SEGMENT INFORMATION - Information about Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Interest income	$ 268,505	$ 242,396
Interest expense	(71,985)	(41,511)
Net interest income (loss)	196,520	200,885
Provision for credit losses - (benefit) expense	12,917	16,256
Non-interest income	33,983	32,518
Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	268,505	242,396
Net (charge) credit for transfer of funds	0	0
Interest expense	(71,985)	(41,511)
Net interest income (loss)	196,520	200,885
Provision for credit losses - (benefit) expense	12,167	15,502
Non-interest income	33,983	32,518
Direct non-interest expenses	76,461	72,155
Segment income (loss)	141,875	145,746
Average earnings assets	18,022,985	17,709,528
Mortgage Banking Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	15,823	21,788
Non-interest income	3,019	3,074
Mortgage Banking Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	31,443	31,907
Net (charge) credit for transfer of funds	(15,620)	(10,119)
Interest expense	0	0
Net interest income (loss)	15,823	21,788
Provision for credit losses - (benefit) expense	(260)	(506)
Non-interest income	3,019	3,074
Direct non-interest expenses	6,705	5,087
Segment income (loss)	12,397	20,281
Average earnings assets	2,126,465	2,171,061
Consumer Retail Banking Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	148,947	137,744
Non-interest income	23,406	22,034
Consumer Retail Banking Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	94,795	83,174
Net (charge) credit for transfer of funds	96,251	77,735
Interest expense	(42,099)	(23,165)
Net interest income (loss)	148,947	137,744
Provision for credit losses - (benefit) expense	15,418	15,224
Non-interest income	23,406	22,034
Direct non-interest expenses	42,645	41,627
Segment income (loss)	114,290	102,927
Average earnings assets	3,472,998	3,174,150
Commercial And Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	14,928	14,940
Non-interest income	4,501	4,175
Commercial And Corporate Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	72,112	62,343
Net (charge) credit for transfer of funds	(57,184)	(47,403)
Interest expense	0	0
Net interest income (loss)	14,928	14,940
Provision for credit losses - (benefit) expense	(2,439)	(2,536)
Non-interest income	4,501	4,175
Direct non-interest expenses	10,339	9,365
Segment income (loss)	11,529	12,286
Average earnings assets	4,022,173	3,713,633
Treasury And Investments Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	(6,532)	(658)
Non-interest income	83	160
Treasury And Investments Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	28,058	27,466
Net (charge) credit for transfer of funds	(21,472)	(19,539)
Interest expense	(13,118)	(8,585)
Net interest income (loss)	(6,532)	(658)
Provision for credit losses - (benefit) expense	(69)	(9)
Non-interest income	83	160
Direct non-interest expenses	1,071	947
Segment income (loss)	(7,451)	(1,436)
Average earnings assets	5,900,314	6,216,498
United States Operations Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	18,248	20,930
Non-interest income	901	847
United States Operations Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	34,765	31,114
Net (charge) credit for transfer of funds	(1,975)	(674)
Interest expense	(14,542)	(9,510)
Net interest income (loss)	18,248	20,930
Provision for credit losses - (benefit) expense	82	4,655
Non-interest income	901	847
Direct non-interest expenses	9,110	8,304
Segment income (loss)	9,957	8,818
Average earnings assets	2,087,816	2,067,848
Virgin Islands Operations Segment [Member]
Segment Reporting Information [Line Items]
Net interest income (loss)	5,106	6,141
Non-interest income	2,073	2,228
Virgin Islands Operations Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest income	7,332	6,392
Net (charge) credit for transfer of funds	0	0
Interest expense	(2,226)	(251)
Net interest income (loss)	5,106	6,141
Provision for credit losses - (benefit) expense	(565)	(1,326)
Non-interest income	2,073	2,228
Direct non-interest expenses	6,591	6,825
Segment income (loss)	1,153	2,870
Average earnings assets	$ 413,219	$ 366,338