Commitments and Contingencies (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Jan. 09, 2015
Capital Addition Purchase Commitments [Member]
Long-term Purchase Commitment [Line Items]
Purchase commitments	$ 1
Corn [Member]
Long-term Purchase Commitment [Line Items]
Purchase commitments	43
Natural Gas [Member]
Long-term Purchase Commitment [Line Items]
Purchase commitments	13
Flour [Member]
Long-term Purchase Commitment [Line Items]
Purchase commitments	6
Subsequent Event [Member] | Dryers [Member]
Long-term Purchase Commitment [Line Items]
Purchase commitment, remaining minimum amount committed		$ 5,439