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], Current liabilities [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2014
Commodity Contracts [Member] | Current liabilities [Member]
Liability Derivatives
Fair Value of Derivative Instruments	$ 1.5