FIXED ASSETS (Schedule Of Fixed Assets) (Details) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Gross fixed assets	$ 928,514	$ 901,422
Accumulated depreciation	(431,101)	(399,472)
PP&E Net including assets held for sale	497,413	501,950
Fixed assets, net	497,064	501,884
Land and land improvements
Property, Plant and Equipment [Line Items]
Gross fixed assets	38,002	37,835
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Gross fixed assets	191,585	192,874
Machinery, equipment and computer systems
Property, Plant and Equipment [Line Items]
Gross fixed assets	618,016	607,869
Trucks, trailers and automobiles
Property, Plant and Equipment [Line Items]
Gross fixed assets	32,595	32,723
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Gross fixed assets	4,559	4,720
Construction in progress
Property, Plant and Equipment [Line Items]
Gross fixed assets	41,032	22,098
Capital leases
Property, Plant and Equipment [Line Items]
Gross fixed assets	2,725	3,303
Fixed assets held for sale
Property, Plant and Equipment [Line Items]
Fixed assets held for sale	$ (349)	$ (66)