Accounting Policies (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($)
Accounting Policies [Abstract]
Reclassified amount between Accumulated Other Comprehensive Income and Retained Earnings	$ 700

Reclassified amount between accumulated other comprehensive income and retained earnings.

No definition available.

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