Carrying or notional amounts and estimated fair values for financial instruments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011		Jun. 30, 2011	Dec. 31, 2010
Assets Fair Value Disclosure Abstract
Cash And Due From Banks	$ 515,338		$ 535,282		$ 587,965	$ 452,373
Money market investments	949,828		1,376,174
Marketable Securities, Alternative [Abstract]
Servicing Asset At Fair Value Amount	155,711		151,323		162,619	166,907
Derivative Fair Value Of Derivative Asset	53,244		61,886
Deposits, by Type [Abstract]
Time Deposits	9,570,321		10,710,040
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase	1,426,636		2,141,097
Notes Payable [Abstract]
Other Notes Payable	24,520		25,070
Fixed Rate 6125 To 8327 Percent Junior Subordinated Deferrable Interest Debentures Due 2027 To 2034 [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	439,800		439,800
Fixed Rate 500 Percent Until December 2013 And 900 Percent Thereafter Junior Subordinated Deferrable Interest Debentures With No Stated Maturity [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	484,162	[1]	470,037	[1]
Fair Value, Inputs, Level 1 [Member]
Assets Fair Value Disclosure Abstract
Cash And Due From Banks	515,338
Money market investments	0
Trading account securities	0	[2]
Available For Sale Securities Fair Value Disclosure	3,523	[2]
Held To Maturity Securities Fair Value Disclosure	0
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock	0
Federal Reserve Bank Stock	0
Trust Preferred Securities	0
Other Investments	0
Total other investment securities	0
Loans held-for-sale	0
FDIC loss share asset	0
Servicing Asset At Fair Value Amount	0
Derivative Fair Value Of Derivative Asset	0
Deposits, by Type [Abstract]
Demand Deposit Accounts	0
Time Deposits	0
Deposits	0
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Federal Funds Purchased	0
Securities Sold under Agreements to Repurchase	0
Assets sold under agreements to repurchase	0
Other short-term borrowings	0	[3]
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term	0
Medium-term Notes	0
Other Notes Payable	0
Notes payable	0
Derivative Financial Instruments Liabilities Fair Value Disclosure	0
Business Acquisition, Contingent Consideration, at Fair Value	0
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit	0
Letters of credit Fair Value Disclosure	0
Fair Value, Inputs, Level 1 [Member] | Structured Finance [Member]
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase	0
Fair Value, Inputs, Level 1 [Member] | Fixed Rate 6125 To 8327 Percent Junior Subordinated Deferrable Interest Debentures Due 2027 To 2034 [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	0
Fair Value, Inputs, Level 1 [Member] | Fixed Rate 500 Percent Until December 2013 And 900 Percent Thereafter Junior Subordinated Deferrable Interest Debentures With No Stated Maturity [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	0
Fair Value, Inputs, Level 1 [Member] | Obligations of Puerto Rico, States and political subdivisions
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	0
Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	0
Fair Value, Inputs, Level 1 [Member] | Other
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	0
Fair Value, Inputs, Level 2 [Member]
Assets Fair Value Disclosure Abstract
Cash And Due From Banks	0
Money market investments	949,828
Trading account securities	394,547	[2]
Available For Sale Securities Fair Value Disclosure	5,065,892	[2]
Held To Maturity Securities Fair Value Disclosure	2,885
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock	78,650
Federal Reserve Bank Stock	79,563
Trust Preferred Securities	13,197
Other Investments	0
Total other investment securities	171,410
Loans held-for-sale	4,689
FDIC loss share asset	0
Servicing Asset At Fair Value Amount	0
Derivative Fair Value Of Derivative Asset	53,250
Deposits, by Type [Abstract]
Demand Deposit Accounts	17,844,459
Time Deposits	9,661,260
Deposits	27,505,719
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Federal Funds Purchased	0
Securities Sold under Agreements to Repurchase	795,140
Assets sold under agreements to repurchase	1,524,802
Other short-term borrowings	316,200	[3]
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term	683,701
Medium-term Notes	290,459
Other Notes Payable	0
Notes payable	1,303,073
Derivative Financial Instruments Liabilities Fair Value Disclosure	58,410
Business Acquisition, Contingent Consideration, at Fair Value	0
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit	0
Letters of credit Fair Value Disclosure	0
Fair Value, Inputs, Level 2 [Member] | Structured Finance [Member]
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase	729,662
Fair Value, Inputs, Level 2 [Member] | Fixed Rate 6125 To 8327 Percent Junior Subordinated Deferrable Interest Debentures Due 2027 To 2034 [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	328,913
Fair Value, Inputs, Level 2 [Member] | Fixed Rate 500 Percent Until December 2013 And 900 Percent Thereafter Junior Subordinated Deferrable Interest Debentures With No Stated Maturity [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	0
Fair Value, Inputs, Level 2 [Member] | Obligations of Puerto Rico, States and political subdivisions
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	1,385
Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	0
Fair Value, Inputs, Level 2 [Member] | Other
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	1,500
Fair Value, Inputs, Level 3 [Member]
Assets Fair Value Disclosure Abstract
Cash And Due From Banks	0
Money market investments	0
Trading account securities	22,916	[2]
Available For Sale Securities Fair Value Disclosure	7,382	[2]
Held To Maturity Securities Fair Value Disclosure	123,638
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock	0
Federal Reserve Bank Stock	0
Trust Preferred Securities	1,000
Other Investments	3,538
Total other investment securities	4,538
Loans held-for-sale	369,503
FDIC loss share asset	1,509,000
Servicing Asset At Fair Value Amount	155,711
Derivative Fair Value Of Derivative Asset	0
Deposits, by Type [Abstract]
Demand Deposit Accounts	0
Time Deposits	0
Deposits	0
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Federal Funds Purchased	0
Securities Sold under Agreements to Repurchase	0
Assets sold under agreements to repurchase	0
Other short-term borrowings	0	[3]
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term	0
Medium-term Notes	3,964
Other Notes Payable	24,520
Notes payable	765,906
Derivative Financial Instruments Liabilities Fair Value Disclosure	0
Business Acquisition, Contingent Consideration, at Fair Value	101,013
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit	1,776
Letters of credit Fair Value Disclosure	2,982
Fair Value, Inputs, Level 3 [Member] | Structured Finance [Member]
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase	0
Fair Value, Inputs, Level 3 [Member] | Fixed Rate 6125 To 8327 Percent Junior Subordinated Deferrable Interest Debentures Due 2027 To 2034 [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	0
Fair Value, Inputs, Level 3 [Member] | Fixed Rate 500 Percent Until December 2013 And 900 Percent Thereafter Junior Subordinated Deferrable Interest Debentures With No Stated Maturity [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	737,422
Fair Value, Inputs, Level 3 [Member] | Obligations of Puerto Rico, States and political subdivisions
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	98,457
Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	152
Fair Value, Inputs, Level 3 [Member] | Other
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	25,029
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Fair Value, Inputs, Level 1 [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	0
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Fair Value, Inputs, Level 2 [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	0
Non Covered Under Loss Sharing Agreements With F D I C [Member] | Fair Value, Inputs, Level 3 [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	17,193,518
Covered Under Loss Sharing Agreements With F D I C [Member] | Fair Value, Inputs, Level 1 [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	0
Covered Under Loss Sharing Agreements With F D I C [Member] | Fair Value, Inputs, Level 2 [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	0
Covered Under Loss Sharing Agreements With F D I C [Member] | Fair Value, Inputs, Level 3 [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	4,490,006
Carrying (Reported) Amount, Fair Value Disclosure
Assets Fair Value Disclosure Abstract
Cash And Due From Banks	515,338		535,282
Money market investments	949,828		1,376,174
Trading account securities	417,463	[2]	436,330	[2]
Available For Sale Securities Fair Value Disclosure	5,076,797	[2]	5,009,823	[2]
Held To Maturity Securities Fair Value Disclosure	124,646		125,383
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock	78,650		84,133
Federal Reserve Bank Stock	79,563		79,648
Trust Preferred Securities	14,197		14,197
Other Investments	1,877		1,902
Total other investment securities	174,287		179,880
Loans held-for-sale	364,537		363,093
FDIC loss share asset	1,631,594		1,915,128
Servicing Asset At Fair Value Amount	155,711		151,323
Derivative Fair Value Of Derivative Asset	53,250		61,887
Deposits, by Type [Abstract]
Demand Deposit Accounts	17,844,459		17,232,087
Time Deposits	9,570,321		10,710,040
Deposits	27,414,780		27,942,127
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Federal Funds Purchased	0		0
Securities Sold under Agreements to Repurchase	788,446		1,102,907
Assets sold under agreements to repurchase	1,426,636		2,141,097
Other short-term borrowings	316,200	[3]	296,200	[3]
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term	650,370		642,568
Medium-term Notes	278,731		278,897
Other Notes Payable	24,520		25,070
Notes payable	1,877,583		1,856,372
Derivative Financial Instruments Liabilities Fair Value Disclosure	58,410		66,700
Business Acquisition, Contingent Consideration, at Fair Value	101,013		99,762
Carrying (Reported) Amount, Fair Value Disclosure | Structured Finance [Member]
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase	638,190		1,038,190
Carrying (Reported) Amount, Fair Value Disclosure | Fixed Rate 6125 To 8327 Percent Junior Subordinated Deferrable Interest Debentures Due 2027 To 2034 [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	439,800		439,800
Carrying (Reported) Amount, Fair Value Disclosure | Fixed Rate 500 Percent Until December 2013 And 900 Percent Thereafter Junior Subordinated Deferrable Interest Debentures With No Stated Maturity [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	484,162		470,037
Carrying (Reported) Amount, Fair Value Disclosure | Obligations of Puerto Rico, States and political subdivisions
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	97,999		98,973
Carrying (Reported) Amount, Fair Value Disclosure | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	147		160
Carrying (Reported) Amount, Fair Value Disclosure | Other
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	26,500		26,250
Carrying (Reported) Amount, Fair Value Disclosure | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	20,017,274		19,912,233
Carrying (Reported) Amount, Fair Value Disclosure | Covered Under Loss Sharing Agreements With F D I C [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	3,898,835		4,223,758
Estimate of Fair Value, Fair Value Disclosure
Assets Fair Value Disclosure Abstract
Cash And Due From Banks	515,338		535,282
Money market investments	949,828		1,376,174
Trading account securities	417,463	[2]	436,330	[2]
Available For Sale Securities Fair Value Disclosure	5,076,797	[2]	5,009,823	[2]
Held To Maturity Securities Fair Value Disclosure	126,523		125,254
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock	78,650		84,133
Federal Reserve Bank Stock	79,563		79,648
Trust Preferred Securities	14,197		14,197
Other Investments	3,538		3,605
Total other investment securities	175,948		181,583
Loans held-for-sale	374,193		390,783
FDIC loss share asset	1,509,000		1,755,295
Servicing Asset At Fair Value Amount	155,711		151,323
Derivative Fair Value Of Derivative Asset	53,250		61,887
Deposits, by Type [Abstract]
Demand Deposit Accounts	17,844,459		17,232,087
Time Deposits	9,661,260		10,825,256
Deposits	27,505,719		28,057,343
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Federal Funds Purchased	0		0
Securities Sold under Agreements to Repurchase	795,140		1,107,314
Assets sold under agreements to repurchase	1,524,802		2,273,802
Other short-term borrowings	316,200	[3]	296,200	[3]
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term	683,701		673,505
Medium-term Notes	294,423		282,898
Other Notes Payable	24,520		25,070
Notes payable	2,068,979		1,722,831
Derivative Financial Instruments Liabilities Fair Value Disclosure	58,410		66,700
Business Acquisition, Contingent Consideration, at Fair Value	101,013		99,762
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit	1,776		2,062
Letters of credit Fair Value Disclosure	2,982		2,339
Estimate of Fair Value, Fair Value Disclosure | Structured Finance [Member]
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase	729,662		1,166,488
Estimate of Fair Value, Fair Value Disclosure | Fixed Rate 6125 To 8327 Percent Junior Subordinated Deferrable Interest Debentures Due 2027 To 2034 [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	328,913		284,238
Estimate of Fair Value, Fair Value Disclosure | Fixed Rate 500 Percent Until December 2013 And 900 Percent Thereafter Junior Subordinated Deferrable Interest Debentures With No Stated Maturity [Member]
Notes Payable [Abstract]
Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust	737,422		457,120
Estimate of Fair Value, Fair Value Disclosure | Obligations of Puerto Rico, States and political subdivisions
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	99,842		98,770
Estimate of Fair Value, Fair Value Disclosure | Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	152		151
Estimate of Fair Value, Fair Value Disclosure | Other
Assets Fair Value Disclosure Abstract
Held To Maturity Securities Fair Value Disclosure	26,529		26,333
Estimate of Fair Value, Fair Value Disclosure | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	17,193,518		16,753,889
Estimate of Fair Value, Fair Value Disclosure | Covered Under Loss Sharing Agreements With F D I C [Member]
Marketable Securities, Alternative [Abstract]
Loans held-in-portfolio, net	4,490,006		4,663,327
Notional Amount [Member]
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit	6,996,292		6,695,956
Letters of credit Fair Value Disclosure	$ 140,545		$ 136,341

[1] The debentures are perpetual and may be redeemed by the Corporation at any time, subject to the consent of the Board of Governors of the Federal Reserve System. The discount on the debentures is being amortized over an estimated 30-year term that started in August 2009. The effective interest rate, including the discount accretion, was approximately 16% at June 30, 2012 and December 31, 2011.

[2] Refer to Note 22 to the consolidated financial statements for the fair value by class of financial asset and its hierarchy level.

[3] Refer to Note 14 to the consolidated financial statements for the composition of short-term borrowings.