<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>92</ContextCount>
  <ElementCount>82</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>16</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>3</UnitCount>
  <MyReports>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000090 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>000100 - Statement - Statements of Net Asset Available for Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/StatementsOfNetAssetAvailableForBenefits</Role>
      <ShortName>Statements of Net Asset Available for Benefits</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>000200 - Statement - Statement of Changes in Net Assets Available for Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/StatementStatementOfChangesInNetAssetsAvailableForBenefits</Role>
      <ShortName>Statement of Changes in Net Assets Available for Benefits</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>010101 - Disclosure - Description of the Plan</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/DescriptionOfThePlan</Role>
      <ShortName>Description of the Plan</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>010201 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/DisclosureSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>010301 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>010401 - Disclosure - Party-in-Interest Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/PartyinInterestTransactions</Role>
      <ShortName>Party-in-Interest Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>010501 - Disclosure - Tax Status</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/TaxStatus</Role>
      <ShortName>Tax Status</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>010601 - Disclosure - Plan Termination</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/PlanTermination</Role>
      <ShortName>Plan Termination</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>010701 - Disclosure - Forfeited Amount</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/ForfeitedAmount</Role>
      <ShortName>Forfeited Amount</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>010801 - Disclosure - Risks and Uncertainties</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/RisksAndUncertainties</Role>
      <ShortName>Risks and Uncertainties</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>010901 - Disclosure - Schedule of Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/ScheduleOfAssets</Role>
      <ShortName>Schedule of Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>020202 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>13</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>030303 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/DisclosureFairValueMeasurements</ParentRole>
      <Position>14</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>040101 - Disclosure - Description of the Plan (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/DescriptionOfThePlanNarrativeDetails</Role>
      <ShortName>Description of the Plan (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/DescriptionOfThePlan</ParentRole>
      <Position>15</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>040301 - Disclosure - Fair Value Measurements (Investments Measured at Fair Value) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/FairValueMeasurementsInvestmentsMeasuredAtFairValueDetails</Role>
      <ShortName>Fair Value Measurements (Investments Measured at Fair Value) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/DisclosureFairValueMeasurementsTables</ParentRole>
      <Position>16</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>040401 - Disclosure - Party-in-Interest Transactions (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/PartyinInterestTransactionsNarrativeDetails</Role>
      <ShortName>Party-in-Interest Transactions (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/PartyinInterestTransactions</ParentRole>
      <Position>17</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>040501 - Disclosure - Tax Status (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/TaxStatusNarrativeDetails</Role>
      <ShortName>Tax Status (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/TaxStatus</ParentRole>
      <Position>18</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>040601 - Disclosure - Plan Termination (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/PlanTerminationNarrativeDetails</Role>
      <ShortName>Plan Termination (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/PlanTermination</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>040701 - Disclosure - Forfeited Amount (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/ForfeitedAmountNarrativeDetails</Role>
      <ShortName>Forfeited Amount (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/ForfeitedAmount</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>040901 - Schedule - Schedule of Assets (Schedule of Assets (Held at End of Year I)) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/ScheduleOfAssetsScheduleOfAssetsHeldAtEndOfYearIDetails</Role>
      <ShortName>Schedule of Assets (Schedule of Assets (Held at End of Year I)) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/ScheduleOfAssets</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>040902 - Schedule - Schedule of Assets (Schedule of Assets (Held at End of Year II)) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/ScheduleOfAssetsScheduleOfAssetsHeldAtEndOfYearIIDetails</Role>
      <ShortName>Schedule of Assets (Schedule of Assets (Held at End of Year II)) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/ScheduleOfAssets</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="fbp-20251231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>040903 - Schedule - Schedule of Assets (Schedule of Assets (Held at End of Year III)) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.firstbankpr.com/role/ScheduleOfAssetsScheduleOfAssetsHeldAtEndOfYearIIIDetails</Role>
      <ShortName>Schedule of Assets (Schedule of Assets (Held at End of Year III)) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.firstbankpr.com/role/ScheduleOfAssets</ParentRole>
      <Position>23</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="11-K" isDefinitelyFs="true" isUsgaap="true" original="fbp-20251231.htm">fbp-20251231.htm</File>
    <File>fbp-20251231.xsd</File>
    <File>fbp-20251231_cal.xml</File>
    <File>fbp-20251231_def.xml</File>
    <File>fbp-20251231_lab.xml</File>
    <File>fbp-20251231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>fbp-20251231p1i0.gif</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="234">http://fasb.org/us-gaap-ebp/2025</BaseTaxonomy>
    <BaseTaxonomy items="1">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="6">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
