Allowance for loan losses ending balance and the loan balance by portfolio segments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011		Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	$ 766,030		$ 803,264	$ 815,308		$ 746,847	$ 736,505	$ 793,225
Loans held-in-portfolio:
Loans held-in-portfolio	24,682,139			24,951,299
Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	87,508			58,986
Ending balance: loans collectively evaluated for impairment	561,027			631,377
Allowance for loan losses	648,535			690,363
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	1,235,372			1,226,021
Ending balance: loans collectively evaluated for impairment	19,430,437			19,376,575
Loans held-in-portfolio	20,665,809	[1]		20,602,596	[1]
Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	14,278			27,086
Ending balance: loans collectively evaluated for impairment	103,217			97,859
Allowance for loan losses	117,495			124,945
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	76,695			76,798
Ending balance: loans collectively evaluated for impairment	3,939,635			4,271,905
Loans held-in-portfolio	4,016,330			4,348,703
PUERTO RICO
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	564,052			578,347
Loans held-in-portfolio:
Loans held-in-portfolio	18,932,561			19,188,842
PUERTO RICO | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	70,969			43,348
Ending balance: loans collectively evaluated for impairment	375,588			410,054
Allowance for loan losses	446,557		447,536	453,402		414,903	423,311	455,431
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	1,022,045			929,868
Ending balance: loans collectively evaluated for impairment	13,894,186			13,910,271
Loans held-in-portfolio	14,916,231			14,840,139
PUERTO RICO | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	14,278			27,086
Ending balance: loans collectively evaluated for impairment	103,217			97,859
Allowance for loan losses	117,495		138,496	124,945		57,169	9,159	0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	76,695			76,798
Ending balance: loans collectively evaluated for impairment	3,939,635			4,271,905
Loans held-in-portfolio	4,016,330			4,348,703
UNITED STATES | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	16,539			15,638
Ending balance: loans collectively evaluated for impairment	185,439			221,323
Allowance for loan losses	201,978		217,232	236,961		274,775	304,035	337,794
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	213,327			296,153
Ending balance: loans collectively evaluated for impairment	5,536,251			5,466,304
Loans held-in-portfolio	5,749,578			5,762,457
Commercial Portfolio Segment Member
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	372,356		403,649	463,904		391,774	349,226	399,924
Loans held-in-portfolio:
Loans held-in-portfolio	11,933,991			12,486,069
Commercial Portfolio Segment Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	6,830			11,738
Ending balance: loans collectively evaluated for impairment	289,934			357,694
Allowance for loan losses	296,764			369,432
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	495,032			556,329
Ending balance: loans collectively evaluated for impairment	9,107,783			9,416,998
Loans held-in-portfolio	9,602,815			9,973,327
Commercial Portfolio Segment Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	14,278			27,086
Ending balance: loans collectively evaluated for impairment	61,314			67,386
Allowance for loan losses	75,592			94,472
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	76,695			76,798
Ending balance: loans collectively evaluated for impairment	2,254,481			2,435,944
Loans held-in-portfolio	2,331,176			2,512,742
Commercial Portfolio Segment Member | PUERTO RICO
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	279,438			349,925
Loans held-in-portfolio:
Loans held-in-portfolio	8,494,456			8,983,324
Commercial Portfolio Segment Member | PUERTO RICO | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	5,497			10,407
Ending balance: loans collectively evaluated for impairment	198,349			245,046
Allowance for loan losses	203,846		221,329	255,453		227,133	219,214	256,643
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	378,660			403,089
Ending balance: loans collectively evaluated for impairment	5,784,620			6,067,493
Loans held-in-portfolio	6,163,280			6,470,582
Commercial Portfolio Segment Member | PUERTO RICO | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	14,278			27,086
Ending balance: loans collectively evaluated for impairment	61,314			67,386
Allowance for loan losses	75,592		90,070	94,472		47,829	1,935	0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	76,695			76,798
Ending balance: loans collectively evaluated for impairment	2,254,481			2,435,944
Loans held-in-portfolio	2,331,176			2,512,742
Commercial Portfolio Segment Member | UNITED STATES | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	1,333			1,331
Ending balance: loans collectively evaluated for impairment	91,585			112,648
Allowance for loan losses	92,918		92,250	113,979		116,812	128,077	143,281
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	116,372			153,240
Ending balance: loans collectively evaluated for impairment	3,323,163			3,349,505
Loans held-in-portfolio	3,439,535			3,502,745
Commercial Real Estate Construction Financing Receivable Member
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	32,770		38,860	28,916		24,076	40,510	39,785
Loans held-in-portfolio:
Loans held-in-portfolio	719,508			786,765
Commercial Real Estate Construction Financing Receivable Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	434			289
Ending balance: loans collectively evaluated for impairment	8,708			8,192
Allowance for loan losses	9,142			8,481
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	61,007			91,710
Ending balance: loans collectively evaluated for impairment	188,736			148,229
Loans held-in-portfolio	249,743			239,939
Commercial Real Estate Construction Financing Receivable Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	23,628			20,435
Allowance for loan losses	23,628			20,435
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	469,765			546,826
Loans held-in-portfolio	469,765			546,826
Commercial Real Estate Construction Financing Receivable Member | PUERTO RICO
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	31,092			26,285
Loans held-in-portfolio:
Loans held-in-portfolio	671,529			707,767
Commercial Real Estate Construction Financing Receivable Member | PUERTO RICO | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	434			289
Ending balance: loans collectively evaluated for impairment	7,030			5,561
Allowance for loan losses	7,464		6,671	5,850		7,073	11,438	16,074
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	49,003			49,747
Ending balance: loans collectively evaluated for impairment	152,761			111,194
Loans held-in-portfolio	201,764			160,941
Commercial Real Estate Construction Financing Receivable Member | PUERTO RICO | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	23,628			20,435
Allowance for loan losses	23,628		29,727	20,435		9,291	6,934	0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	469,765			546,826
Loans held-in-portfolio	469,765			546,826
Commercial Real Estate Construction Financing Receivable Member | UNITED STATES | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	1,678			2,631
Allowance for loan losses	1,678		2,462	2,631		7,712	22,138	23,711
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	12,004			41,963
Ending balance: loans collectively evaluated for impairment	35,975			37,035
Loans held-in-portfolio	47,979			78,998
Mortgages
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	161,439		135,996	107,571		78,007	80,169	70,868
Loans held-in-portfolio:
Loans held-in-portfolio	7,016,449			6,691,414
Mortgages | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	59,723			29,063
Ending balance: loans collectively evaluated for impairment	90,099			73,198
Allowance for loan losses	149,822			102,261
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	510,659			382,880
Ending balance: loans collectively evaluated for impairment	5,389,314			5,135,580
Loans held-in-portfolio	5,899,973			5,518,460
Mortgages | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	11,617			5,310
Allowance for loan losses	11,617			5,310
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	1,116,476			1,172,954
Loans held-in-portfolio	1,116,476			1,172,954
Mortgages | PUERTO RICO
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	131,956			77,632
Loans held-in-portfolio:
Loans held-in-portfolio	5,930,697			5,862,437
Mortgages | PUERTO RICO | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	44,708			14,944
Ending balance: loans collectively evaluated for impairment	75,631			57,378
Allowance for loan losses	120,339		96,507	72,322		55,140	55,867	42,029
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	457,359			333,346
Ending balance: loans collectively evaluated for impairment	4,356,862			4,356,137
Loans held-in-portfolio	4,814,221			4,689,483
Mortgages | PUERTO RICO | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	11,617			5,310
Allowance for loan losses	11,617		10,517	5,310		35	59	0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	1,116,476			1,172,954
Loans held-in-portfolio	1,116,476			1,172,954
Mortgages | UNITED STATES | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	15,015			14,119
Ending balance: loans collectively evaluated for impairment	14,468			15,820
Allowance for loan losses	29,483		28,972	29,939		22,832	24,243	28,839
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	53,300			49,534
Ending balance: loans collectively evaluated for impairment	1,032,452			779,443
Loans held-in-portfolio	1,085,752			828,977
Legacy [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	44,011		54,725	46,228		73,545	69,912	76,405
Loans held-in-portfolio:
Loans held-in-portfolio	509,829			648,409
Legacy [Member] | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	99			57
Ending balance: loans collectively evaluated for impairment	43,912			46,171
Allowance for loan losses	44,011			46,228
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	29,289			48,890
Ending balance: loans collectively evaluated for impairment	480,540			599,519
Loans held-in-portfolio	509,829	[2]		648,409	[2]
Legacy [Member] | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	0			0
Allowance for loan losses	0			0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	0			0
Loans held-in-portfolio	0			0
Legacy [Member] | UNITED STATES | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	99			57
Ending balance: loans collectively evaluated for impairment	43,912			46,171
Allowance for loan losses	44,011		54,725	46,228		73,545	69,912	76,405
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	29,289			48,890
Ending balance: loans collectively evaluated for impairment	480,540			599,519
Loans held-in-portfolio	509,829			648,409
Finance Leases Portfolio Segment Member
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	2,957		4,967	4,651		5,045	6,608	7,154
Loans held-in-portfolio:
Loans held-in-portfolio	537,917			548,706
Finance Leases Portfolio Segment Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	766			793
Ending balance: loans collectively evaluated for impairment	2,191			3,858
Allowance for loan losses	2,957			4,651
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	5,528			6,104
Ending balance: loans collectively evaluated for impairment	532,389			542,602
Loans held-in-portfolio	537,917			548,706
Finance Leases Portfolio Segment Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	0			0
Allowance for loan losses	0			0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	0			0
Loans held-in-portfolio	0			0
Finance Leases Portfolio Segment Member | PUERTO RICO
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	2,957			4,651
Loans held-in-portfolio:
Loans held-in-portfolio	537,917			548,706
Finance Leases Portfolio Segment Member | PUERTO RICO | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	766			793
Ending balance: loans collectively evaluated for impairment	2,191			3,858
Allowance for loan losses	2,957		4,967	4,651		5,045	6,608	7,154
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	5,528			6,104
Ending balance: loans collectively evaluated for impairment	532,389			542,602
Loans held-in-portfolio	537,917			548,706
Finance Leases Portfolio Segment Member | PUERTO RICO | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	0			0
Allowance for loan losses	0		0	0		0	0	0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	0			0
Loans held-in-portfolio	0			0
Consumer Portfolio Segment Member
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	152,497		165,067	164,038		174,400	190,080	199,089
Loans held-in-portfolio:
Loans held-in-portfolio	3,964,445			3,789,936
Consumer Portfolio Segment Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	19,656			17,046
Ending balance: loans collectively evaluated for impairment	126,183			142,264
Allowance for loan losses	145,839			159,310
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	133,857			140,108
Ending balance: loans collectively evaluated for impairment	3,731,675			3,533,647
Loans held-in-portfolio	3,865,532			3,673,755
Consumer Portfolio Segment Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	6,658			4,728
Allowance for loan losses	6,658			4,728
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	98,913			116,181
Loans held-in-portfolio	98,913			116,181
Consumer Portfolio Segment Member | PUERTO RICO
Financing Receivable Allowance For Credit Losses Roll Forward
Allowance for loan losses	118,609			119,854
Loans held-in-portfolio:
Loans held-in-portfolio	3,297,962			3,086,608
Consumer Portfolio Segment Member | PUERTO RICO | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	19,564			16,915
Ending balance: loans collectively evaluated for impairment	92,387			98,211
Allowance for loan losses	111,951		118,062	115,126		120,512	130,184	133,531
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	131,495			137,582
Ending balance: loans collectively evaluated for impairment	3,067,554			2,832,845
Loans held-in-portfolio	3,199,049			2,970,427
Consumer Portfolio Segment Member | PUERTO RICO | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	6,658			4,728
Allowance for loan losses	6,658		8,182	4,728		14	231	0
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	0			0
Ending balance: loans collectively evaluated for impairment	98,913			116,181
Loans held-in-portfolio	98,913			116,181
Consumer Portfolio Segment Member | UNITED STATES | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable Allowance For Credit Losses Roll Forward
Ending balance: loans individually evaluated for impairment	92			131
Ending balance: loans collectively evaluated for impairment	33,796			44,053
Allowance for loan losses	33,888		38,823	44,184		53,874	59,665	65,558
Loans held-in-portfolio:
Ending balance: loans individually evaluated for impairment	2,362			2,526
Ending balance: loans collectively evaluated for impairment	664,121			700,802
Loans held-in-portfolio	$ 666,483			$ 703,328

[1] Non-covered loans held-in-portfolio at June 30, 2012 are net of $98 million in unearned income and exclude $365 million in loans held-for-sale. (December 31, 2011 - $101 million in unearned income and $363 million in loans held-for-sale.)

[2] The legacy portfolio is comprised of commercial loans, construction loans and lease financings related to certain lending products exited by the Corporation as part of restructuring efforts carried out in prior years at the BPNA reportable segment.