Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended				1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Jun. 30, 2010	Jun. 30, 2010 PUERTO RICO	Jun. 30, 2011 PUERTO RICO	Jun. 30, 2010 PUERTO RICO	Jun. 30, 2011 PUERTO RICO	Jun. 30, 2010 PUERTO RICO	Dec. 31, 2010 PUERTO RICO	Jun. 30, 2011 PUERTO RICO Commercial Banking	Jun. 30, 2011 PUERTO RICO Net	Jun. 30, 2011 PUERTO RICO Net	Jun. 30, 2011 PUERTO RICO Gross	Jun. 30, 2011 UNITED STATES	Dec. 31, 2010 UNITED STATES	Jun. 30, 2011 Other assets	Jun. 30, 2011 Other liabilities	Dec. 31, 2010 Other liabilities
Income Taxes [Line Items]
Tax benefit related to the timing of loan charge-offs for tax purposes												$ (59,600,000)	$ (53,600,000)	$ (143,000,000)
Payment to the Puerto Rico Treasury Department								89,400,000
Tax benefit related to the tax benefit of the exempt income		6,000,000				15,206,000	2,331,000	17,613,000	12,036,000
Effective tax rate						(53.00%)	(158.00%)	47.00%	(16.00%)		22.00%
Reduction in net deferred tax asset due to a reduction in the marginal corporate income tax rate								103,287,000
Marginal corporate income tax rate					40.95%	30.00%				39.00%
Sur tax rate					5.00%
Net deferred tax asset	362,036,000		388,466,000	340,146,000		371,000,000		371,000,000									362,000,000
Deferred tax liabilities	208,378,000		167,504,000															14,000,000	11,000,000
Deferred tax asset, minimum percentage of likelihood that it will not be realized	50.00%
Deferred tax assets, valuation allowance	1,257,619,000		1,268,589,000												1,300,000,000	1,300,000,000
Unrecognized tax benefits, accrued interest	7,200,000		6,100,000	7,100,000
Accrual for the payment of penalties	0		0	0
Total amount of unrecognized tax benefits, that if recognized, would affect effective tax rate	33,400,000		31,600,000	32,100,000
Anticipated reduction in the total amount of unrecognized tax benefits within the next 12 months	$ 8,000,000