Other Comprehensive (Loss) Income - Schedule of Components of Comprehensive Income (Loss) (Details) $ in Thousands, £ in Millions			3 Months Ended				6 Months Ended
	Apr. 06, 2020 USD ($)	Apr. 06, 2020 GBP (£)	Jun. 27, 2020 USD ($)	Mar. 28, 2020 USD ($)	Jun. 29, 2019 USD ($)	Mar. 30, 2019 USD ($)	Jun. 27, 2020 USD ($)	Jun. 29, 2019 USD ($)
Other Comprehensive Income (Loss)
Pre-tax			$ (4,676)		$ (5,691)		$ (19,661)	$ 2,353
Tax			(2,259)		40		(2,265)	11
Total change in other comprehensive income (loss)			(2,417)	$ (14,979)	(5,731)	$ 8,073	(17,396)	2,342
Pension and postretirement liability and reclassification adjustments
Other Comprehensive Income (Loss)
Pre-tax			(13,098)		201		(12,543)	123
Tax			(2,259)		40		(2,265)	11
Total change in other comprehensive income (loss)			(10,839)		161		(10,278)	112
Benefit obligation,unamortized actuarial loss	$ 13,400	£ 10.9
Foreign currency translation adjustment
Other Comprehensive Income (Loss)
Pre-tax			8,422		(5,892)		(7,118)	2,230
Tax			0		0		0	0
Total change in other comprehensive income (loss)			$ 8,422		$ (5,892)		$ (7,118)	$ 2,230