INTEREST AND DIVIDEND ON INVESTMENTS- Components of interest and dividend income on investments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Components of interest and dividend income on investments [Abstract]
Interest income on investment securities and money market investments	$ 53,604	$ 54,095	$ 45,694
Dividends on FHLB stock	1,169fbp_DividendsOnFederalHomeLoanBankStock	1,359fbp_DividendsOnFederalHomeLoanBankStock	1,427fbp_DividendsOnFederalHomeLoanBankStock
Total interest and dividends on investments	$ 54,773us-gaap_InterestAndOtherIncome	$ 55,454us-gaap_InterestAndOtherIncome	$ 47,121us-gaap_InterestAndOtherIncome

The amount of interest income and other income recognized during the period. Included in this element is interest derived from investments in debt securities, cash and cash equivalents, and other investments which reflect the time value of money or transactions in which the payments are for the use or forbearance of money and other income from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business).

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration