Supplemental Stockholders' Equity Information Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 26, 2017	Mar. 27, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 25, 2016	$ (479,816)
Income tax expense	3,531	$ 3,103
Other comprehensive income, net of tax	5,565	5,091
Balance as of March 26, 2017	(474,251)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 25, 2016	(1,822)
Other comprehensive income before reclassifications, before tax	2,175
Amounts reclassified from accumulated other comprehensive loss, before tax	0
Income tax expense	795
Other comprehensive income, net of tax	1,380
Balance as of March 26, 2017	(442)
Funded Status of Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 25, 2016	(477,994)
Other comprehensive income before reclassifications, before tax	0
Amounts reclassified from accumulated other comprehensive loss, before tax	6,921
Income tax expense	2,736
Other comprehensive income, net of tax	4,185
Balance as of March 26, 2017	(473,809)
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance as of December 25, 2016	(479,816)
Other comprehensive income before reclassifications, before tax	2,175
Amounts reclassified from accumulated other comprehensive loss, before tax	6,921
Income tax expense	3,531
Other comprehensive income, net of tax	5,565	$ 5,091
Balance as of March 26, 2017	$ (474,251)