INVESTMENT SECURITIES - Investment Securities Available for Sale (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	$ 2,003,704		$ 2,049,262
Non credit loss component of OTTI recorded in OCI	12,774		14,310
Unrealized gain on available-for-sale securities	27,750		22,125
Gross unrealized losses	41,543		78,795
Fair value	1,977,137		1,978,282
Weighted average yield	2.52%		2.57%
Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	61,100
Fair value	46,400
United States And Puerto Rico Government Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	375,925		342,777
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	13		1
Gross unrealized losses	23,522		34,454
Fair value	352,416		308,324
Weighted average yield	1.89%		1.96%
Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	1,627,744		1,706,450
Non credit loss component of OTTI recorded in OCI	12,774		14,310
Unrealized gain on available-for-sale securities	27,737		22,124
Gross unrealized losses	18,000		44,339
Fair value	1,624,707		1,669,925
Weighted average yield	2.67%		2.69%
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	376,731		426,475
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	20,472		18,533
Gross unrealized losses	0		0
Fair value	397,203		445,008
Weighted average yield	3.83%		3.82%
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	876,637		891,952
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	6,404		3,457
Gross unrealized losses	13,735		33,626
Fair value	869,306		861,783
Weighted average yield	2.38%		2.38%
Mortgage Backed Securities Issued By Private Enterprises [Member] | Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	48,889		55,175
Non credit loss component of OTTI recorded in OCI	12,774		14,310
Unrealized gain on available-for-sale securities	1		1
Gross unrealized losses	0		0
Fair value	36,116		40,866
Weighted average yield	2.17%		2.24%
Due Within One Year [Member] | U S Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	7,496		7,498
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	7,498		7,499
Weighted average yield	0.11%		0.12%
Due Within One Year [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost			10,000
Non credit loss component of OTTI recorded in OCI			0
Unrealized gain on available-for-sale securities			0
Gross unrealized losses			210
Fair value			9,790
Weighted average yield			3.50%
After One To Five Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	174,161		50,000
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	1		0
Gross unrealized losses	4,225		1,408
Fair value	169,937		48,592
Weighted average yield	1.18%		1.05%
After One To Five Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	39,816		0
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	0		0
Gross unrealized losses	10,006		0
Fair value	29,810		0
Weighted average yield	4.49%		0.00%
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	49		86
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	1		4
Gross unrealized losses	0		0
Fair value	50		90
Weighted average yield	3.34%		3.48%
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	4,639		1,389
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	201		84
Gross unrealized losses	0		0
Fair value	4,840		1,473
Weighted average yield	3.44%		4.82%
After One To Five 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			82
Non credit loss component of OTTI recorded in OCI			0
Unrealized gain on available-for-sale securities			0
Gross unrealized losses			1
Fair value			81
Weighted average yield			3.01%
After Five To Ten Years [Member] | US Government Sponsored Enterprises Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	133,121		214,271
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	9		0
Gross unrealized losses	4,538		13,368
Fair value	128,592		200,903
Weighted average yield	1.52%		1.31%
After Five To Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	885		40,699
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	1		0
Gross unrealized losses	0		12,962
Fair value	886		27,737
Weighted average yield	5.20%		4.51%
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	1,534		800
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	84		37
Gross unrealized losses	0		0
Fair value	1,618		837
Weighted average yield	3.28%		2.47%
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	9,640		7,765
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	467		389
Gross unrealized losses	15		0
Fair value	10,092		8,154
Weighted average yield	3.49%		4.09%
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	115		127
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	1		1
Gross unrealized losses	0		0
Fair value	116		128
Weighted average yield	7.27%		7.27%
After Ten Years [Member] | Puerto Rico Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	20,446		20,309
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	0		0
Gross unrealized losses	4,753		6,506
Fair value	15,693		13,803
Weighted average yield	5.83%		5.82%
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	325,487		332,766
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	860		133
Gross unrealized losses	4,265		10,712
Fair value	322,082		322,187
Weighted average yield	2.19%		2.16%
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	375,148		425,589
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	20,387		18,492
Gross unrealized losses	0		0
Fair value	395,535		444,081
Weighted average yield	3.83%		3.82%
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	862,358		882,798
Non credit loss component of OTTI recorded in OCI	0		0
Unrealized gain on available-for-sale securities	5,736		2,984
Gross unrealized losses	13,720		33,626
Fair value	854,374		852,156
Weighted average yield	2.36%		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	48,774		55,048
Non credit loss component of OTTI recorded in OCI	12,774		14,310
Unrealized gain on available-for-sale securities	0		0
Gross unrealized losses	0		0
Fair value	36,000		40,738
Weighted average yield	2.17%		2.24%
Equity Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	35	[1]	35	[1]
Non credit loss component of OTTI recorded in OCI	0	[1]	0	[1]
Unrealized gain on available-for-sale securities	0	[1]	0	[1]
Gross unrealized losses	21	[1]	2	[1]
Fair value	$ 14	[1]	$ 33	[1]
Weighted average yield	0.00%	[1]	0.00%	[1]

[1]  Represents common shares of another financial institution in Puerto Rico.