LOAN PORTFOLIO - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended					9 Months Ended			12 Months Ended
		Sep. 30, 2016		Jun. 30, 2016	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2016		Sep. 30, 2015	Dec. 31, 2015		May 31, 2016	Dec. 31, 2014
Accounts Notes And Loans Receivable [Line Items]
Interest Income Impaired Loans					$ 7,800				$ 24,800
Interest Income on Impaired Loans Accrual Basis		$ 6,427			6,900		$ 18,851		19,800
Contractually outstanding principal and interest at acquisition		210,600					210,600			$ 218,100
Financing Receivable Significant Purchases							65,200
Securitization of mortgage loans into mortgage backed securities							238,600
Total gross loans held for investment portfolio		8,863,654			9,140,462		8,863,654		9,140,462	9,112,382
Total TDR loans		656,318		$ 670,991	681,963	$ 634,761	656,318		681,963	661,591			$ 694,453
Outstanding unfunded commitments on TDR loans		5,700					5,700
Provsion of PCI Loans		0			0		2,895		3,163
Classified and non-performing loans sold						147,500
Other real estate owned sold						2,900
Sale price of bulk sale						87,300
Reserves allocated to bulk sale						15,300
Total charge-offs bulk sale						61,400
Porfessional fees						900
Pre-tax loss						48,700
Loans held for sale		56,779					56,779			35,869
Proceeds From Sale Of Loans Held For Investment							20,186		107,702
Puerto Rico Housing Finance Authority Restricted Net Position						77,400
Puerto Rico Housing Finance Authority Covered Loans						552,000
Threshold Mortgage Loans Principal Amount Puerto Rico Housing Financing Authority		$ 75,000					75,000
Principal Payment Defaulted Government												$ 367,000
Reserve Coverage Ratio		16.00%
Puerto Rico Government General Obligations Moratorium On Payment				780,000
Puerto Rico Government Development Bank Interest Payment Default		$ 28,000
Interest Paid							104,031		70,016
Financing Receivable Allowance For Credit Losses Write Offs Impaired Loans	[1]	30,426			7,498		50,027		90,026
Impaired Financing Receivable Related Allowance		72,682		86,372	51,859	49,918	72,682		51,859	52,581			$ 55,205
Mortgage Loans In Process Of Foreclosure Amount		135,000					$ 135,000
Mortgage Loans Foreclosure Delinquency Threshold							3 months 28 days
Puerto Rico Tourism Development Fund [Member]
Accounts Notes And Loans Receivable [Line Items]
Outstanding of credit facilities granted		128,000					$ 128,000			129,400
Financing Receivable Commercial Governments Book Value		112,800					112,800
Financing Receivable Commercial Governments Collections							600			5,300
Proceeds From Interest Received							$ 1,600
Financing Receivable Allowance For Credit Losses Write Offs Impaired Loans		$ 13,700
Impaired Financing Receivable Related Allowance				$ 12,800
Unpaid Principal Balance Percentage		76.00%					76.00%
GNMA
Accounts Notes And Loans Receivable [Line Items]
Loans repurchased							$ 20,900		10,600
FNMA and FHLMC
Accounts Notes And Loans Receivable [Line Items]
Loans repurchased							700		1,300
Residential Mortgage [Member]
Accounts Notes And Loans Receivable [Line Items]
Total gross loans held for investment portfolio		$ 3,299,942			3,330,089		3,299,942		3,330,089
Impaired Financing Receivable Related Allowance		9,667			18,705		9,667		18,705
Government Guaranteed Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing Receivable Significant Sales							108,500
Total TDR loans		67,900					67,900			77,600
Government Guaranteed Residential Mortgage Loans Indirect Exposure		121,400					121,400
Loans in trial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total TDR loans		5,600					5,600
Non Accrual [Member]
Accounts Notes And Loans Receivable [Line Items]
Total TDR loans		240,399	[2]				240,399	[2]		246,683	[3]
Troubled Debt Restructurings [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Loan And Lease Losses Write Offs Net Loans Sold					45,300
Loans Split [Member]
Accounts Notes And Loans Receivable [Line Items]
Total TDR loans		38,004			40,632		38,004		40,632
Financing receivable loans restructured recorded investment accruals		37,900
Non Fha Va Residential Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total TDR loans		378,721					378,721			382,672
Commercial And Industrial Loan [Member]
Accounts Notes And Loans Receivable [Line Items]
Interest Income on Impaired Loans Accrual Basis		631					1,721
Total TDR loans		150,890					150,890			150,254
Classified and non-performing loans sold						45,800
Impaired Financing Receivable Related Allowance		28,668					28,668			18,096
Commercial Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Interest Income on Impaired Loans Accrual Basis		342					938
Total TDR loans		43,972					43,972			44,498
Classified and non-performing loans sold						90,700
Proceeds From Sale Of Loans Held For Investment							20,200		20,000
Impaired Financing Receivable Related Allowance		25,907					25,907			3,073
Construction Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total gross loans held for investment portfolio		124,298			163,956		124,298		163,956
Total TDR loans		40,200					40,200
Classified and non-performing loans sold						$ 11,000
Impaired Financing Receivable Related Allowance		3,004			2,128		3,004		2,128
Consumer Loan [Member]
Accounts Notes And Loans Receivable [Line Items]
Total gross loans held for investment portfolio		1,727,389			1,861,555		1,727,389		1,861,555
Total TDR loans		42,500					42,500
Impaired Financing Receivable Related Allowance		5,436			$ 8,600		5,436		8,600
Commercial Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
Interest Income on Impaired Loans Accrual Basis		0					0
Total TDR loans		36,953					36,953			39,466
Impaired Financing Receivable Related Allowance		1,977					1,977			0
Residential Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
Interest Income on Impaired Loans Accrual Basis		0					0
Total TDR loans		357					357			3,482
Impaired Financing Receivable Related Allowance		124					124			142
Land Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
Interest Income on Impaired Loans Accrual Basis		21					52
Total TDR loans		2,880					2,880			2,766
Impaired Financing Receivable Related Allowance		903					$ 903			1,060
P R
Accounts Notes And Loans Receivable [Line Items]
Credit risk concentration							78.00%
Outstanding of credit facilities granted		134,000					$ 134,000			153,200
Financing Receivable Commercial Governments Book Value		126,200					126,200
P R | Puerto Rico Government and Political Subdivisions [Member]
Accounts Notes And Loans Receivable [Line Items]
Outstanding of credit facilities granted		35,700					35,700
P R | Public Corporations [Member]
Accounts Notes And Loans Receivable [Line Items]
Outstanding of credit facilities granted		91,400					91,400
Financing Receivable Commercial Governments Book Value		83,700					83,700
P R | Government [Member]
Accounts Notes And Loans Receivable [Line Items]
Outstanding of credit facilities granted		6,900					6,900
P R | Puerto Rico Electric PowerAuthority [Member]
Accounts Notes And Loans Receivable [Line Items]
Outstanding of credit facilities granted		74,600					74,600
Financing Receivable Commercial Governments Book Value		66,900					$ 66,900
V I
Accounts Notes And Loans Receivable [Line Items]
Credit risk concentration							7.00%
Outstanding of credit facilities granted		$ 65,600					$ 65,600			$ 126,200
U S
Accounts Notes And Loans Receivable [Line Items]
Credit risk concentration							15.00%
Impaired Financing Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance For Loan And Lease Losses Write Offs Net Loans Sold									$ 63,900

[1] For the nine-month period ended September 30, 2015, includes $63.9 million of charge-offs related to a bulk sale of assets completed in the second quarter of 2015, mostly comprised of non-performing and adversely classified commercial loans, as further discussed below.

[2] Included in non-accrual loans are $121.3 million in loans that are performing under the terms of the restructuring agreement but are reported in non-accrual status until the restructured loans meet the criteria of sustained payment performance under the revised terms for reinstatement to accrual status and are deemed fully collectible.

[3] Included in non-accrual loans are $118.2 million in loans that are performing under the terms of the restructuring agreement but are reported in non-accrual status until the restructured loans meet the criteria of sustained payment performance under the revised terms for reinstatement to accrual status and there is no doubt about full collectability.