Derivative Financial Instruments and Fair Value Measurements - Summary of Derivative Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Commodities Contracts - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Assets - Fair Value	$ 2,416	$ 317
Liabilities - Fair Value	12	10,713
Level 2
Derivatives, Fair Value [Line Items]
Assets - Fair Value	2,416	317
Liabilities - Fair Value	$ 12	$ 10,713