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NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Loans held for investment (Detail) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Sep. 01, 2020	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Interest Receivable			$ 61,507	$ 69,505
Threshold Period Past Due Of Financing Receivables To Be Considered Nonperforming			90 days
Financing Receivable, Nonaccrual, Interest Income			$ 2,270	2,029
Troubled Debt Restructurings Sustained Performance Period			6 months
Loans held for investment			$ 11,060,658	11,777,289
Financing Receivable, Individually Evaluated for Impairment			$ 500
Nonacrual Sustained Performance Period			6 months
Increase (decrease) in provision for credit losses		$ 1,100
Loans Foreclosure Delinquency Threshold			120 days
Amount classified as loss and charged-off		$ 4,100
Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, Interest Income			$ 2,000	1,900
PCD loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			117,500	130,900
BSPR
Financing Receivable, Past Due [Line Items]
Fair value of PCD loans	$ 752,800
ACL for PCD loans	$ 28,700
Loans and Finance Receivables [Member]
Financing Receivable, Past Due [Line Items]
Interest Receivable			$ 48,100	57,200
Auto loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Threshold Period Past Due, Writeoff			365 days
Small Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Threshold Period Past Due, Writeoff			180 days
Loans Foreclosure Delinquency Threshold			120 days
Finance Leases [Member]
Financing Receivable, Past Due [Line Items]
Loans Foreclosure Delinquency Threshold			120 days
Residential Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Threshold Period Past Due, Writeoff			180 days
Loans held for investment			$ 2,978,895	3,521,954
Loans Foreclosure Delinquency Threshold			120 days
Residential Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			$ 55,127	125,367
Residential Portfolio Segment [Member] \| Doral Bank Transaction Member [Member] \| PCD loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			$ 115,100
Residential Portfolio Segment [Member] \| Puerto Rico Housing Finance Authority [Member]
Financing Receivable, Past Due [Line Items]
Period Of Guaranteed Residential Mortgage Loans That Are No Longer Accruing Interest			90 days
Residential Portfolio Segment [Member] \| FHA/VA government-guaranteed loans [Member]
Financing Receivable, Past Due [Line Items]
Period Of Guaranteed Residential Mortgage Loans That Are No Longer Accruing Interest			15 months
Financing Receivable, Nonaccrual, Interest Income			$ 0	0
Loans held for investment			125,392	150,734
Residential Portfolio Segment [Member] \| FHA/VA government-guaranteed loans [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			$ 0	0
Residential Portfolio Segment [Member] \| FHA/VA government-guaranteed loans [Member] \| Puerto Rico Housing Finance Authority [Member]
Financing Receivable, Past Due [Line Items]
Past due 90 days and still accruing			90 days
Commercial Portfolio Segment [Member] \| COVID-19 [Member] \| Section 4013 [Member]
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Gross			$ 342,400
Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, Interest Income			201	194
Loans held for investment			2,167,469	2,230,602
Commercial Portfolio Segment [Member] \| Mortgage Receivable [Member] \| Doral Bank Transaction Member [Member] \| PCD loans [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			2,400
Commercial Portfolio Segment [Member] \| Commercial And Industrial Sector [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, Interest Income			183	157
Loans held for investment			2,887,251	3,202,590
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, Interest Income			61	80
Loans held for investment			138,999	212,500
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			2,888,044	2,609,643
Consumer Portfolio Segment [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			10,454	16,259
Consumer Portfolio Segment [Member] \| Auto loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, Interest Income			99	176
Loans held for investment			1,571,540	1,296,424
Consumer Portfolio Segment [Member] \| Auto loans [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			$ 6,684	8,887
Consumer Portfolio Segment [Member] \| Personal Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Threshold Period Past Due, Writeoff			120 days
Financing Receivable, Nonaccrual, Interest Income			$ 92	49
Loans held for investment			316,182	372,168
Consumer Portfolio Segment [Member] \| Personal Loans [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			1,208	1,623
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, Interest Income			15	13
Loans held for investment			135,091	148,238
Consumer Portfolio Segment [Member] \| Other Loans [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			1,696	4,283
Consumer Portfolio Segment [Member] \| Finance Leases [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Nonaccrual, Interest Income			2	25
Loans held for investment			575,005	472,989
Consumer Portfolio Segment [Member] \| Finance Leases [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			$ 866	1,466
Consumer Portfolio Segment [Member] \| Credit Card Receivables [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Threshold Period Past Due, Writeoff			180 days
Financing Receivable, Nonaccrual, Interest Income			$ 0	0
Loans held for investment			290,226	319,824
Consumer Portfolio Segment [Member] \| Credit Card Receivables [Member] \| Nonperforming Financial Instruments [Member]
Financing Receivable, Past Due [Line Items]
Loans held for investment			$ 0	$ 0