DERIVATIVE FINANCIAL INSTRUMENTS (Schedule of Outstanding Derivative Instruments and Cash Collateral) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 24, 2017	Dec. 25, 2016
Fair values:
Cash collateral posted with brokers	$ 4,841	$ 4,979
Corn
Derivatives Coverage:
Derivatives coverage (as a percentage)	0.70%	2.30%
Period through which stated percent of needs are covered:
Maturity date	Sep. 30, 2018	Sep. 30, 2018
Soybean meal
Derivatives Coverage:
Derivatives coverage (as a percentage)	0.20%	0.30%
Period through which stated percent of needs are covered:
Maturity date	Aug. 31, 2018	Jul. 31, 2017
Commodity
Fair values:
Derivative assets, gross	$ 3,368	$ 5,439
Derivative liabilities, gross	(3,782)	(6,827)
Foreign currency
Fair values:
Derivative assets, gross	586	516
Derivative liabilities, gross	$ (387)	$ 153