Note Allowance for loan losses (Activity in Allowance for Loan Losses Related to ASC 310-30 Acquired Loans) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable
Balance at beginning of period	$ 538,472	$ 588,697	$ 537,111	$ 601,792
Provision for loan losses	(40,472)	(76,234)	(85,307)	(116,269)
Balance at end of period	548,720	550,813	548,720	550,813
Westernbank Puerto Rico | Acquired loans in an FDIC assisted transaction | Credit Impaired Loans | ASC Subtopic 310-30
Accounts, Notes, Loans and Financing Receivable
Balance at beginning of period	62,967	68,386	63,563	78,846
Provision for loan losses	(5,861)	12,269	(4,070)	20,870
Net recoveries (charge-offs)	9,889	(33,606)	7,502	(52,667)
Balance at end of period	$ 66,995	$ 47,049	$ 66,995	$ 47,049