Note Commitments and contingencies (FDIC dealings section) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Nov. 12, 2015	Jun. 30, 2015	Apr. 13, 2015	Apr. 01, 2015	Nov. 25, 2014
FDIC Dealings [Line Items]
Write-off	$ 59,937	$ 81,815
Loans and Leases Receivable, Gross, Carrying Amount, Covered	625,130		$ 646,115
F D I C Indemnification Asset	219,448		310,221
FDIC
FDIC Dealings [Line Items]
Business Combination Contingent Consideration Liability	120,188		119,745
Banco Popular de Puerto Rico | Pending Dispute With FDIC
FDIC Dealings [Line Items]
Unreimbursed Claims Submitted to the FDIC					$ 6,900
Payments Withheld By The FDIC				$ 5,500
F D I C Indemnification Asset	149,000
Covered loans
FDIC Dealings [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered	$ 625,130		$ 646,115
Covered loans | Banco Popular de Puerto Rico | Pending Dispute With FDIC
FDIC Dealings [Line Items]
Loss Claim Disputed Amount								$ 66,600
Write-off		$ 53,300
F D I C Reimbursable Expenses Clawed Back							$ 1,700
Loss Contingency Increase In Damages Sought Value						$ 1,700