Supplemental Stockholders' Equity Information -Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2018	Mar. 26, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	$ 897,363	$ 844,244
Income tax expense	2,820	3,531
Other comprehensive income, net of tax	7,842	5,565
AOCI reclassification to Retained Earnings	(94,135)
Balance, end of period	958,077	856,963
Curtailment recorded	2,600
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	6,328
Other comprehensive income before reclassifications, before tax	2,273
Amounts reclassified from accumulated other comprehensive loss, before tax	0
Income tax expense	602
Other comprehensive income, net of tax	1,671
AOCI reclassification to Retained Earnings	1,576
Balance, end of period	9,575
Funded Status of Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	(427,819)
Other comprehensive income before reclassifications, before tax	2,597
Amounts reclassified from accumulated other comprehensive loss, before tax	7,163
Income tax expense	2,580
Other comprehensive income, net of tax	7,180
AOCI reclassification to Retained Earnings	(95,378)
Balance, end of period	(516,017)
Net unrealized Loss on available-for-sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	(1,538)
Other comprehensive income before reclassifications, before tax	(1,371)
Amounts reclassified from accumulated other comprehensive loss, before tax	0
Income tax expense	(362)
Other comprehensive income, net of tax	(1,009)
AOCI reclassification to Retained Earnings	(333)
Balance, end of period	(2,880)
Parent
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	897,279	847,815
Other comprehensive income before reclassifications, before tax	3,499
Amounts reclassified from accumulated other comprehensive loss, before tax	7,163
Income tax expense	2,820
Other comprehensive income, net of tax	7,842	5,565
AOCI reclassification to Retained Earnings	(94,135)
Balance, end of period	957,991	$ 860,600
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	(423,029)
Balance, end of period	$ (509,322)