Summary of significant accounting policies - Additional Information (Detail)	Jun. 30, 2015 USD ($)
Significant Accounting Policies [Line Items]
Change Allowance For Loan Losses Additional Enhancements	$ 21,400,000
Banco Popular De Puerto Rico [Member] | Non Covered Loans [Member]
Significant Accounting Policies [Line Items]
Change Allowance For Loan Losses Additional Enhancements	20,500,000
Banco Popular North America [Member] | Non Covered Loans [Member]
Significant Accounting Policies [Line Items]
Change Allowance For Loan Losses Additional Enhancements	$ 1,000,000