INVESTMENT SECURITIES - Investment Securities Available for Sale (Detail) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 1,893,862	$ 1,906,391
Non credit loss component of OTTI recorded in OCI		23,920	29,608
Unrealized gain on available-for-sale securities		36,028	23,904
Gross unrealized losses		1,715	14,292
Fair value		$ 1,904,255	$ 1,886,395
Weighted average yield		2.34%	2.38%
Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 43,400
United States And Puerto Rico Government Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		515,692	$ 514,307
Non credit loss component of OTTI recorded in OCI		15,463	19,917
Unrealized gain on available-for-sale securities		3,451	655
Gross unrealized losses		1,683	6,270
Fair value		$ 501,997	$ 488,775
Weighted average yield		1.69%	1.75%
Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 1,377,662	$ 1,391,984
Non credit loss component of OTTI recorded in OCI		8,457	9,691
Unrealized gain on available-for-sale securities		32,571	23,249
Gross unrealized losses		32	8,022
Fair value		$ 1,401,744	$ 1,397,520
Weighted average yield		2.59%	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		$ 277,808	$ 288,047
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		4,094	1,104
Gross unrealized losses		5	1,706
Fair value		$ 281,897	$ 287,445
Weighted average yield		2.15%	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		$ 270,491	$ 285,584
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		15,938	16,009
Gross unrealized losses		6	20
Fair value		$ 286,423	$ 301,573
Weighted average yield		3.83%	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		$ 796,312	$ 783,356
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		12,539	6,135
Gross unrealized losses		21	6,296
Fair value		$ 808,830	$ 783,195
Weighted average yield		2.33%	2.35%
Mortgage Backed Securities Issued By Private Enterprises [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 33,051	$ 34,997
Non credit loss component of OTTI recorded in OCI		8,457	9,691
Unrealized gain on available-for-sale securities		0	1
Gross unrealized losses		0	0
Fair value		$ 24,594	$ 25,307
Weighted average yield		2.34%	2.26%
Due Within One Year [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 14,626	$ 14,624
Non credit loss component of OTTI recorded in OCI		0
Unrealized gain on available-for-sale securities		10	4
Gross unrealized losses		0	10
Fair value		$ 14,636	$ 14,618
Weighted average yield		0.68%	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
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		0	0
Gross unrealized losses		0	0
Fair value		$ 1	$ 2
Weighted average yield		1.78%	1.70%
After One To Five Years [Member] | U S Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 7,525	$ 7,530
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		0	0
Gross unrealized losses		7	33
Fair value		$ 7,518	$ 7,497
Weighted average yield		0.57%	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		$ 385,103	$ 384,323
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		2,148	174
Gross unrealized losses		0	4,305
Fair value		$ 387,251	$ 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
Non credit loss component of OTTI recorded in OCI		11,501	14,662
Unrealized gain on available-for-sale securities		0	0
Gross unrealized losses		0	0
Fair value		$ 9,922	$ 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
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		0	0
Gross unrealized losses		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		$ 100	$ 109
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		4	5
Gross unrealized losses		0	0
Fair value		$ 104	$ 114
Weighted average yield		4.29%	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		$ 30,223	$ 2,552
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		63	74
Gross unrealized losses		21	0
Fair value		$ 30,265	$ 2,626
Weighted average yield		1.50%	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		$ 51,089	$ 58,150
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		1,131	343
Gross unrealized losses		0	242
Fair value		$ 52,220	$ 58,251
Weighted average yield		2.42%	2.34%
After Five To Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 855	$ 855
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		1	0
Gross unrealized losses		0	0
Fair value		$ 856	$ 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		$ 321	$ 336
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		31	31
Gross unrealized losses		0	0
Fair value		$ 352	$ 367
Weighted average yield		4.95%	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		$ 112,732	$ 120,298
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		2,839	3,182
Gross unrealized losses		0	0
Fair value		$ 115,571	$ 123,480
Weighted average yield		3.07%	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		$ 21,429	$ 21,557
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		835	433
Gross unrealized losses		0	233
Fair value		$ 22,264	$ 21,757
Weighted average yield		2.73%	2.73%
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		$ 89	$ 92
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		0	1
Gross unrealized losses		0	0
Fair value		$ 89	$ 93
Weighted average yield		7.26%	7.26%
After Ten Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 13,930
Non credit loss component of OTTI recorded in OCI		0
Unrealized gain on available-for-sale securities		14
Gross unrealized losses		20
Fair value		$ 13,924
Weighted average yield		0.84%
After Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost		$ 21,141	$ 23,162
Non credit loss component of OTTI recorded in OCI		3,962	5,255
Unrealized gain on available-for-sale securities		147	134
Gross unrealized losses		1,656	1,680
Fair value		$ 15,670	$ 16,361
Weighted average yield		5.38%	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		$ 277,487	$ 287,711
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		4,063	1,073
Gross unrealized losses		5	1,706
Fair value		$ 281,545	$ 287,078
Weighted average yield		2.15%	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		$ 157,658	$ 165,175
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		13,095	12,822
Gross unrealized losses		6	20
Fair value		$ 170,747	$ 177,977
Weighted average yield		4.38%	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		$ 744,660	$ 759,247
Non credit loss component of OTTI recorded in OCI		0	0
Unrealized gain on available-for-sale securities		11,641	5,628
Gross unrealized losses		0	6,063
Fair value		$ 756,301	$ 758,812
Weighted average yield		2.35%	2.34%
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		$ 32,962	$ 34,905
Non credit loss component of OTTI recorded in OCI		8,457	9,691
Unrealized gain on available-for-sale securities		0	0
Gross unrealized losses		0	0
Fair value		$ 24,505	$ 25,214
Weighted average yield		2.34%	2.26%
Equity Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	[1]	$ 408
Non credit loss component of OTTI recorded in OCI	[1]	0
Unrealized gain on available-for-sale securities	[1]	6
Gross unrealized losses	[1]	0
Fair value	[1]	$ 414
Weighted average yield		0.00%

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