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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.

No definition available.

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Amount before allowance of commercial construction loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5066-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(a)(2))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_LoansReceivableCommercialConstruction
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount before allowance of commercial loans to develop land for sale or construction thereon. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

Name:	us-gaap_LoansReceivableCommercialDevelopment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount before allowance of mortgage loans on existing land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5066-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(a)(3))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Data Type:	xbrli:monetaryItemType
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Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=fbp_ResidentialConstructionFinancingReceivableMember
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Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=fbp_CommercialRealEstateConstructionPortfolioSegmentMember
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Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_DoubtfulMember
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Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_UnlikelyToBeCollectedFinancingReceivableMember
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