Commitments and contingencies - Additional Information (Detail) (USD $)	3 Months Ended			0 Months Ended
	Mar. 31, 2015 D		Mar. 31, 2014	Apr. 09, 2015	Dec. 31, 2014		Apr. 30, 2015
Commitments and Contingencies Disclosure [Line Items]
Unrecorded Unconditional Purchase Obligation Balance Sheet Amount	$ 9,000,000				$ 9,000,000
True Up Payment Term	45
Loans And Leases Receivable Net Of Deferred Income	21,012,930,000	[1]			19,404,451,000	[1]
Write-off	(81,815,000)		(112,773,000)
Loans and Leases Receivable, Gross, Carrying Amount, Covered	2,456,552,000				2,542,662,000
F D I C Reimbursable Expenses	21,545,000		12,745,000
Commercial Real Estate [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered	1,470,575,000				1,511,472,000
Commercial Real Estate Construction Financing Receivable Member
Commitments and Contingencies Disclosure [Line Items]
Loans And Leases Receivable Net Of Deferred Income	690,728,000				251,820,000
Write-off	(9,046,000)		(23,397,000)
Loans and Leases Receivable, Gross, Carrying Amount, Covered	57,825,000				70,336,000
Mortgages [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans And Leases Receivable Net Of Deferred Income	7,189,227,000				6,502,886,000
Write-off	(14,580,000)		(11,920,000)
Loans and Leases Receivable, Gross, Carrying Amount, Covered	795,477,000				822,986,000
Consumer [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans And Leases Receivable Net Of Deferred Income	3,820,620,000				3,870,271,000
Write-off	(32,217,000)		(34,877,000)
Loans and Leases Receivable, Gross, Carrying Amount, Covered	32,103,000				34,559,000
Covered Under Loss Sharing Agreements With F D I C [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered	2,456,552,000				2,542,662,000
Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Real Estate Construction Financing Receivable Member
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered	57,825,000				70,336,000
Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered	795,477,000				822,986,000
Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount, Covered	32,103,000				34,559,000
Minimum Member
Commitments and Contingencies Disclosure [Line Items]
Loss Contingency Range Of Possible Loss Portion Not Accrued	0
Maximum Member
Commitments and Contingencies Disclosure [Line Items]
Loss Contingency Range Of Possible Loss Portion Not Accrued	35,000,000
Federal Deposit Insurance Corporation [Member]
Commitments and Contingencies Disclosure [Line Items]
Business Combination Contingent Consideration Liability	125,140,000				129,304,000
Banco Popular De Puerto Rico [Member] | Arbitration With F D I C Regarding Reimbursement For Westernbank Loans [Member]
Commitments and Contingencies Disclosure [Line Items]
F D I C Indemnification Asset Cash Payments Received				27,900,000
Total Unreimbursed F D I C Shared Loss Claims	243,200,000			215,300,000
Unreimbursed Claims Submitted to the FDIC							80,100,000
Unreimbursed Claims Yet To Be Submitted To The FDIC							135,200,000
Banco Popular De Puerto Rico [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Pending Dispute With the FDIC of November 25, 2014
Commitments and Contingencies Disclosure [Line Items]
Write-off	53,300,000
Loss Claim Disputed Amount	66,600,000
F D I C Reimbursable Expenses	1,400,000
F D I C Reimbursable Expenses Clawed Back	1,700,000
Loss Contingency Increase In Damages Sought Value	1,700,000
Banco Popular De Puerto Rico [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Real Estate [Member]
Commitments and Contingencies Disclosure [Line Items]
Ratio Of Loan Type Portfolio To Total Loan Portfolio	64.00%
Banco Popular De Puerto Rico [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Real Estate Construction Financing Receivable Member
Commitments and Contingencies Disclosure [Line Items]
Ratio Of Loan Type Portfolio To Total Loan Portfolio	3.00%
Banco Popular De Puerto Rico [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages [Member]
Commitments and Contingencies Disclosure [Line Items]
Ratio Of Loan Type Portfolio To Total Loan Portfolio	32.00%
Banco Popular De Puerto Rico [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer [Member]
Commitments and Contingencies Disclosure [Line Items]
Ratio Of Loan Type Portfolio To Total Loan Portfolio	1.00%
Credit Concentration Risk Member | Government | PR Government Indirect Exposure [Member] | Housing Bonds backed by GNMA, FNMA or residential CMOs
Commitments and Contingencies Disclosure [Line Items]
Concentration Of Risk Credit Facilities	49,000,000				49,000,000
Credit Concentration Risk Member | Government | PR Government Indirect Exposure [Member] | Long-term Debt [Member]
Commitments and Contingencies Disclosure [Line Items]
Concentration Of Risk Credit Facilities	31,000,000				32,000,000
Credit Concentration Risk Member | Outstanding Balance [Member] | Government | PR Government Direct Exposure [Member]
Commitments and Contingencies Disclosure [Line Items]
Concentration Of Risk Credit Facilities	812,966,000				811,026,000
Loans And Leases Receivable Net Of Deferred Income	698,398,000				689,045,000
Investments	114,568,000				121,981,000
Credit Concentration Risk Member | Outstanding Balance [Member] | Government | PR Government Direct Exposure [Member] | From PR Government And Public Corporations [Member]
Commitments and Contingencies Disclosure [Line Items]
Concentration Of Risk Credit Facilities	335,901,000				336,459,000
Credit Concentration Risk Member | Outstanding Balance [Member] | Government | PR Government Direct Exposure [Member] | From Municipalities [Member]
Commitments and Contingencies Disclosure [Line Items]
Concentration Of Risk Credit Facilities	477,065,000				474,567,000
Credit Concentration Risk Member | Outstanding Balance [Member] | Government | PR Government Indirect Exposure [Member]
Commitments and Contingencies Disclosure [Line Items]
Loans and Leases Receivable, Consumer, Mortgage with PRHA	296,000,000				289,000,000
Credit Concentration Risk Member | Total [Member] | Government | PR Government Direct Exposure [Member]
Commitments and Contingencies Disclosure [Line Items]
Concentration Of Risk Credit Facilities	994,669,000				1,017,088,000
Credit Concentration Risk Member | Total [Member] | Government | PR Government Indirect Exposure [Member]
Commitments and Contingencies Disclosure [Line Items]
Concentration Of Risk Credit Facilities	376,000,000				370,000,000
Commitments To Extend Credit Member
Commitments and Contingencies Disclosure [Line Items]
Reserve of potential losses associated with unfunded loan commitments	11,000,000				13,000,000
Putative Class Action [Member] | Bpna [Member]
Commitments and Contingencies Disclosure [Line Items]
Litigation Settlement Amount	25,000
Potential Class Action Lawsuit Of Improper Job Classification [Member] | Bpna [Member]
Commitments and Contingencies Disclosure [Line Items]
Litigation Settlement Amount	800,000
Multiple Arbitration Proceedings Against Popular Securities And Two Other PR Broker Dealers [Member] | Popular Securities [Member]
Commitments and Contingencies Disclosure [Line Items]
Loss Contingency Aggregate Claims Damages Sought	99,000,000
Loss Contingency Claim Of One Single Arbitration Case	$ 78,000,000

[1] Non-covered loans held-in-portfolio at March 31, 2015 are net of $97 million in unearned income and exclude $161 million in loans held-for-sale. (December 31, 2014 - $94 million in unearned income and $106 million in loans held-for-sale.)