Supplemental Stockholders' Equity Information Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2016	Jun. 28, 2015	Jun. 26, 2016	Jun. 28, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ 2,477	$ 4,256	$ 5,580	$ 20,576
Accumulated Defined Benefit Plans Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense			5,214
Accumulated Defined Benefit Plans Adjustment | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassification, before tax			13,103
Income tax expense			5,214
Total reclassification, net of tax			7,889
Selling, General and Administrative Expenses | Accumulated Defined Benefit Plans Adjustment | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service credit			(5,192)
Amortization of actuarial loss			$ 18,295