Additional loan interest income.

No definition available.

Name:	fbp_AdditionalLoanInterestIncome
Namespace Prefix:	fbp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Discount accretion loan interest income.

+ References

No definition available.

+ Details

Name:	fbp_DiscountAccretionLoanInterestIncome
Namespace Prefix:	fbp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Refers to payments that exceeded initial carrying values of purchased impaired laons.

+ References

No definition available.

+ Details

Name:	fbp_PaymentsThatExceededInitialCarryingAmountOnPurchasedImpairedLoans
Namespace Prefix:	fbp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

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

- Definition

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL49126937-111524

+ Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_FixedRateResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=fbp_PurchasedImpairedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=fbp_CarolinaBankHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans and Asset Quality Information (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Oct. 01, 2017	Mar. 03, 2017
Recorded loans with a fair value				$ 606,200	$ 497,500
Payments that exceeded the initial carrying amount on purchased impaired loans	$ 190	$ 564
Discount accretion loan interest income - purchased impaired loans paid off	149	558
Additional loan interest income - purchased impaired loans paid off	41	6
Real estate - mortgage - residential (1-4 family) first mortgages [Member]
Nonaccrual loans in process of foreclosure	400		$ 800
Purchased Impaired Loans [Member]
Recorded loans with a fair value				$ 9,900	$ 19,300
Purchased Impaired Loans [Member] \| Carolina Bank Holdings, Inc. [Member] \| 90 Days or More Past Due [Member]
Recorded loans with a fair value	$ 500	$ 400	$ 600