INCOME TAXES - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Income Tax Contingency [Line Items]
Valuation allowance	$ 186,900			$ 186,900
Percentage of dividend received deduction from controlled subsidiaries				100.00%
Percentage of dividend received from other taxable domestic corporations				85.00%
Income tax expense	(8,398)		$ 10,444	$ (7,181)	$ 23,690
Deferred Tax Assets Net	299,800			$ 299,800
Minimum percentage of bank net taxable income for paying Income tax at normal rate				20.00%
Effective Tax Rate Pretax Losses				20.00%	24.00%
Effective Income Tax Rate Continuing Operations				(2.00%)	25.00%
Income Tax Benefit Change In Tax Status		$ 13,200
Effective Income Tax Rate Excluding Discrete Items				21.00%
Puerto Rico [Member]
Income Tax Contingency [Line Items]
Statute of limitations under income tax act				4 years
United States [Member]
Income Tax Contingency [Line Items]
Income tax expense	1,600
Statute of limitations under income tax act				3 years
Virgin Islands [Member]
Income Tax Contingency [Line Items]
Statute of limitations under income tax act				3 years
FirstBank [Member]
Income Tax Contingency [Line Items]
Valuation allowance	146,600			$ 146,600		$ 171,000
Deferred Tax Assets Net	$ 299,500			$ 299,500		$ 277,400
Valuation Allowance Deferred Tax Asset Change In Amount		(13,900)
FirstBank Insurance [Member]
Income Tax Contingency [Line Items]
Deferred Tax Asset Change In Amount		$ 700