Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jul. 04, 2020	Apr. 04, 2020	Jun. 29, 2019	Mar. 30, 2019	Jul. 04, 2020	Jun. 29, 2019
Cumulative balance of each component of other comprehensive income (loss) and income tax effects [Roll Forward]
Beginning Balance		$ (26,646)			$ (26,646)
Other comprehensive income before reclassifications					(3,041)
Tax effect					0
Other comprehensive income before reclassifications, net of tax					(3,041)
Amounts reclassified out of AOCI					4,442
Tax effect					(1,081)
Amounts reclassified out of AOCI, net of tax					3,361
Net other comprehensive income	$ 21,848	(21,528)	$ 9,007	$ (8,532)	320	$ 475
Ending Balance	(26,326)				(26,326)
Pension and Other Post-Retirement Actuarial Items [Member]
Cumulative balance of each component of other comprehensive income (loss) and income tax effects [Roll Forward]
Beginning Balance		(68,020)			(68,020)
Other comprehensive income before reclassifications					0
Tax effect					0
Other comprehensive income before reclassifications, net of tax					0
Amounts reclassified out of AOCI					4,442
Tax effect					(1,081)
Amounts reclassified out of AOCI, net of tax					3,361
Net other comprehensive income					3,361
Ending Balance	(64,659)				(64,659)
Currency Translation Adjustment [Member]
Cumulative balance of each component of other comprehensive income (loss) and income tax effects [Roll Forward]
Beginning Balance		41,374			41,374
Other comprehensive income before reclassifications					(3,041)
Tax effect					0
Other comprehensive income before reclassifications, net of tax					(3,041)
Amounts reclassified out of AOCI					0
Tax effect					0
Amounts reclassified out of AOCI, net of tax					0
Net other comprehensive income					(3,041)
Ending Balance	38,333				38,333
Accumulated Other Comprehensive Income (Loss) [Member]
Cumulative balance of each component of other comprehensive income (loss) and income tax effects [Roll Forward]
Beginning Balance		(26,646)			(26,646)
Net other comprehensive income	21,848	$ (21,528)	$ 9,007	$ (8,532)
Ending Balance	$ (26,326)				$ (26,326)