Derivative Financial Instruments and Fair Value Measurements - Derivatives Recorded at Fair Value in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 2,416	$ 317
Derivative Liability, Fair Value, Gross Liability	12	10,713
Current | Not Designated As Hedging Instruments | Commodities Contracts
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2,416	317
Derivative Liability, Fair Value, Gross Liability	12	10,023
Non-current | Not Designated As Hedging Instruments | Commodities Contracts
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	$ 0	$ 690