SEGMENT INFORMATION - Information about Reportable Segments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Interest income	$ 585,292	$ 605,569	$ 633,949
Net (charge) credit for transfer of funds	0	0	0
Interest expense	(101,174)	(103,303)	(115,876)
Net interest income	484,118	502,266	518,073
Provision for loan and lease losses	(86,733)	(172,045)	(109,530)
Non-interest income	87,954	67,882	68,627
Direct non-interest expenses	(253,954)	(279,957)	(283,980)
Segment income	231,385	118,146	193,190
Average earnings assets	11,466,576	11,862,290	12,046,932
Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Interest income	138,955	141,820	115,997
Net (charge) credit for transfer of funds	(49,435)	(49,149)	(37,375)
Interest expense	0	0	0
Net interest income	89,520	92,671	78,622
Provision for loan and lease losses	(24,873)	(30,017)	(17,605)
Non-interest income	19,531	16,027	13,515
Direct non-interest expenses	(38,170)	(37,345)	(39,444)
Segment income	46,008	41,336	35,088
Average earnings assets	2,562,245	2,607,230	2,142,122
Consumer Loan [Member]
Segment Reporting Information [Line Items]
Interest income	179,485	194,961	215,170
Net (charge) credit for transfer of funds	13,996	17,260	17,629
Interest expense	(24,787)	(23,774)	(24,445)
Net interest income	168,694	188,447	208,354
Provision for loan and lease losses	(34,246)	(46,657)	(79,932)
Non-interest income	44,535	41,854	40,018
Direct non-interest expenses	(112,787)	(133,397)	(126,290)
Segment income	66,196	50,247	42,150
Average earnings assets	1,951,214	1,951,047	1,967,202
Commercial And Corporate [Member]
Segment Reporting Information [Line Items]
Interest income	123,084	133,067	163,242
Net (charge) credit for transfer of funds	(26,364)	(17,299)	(12,364)
Interest expense	0	0	0
Net interest income	96,720	115,768	150,878
Provision for loan and lease losses	(28,578)	(101,604)	(40,084)
Non-interest income	7,811	12,487	5,241
Direct non-interest expenses	(40,676)	(42,470)	(46,963)
Segment income	35,277	(15,819)	69,072
Average earnings assets	2,497,037	2,891,988	3,613,354
Treasury And Investments [Member]
Segment Reporting Information [Line Items]
Interest income	50,372	49,534	54,223
Net (charge) credit for transfer of funds	60,787	36,908	20,463
Interest expense	(57,924)	(60,221)	(68,517)
Net interest income	53,235	26,221	6,169
Provision for loan and lease losses	0	0	0
Non-interest income	5,423	(15,897)	264
Direct non-interest expenses	(4,047)	(3,840)	(5,368)
Segment income	54,611	6,484	1,065
Average earnings assets	2,616,877	2,740,120	2,691,906
United States Operations [Member]
Segment Reporting Information [Line Items]
Interest income	56,037	46,804	44,882
Net (charge) credit for transfer of funds	1,016	12,280	11,647
Interest expense	(15,240)	(16,192)	(19,273)
Net interest income	41,813	42,892	37,256
Provision for loan and lease losses	1,369	7,955	27,650
Non-interest income	3,554	2,795	2,450
Direct non-interest expenses	(30,678)	(28,674)	(26,596)
Segment income	16,058	24,968	40,760
Average earnings assets	1,226,633	1,024,939	976,151
Virgin Islands Operations [Member]
Segment Reporting Information [Line Items]
Interest income	37,359	39,383	40,435
Net (charge) credit for transfer of funds	0	0	0
Interest expense	(3,223)	(3,116)	(3,641)
Net interest income	34,136	36,267	36,794
Provision for loan and lease losses	(405)	(1,722)	441
Non-interest income	7,100	10,616	7,139
Direct non-interest expenses	(27,596)	(34,231)	(39,319)
Segment income	13,235	10,930	5,055
Average earnings assets	$ 612,570	$ 646,966	$ 656,197