Supplemental Stockholders' Equity Information - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2021	Jun. 28, 2020	Jun. 27, 2021	Jun. 28, 2020
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	$ 1,355,462	$ 1,193,574	$ 1,328,111	$ 1,173,863
Income tax (benefit)/expense	1,756	2,848	2,465	4,763
Other comprehensive income, net of tax	4,809	8,077	6,737	13,020
Balance, end of period	1,418,787	1,231,031	1,418,787	1,231,031
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period			8,386
Other comprehensive income before reclassifications, before tax			(1,767)
Amounts reclassified from accumulated other comprehensive loss, before tax			0
Income tax (benefit)/expense			(473)
Other comprehensive income, net of tax			(1,294)
Balance, end of period	7,092		7,092
Funded Status of Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period			(421,698)
Other comprehensive income before reclassifications, before tax			0
Amounts reclassified from accumulated other comprehensive loss, before tax			12,815
Income tax (benefit)/expense			3,432
Other comprehensive income, net of tax			9,383
Balance, end of period	(412,315)		(412,315)
Net Unrealized Gain on Available-For-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period			3,131
Other comprehensive income before reclassifications, before tax			(1,846)
Amounts reclassified from accumulated other comprehensive loss, before tax			0
Income tax (benefit)/expense			(494)
Other comprehensive income, net of tax			(1,352)
Balance, end of period	1,779		1,779
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance, beginning of period	(408,253)	(490,033)	(410,181)	(494,976)
Other comprehensive income before reclassifications, before tax			(3,613)
Amounts reclassified from accumulated other comprehensive loss, before tax			12,815
Income tax (benefit)/expense			2,465
Other comprehensive income, net of tax	4,809	8,077	6,737	13,020
Balance, end of period	$ (403,444)	$ (481,956)	$ (403,444)	$ (481,956)