Changes in the accretable yield for the acquired loans in the Westernbank FDIC-assisted transaction (Detail) (Westernbank Puerto Rico [Member], Acquired Loans In An F D I C Assisted Transaction [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Accretable yield
Beginning Balance	$ 1,574,850	$ 1,616,919	$ 1,470,259	$ 1,331,108
Accretion	(66,168)	(96,418)	(209,493)	(269,535)
Reclassifications from nonaccretable balance	0	0	0	0
Change In Expected Cash Flows	(37,800)	(23,936)	210,116	434,992
Ending Balance	1,470,882	1,496,565	1,470,882	1,496,565
Carrying amount of loans
Beginning Balance	3,729,489	4,216,808	4,036,471	4,539,928
Accretion	66,168	96,418	209,493	269,535
Collections	(168,448)	(173,867)	(618,755)	(670,104)
Ending Balance	3,627,209	4,139,359	3,627,209	4,139,359
Less: Allowance for loan losses	(103,547)	(62,446)	(103,547)	(62,446)	(83,477)
Carrying amount, net of allowance	3,523,662	4,076,913	3,523,662	4,076,913	3,952,994
Performing Financing Receivable Member
Accretable yield
Beginning Balance	1,550,959	1,546,233	1,428,764	1,307,927
Accretion	(61,540)	(66,808)	(191,989)	(203,683)
Reclassifications from nonaccretable balance	0	0	0	0
Change In Expected Cash Flows	(29,029)	(26,964)	223,615	348,217
Ending Balance	1,460,390	1,452,461	1,460,390	1,452,461
Carrying amount of loans
Beginning Balance	3,244,957	3,588,002	3,446,451	3,894,379
Accretion	61,540	66,808	191,989	203,683
Collections	(149,583)	(164,904)	(481,526)	(608,156)
Ending Balance	3,156,914	3,489,906	3,156,914	3,489,906
Less: Allowance for loan losses	(64,015)	(49,386)	(64,015)	(49,386)	(62,951)
Carrying amount, net of allowance	3,092,899	3,440,520	3,092,899	3,440,520	3,383,500
Nonperforming Financing Receivable Member
Accretable yield
Beginning Balance	23,891	70,686	41,495	23,181
Accretion	(4,628)	(29,610)	(17,504)	(65,852)
Reclassifications from nonaccretable balance	0	0	0	0
Change In Expected Cash Flows	(8,771)	3,028	(13,499)	86,775
Ending Balance	10,492	44,104	10,492	44,104
Carrying amount of loans
Beginning Balance	484,532	628,806	590,020	645,549
Accretion	4,628	29,610	17,504	65,852
Collections	(18,865)	(8,963)	(137,229)	(61,948)
Ending Balance	470,295	649,453	470,295	649,453
Less: Allowance for loan losses	(39,532)	(13,060)	(39,532)	(13,060)	(20,526)
Carrying amount, net of allowance	$ 430,763	$ 636,393	$ 430,763	$ 636,393	$ 569,494