INVESTMENT SECURITIES - OTTI Losses on Available-for-Sale Debt Securities (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Total other-than-temporary impairment losses		$ (1,845)	$ (35,806)	$ 0
Credit losses on debt securities for which an OTTI was no previously recognized		0	15,889
Portion of loss previously recognized in other comprehensive income		0	0	0
Other Than Temporary Impairment Not Credit Losses Recognized In Earnings Additions No Previous Impairment		(4,842)	19,289	(388)
Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net	[1]	$ (6,687)	$ (16,517)	$ (388)

[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.