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,889,081		2,828,431
ACL for loans and finance leases	(40,272)	(42,448)	(40,654)	(40,651)	(46,051)	(57,397)
Residential Portfolio Segment [Member] \| Puerto Rico and Virgin Islands regions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,367,018		2,323,205
Residential Portfolio Segment [Member] \| Florida region [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	522,063		505,226
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	259,863		228,396
ACL for loans and finance leases	(5,360)	(4,551)	(3,824)	(3,998)	(5,646)	(5,605)
Commercial Portfolio Segment [Member] \| Construction Loans [Member] \| Puerto Rico and Virgin Islands regions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	235,313		184,427
Commercial Portfolio Segment [Member] \| Construction Loans [Member] \| Florida region [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	24,550		43,969
Commercial Portfolio Segment [Member] \| Commercial Mortgage Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,549,375		2,565,984
ACL for loans and finance leases	(25,366)	(22,746)	(22,447)	(24,205)	(30,078)	(32,631)
Commercial Portfolio Segment [Member] \| Commercial Mortgage Loans [Member] \| Puerto Rico and Virgin Islands regions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,765,181		1,867,894
Commercial Portfolio Segment [Member] \| Commercial Mortgage Loans [Member] \| Florida region [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	784,194		698,090
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member}
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,614,241		3,366,038
ACL for loans and finance leases	(37,854)	(39,359)	(33,034)	(35,099)	(35,440)	(33,996)
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member} \| Puerto Rico and Virgin Islands regions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,451,416		2,325,875
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member} \| Florida region [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,162,825		1,040,163
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,736,124		3,757,707
ACL for loans and finance leases	(138,138)	$ (139,474)	(143,983)	$ (143,043)	$ (137,317)	$ (132,214)
Consumer Portfolio Segment [Member] \| Puerto Rico and Virgin Islands regions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,730,287		3,750,205
Consumer Portfolio Segment [Member] \| Florida region [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 5,837		$ 7,502