SEGMENT INFORMATION - Information about Reportable Segments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Interest income	$ 1,023,486	$ 862,614	$ 794,708
Interest expense	(226,376)	(67,321)	(64,779)
Net interest income (loss)	797,110	795,293	729,929
Provision for credit losses - (benefit) expense	66,644	25,679	(61,720)
Non-interest income	132,694	123,092	121,164
Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	1,023,486	862,614	794,708
Net (charge) credit for transfer of funds	0	0	0
Interest expense	(226,376)	(67,321)	(64,779)
Net interest income (loss)	797,110	795,293	729,929
Provision for credit losses - (benefit) expense	60,940	27,696	65,698
Non-interest income	132,694	123,092	121,164
Direct non-interest expenses	302,726	287,821	(296,780)
Segment income (loss)	566,138	602,868	620,011
Average earnings assets	17,866,659	18,516,894	19,235,941
Mortgage Banking Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	78,710	98,920	104,638
Non-interest income	11,400	15,950	24,278
Mortgage Banking Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	126,625	130,185	144,203
Net (charge) credit for transfer of funds	(47,915)	(31,265)	(39,565)
Interest expense	0	0	0
Net interest income (loss)	78,710	98,920	104,638
Provision for credit losses - (benefit) expense	(7,531)	(7,643)	16,030
Non-interest income	11,400	15,950	24,278
Direct non-interest expenses	23,469	23,049	(29,125)
Segment income (loss)	74,172	99,464	115,821
Average earnings assets	2,143,179	2,233,245	2,506,365
Consumer Retail Banking Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	575,436	442,624	281,703
Non-interest income	83,241	78,457	69,774
Consumer Retail Banking Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	354,970	302,631	271,127
Net (charge) credit for transfer of funds	356,262	173,917	38,859
Interest expense	(135,796)	(33,924)	(28,283)
Net interest income (loss)	575,436	442,624	281,703
Provision for credit losses - (benefit) expense	65,887	57,123	(20,322)
Non-interest income	83,241	78,457	69,774
Direct non-interest expenses	173,158	162,663	(165,357)
Segment income (loss)	419,632	301,295	165,798
Average earnings assets	3,295,486	2,918,800	2,551,278
Commercial And Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	54,658	109,822	191,917
Non-interest income	21,277	18,189	16,032
Commercial And Corporate Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	265,395	205,888	201,684
Net (charge) credit for transfer of funds	(210,737)	(96,066)	(9,767)
Interest expense	0	0	0
Net interest income (loss)	54,658	109,822	191,917
Provision for credit losses - (benefit) expense	(6,189)	(20,241)	67,544
Non-interest income	21,277	18,189	16,032
Direct non-interest expenses	39,718	37,131	(36,219)
Segment income (loss)	42,406	111,121	239,274
Average earnings assets	3,780,195	3,626,107	3,793,945
Treasury And Investments Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	(13,916)	39,600	59,331
Non-interest income	2,038	(74)	227
Treasury And Investments Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	116,382	104,215	67,841
Net (charge) credit for transfer of funds	(93,405)	(43,838)	14,687
Interest expense	(36,893)	(20,777)	(23,197)
Net interest income (loss)	(13,916)	39,600	59,331
Provision for credit losses - (benefit) expense	20	(434)	136
Non-interest income	2,038	(74)	227
Direct non-interest expenses	3,799	3,702	(4,093)
Segment income (loss)	(15,697)	36,258	55,601
Average earnings assets	6,186,018	7,300,208	7,827,326
United States Operations Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	79,423	80,485	65,967
Non-interest income	6,697	2,860	3,963
United States Operations Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	132,490	94,782	82,194
Net (charge) credit for transfer of funds	(4,205)	(2,748)	(4,214)
Interest expense	(48,862)	(11,549)	(12,013)
Net interest income (loss)	79,423	80,485	65,967
Provision for credit losses - (benefit) expense	8,687	(3,073)	975
Non-interest income	6,697	2,860	3,963
Direct non-interest expenses	34,682	33,365	(33,902)
Segment income (loss)	42,751	53,053	37,003
Average earnings assets	2,072,292	2,069,030	2,126,528
Virgin Islands Operations Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	22,799	23,842	26,373
Non-interest income	8,041	7,710	6,890
Virgin Islands Operations Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	27,624	24,913	27,659
Net (charge) credit for transfer of funds	0	0	0
Interest expense	(4,825)	(1,071)	(1,286)
Net interest income (loss)	22,799	23,842	26,373
Provision for credit losses - (benefit) expense	66	1,964	1,335
Non-interest income	8,041	7,710	6,890
Direct non-interest expenses	27,900	27,911	(28,084)
Segment income (loss)	2,874	1,677	6,514
Average earnings assets	$ 389,489	$ 369,504	$ 430,499