Supplemental Stockholders' Equity Information Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 27, 2015			$ (509,094)
Income tax expense	$ 2,912	$ 3,635	8,492	$ 24,211
Other comprehensive income, net of tax	4,244	$ 5,049	13,273	36,333
Balance as of September 25, 2016	(495,821)		(495,821)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 27, 2015			17
Other comprehensive income before reclassifications, before tax			2,110
Amounts reclassified from accumulated other comprehensive loss, before tax			0
Income tax expense			671
Other comprehensive income, net of tax			1,439
Balance as of September 25, 2016	1,456		1,456
Funded Status of Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 27, 2015			(509,111)
Other comprehensive income before reclassifications, before tax			0
Amounts reclassified from accumulated other comprehensive loss, before tax			19,655
Income tax expense			7,821
Other comprehensive income, net of tax			11,834
Balance as of September 25, 2016	(497,277)		(497,277)
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 27, 2015			(509,094)
Other comprehensive income before reclassifications, before tax			2,110
Amounts reclassified from accumulated other comprehensive loss, before tax			19,655
Income tax expense			8,492
Other comprehensive income, net of tax			13,273	$ 36,282
Balance as of September 25, 2016	$ (495,821)		$ (495,821)