Derivative Financial Instruments and Fair Value Measurements - Derivatives Recorded at Fair Value in Consolidated Balance Sheets (Detail) - Not Designated As Hedging Instruments - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 455	$ 2
Derivative Liabilities	5,272	4,392
Current | Commodities Contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	455	2
Derivative Liabilities	$ 5,272	$ 4,392