Selected Balance Sheet information (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Total assets	$ 36,503,366		$ 37,348,432
Deposits	26,319,499		27,942,127
PUERTO RICO
Segment Reporting Information [Line Items]
Total assets	26,533,351		27,410,644
Loans	18,315,321		18,594,751
Deposits	19,334,183		20,696,606
UNITED STATES
Segment Reporting Information [Line Items]
Total assets	8,787,390		8,708,709
Loans	5,837,485		5,845,359
Deposits	6,022,331		6,151,959
Other Countries [Member]
Segment Reporting Information [Line Items]
Total assets	1,182,625		1,229,079
Loans	841,963		874,282
Deposits	$ 962,985	[1]	$ 1,093,562	[1]

[1] Represents deposits from BPPR operations located in the US and British Virgin Islands.