INVESTMENT SECURITIES - Investment Securities Available for Sale (Detail) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 1,831,740	$ 1,906,391
Noncredit Loss Component of OTTI Recorded in OCI		23,695	29,608
Gross unrealized gain		37,691	23,904
Gross unrealized loss		1,883	14,292
Fair value		$ 1,843,853	$ 1,886,395
Weighted average yield		2.17%	2.38%
Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 43,500
United States And Puerto Rico Government Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		602,121	$ 514,307
Noncredit Loss Component of OTTI Recorded in OCI		15,219	19,917
Gross unrealized gain		3,349	655
Gross unrealized loss		1,742	6,270
Fair value		$ 588,509	$ 488,775
Weighted average yield		1.53%	1.75%
Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 1,229,106	$ 1,391,984
Noncredit Loss Component of OTTI Recorded in OCI		8,476	9,691
Gross unrealized gain		34,336	23,249
Gross unrealized loss		141	8,022
Fair value		$ 1,254,825	$ 1,397,520
Weighted average yield		2.48%	2.61%
Federal Home Loan Mortgage Corporation Certificates And Obligations F H L M C [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 257,830	$ 288,047
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		3,649	1,104
Gross unrealized loss		62	1,706
Fair value		$ 261,417	$ 287,445
Weighted average yield		2.10%	2.15%
Government National Mortgage Association Certificates And Obligations G N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 229,624	$ 285,584
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		15,092	16,009
Gross unrealized loss		0	20
Fair value		$ 244,716	$ 301,573
Weighted average yield		3.81%	3.83%
Federal National Mortgage Association Certificates And Obligations F N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 651,582	$ 783,356
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		15,563	6,135
Gross unrealized loss		39	6,296
Fair value		$ 667,106	$ 783,195
Weighted average yield		2.29%	2.35%
Collateralized Mortgage Obligations Issued And Guaranteed By Fhlmc Fnma And Gnma [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 59,383
Noncredit Loss Component of OTTI Recorded in OCI		0
Gross unrealized gain		32
Gross unrealized loss		40
Fair value		$ 59,375
Weighted average yield		1.20%
Mortgage Backed Securities Issued By Private Enterprises [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 30,687	$ 34,997
Noncredit Loss Component of OTTI Recorded in OCI		8,476	9,691
Gross unrealized gain		0	1
Gross unrealized loss		0	0
Fair value		$ 22,211	$ 25,307
Weighted average yield		2.37%	2.26%
Due Within One Year [Member] | U S Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 7,513
Noncredit Loss Component of OTTI Recorded in OCI		0
Gross unrealized gain		1
Gross unrealized loss		0
Fair value		$ 7,514
Weighted average yield		0.57%
Due Within One Year [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 9,629	$ 14,624
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		4	4
Gross unrealized loss		0	10
Fair value		$ 9,633	$ 14,618
Weighted average yield		0.70%	0.68%
Due Within One Year [Member] | Government National Mortgage Association Certificates And Obligations G N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 1	$ 2
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		0	0
Gross unrealized loss		0	0
Fair value		$ 1	$ 2
Weighted average yield		1.69%	1.70%
After One To Five Years [Member] | U S Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost			$ 7,530
Noncredit Loss Component of OTTI Recorded in OCI			0
Gross unrealized gain			0
Gross unrealized loss			33
Fair value			$ 7,497
Weighted average yield			0.57%
After One To Five Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 496,782	$ 384,323
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		3,215	174
Gross unrealized loss		53	4,305
Fair value		$ 499,944	$ 380,192
Weighted average yield		1.32%	1.32%
After One To Five Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 21,423	$ 25,663
Noncredit Loss Component of OTTI Recorded in OCI		12,023	14,662
Gross unrealized gain		0	0
Gross unrealized loss		0	0
Fair value		$ 9,400	$ 11,001
Weighted average yield		4.38%	4.38%
After One To Five Years [Member] | Other Available For Sale Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 100	$ 100
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		0	0
Gross unrealized loss		0	0
Fair value		$ 100	$ 100
Weighted average yield		1.50%	1.50%
After One To Five Years [Member] | Government National Mortgage Association Certificates And Obligations G N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 93	$ 109
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		3	5
Gross unrealized loss		0	0
Fair value		$ 96	$ 114
Weighted average yield		3.85%	4.26%
After One To Five Years [Member] | Federal National Mortgage Association Certificates And Obligations F N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 22,594	$ 2,552
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		452	74
Gross unrealized loss		0	0
Fair value		$ 23,046	$ 2,626
Weighted average yield		1.99%	3.32%
After Five To Ten Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost			$ 58,150
Noncredit Loss Component of OTTI Recorded in OCI			0
Gross unrealized gain			343
Gross unrealized loss			242
Fair value			$ 58,251
Weighted average yield			2.34%
After Five To Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 845	$ 855
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		6	0
Gross unrealized loss		0	0
Fair value		$ 851	$ 855
Weighted average yield		5.20%	5.20%
After Five To Ten Years [Member] | Federal Home Loan Mortgage Corporation Certificates And Obligations F H L M C [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 6,314	$ 336
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		145	31
Gross unrealized loss		0	0
Fair value		$ 6,459	$ 367
Weighted average yield		2.31%	4.95%
After Five To Ten Years [Member] | Government National Mortgage Association Certificates And Obligations G N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 98,314	$ 120,298
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		2,557	3,182
Gross unrealized loss		0	0
Fair value		$ 100,871	$ 123,480
Weighted average yield		3.05%	3.07%
After Five To Ten Years [Member] | Federal National Mortgage Association Certificates And Obligations F N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 26,448	$ 21,557
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		577	433
Gross unrealized loss		19	233
Fair value		$ 27,006	$ 21,757
Weighted average yield		2.06%	2.73%
After Five To Ten Years [Member] | Collateralized Mortgage Obligations Issued And Guaranteed By Fhlmc Fnma And Gnma [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 19,853
Noncredit Loss Component of OTTI Recorded in OCI		0
Gross unrealized gain		7
Gross unrealized loss		33
Fair value		$ 19,827
Weighted average yield		1.18%
After Five To Ten Years [Member] | Mortgage Backed Securities Issued By Private Enterprises [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 81	$ 92
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		0	1
Gross unrealized loss		0	0
Fair value		$ 81	$ 93
Weighted average yield		7.20%	7.26%
After Ten Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 44,724
Noncredit Loss Component of OTTI Recorded in OCI		0
Gross unrealized gain		7
Gross unrealized loss		133
Fair value		$ 44,598
Weighted average yield		0.87%
After Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 21,205	$ 23,162
Noncredit Loss Component of OTTI Recorded in OCI		3,196	5,255
Gross unrealized gain		116	134
Gross unrealized loss		1,556	1,680
Fair value		$ 16,569	$ 16,361
Weighted average yield		5.39%	5.40%
After Ten Years [Member] | Federal Home Loan Mortgage Corporation Certificates And Obligations F H L M C [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 251,516	$ 287,711
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		3,504	1,073
Gross unrealized loss		62	1,706
Fair value		$ 254,958	$ 287,078
Weighted average yield		2.10%	2.14%
After Ten Years [Member] | Government National Mortgage Association Certificates And Obligations G N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 131,216	$ 165,175
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		12,532	12,822
Gross unrealized loss		0	20
Fair value		$ 143,748	$ 177,977
Weighted average yield		4.37%	4.38%
After Ten Years [Member] | Federal National Mortgage Association Certificates And Obligations F N M A [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 602,540	$ 759,247
Noncredit Loss Component of OTTI Recorded in OCI		0	0
Gross unrealized gain		14,534	5,628
Gross unrealized loss		20	6,063
Fair value		$ 617,054	$ 758,812
Weighted average yield		2.31%	2.34%
After Ten Years [Member] | Collateralized Mortgage Obligations Issued And Guaranteed By Fhlmc Fnma And Gnma [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 39,530
Noncredit Loss Component of OTTI Recorded in OCI		0
Gross unrealized gain		25
Gross unrealized loss		7
Fair value		$ 39,548
Weighted average yield		1.21%
After Ten Years [Member] | Mortgage Backed Securities Issued By Private Enterprises [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 30,606	$ 34,905
Noncredit Loss Component of OTTI Recorded in OCI		8,476	9,691
Gross unrealized gain		0	0
Gross unrealized loss		0	0
Fair value		$ 22,130	$ 25,214
Weighted average yield		2.37%	2.26%
Equity Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	[1]	$ 413
Noncredit Loss Component of OTTI Recorded in OCI	[1]	0
Gross unrealized gain	[1]	6
Gross unrealized loss	[1]	0
Fair value	[1]	$ 419
Weighted average yield	[1]	2.15%

[1] Equity securities consisted of investment in a Community Reinvestment Act Qualified Investment Fund.