Income Taxes - Additional Information (Detail) (USD $)								3 Months Ended		9 Months Ended		12 Months Ended	3 Months Ended			9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	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]	Sep. 30, 2014 Other Liabilities Member	Dec. 31, 2013 Other Liabilities Member	Sep. 30, 2014 PUERTO RICO	Sep. 30, 2013 PUERTO RICO	Sep. 30, 2014 PUERTO RICO	Sep. 30, 2013 PUERTO RICO	Dec. 31, 2013 PUERTO RICO	Sep. 30, 2014 PUERTO RICO Amendment To The Internal Revenue Code [Member]	Jun. 30, 2014 PUERTO RICO Amendment To The Internal Revenue Code [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 PUERTO RICO Westernbank Assets Capital Gain Treatment [Member] Closing Agreement with the Puerto Rico Department of Treasury [Member]	Sep. 30, 2014 Parent Company [Member] PUERTO RICO Westernbank Assets Capital Gain Treatment [Member] Closing Agreement with the Puerto Rico Department of Treasury [Member]
Income Taxes [Line Items]
Income Taxes Paid															$ 45,000,000	$ 45,000,000
Marginal Income Tax Rate								39.00%				30.00%
Deferred Tax Assets Net	758,347,000	761,768,000						755,000,000		755,000,000
Unrecognized Tax Benefits Interest On Income Taxes Accrued	3,000,000	3,600,000
Unrecognized Tax Benefits That Would Impact Effective Tax Rate	9,700,000	11,900,000
Significant Change In Unrecognized Tax Benefits Is Reasonably Possible Amount Of Unrecorded Benefit	7,100,000
Unrecognized Tax Benefits Current Interest On Income Taxes Accrued	452,000	1,400,000
Income Tax Expense Benefit								26,667,000	17,768,000	45,807,000	(276,489,000)		20,000,000		23,400,000
Deferred Tax Liabilities	152,289,000	134,528,000				36,000,000	2,000,000
Deferred Tax Assets Valuation Allowance	1,210,780,000	1,257,977,000															14,100,000
Capital Gains Tax Rate													20.00%	15.00%
Senior Long Term Notes			450,000,000	450,000,000	0
Income Tax Reconciliation Change In Enacted Tax Rate								20,048,000	0	20,048,000	(197,467,000)
Unrecognized Tax Benefits Period Increases Decreases										$ (3,601,000)	$ (7,727,000)