DERIVATIVE FINANCIAL INSTRUMENTS (Schedule of Outstanding Derivative Instruments and Cash Collateral) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 25, 2016
Fair values:
Cash collateral posted with brokers	$ 8,021	$ 4,979
Corn
Derivatives Coverage:
Derivatives Coverage	3.10%	2.30%
Soybean meal
Derivatives Coverage:
Derivatives Coverage	1.70%	0.30%
Commodity
Fair values:
Derivative assets	$ 722	$ 5,439
Derivative liabilities	(3,847)	(6,827)
Foreign currency instruments
Fair values:
Derivative assets	45	516
Derivative liabilities	$ (211)	$ (153)