REVENUE FROM CONTRACT WITH CUSTOMERS (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Net interest income	$ 148,696	$ 144,425	$ 422,555	$ 427,152
Non-interest income (loss)	29,934	21,401	81,026	66,167
Total Revenue	178,630	165,826	503,581	493,319
Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	5,848	6,108	16,280	17,711
Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	1,473	1,983	7,436	8,258
Total Revenue			3,300	3,000
Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	2,217	1,598	4,105	4,209
Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	5,142	5,917	13,513	17,089
Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	2,274	1,440	6,536	5,235
Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	12,980	4,355	33,156	13,665
Mortgage Banking Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	20,666	16,991	55,177	52,051
Non-interest income (loss)	6,756	4,400	14,843	12,255
Total Revenue	27,422	21,391	70,020	64,306
Mortgage Banking Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Mortgage Banking Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Mortgage Banking Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Mortgage Banking Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Mortgage Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	49	67	215	141
Mortgage Banking Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	6,707	4,333	14,628	12,114
Consumer Retail Banking Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	54,323	62,164	165,609	185,914
Non-interest income (loss)	12,315	12,705	36,634	39,238
Total Revenue	66,638	74,869	202,243	225,152
Consumer Retail Banking Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	3,021	3,771	8,777	10,704
Consumer Retail Banking Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	1,377	1,854	6,933	7,799
Consumer Retail Banking Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	1,941	1,017	3,535	2,953
Consumer Retail Banking Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	4,778	4,897	12,380	14,040
Consumer Retail Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	846	828	1,882	2,651
Consumer Retail Banking Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	352	338	3,127	1,091
Commercial And Corporate Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	35,803	25,699	86,631	69,171
Non-interest income (loss)	2,838	2,331	7,673	7,146
Total Revenue	38,641	28,030	94,304	76,317
Commercial And Corporate Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	2,044	1,443	5,049	4,355
Commercial And Corporate Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Commercial And Corporate Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	271	0	467
Commercial And Corporate Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	16	283	45	927
Commercial And Corporate Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	700	300	1,591	1,042
Commercial And Corporate Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	78	34	988	355
Treasury And Investments Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	18,577	18,147	55,549	52,804
Non-interest income (loss)	5,457	(433)	13,777	(287)
Total Revenue	24,034	17,714	69,326	52,517
Treasury And Investments Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Treasury And Investments Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Treasury And Investments Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Treasury And Investments Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
Treasury And Investments Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	89	0
Treasury And Investments Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	5,457	(433)	13,688	(287)
United States Operations Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	12,918	14,977	39,939	47,328
Non-interest income (loss)	1,058	640	2,534	1,942
Total Revenue	13,976	15,617	42,473	49,270
United States Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	125	172	416	458
United States Operations Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	5	22	24	51
United States Operations Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	0	0	0	0
United States Operations Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	(2)	212	12	561
United States Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	537	169	1,366	526
United States Operations Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	393	65	716	346
Virgin Islands Operations Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	6,409	6,447	19,650	19,884
Non-interest income (loss)	1,510	1,758	5,565	5,873
Total Revenue	7,919	8,205	25,215	25,757
Virgin Islands Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	658	722	2,038	2,194
Virgin Islands Operations Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	91	107	479	408
Virgin Islands Operations Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	276	310	570	789
Virgin Islands Operations Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	350	525	1,076	1,561
Virgin Islands Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	142	76	1,393	875
Virgin Islands Operations Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	$ (7)	$ 18	$ 9	$ 46