Accumulated Other Comprehensive Income (Loss) - Activity in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail)	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Equity [Abstract]
Federal and State income tax rate	39.50%	39.50%

Income tax expense benefit combined federal and state effective income tax rate.

No definition available.

Name:	fwv_IncomeTaxExpenseBenefitCombinedFederalAndStateEffectiveIncomeTaxRate
Namespace Prefix:	fwv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration