LOAN PORTFOLIO - Activity for Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Impaired Loans:
Balance at beginning of period	$ 919,112	$ 1,465,294
Loans determined impaired during the period	306,390	280,860
Charge-offs	(106,154)	(307,428)
Impaired Loans Sold	(4,500)fbp_ImpairedLoansSold	(201,409)fbp_ImpairedLoansSold
Impaired Loans Transferred to Held For Sale	0	(145,415)
Increases to impaired loans (disbursements)	5,028	6,624
Foreclosures	(40,582)fbp_ForeclosuresOfImpairedLoans	(45,094)fbp_ForeclosuresOfImpairedLoans
Loans no longer considered impaired	(22,333)fbp_ImpairedLoansRemoved	(49,299)fbp_ImpairedLoansRemoved
Paid in full or partial payments	(111,554)	(85,021)
Balance at end of period	$ 945,407	$ 919,112

Amount of direct write-downs of financing receivables charged against the allowance related to impaired loans.

No definition available.

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

- Definition

Amount of real estate investments acquired through foreclosure during the period related to impaired loans.

+ References

No definition available.

+ Details

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

- Details

Name:	fbp_ImpairedCommercialLoanStatisticAbstract
Namespace Prefix:	fbp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of loans determined to be impaired during the period.

+ References

No definition available.

+ Details

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

- Definition

Disbursements during the period on existing commitments of Impaired loans.

+ References

No definition available.

+ Details

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

- Definition

Principal repayments related to Impaired Loans.

+ References

No definition available.

+ Details

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

- Definition

Amount of loans no longer reported as Impaired loans.

+ References

No definition available.

+ Details

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

- Definition

Impaired loans sold during the period.

+ References

No definition available.

+ Details

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

- Definition

Imapired loans transferred to loans held for sale during the period.

+ References

No definition available.

+ Details

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

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953550-111524

+ Details

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