REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Net interest income (loss)	$ 807,479	$ 797,110	$ 795,293
Service charges and fees on deposit accounts	38,819	38,042	37,823
Insurance commission income	13,570	12,763	13,743
Card and processing income	46,758	43,909	40,416
Other non-interest income	18,892	25,788	15,850
Total non-interest income	130,722	132,694	123,092
Total Revenues (Loss)	938,201	929,804	918,385
Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	11,438	12,565	11,033
Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	20,137	25,415	20,077
Mortgage Banking Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income (loss)	72,455	75,774	78,098
Service charges and fees on deposit accounts	0	0	0
Insurance commission income	0	0	0
Card and processing income	0	0	0
Total non-interest income	13,507	11,213	15,698
Total Revenues (Loss)	85,962	86,987	93,796
Mortgage Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	189	289	341
Mortgage Banking Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	13,318	10,924	15,357
Consumer (Retail) Banking Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income (loss)	550,820	484,306	463,203
Service charges and fees on deposit accounts	30,608	29,946	29,702
Insurance commission income	12,781	11,906	12,733
Card and processing income	40,223	37,853	35,042
Total non-interest income	96,239	92,608	88,857
Total Revenues (Loss)	647,059	576,914	552,060
Consumer (Retail) Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	7,238	8,049	7,021
Consumer (Retail) Banking Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	5,389	4,854	4,359
Commercial and Corporate Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income (loss)	157,672	142,313	143,776
Service charges and fees on deposit accounts	4,538	4,553	4,616
Insurance commission income	0	0	0
Card and processing income	899	1,647	1,501
Total non-interest income	6,996	11,053	7,274
Total Revenues (Loss)	164,668	153,366	151,050
Commercial and Corporate Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	751	849	874
Commercial and Corporate Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	808	4,004	283
Treasury and Investments Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income (loss)	(112,151)	(31,944)	(13,964)
Service charges and fees on deposit accounts	0	0	0
Insurance commission income	0	0	0
Card and processing income	0	0	0
Total non-interest income	455	2,125	(161)
Total Revenues (Loss)	(111,696)	(29,819)	(14,125)
Treasury and Investments Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	0	0	0
Treasury and Investments Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	455	2,125	(161)
United States Operations Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income (loss)	77,988	70,798	74,168
Service charges and fees on deposit accounts	613	648	607
Insurance commission income	178	202	15
Card and processing income	115	99	67
Total non-interest income	3,589	6,839	3,006
Total Revenues (Loss)	81,577	77,637	77,174
United States Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	2,649	2,485	2,113
United States Operations Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	34	3,405	204
Virgin Islands Operations Segment [Member]
Disaggregation Of Revenue [Line Items]
Net interest income (loss)	60,695	55,863	50,012
Service charges and fees on deposit accounts	3,060	2,895	2,898
Insurance commission income	611	655	995
Card and processing income	5,521	4,310	3,806
Total non-interest income	9,936	8,856	8,418
Total Revenues (Loss)	70,631	64,719	58,430
Virgin Islands Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	611	893	684
Virgin Islands Operations Segment [Member] | Not in scope of Topic 606 [Member]
Disaggregation Of Revenue [Line Items]
Other non-interest income	$ 133	$ 103	$ 35