Activity in Allowance for Loan Losses Related to ASC 310-30 Acquired Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 635,219	$ 766,030	$ 730,607	$ 815,308
Provision for loan losses	72,663	106,208	545,927	326,130
Charge-offs	(104,320)	(144,323)	(374,886)	(479,007)
Balance at end of period	642,928	761,172	642,928	761,172
Westernbank Puerto Rico [Member] | Acquired Loans In An F D I C Assisted Transaction [Member] | Nonperforming Financing Receivable Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	91,195	93,971	95,407	83,477
Provision for loan losses	23,316	17,881	54,924	57,472
Charge-offs	(5,637)	(8,305)	(41,457)	(37,402)
Balance at end of period	$ 108,874	$ 103,547	$ 108,874	$ 103,547