INVESTMENT SECURITIES - Additional Information (Detail) - USD ($)			3 Months Ended			12 Months Ended
		Aug. 01, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Investments [Line Items]
Proceeds from sale of available-for-sale securities						$ 219,780,000	$ 0	$ 4,861,000
Percentage Of Debt Securities Government And Government Sponsored Agencies						97.00%
Amortized cost of private label of mortgage backed security						$ 1,908,142,000
Maximum loan to value ratio						80.00%
Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities						$ 390,286,000	296,950,000	233,046,000
Fair Value				$ 1,886,395,000		1,881,920,000	1,886,395,000
Amortized cost				$ 1,906,391,000		$ 1,908,557,000	$ 1,906,391,000
Weighted average yield				2.38%		2.14%	2.38%
Net gain on sale of investments						$ 6,104,000	$ 0	262,000
Interest Receivable				$ 48,697,000		45,453,000	48,697,000
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net	[1]					$ 6,687,000	16,517,000	$ 388,000
Percentage Of Held To Maturity Securities						87.00%
Percentage Of Stockholders Equity Exceeded By Securities Issuers						10.00%
Puerto Rico Government Development Bank Interest Payment Default		$ 28,000,000
Maximum [Member]
Schedule Of Investments [Line Items]
Recovery Rate						80.00%
Minimum [Member]
Schedule Of Investments [Line Items]
Recovery Rate						35.00%
Weighted Average [Member]
Schedule Of Investments [Line Items]
Recovery Rate						61.00%
U S Treasury Securities [Member]
Schedule Of Investments [Line Items]
Proceeds from sale of available-for-sale securities						$ 15,000,000
Net gain on sale of investments						8,000
Mortgage Backed Securities Issued By Private Enterprises [Member]
Schedule Of Investments [Line Items]
Credit related impairment loss is related to Private label MBS						400,000
Amortized cost						28,800,000
Puerto Rico Government obligations [Member]
Schedule Of Investments [Line Items]
Amortized cost						42,700,000
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net			$ 6,300,000	3,000,000	$ 12,900,000
Puerto Rico Government obligations [Member] | Puerto Rico Government Debt Securities Other Than Temporary Impairment [Member]
Schedule Of Investments [Line Items]
Fair Value						20,500,000
Amortized cost						$ 35,600,000
Default Rate						100.00%
Puerto Rico Government obligations [Member] | Puerto Rico Buildings Authority [Member]
Schedule Of Investments [Line Items]
Fair Value						$ 11,300,000
Amortized cost						13,300,000
Puerto Rico Government obligations [Member] | Puerto Rico Government Development Bank [Member]
Schedule Of Investments [Line Items]
Fair Value						9,200,000
Amortized cost						22,300,000
Interest Receivable						900,000
Mortgage Backed Securities [Member]
Schedule Of Investments [Line Items]
Proceeds from sale of available-for-sale securities						204,800,000
Fair Value				1,397,520,000		1,348,725,000	1,397,520,000
Amortized cost				$ 1,391,984,000		$ 1,356,342,000	$ 1,391,984,000
Weighted average yield				2.61%		2.49%	2.61%
Net gain on sale of investments						$ 6,100,000
Mortgage Backed Securities [Member] | Collateralized Mortgage Obligations [Member]
Schedule Of Investments [Line Items]
Fair Value						58,812,000
Amortized cost						$ 58,971,000
Weighted average yield						1.43%

[1] (1) For the years ended December 31, 2016 and 2015, approximately $6.3 million and $15.9 million, respectively, of the credit impairment recognized in earnings consisted of credit losses on Puerto Rico government debt securities. The remaining impairment losses were associated with credit losses on private label MBS.