Annual report pursuant to Section 13 and 15(d)

Quarterly Operating Results (Unaudited) - Summary of Quarterly Results of Operations (Parenthetical) (Detail)

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Quarterly Operating Results (Unaudited) - Summary of Quarterly Results of Operations (Parenthetical) (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Quarterly Financial Information Disclosure [Abstract]            
Loss on contract recognized $ 1.6us-gaap_LossOnContracts $ 0.3us-gaap_LossOnContracts $ 4.7us-gaap_LossOnContracts $ 18.2us-gaap_LossOnContracts $ 10.9us-gaap_LossOnContracts $ 0.6us-gaap_LossOnContracts
Impairment charge of asset held for sale 3.2us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf          
Increase in allowance for doubtful accounts $ 3.6us-gaap_AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease