INVESTMENT SECURITIES - Investment Securities Available for Sale (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	$ 1,977,681		$ 1,976,261
Non credit loss component of OTTI recorded in OCI	11,296		12,141
Unrealized gain on available-for-sale securities	37,708		31,951
Gross unrealized losses	29,867		30,405
Fair value	1,974,226		1,965,666
Weighted average yield	2.48%		2.49%
Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	65,500
Fair value	41,500		27,408
United States And Puerto Rico Government Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	453,831		407,832
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	1,169		290
Gross unrealized losses	27,025		24,286
Fair value	427,975		383,836
Weighted average yield	1.90%		1.86%
Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	1,523,750		1,568,429
Non credit loss component of OTTI recorded in OCI	11,296		12,141
Unrealized gain on available-for-sale securities	36,539		31,661
Gross unrealized losses	2,842		6,119
Fair value	1,546,151		1,581,830
Weighted average yield	2.65%		2.66%
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	305,060
Non credit loss component of OTTI recorded in OCI	0
Unrealized gain on available-for-sale securities	2,779
Gross unrealized losses	560
Fair value	307,279
Weighted average yield	2.17%
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	340,383		355,989
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	22,900		21,459
Gross unrealized losses	0		0
Fair value	363,283		377,448
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	835,187		851,341
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	10,860		8,458
Gross unrealized losses	2,282		4,859
Fair value	843,765		854,940
Weighted average yield	2.37%		2.37%
Mortgage Backed Securities Issued By Private Enterprises [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	43,120		45,788
Non credit loss component of OTTI recorded in OCI	11,296		12,141
Unrealized gain on available-for-sale securities	0		1
Gross unrealized losses	0		0
Fair value	31,824		33,648
Weighted average yield	2.15%		2.17%
Due Within One Year [Member] | U S Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	7,500		7,498
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	7,500		7,499
Weighted average yield	0.11%		0.11%
Due Within One Year [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted average yield	0.00%
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	17
Non credit loss component of OTTI recorded in OCI	0
Unrealized gain on available-for-sale securities	0
Gross unrealized losses	0
Fair value	17
Weighted average yield	3.52%
After One To Five Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	278,054		260,889
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	318		42
Gross unrealized losses	1,918		4,219
Fair value	276,454		256,712
Weighted average yield	1.25%		1.22%
After One To Five Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	39,836		39,827
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	0		0
Gross unrealized losses	16,922		12,419
Fair value	22,914
Weighted average yield	4.49%		4.49%
After One To Five Years [Member] | Other Available For Sale Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	100	[1]
Non credit loss component of OTTI recorded in OCI	0	[1]
Unrealized gain on available-for-sale securities	0	[1]
Gross unrealized losses	0	[1]
Fair value	100	[1]
Weighted average yield	1.50%
After One To Five 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	432
Non credit loss component of OTTI recorded in OCI	0
Unrealized gain on available-for-sale securities	46
Gross unrealized losses	0
Fair value	478
Weighted average yield	4.95%
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	55		39
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	2		1
Gross unrealized losses	0		0
Fair value	57		40
Weighted average yield	3.93%		3.26%
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	3,743		4,160
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	155		181
Gross unrealized losses	0		0
Fair value	3,898		4,341
Weighted average yield	3.37%		3.40%
After Five To Ten Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	102,745		78,234
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	850		246
Gross unrealized losses	1,037		2,077
Fair value	102,558		76,403
Weighted average yield	1.93%		1.72%
After Five To Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	875		886
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	875		887
Weighted average yield	5.20%		5.20%
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	24,189		17,108
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	956		501
Gross unrealized losses	0		0
Fair value	25,145		17,609
Weighted average yield	3.62%		3.65%
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	16,924		9,584
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	646		521
Gross unrealized losses	31		5
Fair value	17,539		10,100
Weighted average yield	2.90%		3.49%
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	108		111
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	108		112
Weighted average yield	7.26%		7.27%
After Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	24,821		20,498
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	1		0
Gross unrealized losses	7,148		5,571
Fair value	17,674		14,927
Weighted average yield	5.37%		5.83%
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	304,628		315,311
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	2,733		1,743
Gross unrealized losses	560		1,260
Fair value	306,801		315,794
Weighted average yield	2.17%		2.17%
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	316,122		338,842
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	21,942		20,957
Gross unrealized losses	0		0
Fair value	338,064		359,799
Weighted average yield	3.85%		3.83%
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	814,520		837,597
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	10,059		7,756
Gross unrealized losses	2,251		4,854
Fair value	822,328		840,499
Weighted average yield	2.35%		2.36%
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	43,012		45,677
Non credit loss component of OTTI recorded in OCI	11,296		12,141
Unrealized gain on available-for-sale securities	0		0
Gross unrealized losses	0		0
Fair value	$ 31,716		$ 33,536
Weighted average yield	2.15%		2.17%
Equity Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted average yield	0.00%

[1] Represents investment in a Community Investment Fund.