Allowance for loan losses - Additional Information (Detail) (USD $)	9 Months Ended			9 Months Ended		12 Months Ended											9 Months Ended		12 Months Ended													3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Banco Popular North America [Member]	Sep. 30, 2013 Banco Popular North America [Member]	Dec. 31, 2013 Banco Popular North America [Member]	Dec. 31, 2012 Banco Popular North America [Member]	Jun. 30, 2014 Banco Popular North America [Member]	Sep. 30, 2014 Covered Under Loss Sharing Agreements With F D I C [Member]	Jun. 30, 2014 Covered Under Loss Sharing Agreements With F D I C [Member]	Dec. 31, 2013 Covered Under Loss Sharing Agreements With F D I C [Member]	Jun. 30, 2014 Covered Under Loss Sharing Agreements With F D I C [Member] Banco Popular De Puerto Rico [Member]	Sep. 30, 2014 Non Covered Loans [Member]		Jun. 30, 2014 Non Covered Loans [Member]	Dec. 31, 2013 Non Covered Loans [Member]	Sep. 30, 2014 Non Covered Loans [Member] Banco Popular De Puerto Rico [Member]	Sep. 30, 2013 Non Covered Loans [Member] Banco Popular De Puerto Rico [Member]	Dec. 31, 2013 Non Covered Loans [Member] Banco Popular De Puerto Rico [Member]	Dec. 31, 2012 Non Covered Loans [Member] Banco Popular De Puerto Rico [Member]	Jun. 30, 2014 Non Covered Loans [Member] Banco Popular De Puerto Rico [Member]	Sep. 30, 2014 Commercial Real Estate Construction Financing Receivable Member Covered Under Loss Sharing Agreements With F D I C [Member]	Dec. 31, 2013 Commercial Real Estate Construction Financing Receivable Member Covered Under Loss Sharing Agreements With F D I C [Member]	Sep. 30, 2014 Commercial Real Estate Construction Financing Receivable Member Non Covered Loans [Member]		Dec. 31, 2013 Commercial Real Estate Construction Financing Receivable Member Non Covered Loans [Member]	Sep. 30, 2014 Commercial Portfolio Segment Member Covered Under Loss Sharing Agreements With F D I C [Member]	Dec. 31, 2013 Commercial Portfolio Segment Member Covered Under Loss Sharing Agreements With F D I C [Member]	Sep. 30, 2014 Commercial Portfolio Segment Member Non Covered Loans [Member]		Dec. 31, 2013 Commercial Portfolio Segment Member Non Covered Loans [Member]	Sep. 30, 2014 Commercial Construction Legacy Portfolios [Member]	Sep. 30, 2014 Mortgage Consumer Portfolios [Member]	Sep. 30, 2014 Commercial Construction Portfolios [Member]	Sep. 30, 2014 Loan Commercial Real Estate Construction Financing Receivable Member	Dec. 31, 2013 Loan Commercial Real Estate Construction Financing Receivable Member	Sep. 30, 2014 Loan Commercial Portfolio Segment Member	Dec. 31, 2013 Loan Commercial Portfolio Segment Member
Financing Receivable, Modifications [Line Items]
Financing Receivable Modifications Recorded Investment									$ 10,972,000		$ 21,448,000		$ 1,092,044,000	[1]		$ 950,337,000						$ 2,419,000	$ 3,464,000	$ 11,567,000	[1]	$ 11,290,000	$ 3,649,000	$ 17,406,000	$ 311,657,000	[1]	$ 189,602,000
Loans And Leases Receivable Impaired Commitment To Lend																																			697,000	0	8,000,000	3,000,000
Credit Card T D R Modification Time Period	24
Recorded Investment Loan Split	2,100,000		14,300,000
Charge Offs Included Recorded Investment Loan Split	14,000		3,500,000
Recorded Investment Period End	2,300,000		1,900,000
Allowance Loans Modified Loan Split	111,000		401,000
Change Allowance For Loan Losses Recalibration And Enhancements Of The Enviromental Factors Adjustments		(17,000,000)						(3,700,000)				800,000									(14,100,000)
Change Allowance For Loan Losses Increased Look Back Period For Determining Recent Loss Trend Adjustment For Consumer And Mortgage Loans		1,000,000						100,000													900,000
Historical Loss Period																																	18-months	3-year
Recent Loss Trend Adjustment																																12-months	6-months
Net Impact Revisions										$ 800,000					$ 18,700,000
Recent Loss Trend Adjustment Percentage				12.00%	23.00%	29.00%	8.00%										33.00%	12.00%	27.00%	32.00%

[1] Excludes TDRs from discontinued operations.