Derivative Instruments and Hedging Activities - Location and Fair Value Amounts of Derivative Instruments Not Qualifying as Hedging Instruments Reported in Balance Sheet (Detail) (Commodity Contracts [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2014
Asset Derivatives
Fair Value of Derivative Instruments	$ 1.4
Current assets [Member]
Asset Derivatives
Fair Value of Derivative Instruments	1.2
Long-term assets [Member]
Asset Derivatives
Fair Value of Derivative Instruments	$ 0.2