INVESTMENT SECURITIES - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended					9 Months Ended
		Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule Of Investments [Line Items]
Proceeds from sale of available-for-sale securities							$ 219,780	$ 0
Percentage Of Debt Securities Government And Government Sponsored Agencies		97.00%					97.00%
Maximum loan to value ratio							80.00%
Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities							$ 270,345	212,972
Total investment securities available for sale		$ 1,843,853		$ 1,886,395			1,843,853
Impairement on equity securities		6,096			$ 0		6,104	0
Fair value		1,843,853		1,886,395			1,843,853
Amortized cost		$ 1,831,740		$ 1,906,391			$ 1,831,740
Weighted average yield		2.17%		2.38%			2.17%
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Default Rate							100.00%
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net	[1]	$ 0			$ 231		$ 6,687	13,484
Percentage Of Held To Maturity Securities		87.00%
Interest Receivable		$ 41,439		$ 48,697			41,439
Puerto Rico Buildings Authority [Member]
Schedule Of Investments [Line Items]
Total investment securities available for sale		10,100					10,100
Fair value		10,100					10,100
Puerto Rico Government Development Bank [Member]
Schedule Of Investments [Line Items]
Total investment securities available for sale		9,400					9,400
Fair value		9,400					9,400
Interest Receivable		900					$ 900
Maximum [Member]
Schedule Of Investments [Line Items]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Recovery Rate							80.00%
Minimum [Member]
Schedule Of Investments [Line Items]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Recovery Rate							35.00%
Weighted Average [Member]
Schedule Of Investments [Line Items]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Recovery Rate							61.00%
Mortgage Backed Securities Issued By Private Enterprises [Member]
Schedule Of Investments [Line Items]
Amortized cost		30,600					$ 30,600
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net							400	600
Puerto Rico Government obligations [Member]
Schedule Of Investments [Line Items]
Amortized cost		43,500					43,500
Change in net unrealized gains		300					13,400
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net			$ 6,300	$ 3,000		$ 12,900	6,300	$ 12,900
Puerto Rico Government obligations [Member] | Puerto Rico Government Debt Securities Other Than Temporary Impairment [Member]
Schedule Of Investments [Line Items]
Total investment securities available for sale		19,500					19,500
Fair value		19,500					19,500
Amortized cost		35,600					35,600
Puerto Rico Government obligations [Member] | Puerto Rico Buildings Authority [Member]
Schedule Of Investments [Line Items]
Amortized cost		13,300					13,300
Puerto Rico Government obligations [Member] | Puerto Rico Government Development Bank [Member]
Schedule Of Investments [Line Items]
Amortized cost		$ 22,000					$ 22,000

[1] For the nine-month periods ended September 30, 2016 and 2015, approximately $6.3 million and $12.9 million, respectively, of the credit impairment recognized in earnings consisted of credit losses on Puerto Rico Government debt securities and $0.4 million and $0.6 million, respectively, was associated with credit losses on private label MBS.