OTHER REAL ESTATE OWNED- Additional information (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Other Real Estate And Foreclosed Assets [Abstract]
Transfers From Loans to Other Receivable	$ 22.6	$ 15.0

Amount of foreclosures completed that meet the conditions of ASC 310-40 and are presented as a receivable (other assets) in the statement of financial condition.

No definition available.

Name:	fbp_TransfersFromLoanstoOtherReceivable
Namespace Prefix:	fbp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant