Derivatives and Fair Value Measurements - Location and Amount of Gains and Losses Reported in Consolidated Statements of Comprehensive Income (Detail) (Derivatives not designated as hedging instruments under ASC 815 [Member], Commodity contracts [Member], Cost of Sales [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Derivatives not designated as hedging instruments under ASC 815 [Member] | Commodity contracts [Member] | Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives, Total	$ 0.2	$ (0.3)