Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 636,914	$ 628,846
Accumulated depreciation	(417,351)	(401,023)
Property, plant and equipment, net	219,563	227,823
Land and land improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	10,585	10,585
Building and building improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	84,552	82,142
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	514,161	516,443
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	8,170	8,570
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 19,446	$ 11,106