Average recorded investment and interest income recognized on impaired loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 1,323,538	$ 811,722
Impaired Financing Receivable Interest Income Accrual Method	7,971	3,348
Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	81,327	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
Non Covered Loans [Member] | Commercial Multi Family [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	25,908	20,726
Impaired Financing Receivable Interest Income Accrual Method	90	106
Non Covered Loans [Member] | Commercial Real Estate Non Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	120,858	120,125
Impaired Financing Receivable Interest Income Accrual Method	668	231
Non Covered Loans [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	246,354	198,499
Impaired Financing Receivable Interest Income Accrual Method	576	515
Non Covered Loans [Member] | Commercial And Industrial Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	161,122	101,979
Impaired Financing Receivable Interest Income Accrual Method	520	283
Non Covered Loans [Member] | Commercial Real Estate Construction Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	77,930	178,074
Impaired Financing Receivable Interest Income Accrual Method	16	173
Non Covered Loans [Member] | Mortgages
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	416,817	134,117
Impaired Financing Receivable Interest Income Accrual Method	6,055	2,012
Non Covered Loans [Member] | Legacy [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	48,311	58,202
Impaired Financing Receivable Interest Income Accrual Method	46	28
Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	5,758	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Credit Card Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	38,959	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
Non Covered Loans [Member] | Consumer Loan [Member] | Home Equity Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
Non Covered Loans [Member] | Consumer Loan [Member] | Personal [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	92,901	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Loans Auto Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	46	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Other Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	7,247	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	1,041,827	510,495
Impaired Financing Receivable Interest Income Accrual Method	6,829	2,884
PUERTO RICO | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	81,327	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO | Non Covered Loans [Member] | Commercial Multi Family [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	15,721	14,744
Impaired Financing Receivable Interest Income Accrual Method	0	106
PUERTO RICO | Non Covered Loans [Member] | Commercial Real Estate Non Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	56,977	27,542
Impaired Financing Receivable Interest Income Accrual Method	181	117
PUERTO RICO | Non Covered Loans [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	201,750	183,972
Impaired Financing Receivable Interest Income Accrual Method	576	446
PUERTO RICO | Non Covered Loans [Member] | Commercial And Industrial Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	128,146	91,570
Impaired Financing Receivable Interest Income Accrual Method	483	252
PUERTO RICO | Non Covered Loans [Member] | Commercial Real Estate Construction Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	50,385	61,153
Impaired Financing Receivable Interest Income Accrual Method	16	49
PUERTO RICO | Non Covered Loans [Member] | Mortgages
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	365,100	131,514
Impaired Financing Receivable Interest Income Accrual Method	5,573	1,914
PUERTO RICO | Non Covered Loans [Member] | Legacy [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO | Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	5,758	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO | Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Credit Card Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	38,959	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO | Non Covered Loans [Member] | Consumer Loan [Member] | Home Equity Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO | Non Covered Loans [Member] | Consumer Loan [Member] | Personal [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	92,901	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO | Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Loans Auto Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
PUERTO RICO | Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Other Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	4,803	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
UNITED STATES
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	281,711	301,227
Impaired Financing Receivable Interest Income Accrual Method	1,142	464
UNITED STATES | Covered Under Loss Sharing Agreements With F D I C [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
UNITED STATES | Non Covered Loans [Member] | Commercial Multi Family [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	10,187	5,982
Impaired Financing Receivable Interest Income Accrual Method	90	0
UNITED STATES | Non Covered Loans [Member] | Commercial Real Estate Non Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	63,881	92,583
Impaired Financing Receivable Interest Income Accrual Method	487	114
UNITED STATES | Non Covered Loans [Member] | Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	44,604	14,527
Impaired Financing Receivable Interest Income Accrual Method	0	69
UNITED STATES | Non Covered Loans [Member] | Commercial And Industrial Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	32,976	10,409
Impaired Financing Receivable Interest Income Accrual Method	37	31
UNITED STATES | Non Covered Loans [Member] | Commercial Real Estate Construction Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	27,545	116,921
Impaired Financing Receivable Interest Income Accrual Method	0	124
UNITED STATES | Non Covered Loans [Member] | Mortgages
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	51,717	2,603
Impaired Financing Receivable Interest Income Accrual Method	482	98
UNITED STATES | Non Covered Loans [Member] | Legacy [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	48,311	58,202
Impaired Financing Receivable Interest Income Accrual Method	46	28
UNITED STATES | Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
UNITED STATES | Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Credit Card Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
UNITED STATES | Non Covered Loans [Member] | Consumer Loan [Member] | Home Equity Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
UNITED STATES | Non Covered Loans [Member] | Consumer Loan [Member] | Personal [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	0	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
UNITED STATES | Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Loans Auto Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	46	0
Impaired Financing Receivable Interest Income Accrual Method	0	0
UNITED STATES | Non Covered Loans [Member] | Consumer Loan [Member] | Consumer Other Financing Receivable Member
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	2,444	0
Impaired Financing Receivable Interest Income Accrual Method	$ 0	$ 0