DERIVATIVE FINANCIAL INSTRUMENTS (Schedule of Outstanding Derivative Instruments and Cash Collateral) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 25, 2016	Dec. 27, 2015
Fair values:
Cash collateral posted with brokers	$ 15,280	$ 9,381
Corn [Member]
Derivatives Coverage:
Derivatives coverage (as a percentage)	3.90%	7.00%
Period through which stated percent of needs are covered:
Maturity date	May 31, 2017	Mar. 31, 2017
Soybean Meal [Member]
Derivatives Coverage:
Derivatives coverage (as a percentage)	10.50%	4.10%
Period through which stated percent of needs are covered:
Maturity date	Jul. 30, 2017	Jul. 31, 2016
Commodity [Member]
Fair values:
Derivative assets, gross	$ 5,543	$ 1,677
Derivative liabilities, gross	$ (13,313)	$ (5,436)