Losses and Loss Adjustment Expenses Incurred and Paid - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Insurance [Abstract]
Percentage of physical damage component on ending liability for unpaid losses and loss adjustment expenses	5.00%
Unpaid losses and loss adjustment expenses	$ 2,271	$ (30,636)	$ (845)

Amount of expense (gain) for claims incurred in prior reporting periods and related claims settlement costs.

No definition available.

Name:	fac_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentGainLosses
Namespace Prefix:	fac_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration