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				3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Covered Under Loss Sharing Agreements With F D I C [Member]	Dec. 31, 2013 Covered Under Loss Sharing Agreements With F D I C [Member]	Sep. 30, 2014 Westernbank Puerto Rico [Member] Acquired Loans In An F D I C Assisted Transaction [Member] Nonperforming Financing Receivable Member	Sep. 30, 2013 Westernbank Puerto Rico [Member] Acquired Loans In An F D I C Assisted Transaction [Member] Nonperforming Financing Receivable Member	Sep. 30, 2014 Westernbank Puerto Rico [Member] Acquired Loans In An F D I C Assisted Transaction [Member] Nonperforming Financing Receivable Member	Sep. 30, 2013 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	$ 624,911	$ 635,219	$ 640,555	$ 730,607	$ 89,688	$ 102,092	$ 90,892	$ 91,195	$ 93,915	$ 95,407
Provision for loan losses	80,629	72,663	215,379	545,927			15,693	23,316	51,199	54,924
Charge-offs	(92,861)	(104,320)	(289,609)	(374,886)			(20,945)	(5,637)	(59,474)	(41,457)
Recoveries	30,952	39,366	97,508	103,925
Net write-down related to loans sold	(32,256)	0	(32,256)	(362,645)
Balance at end of period	$ 611,375	$ 642,928	$ 611,375	$ 642,928	$ 89,688	$ 102,092	$ 85,640	$ 108,874	$ 85,640	$ 108,874