REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation Of Revenue [Line Items]
Net interest income	$ 199,728	$ 207,910	$ 600,428	$ 589,720
Noninterest Income	30,296	29,693	99,085	93,492
Total Revenues	230,024	237,603	699,513	683,212
Other non-interest income	4,292	4,015	17,329	11,495
Service charges and fees on deposit accounts [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	9,552	9,820	28,380	28,649
Insurance commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	2,790	2,624	10,384	10,845
Merchant-related income [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	2,494	2,167	7,713	7,192
Credit and debit card fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	8,347	7,667	25,181	22,621
Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	2,943	2,443	9,539	9,108
Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	4,170	4,972	17,888	15,077
Mortgage Banking Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income	18,279	24,338	61,427	76,452
Noninterest Income	3,021	3,733	9,157	13,152
Total Revenues	21,300	28,071	70,584	89,604
Mortgage Banking Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Mortgage Banking Segment [Member] | Insurance commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Mortgage Banking Segment [Member] | Merchant-related income [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Mortgage Banking Segment [Member] | Credit and debit card fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Mortgage Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	50	85	244	287
Mortgage Banking Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	2,971	3,648	8,913	12,865
Consumer Retail Banking Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income	147,066	118,408	427,407	310,351
Noninterest Income	20,170	19,121	62,425	59,367
Total Revenues	167,236	137,529	489,832	369,718
Consumer Retail Banking Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	5,286	5,744	15,859	16,778
Consumer Retail Banking Segment [Member] | Insurance commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	2,596	2,485	9,700	10,176
Consumer Retail Banking Segment [Member] | Merchant-related income [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	2,156	1,458	6,454	4,991
Consumer Retail Banking Segment [Member] | Credit and debit card fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	7,826	7,209	23,581	21,271
Consumer Retail Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	1,262	1,228	3,922	4,404
Consumer Retail Banking Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	1,044	997	2,909	1,747
Commercial And Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income	13,212	22,861	41,085	94,655
Noninterest Income	4,468	4,276	16,788	13,278
Total Revenues	17,680	27,137	57,873	107,933
Commercial And Corporate Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	3,406	3,169	9,886	9,214
Commercial And Corporate Segment [Member] | Insurance commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Commercial And Corporate Segment [Member] | Merchant-related income [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	347	0	1,101
Commercial And Corporate Segment [Member] | Credit and debit card fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	24	21	74	58
Commercial And Corporate Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	853	340	2,801	2,329
Commercial And Corporate Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	185	399	4,027	576
Treasury And Investments Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income	(4,055)	14,827	(7,502)	33,702
Noninterest Income	(3)	33	1,837	(130)
Total Revenues	(4,058)	14,860	(5,665)	33,572
Treasury And Investments Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Treasury And Investments Segment [Member] | Insurance commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Treasury And Investments Segment [Member] | Merchant-related income [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Treasury And Investments Segment [Member] | Credit and debit card fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Treasury And Investments Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	0	0	0	0
Treasury And Investments Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	(3)	33	1,837	(130)
United States Operations Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income	19,749	21,494	60,369	56,664
Noninterest Income	847	773	2,849	2,195
Total Revenues	20,596	22,267	63,218	58,859
United States Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	155	151	492	446
United States Operations Segment [Member] | Insurance commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	68	16	175	65
United States Operations Segment [Member] | Merchant-related income [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	19	32	87	54
United States Operations Segment [Member] | Credit and debit card fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	4	(2)	16	(6)
United States Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	615	595	1,858	1,579
United States Operations Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	(14)	(19)	221	57
Virgin Islands Operations Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income	5,477	5,982	17,642	17,896
Noninterest Income	1,793	1,757	6,029	5,630
Total Revenues	7,270	7,739	23,671	23,526
Virgin Islands Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	705	756	2,143	2,211
Virgin Islands Operations Segment [Member] | Insurance commissions [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	126	123	509	604
Virgin Islands Operations Segment [Member] | Merchant-related income [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	319	330	1,172	1,046
Virgin Islands Operations Segment [Member] | Credit and debit card fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	493	439	1,510	1,298
Virgin Islands Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	163	195	714	509
Virgin Islands Operations Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Noninterest Income	$ (13)	$ (86)	$ (19)	$ (38)