Discontinued Operations - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended		12 Months Ended
	Dec. 19, 2013	Sep. 27, 2012	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of ownership interests, Disposal Group		$ 227.5
Percentage of ownership in TCAE by TPS GO		96.06%
Foreign tax credits			22.9
Awarded damages	21.1
Prime interest rate	2.00%
Reimburse costs incurred	7.5
TPS GO [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of ownership interests, Disposal Group		12.5
TPS SJI [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of ownership interests, Disposal Group		213.5
TGS [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of ownership interests, Disposal Group		$ 1.5