LOANS HELD FOR INVESTMENT - Corporation's Nonaccrual Status and Loans 90 Days or More Still Accruing (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	$ 28,972	$ 28,972
Nonaccrual Loans with ACL	172,318	172,318
Total Nonaccrual Loans	201,290	201,290	$ 210,668
Loans Past Due 90 days or more and Still Accruing	157,410	157,410	135,042
Interest Income Recognized on Nonaccrual Loans	412	1,497
Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	28,535	28,535
Nonaccrual Loans with ACL	156,790	156,790
Total Nonaccrual Loans	185,325	185,325	196,383
Loans Past Due 90 days or more and Still Accruing	157,159	157,159	134,913
Interest Income Recognized on Nonaccrual Loans	374	1,307
Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	437	437
Nonaccrual Loans with ACL	15,528	15,528
Total Nonaccrual Loans	15,965	15,965	14,285
Loans Past Due 90 days or more and Still Accruing	251	251	129
Interest Income Recognized on Nonaccrual Loans	38	190
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	9,887	9,887
Nonaccrual Loans with ACL	112,910	112,910
Total Nonaccrual Loans	122,797	122,797	121,408
Loans Past Due 90 days or more and Still Accruing	40,595	40,595	40,208
Interest Income Recognized on Nonaccrual Loans	288	969
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	9,697	9,697
Nonaccrual Loans with ACL	98,600	98,600
Total Nonaccrual Loans	108,297	108,297	108,117
Loans Past Due 90 days or more and Still Accruing	40,595	40,595	40,208
Interest Income Recognized on Nonaccrual Loans	269	835
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	190	190
Nonaccrual Loans with ACL	14,310	14,310
Total Nonaccrual Loans	14,500	14,500	13,291
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	19	134
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	111,132	111,132	81,140
Interest Income Recognized on Nonaccrual Loans	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	110,882	110,882	81,011
Interest Income Recognized on Nonaccrual Loans	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	250	250	129
Interest Income Recognized on Nonaccrual Loans	0	0
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	6,692	6,692
Nonaccrual Loans with ACL	14,190	14,190
Total Nonaccrual Loans	20,882	20,882	18,773
Loans Past Due 90 days or more and Still Accruing	1,014	1,014	7,061
Interest Income Recognized on Nonaccrual Loans	43	119
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	6,445	6,445
Nonaccrual Loans with ACL	13,444	13,444
Total Nonaccrual Loans	19,889	19,889	18,458
Loans Past Due 90 days or more and Still Accruing	1,014	1,014	7,061
Interest Income Recognized on Nonaccrual Loans	24	67
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	247	247
Nonaccrual Loans with ACL	746	746
Total Nonaccrual Loans	993	993	315
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	19	52
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	11,437	11,437
Nonaccrual Loans with ACL	18,214	18,214
Total Nonaccrual Loans	29,651	29,651	40,076
Loans Past Due 90 days or more and Still Accruing	3,328	3,328	2,222
Interest Income Recognized on Nonaccrual Loans	35	142
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	11,437	11,437
Nonaccrual Loans with ACL	18,214	18,214
Total Nonaccrual Loans	29,651	29,651	40,076
Loans Past Due 90 days or more and Still Accruing	3,328	3,328	2,222
Interest Income Recognized on Nonaccrual Loans	35	142
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	0	0
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	956	956
Nonaccrual Loans with ACL	12,134	12,134
Total Nonaccrual Loans	13,090	13,090	9,782
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	19	61
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	956	956
Nonaccrual Loans with ACL	12,134	12,134
Total Nonaccrual Loans	13,090	13,090	9,782
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	19	61
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	0	0
Consumer Portfolio Segment [Member] | Auto loans [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	9,071	9,071
Total Nonaccrual Loans	9,071	9,071	12,220
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	17	138
Consumer Portfolio Segment [Member] | Auto loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	9,071	9,071
Total Nonaccrual Loans	9,071	9,071	12,057
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	17	138
Consumer Portfolio Segment [Member] | Auto loans [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	163
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	0	0
Consumer Portfolio Segment [Member] | Finance Leases [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	879	879
Total Nonaccrual Loans	879	879	1,354
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	2	23
Consumer Portfolio Segment [Member] | Finance Leases [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	879	879
Total Nonaccrual Loans	879	879	1,354
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	2	23
Consumer Portfolio Segment [Member] | Finance Leases [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	0	0
Consumer Portfolio Segment [Member] | Personal Loans [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	1,445	1,445
Total Nonaccrual Loans	1,445	1,445	1,528
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	8	36
Consumer Portfolio Segment [Member] | Personal Loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	1,445	1,445
Total Nonaccrual Loans	1,445	1,445	1,523
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	8	36
Consumer Portfolio Segment [Member] | Personal Loans [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	5
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	0	0
Consumer Portfolio Segment [Member] | Credit cards [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	1,340	1,340	4,411
Interest Income Recognized on Nonaccrual Loans	0	0
Consumer Portfolio Segment [Member] | Credit cards [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	1,340	1,340	4,411
Interest Income Recognized on Nonaccrual Loans	0	0
Consumer Portfolio Segment [Member] | Credit cards [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	0	0
Total Nonaccrual Loans	0	0	0
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	0	0
Consumer Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	3,475	3,475
Total Nonaccrual Loans	3,475	3,475	5,527
Loans Past Due 90 days or more and Still Accruing	1	1	0
Interest Income Recognized on Nonaccrual Loans	0	9
Consumer Portfolio Segment [Member] | Other Loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	3,003	3,003
Total Nonaccrual Loans	3,003	3,003	5,016
Loans Past Due 90 days or more and Still Accruing	0	0	0
Interest Income Recognized on Nonaccrual Loans	0	5
Consumer Portfolio Segment [Member] | Other Loans [Member] | Florida region [Member]
Financing Receivable, Nonaccrual [Line Items]
Nonaccrual Loans with No ACL	0	0
Nonaccrual Loans with ACL	472	472
Total Nonaccrual Loans	472	472	511
Loans Past Due 90 days or more and Still Accruing	1	1	$ 0
Interest Income Recognized on Nonaccrual Loans	$ 0	$ 4