PROPERTY, PLANT AND EQUIPMENT (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 25, 2017	Jun. 26, 2016	Jun. 25, 2017	Jun. 26, 2016	Dec. 25, 2016
Property, Plant and Equipment [Abstract]
Depreciation	$ 52,000	$ 43,500	$ 97,800	$ 81,900
Payments for capital projects			174,150	93,978
Transfer of property, plant and equipment			139,600	128,100
Proceeds from property disposals	2,000	7,500	1,466	8,097
Net gain (loss) on property disposals	900	$ 6,600	768	$ 6,755
Assets held for sale	5,542		5,542		$ 5,259
Impairment			3,500
Idled assets, carrying amount	52,700		52,700
Idled assets, depreciable value	174,000		174,000
Idled assets, accumulated depreciation	$ 121,300		$ 121,300