LOANS HELD FOR INVESTMENT - Corporation's Residential Mortgage Loans By Origination Year Based on Original Credit Score (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment	$ 11,777,289	$ 9,002,205
Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment	9,788,106	7,128,277
Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment	1,989,183	1,873,928
Residential Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	82,522
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	124,261
Financing Receivable, Originated Two Years before Latest Fiscal Year	180,927
Financing Receivable, Originated Three Years before Latest Fiscal Year	169,816
Financing Receivable, Originated Four Years before Latest Fiscal Year	202,665
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	2,761,763
Financing Receivable, Revolving	0
Loans held for investment	3,521,954	2,933,773
Residential Portfolio Segment [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	39,911
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	71,663
Financing Receivable, Originated Two Years before Latest Fiscal Year	117,519
Financing Receivable, Originated Three Years before Latest Fiscal Year	78,018
Financing Receivable, Originated Four Years before Latest Fiscal Year	121,758
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	2,573,334
Financing Receivable, Revolving	0
Loans held for investment	3,002,203	2,367,587
Residential Portfolio Segment [Member] | Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	42,611
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	52,598
Financing Receivable, Originated Two Years before Latest Fiscal Year	63,408
Financing Receivable, Originated Three Years before Latest Fiscal Year	91,798
Financing Receivable, Originated Four Years before Latest Fiscal Year	80,907
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	188,429
Financing Receivable, Revolving	0
Loans held for investment	519,751	566,186
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	278
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,416
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,594
Financing Receivable, Originated Three Years before Latest Fiscal Year	4,639
Financing Receivable, Originated Four Years before Latest Fiscal Year	9,673
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	131,134
Financing Receivable, Revolving	0
Loans held for investment	150,734	123,909
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	278
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	2,416
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,594
Financing Receivable, Originated Three Years before Latest Fiscal Year	4,354
Financing Receivable, Originated Four Years before Latest Fiscal Year	9,673
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	130,249
Financing Receivable, Revolving	0
Loans held for investment	149,564	122,429
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0
Financing Receivable, Originated Two Years before Latest Fiscal Year	0
Financing Receivable, Originated Three Years before Latest Fiscal Year	285
Financing Receivable, Originated Four Years before Latest Fiscal Year	0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	885
Financing Receivable, Revolving	0
Loans held for investment	1,170	1,480
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment	3,371,220	2,809,864
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment	2,852,639	2,245,158
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Loans held for investment	518,581	564,706
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Fico Score Less Than 620 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	46
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	77
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,973
Financing Receivable, Originated Three Years before Latest Fiscal Year	55
Financing Receivable, Originated Four Years before Latest Fiscal Year	74
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	326,295
Financing Receivable, Revolving	0
Loans held for investment	329,520	290,239
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Fico Score Less Than 620 [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	46
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	77
Financing Receivable, Originated Two Years before Latest Fiscal Year	464
Financing Receivable, Originated Three Years before Latest Fiscal Year	55
Financing Receivable, Originated Four Years before Latest Fiscal Year	74
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	325,474
Financing Receivable, Revolving	0
Loans held for investment	326,190	286,754
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Fico Score Less Than 620 [Member] | Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0
Financing Receivable, Originated Two Years before Latest Fiscal Year	2,509
Financing Receivable, Originated Three Years before Latest Fiscal Year	0
Financing Receivable, Originated Four Years before Latest Fiscal Year	0
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	821
Financing Receivable, Revolving	0
Loans held for investment	3,330	3,485
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 620 and less than 680 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	5,690
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	8,438
Financing Receivable, Originated Two Years before Latest Fiscal Year	11,749
Financing Receivable, Originated Three Years before Latest Fiscal Year	16,174
Financing Receivable, Originated Four Years before Latest Fiscal Year	20,154
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	527,524
Financing Receivable, Revolving	0
Loans held for investment	589,729	467,930
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 620 and less than 680 [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	2,144
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	3,370
Financing Receivable, Originated Two Years before Latest Fiscal Year	8,309
Financing Receivable, Originated Three Years before Latest Fiscal Year	7,416
Financing Receivable, Originated Four Years before Latest Fiscal Year	8,721
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	511,349
Financing Receivable, Revolving	0
Loans held for investment	541,309	416,766
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 620 and less than 680 [Member] | Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	3,546
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	5,068
Financing Receivable, Originated Two Years before Latest Fiscal Year	3,440
Financing Receivable, Originated Three Years before Latest Fiscal Year	8,758
Financing Receivable, Originated Four Years before Latest Fiscal Year	11,433
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	16,175
Financing Receivable, Revolving	0
Loans held for investment	48,420	51,164
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 680 and less than 740 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	26,819
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	39,785
Financing Receivable, Originated Two Years before Latest Fiscal Year	54,201
Financing Receivable, Originated Three Years before Latest Fiscal Year	53,426
Financing Receivable, Originated Four Years before Latest Fiscal Year	64,472
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	742,291
Financing Receivable, Revolving	0
Loans held for investment	980,994	777,835
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 680 and less than 740 [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	15,009
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	24,265
Financing Receivable, Originated Two Years before Latest Fiscal Year	40,391
Financing Receivable, Originated Three Years before Latest Fiscal Year	24,308
Financing Receivable, Originated Four Years before Latest Fiscal Year	37,765
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	700,059
Financing Receivable, Revolving	0
Loans held for investment	841,797	626,291
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 680 and less than 740 [Member] | Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	11,810
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	15,520
Financing Receivable, Originated Two Years before Latest Fiscal Year	13,810
Financing Receivable, Originated Three Years before Latest Fiscal Year	29,118
Financing Receivable, Originated Four Years before Latest Fiscal Year	26,707
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	42,232
Financing Receivable, Revolving	0
Loans held for investment	139,197	151,544
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 740 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	49,689
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	73,545
Financing Receivable, Originated Two Years before Latest Fiscal Year	109,410
Financing Receivable, Originated Three Years before Latest Fiscal Year	95,522
Financing Receivable, Originated Four Years before Latest Fiscal Year	108,292
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	1,034,519
Financing Receivable, Revolving	0
Loans held for investment	1,470,977	1,273,860
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 740 [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	22,434
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	41,535
Financing Receivable, Originated Two Years before Latest Fiscal Year	65,761
Financing Receivable, Originated Three Years before Latest Fiscal Year	41,885
Financing Receivable, Originated Four Years before Latest Fiscal Year	65,525
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	906,203
Financing Receivable, Revolving	0
Loans held for investment	1,143,343	915,347
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | FICO Score Greater than or equal to 740 [Member] | Florida region [Member}
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Originated in Current Fiscal Year	27,255
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	32,010
Financing Receivable, Originated Two Years before Latest Fiscal Year	43,649
Financing Receivable, Originated Three Years before Latest Fiscal Year	53,637
Financing Receivable, Originated Four Years before Latest Fiscal Year	42,767
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	128,316
Financing Receivable, Revolving	0
Loans held for investment	$ 327,634	$ 358,513