Note Commitments and contingencies (Commitments) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure
Exposure Municipal Loans And Securities	75.00%
Commitments To Extend Credit
Commitments and Contingencies Disclosure
Reserve of potential losses associated with unfunded loan commitments	$ 8,000	$ 8,000
PR Government direct exposure
Commitments and Contingencies Disclosure
Outstanding concentration of risk	455,525	457,988
Total concentration of risk	455,525
PR Government direct exposure \| Loans
Commitments and Contingencies Disclosure
Outstanding concentration of risk	413,100	413,165
PR Government direct exposure \| Securities Investment
Commitments and Contingencies Disclosure
Outstanding concentration of risk	42,425	44,823
PR Government Indirect Exposure
Commitments and Contingencies Disclosure
Outstanding concentration of risk	365,000	368,000
Loans and Leases Receivable, Consumer, Mortgage with PRHA	290,000	293,000
PR Government Indirect Exposure \| PR Housing Bonds backed by second mortgage loans
Commitments and Contingencies Disclosure
Outstanding concentration of risk	45,000	45,000
PR Government Indirect Exposure \| Commercial real estate
Commitments and Contingencies Disclosure
Outstanding concentration of risk	23,000	23,000
PR Government Indirect Exposure \| Pass Through securities that have been economically defeased and refunded
Commitments and Contingencies Disclosure
Outstanding concentration of risk	7,000	$ 7,000
USVI Government Direct Exposure \| From USVI Government And Public Corporations
Commitments and Contingencies Disclosure
Total concentration of risk	$ 75,000

Commitments and Contingencies Disclosure [Line Items]

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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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