Note Commitments and contingencies (Legal Proceedings) - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($) claims units
Josefina Valle v. Popular Community Bank
Legal Matters And Contingencies [Line Items]
Amount Of Settlement Agreement To Be Paid To Qualified Claimants	$ 5.2
Banco Popular de Puerto Rico
Legal Matters And Contingencies [Line Items]
Mortgage Related Investigation	The review has been completed. The review found that while the mailing error extended to approximately 23,000 residential mortgage loans (approximately 50% of which are serviced by the Corporation for third parties), the number of borrowers actually harmed by the mailing error was substantially lower. This was due to, among other things, the fact that the Corporation regularly uses means other than the mail to communicate with borrowers, including email and hand delivery of written notices at our mortgage servicing centers or bank branches. Importantly, more than half of all borrowers potentially subject to such error actually closed on a loss mitigation alternative.
Banco Popular de Puerto Rico | Hazard Insurance Commision Related Litigation
Legal Matters And Contingencies [Line Items]
Loss Contingency Aggregate Claims Damages Sought	$ 400.0
Banco Popular de Puerto Rico | Lilliam Gonzalez Camacho v BPPR
Legal Matters And Contingencies [Line Items]
Loss Contingency Aggregate Claims Damages Sought	$ 400.0
Loss Contingency Number Of Defendants | units	20
Banco Popular de Puerto Rico | Costa Dorada Apartament Corp v BPPR
Legal Matters And Contingencies [Line Items]
Loss Contingency Damages Sought Value	$ 1,000.0
Banco Popular de Puerto Rico | Betteroads Asphalt and Betterecycling Corporation
Legal Matters And Contingencies [Line Items]
Loss Contingency Aggregate Claims Damages Sought	900.0
Banco Popular de Puerto Rico | Hector Robles Rodriguez v Municipio de Ceiba
Legal Matters And Contingencies [Line Items]
Loss Contingency Aggregate Claims Damages Sought	30.0
Multiple Arbitration Proceedings Against Popular Securities And One Other PR Broker Dealers | Popular Securities
Legal Matters And Contingencies [Line Items]
Loss Contingency Aggregate Claims Damages Sought	255.0
Loss Contingency Claim Of One Single Arbitration Case	$ 78.0
Aggregate Arbitrations with Claimed Damages | Popular Securities
Legal Matters And Contingencies [Line Items]
Loss Contingency Pending Claims Number | claims	130
One arbitration with Claimed damages | Popular Securities
Legal Matters And Contingencies [Line Items]
Loss Contingency Pending Claims Number | claims	1
Two Separate putative class action | Banco Popular de Puerto Rico | Costa Dorada Apartament Corp v BPPR
Legal Matters And Contingencies [Line Items]
Loss Contingency Pending Claims Number | claims	2
Minimum
Legal Matters And Contingencies [Line Items]
Loss Contingency Range Of Possible Loss Portion Not Accrued	$ 0.0
Maximum
Legal Matters And Contingencies [Line Items]
Loss Contingency Range Of Possible Loss Portion Not Accrued	$ 26.4