REVENUE FROM CONTRACT WITH CUSTOMERS (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Net interest income	$ 135,210	$ 142,546	$ 273,859	$ 282,727
Non-interest income (loss)	20,892	22,223	51,092	44,766
Total Revenue	156,102	164,769	324,951	327,493
Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	4,474	5,887	10,431	11,603
Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	1,381	2,025	5,963	6,275
Total Revenue	100	4	3,300	2,700
Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	989	1,317	1,888	2,611
Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	3,705	5,769	8,371	11,172
Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	2,594	2,267	4,262	3,795
Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	7,749	4,958	20,177	9,310
Mortgage Banking Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	17,453	17,311	34,511	35,060
Non-interest income (loss)	4,447	4,249	8,087	7,855
Total Revenue	21,900	21,560	42,598	42,915
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)	92	30	166	74
Mortgage Banking Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	4,355	4,219	7,921	7,781
Consumer Retail Banking Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	53,542	62,216	111,286	123,750
Non-interest income (loss)	10,591	12,526	24,319	26,533
Total Revenue	64,133	74,742	135,605	150,283
Consumer Retail Banking Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	2,272	3,409	5,755	6,933
Consumer Retail Banking Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	1,180	1,879	5,556	5,945
Consumer Retail Banking Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	844	1,102	1,594	1,936
Consumer Retail Banking Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	3,385	4,745	7,602	9,143
Consumer Retail Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	419	980	1,036	1,823
Consumer Retail Banking Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	2,491	411	2,776	753
Commercial And Corporate Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	27,247	22,539	50,828	43,472
Non-interest income (loss)	2,824	2,297	4,835	4,815
Total Revenue	30,071	24,836	55,663	48,287
Commercial And Corporate Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	1,441	1,588	3,005	2,912
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	0	0	196
Commercial And Corporate Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	12	324	29	644
Commercial And Corporate Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	479	316	891	742
Commercial And Corporate Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	892	69	910	321
Treasury And Investments Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	17,097	17,862	36,972	34,657
Non-interest income (loss)	(8)	72	8,320	146
Total Revenue	17,089	17,934	45,292	34,803
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)	89	0	89	0
Treasury And Investments Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	(97)	72	8,231	146
United States Operations Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	13,236	16,142	27,021	32,351
Non-interest income (loss)	645	769	1,476	1,302
Total Revenue	13,881	16,911	28,497	33,653
United States Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	123	150	291	286
United States Operations Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	15	18	19	29
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)	4	180	14	349
United States Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	411	224	829	357
United States Operations Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	92	197	323	281
Virgin Islands Operations Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	6,635	6,476	13,241	13,437
Non-interest income (loss)	2,393	2,310	4,055	4,115
Total Revenue	9,028	8,786	17,296	17,552
Virgin Islands Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	638	740	1,380	1,472
Virgin Islands Operations Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	186	128	388	301
Virgin Islands Operations Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	145	215	294	479
Virgin Islands Operations Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	304	520	726	1,036
Virgin Islands Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	1,104	717	1,251	799
Virgin Islands Operations Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income (loss)	$ 16	$ (10)	$ 16	$ 28