REVENUE FROM CONTRACT WITH CUSTOMERS (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Net interest income	$ 138,649	$ 140,181
Non-interest income	30,200	22,543
Total Revenue	168,849	162,724
Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	5,957	5,716
Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	4,582	4,250
Total Revenue	3,100	2,700
Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	899	1,294
Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	4,666	5,403
Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	1,668	1,528
Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	12,428	4,352
Mortgage Banking Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	17,058	17,749
Non-interest income	3,640	3,606
Total Revenue	20,698	21,355
Mortgage Banking Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Mortgage Banking Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Mortgage Banking Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Mortgage Banking Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Mortgage Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	74	44
Mortgage Banking Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	3,566	3,562
Consumer Retail Banking Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	57,744	61,534
Non-interest income	13,728	14,007
Total Revenue	71,472	75,541
Consumer Retail Banking Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	3,483	3,524
Consumer Retail Banking Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	4,376	4,066
Consumer Retail Banking Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	750	834
Consumer Retail Banking Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	4,217	4,398
Consumer Retail Banking Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	617	843
Consumer Retail Banking Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	285	342
Commercial And Corporate Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	23,581	20,933
Non-interest income	2,011	2,518
Total Revenue	25,592	23,451
Commercial And Corporate Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	1,564	1,324
Commercial And Corporate Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Commercial And Corporate Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	196
Commercial And Corporate Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	17	320
Commercial And Corporate Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	412	426
Commercial And Corporate Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	18	252
Treasury And Investments Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	19,875	16,795
Non-interest income	8,328	74
Total Revenue	28,203	16,869
Treasury And Investments Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Treasury And Investments Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Treasury And Investments Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Treasury And Investments Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Treasury And Investments Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
Treasury And Investments Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	8,328	74
United States Operations Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	13,785	16,209
Non-interest income	831	533
Total Revenue	14,616	16,742
United States Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	168	136
United States Operations Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	4	11
United States Operations Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	0	0
United States Operations Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	10	169
United States Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	418	133
United States Operations Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	231	84
Virgin Islands Operations Segment [Member]
Disaggregation of Revenue [Line Items]
Net interest income	6,606	6,961
Non-interest income	1,662	1,805
Total Revenue	8,268	8,766
Virgin Islands Operations Segment [Member] | Service charges and fees on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	742	732
Virgin Islands Operations Segment [Member] | Insurance commissions [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	202	173
Virgin Islands Operations Segment [Member] | Merchant-related income [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	149	264
Virgin Islands Operations Segment [Member] | Credit and debit card fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	422	516
Virgin Islands Operations Segment [Member] | Other service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	147	82
Virgin Islands Operations Segment [Member] | Not inscope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Non-interest income	$ 0	$ 38