Other Assets- Additional Information (Detail) (USD $)	3 Months Ended					9 Months Ended					3 Months Ended	9 Months Ended	3 Months Ended				3 Months Ended
	Sep. 30, 2014		Mar. 31, 2014	Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013	Sep. 30, 2014 PUERTO RICO Westernbank Assets Capital Gain Treatment [Member] Closing Agreement with the Puerto Rico Department of Treasury [Member]	Sep. 30, 2014 PUERTO RICO Westernbank Assets Capital Gain Treatment [Member] Closing Agreement with the Puerto Rico Department of Treasury [Member]	Sep. 30, 2014 UNITED STATES	Sep. 30, 2014 Fixed Rate 700 Percent Notes Due July 2019 [Member]	Jun. 30, 2014 Fixed Rate 700 Percent Notes Due July 2019 [Member]	Dec. 31, 2013 Fixed Rate 700 Percent Notes Due July 2019 [Member]	Jun. 30, 2014 Centro Financiero BHD [Member]	Sep. 30, 2014 Centro Financiero BHD [Member]	Mar. 31, 2014 Centro Financiero BHD [Member]	Dec. 31, 2013 Centro Financiero BHD [Member]
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Equity Method Investment Ownership Percentage																		15.82%	15.79%	19.99%
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax	$ 0	[1]	$ 7,700,000	$ 0	[1]	$ 7,718,000	[1]	$ 0	[1]								$ 7,700,000
Share Of Changes In Stockholders Equity																	14,200,000
Senior Long Term Notes														450,000,000	450,000,000	0
Debt Issuance Costs														9,000,000
Securities Trades Receivables	77,618,000			85,746,000		77,618,000		85,746,000		71,680,000				441,000,000
Bank Owned Life Insurance	0					0				228,805,000			231,200,000
Gain Loss On Sale Of Other Assets													100,000
Income Taxes Paid											45,000,000	45,000,000
Taxes Other						31,800,000
PaymentsForProceedsFromOtherInvestingActivities													$ 231,400,000

[1] All amounts presented are net of tax.