Note Commitments and contingencies (Commitments) - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Line Items]
Exposure Municipal Loans And Securities	75.00%
PR Government direct exposure
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	$ 457,988	$ 483,580
Total concentration of risk	457,988	483,580
PR Government direct exposure \| From Municipalities
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	457,910
Total concentration of risk	457,910
PR Government Indirect Exposure
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	368,000	386,000
Loans and Leases Receivable, Consumer, Mortgage with PRHA	293	310
PR Government Indirect Exposure \| PR Housing Bonds backed by second mortgage loans
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	45,000	44,000
PR Government Indirect Exposure \| Commercial real estate
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	23,000	25,000
PR Government Indirect Exposure \| Pass Through securities that have been economically defeased and refunded
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	7,000	7,000
USVI Government Direct Exposure \| From USVI Government And Public Corporations
Commitments and Contingencies Disclosure [Line Items]
Total concentration of risk	76,000
Commitments To Extend Credit
Commitments and Contingencies Disclosure [Line Items]
Reserve of potential losses associated with unfunded loan commitments	8,000	10,000
Loans \| PR Government direct exposure
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	413,165	434,493
Loans \| PR Government direct exposure \| From Municipalities
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	413,165
Securities Investment \| PR Government direct exposure
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	44,823	$ 49,045
Securities Investment \| PR Government direct exposure \| From Municipalities
Commitments and Contingencies Disclosure [Line Items]
Outstanding concentration of risk	$ 44,745

Commitments and Contingencies Disclosure [Line Items]

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- Definition

Concentration of Risk Credit Facilities with the Puerto Rico government that is outstanding.

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The Corporations exposure to municipal loans and securities was concentrated in the municipalities of San Juan, Guaynabo, Carolina and Bayamon.

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Amount before allowance of consumer mortgage held and guaranteed by the Puerto Rico Housing Authority.

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Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611

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Amount of valuation and qualifying accounts and reserves.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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