PROPERTY, PLANT AND EQUIPMENT (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2016	Jun. 28, 2015	Jun. 26, 2016	Jun. 28, 2015	Dec. 27, 2015
Property, Plant and Equipment [Abstract]
Depreciation	$ 43,500	$ 36,600	$ 81,900	$ 70,600
Payments for capital projects			93,978	87,694
Transfer of property, plant and equipment			128,100	74,200
Proceeds from property disposals	7,500	1,200	8,097	2,115
Net gain (loss) on property disposals	6,600	$ 400	6,755	$ 1,331
Assets held for sale	6,549		6,549		$ 6,555
Idled assets, carrying amount	65,500		65,500
Idled assets, depreciable value	195,400		195,400
Idled assets, accumulated depreciation	$ 129,900		$ 129,900