CECL, Amount Excluded To Be Phased-On During After Two Years

No definition available.

Name:	fbp_CeclAmountExcludedToBePhasedOnDuringAfterTwoYears
Namespace Prefix:	fbp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

In order to avoid limitations on capital distributions and certain discretionary bonus payments, banking organizations will be requiered to hold a specific amount of excess of their minimum risk-based capital ratios.

+ References

No definition available.

+ Details

Name:	fbp_ConservationBuffer
Namespace Prefix:	fbp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

+ References

No definition available.

+ Details

Name:	fbp_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption1
Namespace Prefix:	fbp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	fbp_PercentageOfIncreaseInACLAdjustedInCapitalMeasures
Namespace Prefix:	fbp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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 https://asc.fasb.org/extlink&oid=123594938&loc=d3e13537-108611

+ Details

Name:	us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	srt_ProductOrServiceAxis=fbp_CommercialAndFinancialStandbyLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommitmentsToExtendCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=us-gaap_CreditCardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_RetainedEarningsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAgencyAxis=fbp_BaselIIIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

REGULATORY MATTERS, COMMITMENTS, AND CONTINGENCIES - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Jan. 01, 2020
Commercial And Financial Standby Letters Of Credit [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Commitments to extend credit	$ 93.6
Commitments To Extend Credit [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Commitments to extend credit	2,000.0
Commitments To Extend Credit [Member] \| Credit Card [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Commitments to extend credit	900.0
ASU 2016-13
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Percentage Of Increase In ACL Adjusted In Capital Measures		25.00%	25.00%
CECL, amount excluded to be phased-on during after two years	$ 32.4
ASU 2016-13 \| Cumulative Effect, Period of Adoption, Adjustment [Member] \| Retained Earnings [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Cumulative Effect Of New Accounting Principle In Period Of Adoption 1			$ (32.4)
Basel III [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital Conservation Buffer	2.50%