Carrying or notional amounts and estimated fair values for financial instruments (Detail) - Entity [Domain] - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Assets, Fair Value Disclosure [Abstract]
Cash And Due From Banks		$ 557,248	$ 381,095		$ 423,211
Money market investments		3,254,939	1,822,386
Trading account securities, at fair value		141,595	138,527
Available For Sale Securities		5,585,078	5,315,159
Held To Maturity Securities Fair Value		83,941	94,199
Marketable Securities, Alternative [Abstract]
Servicing Asset At Fair Value Amount		206,357	148,694	$ 151,951	$ 161,099
Derivative Asset, Fair Value, Gross Asset		21,716	25,362
Deposits, by Type [Abstract]
Time Deposits		8,842,257	7,474,445
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Federal Funds Purchased		0	100,000
Securities Sold under Agreements to Repurchase		1,121,244	1,171,657
Notes Payable [Abstract]
Other Notes Payable		19,428	19,830
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 700 Percent Notes Due July 2019 [Member]
Notes Payable [Abstract]
Senior Long Term Notes		450,000	450,000
Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available For Sale Securities		52,114	61,712
Held To Maturity Securities Fair Value		82,346	92,597
Collateralized Mortgage Obligations Issued By Private Enterprise [Member]
Assets, Fair Value Disclosure [Abstract]
Available For Sale Securities		0	0
Collateralized Mortgage Obligations Issued By U S Government Sponsored Enterprises And U S Government [Member]
Assets, Fair Value Disclosure [Abstract]
Available For Sale Securities		1,736,829	1,910,030
Held To Maturity Securities Fair Value		96	102
Other Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available For Sale Securities		10,602	11,306
Held To Maturity Securities Fair Value		1,499	1,500
Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash And Due From Banks		557,248	381,095
Money market investments		3,116,803	1,671,477
Trading account securities, at fair value	[1]	0	0
Available For Sale Securities	[1]	310	323
Held To Maturity Securities Fair Value		0	0
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock		0	0
Federal Reserve Bank Stock		0	0
Trust Preferred Securities		0	0
Other Investments		0	0
Total other investment securities		0	0
Loans held-for-sale		0	0
FDIC loss share asset		0	0
Servicing Asset At Fair Value Amount		0	0
Derivative Asset, Fair Value, Gross Asset		0	0
Deposits, by Type [Abstract]
Demand Deposit Accounts		0	0
Time Deposits		0	0
Deposits		0	0
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase		0	0
Assets sold under agreements to repurchase		0	0
Other short-term borrowings	[2]	0	0
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term		0	0
Medium-term Notes		0	0
Other Notes Payable		0	0
Notes payable		0	0
Derivative Financial Instruments Liabilities Fair Value Disclosure		0	0
Business Combination Contingent Consideration Liability		0	0
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit		0	0
Letters of credit Fair Value Disclosure		0	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	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	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	0
Fair Value, Inputs, Level 1 [Member] | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		0	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		0	0
Fair Value, Inputs, Level 1 [Member] | Other Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		0	0
Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash And Due From Banks		0	0
Money market investments		138,136	150,909
Trading account securities, at fair value	[1]	132,738	129,360
Available For Sale Securities	[1]	5,583,323	5,313,511
Held To Maturity Securities Fair Value		1,499	1,500
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock		69,886	66,773
Federal Reserve Bank Stock		80,510	80,025
Trust Preferred Securities		12,197	12,197
Other Investments		0	0
Total other investment securities		162,593	158,995
Loans held-for-sale		1,143	27,074
FDIC loss share asset		0	0
Servicing Asset At Fair Value Amount		0	0
Derivative Asset, Fair Value, Gross Asset		21,716	25,362
Deposits, by Type [Abstract]
Demand Deposit Accounts		18,908,437	17,333,090
Time Deposits		8,870,017	7,512,683
Deposits		27,778,454	24,845,773
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase		1,125,589	1,269,398
Assets sold under agreements to repurchase		1,125,589	1,269,398
Other short-term borrowings	[2]	101,200	20,200
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term		910,480	814,877
Medium-term Notes		0	460,530
Other Notes Payable		0	0
Notes payable		1,736,084	1,654,807
Derivative Financial Instruments Liabilities Fair Value Disclosure		18,430	23,032
Business Combination Contingent Consideration Liability		0	0
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit		0	0
Letters of credit Fair Value Disclosure		0	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		0	0
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		369,894	379,400
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	0
Fair Value, Inputs, Level 2 [Member] | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		0	0
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		0	0
Fair Value, Inputs, Level 2 [Member] | Other Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		1,499	1,500
Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash And Due From Banks		0	0
Money market investments		0	0
Trading account securities, at fair value	[1]	8,857	9,167
Available For Sale Securities	[1]	1,445	1,325
Held To Maturity Securities Fair Value		82,442	92,699
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock		0	0
Federal Reserve Bank Stock		0	0
Trust Preferred Securities		1,000	1,000
Other Investments		4,999	5,028
Total other investment securities		5,999	6,028
Loans held-for-sale		204,630	87,862
FDIC loss share asset		392,443	481,420
Servicing Asset At Fair Value Amount		206,357	148,694
Derivative Asset, Fair Value, Gross Asset		0	0
Deposits, by Type [Abstract]
Demand Deposit Accounts		0	0
Time Deposits		0	0
Deposits		0	0
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase		0	0
Assets sold under agreements to repurchase		0	0
Other short-term borrowings	[2]	0	1,000
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term		0	0
Medium-term Notes		0	0
Other Notes Payable		19,428	19,830
Notes payable		19,428	19,830
Derivative Financial Instruments Liabilities Fair Value Disclosure		0	0
Business Combination Contingent Consideration Liability		124,837	133,634
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit		1,112	1,716
Letters of credit Fair Value Disclosure		978	486
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	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	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		0	0
Fair Value, Inputs, Level 3 [Member] | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		82,346	92,597
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		96	102
Fair Value, Inputs, Level 3 [Member] | Other Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		0	0
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	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	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		21,546,344	18,079,609
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	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	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		548,171	2,947,909
Carrying (Reported) Amount, Fair Value Disclosure
Assets, Fair Value Disclosure [Abstract]
Cash And Due From Banks		557,248	381,095
Money market investments		3,254,939	1,822,386
Trading account securities, at fair value	[1]	141,595	138,527
Available For Sale Securities	[1]	5,585,078	5,315,159
Held To Maturity Securities Fair Value		101,861	103,170
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock		69,886	66,773
Federal Reserve Bank Stock		80,510	80,025
Trust Preferred Securities		13,197	13,197
Other Investments		1,912	1,911
Total other investment securities		165,505	161,906
Loans held-for-sale		202,287	106,104
FDIC loss share asset		392,947	542,454
Servicing Asset At Fair Value Amount		206,357	148,694
Derivative Asset, Fair Value, Gross Asset		21,716	25,362
Deposits, by Type [Abstract]
Demand Deposit Accounts		18,908,437	17,333,090
Time Deposits		8,842,257	7,474,445
Deposits		27,750,694	24,807,535
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase		1,121,244	1,271,657
Assets sold under agreements to repurchase		1,121,244	1,271,657
Other short-term borrowings	[2]	101,200	21,200
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term		894,800	802,198
Medium-term Notes		0	450,000
Senior Long Term Notes		450,000
Other Notes Payable		19,428	19,830
Notes payable		1,804,028	1,711,828
Derivative Financial Instruments Liabilities Fair Value Disclosure		18,430	23,032
Business Combination Contingent Consideration Liability		124,837	133,634
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		0	0
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		0	0
Carrying (Reported) Amount, Fair Value Disclosure | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		100,270	101,573
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		91	97
Carrying (Reported) Amount, Fair Value Disclosure | Other Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		1,500	1,500
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		21,922,406	18,884,732
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		651,576	2,460,589
Estimate of Fair Value, Fair Value Disclosure
Assets, Fair Value Disclosure [Abstract]
Cash And Due From Banks		557,248	381,095
Money market investments		3,254,939	1,822,386
Trading account securities, at fair value	[1]	141,595	138,527
Available For Sale Securities	[1]	5,585,078	5,315,159
Held To Maturity Securities Fair Value		83,941	94,199
Marketable Securities, Alternative [Abstract]
Federal Home Loan Bank Stock		69,886	66,773
Federal Reserve Bank Stock		80,510	80,025
Trust Preferred Securities		13,197	13,197
Other Investments		4,999	5,028
Total other investment securities		168,592	165,023
Loans held-for-sale		205,773	114,936
FDIC loss share asset		392,443	481,420
Servicing Asset At Fair Value Amount		206,357	148,694
Derivative Asset, Fair Value, Gross Asset		21,716	25,362
Deposits, by Type [Abstract]
Demand Deposit Accounts		18,908,437	17,333,090
Time Deposits		8,870,017	7,512,683
Deposits		27,778,454	24,845,773
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase		1,125,589	1,269,398
Assets sold under agreements to repurchase		1,125,589	1,269,398
Other short-term borrowings	[2]	101,200	21,200
Notes Payable [Abstract]
Federal Home Loan Bank Advances Long Term		910,480	814,877
Medium-term Notes		0	460,530
Senior Long Term Notes		455,710
Other Notes Payable		19,428	19,830
Notes payable		1,755,512	1,674,637
Derivative Financial Instruments Liabilities Fair Value Disclosure		18,430	23,032
Business Combination Contingent Consideration Liability		124,837	133,634
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit		1,112	1,716
Letters of credit Fair Value Disclosure		978	486
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		0	0
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		369,894	379,400
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		0	0
Estimate of Fair Value, Fair Value Disclosure | Puerto Rico States And Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		82,346	92,597
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		96	102
Estimate of Fair Value, Fair Value Disclosure | Other Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Held To Maturity Securities Fair Value		1,499	1,500
Estimate of Fair Value, Fair Value Disclosure | Fair Value, Inputs, Level 1 [Member]
Notes Payable [Abstract]
Senior Long Term Notes		0
Estimate of Fair Value, Fair Value Disclosure | Fair Value, Inputs, Level 2 [Member]
Notes Payable [Abstract]
Senior Long Term Notes		455,710
Estimate of Fair Value, Fair Value Disclosure | Fair Value, Inputs, Level 3 [Member]
Notes Payable [Abstract]
Senior Long Term Notes		0
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		21,546,344	18,079,609
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		548,171	2,947,909
Notional Amount [Member]
Fair Value Off Balance Sheet [Abstract]
Commitments to extend credit		7,108,912	7,135,352
Letters of credit Fair Value Disclosure		$ 51,115	$ 49,182

[1] Refer to Note 38 to the consolidated financial statements for the fair value by class of financial asset and its hierarchy level.

[2] Refer to Note 24 to the consolidated financial statements for the composition of short-term borrowings.