Financial Contracts Hedging Commodity Risks (Detail) - Cash Flow Hedging $ in Thousands	Dec. 31, 2016 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Notional Amount	$ 32,534
Wheat Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Notional Amount	26,353
Soybean Oil Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Notional Amount	2,834
Natural Gas Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Aggregate Notional Amount	$ 3,347