Asset Held for Sale and Discontinued Operations (Phantom) (Details) (Blackfoot, USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Blackfoot
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated Depreciation	$ 4.6

Disposal Group, Including Discontinued Operation, Accumulated Depreciation

No definition available.

Name:	frp_DisposalGroupIncludingDiscontinuedOperationAccumulatedDepreciation
Namespace Prefix:	frp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant