ALLOWANCE FOR CREDIT LOSSES (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) loan	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Financing Receivable, Allowance for Credit Loss [Line Items]
Decrease in allowance for credit losses	$ 3,300
Provision for (recapture of) credit losses	24,119	$ 221	$ 92,672
Net charge-off	(27,700)
Decrease in net charge-offs	22,100
Reclassification of loans held-for-investment portfolio to held-for-sale portfolio	$ 17,476	54,983	2,542
Number of commercial loans | loan	4
Number of commercial loans sold	2
Allowance for credit losses	$ 152,673	155,937	204,809
Changes in Economic and Loss Rate Models and Miscellaneous Reserves
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for (recapture of) credit losses	1,900
Loan sales
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized		30,100
Decrease in allowance for credit losses		20,400
Provision for (recapture of) credit losses		9,700
Financing Receivable, Loan Growth Member
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for (recapture of) credit losses	25,900
Commercial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Decrease in net charge-offs	7,300
Allowance for credit losses	40,546	36,770	62,184
Commercial loans | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for (recapture of) credit losses	11,800
Auto loans and leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Decrease in net charge-offs	(8,900)
Allowance for credit losses	69,919	65,675	71,239
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Decrease in net charge-offs	(3,400)
Allowance for credit losses	23,278	19,175	25,310
Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Decrease in net charge-offs	27,100
Allowance for credit losses	18,930	34,317	46,076
PCD
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	2,250	33,559	49,004
Provision for (recapture of) credit losses	(18,010)	7,760	7,185
Recoveries	7,220	5,877	3,596
Allowance for credit losses	10,832	23,872	43,794	$ 31,495
PCD | Commercial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	69	12,241	36,097
Provision for (recapture of) credit losses	(6,855)	(2,585)	480
Recoveries	3,804	2,929	986
Allowance for credit losses	1,388	4,508	16,405	8,893
PCD | Commercial loans | Puerto Rico | Government
Financing Receivable, Allowance for Credit Loss [Line Items]
Recoveries	2,800
PCD | Auto loans and leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	310	946	2,023
Provision for (recapture of) credit losses	(588)	(894)	187
Recoveries	657	1,209	1,464
Allowance for credit losses	71	312	943	947
PCD | Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	176	22	542
Provision for (recapture of) credit losses	62	(317)	126
Recoveries	94	316	292
Allowance for credit losses	14	34	57	0
PCD | Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	1,695	20,350	10,342
Provision for (recapture of) credit losses	(10,629)	11,556	6,392
Recoveries	2,665	1,423	854
Allowance for credit losses	9,359	19,018	26,389	21,655
Non-PCD
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	61,524	52,987	76,182
Provision for (recapture of) credit losses	42,418	(6,877)	86,532
Recoveries	28,882	30,914	26,423
Allowance for credit losses	141,841	132,065	161,015	85,044
Non-PCD | Commercial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	13,380	8,788	4,979
Provision for (recapture of) credit losses	19,076	(7,130)	18,462
Charge-offs for previously reserved amount	12,300
Recoveries	1,200	2,401	2,741
Allowance for credit losses	39,158	32,262	45,779	25,993
Non-PCD | Auto loans and leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	32,662	26,530	48,547
Provision for (recapture of) credit losses	16,016	(2,373)	51,233
Recoveries	21,131	23,970	19,494
Allowance for credit losses	69,848	65,363	70,296	31,878
Non-PCD | Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	15,198	11,880	21,772
Provision for (recapture of) credit losses	16,084	2,868	16,579
Recoveries	3,237	2,900	3,582
Allowance for credit losses	23,264	19,141	25,253	18,446
Non-PCD | Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Net charge-offs recognized	284	5,789	884
Provision for (recapture of) credit losses	(8,758)	(242)	258
Recoveries	3,314	1,643	606
Allowance for credit losses	9,571	15,299	19,687	$ 8,727
Improved Macroeconomic Conditions
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for (recapture of) credit losses	(15,200)
COVID-19 Pandemic
Financing Receivable, Allowance for Credit Loss [Line Items]
Provision for (recapture of) credit losses			$ 39,900
Total Past Due
Financing Receivable, Allowance for Credit Loss [Line Items]
Reclassification of loans held-for-investment portfolio to held-for-sale portfolio		$ 65,500
Total Past Due | Non-PCD | Mortgage | Loan sales
Financing Receivable, Allowance for Credit Loss [Line Items]
Recoveries	$ 1,100