Pension and Other Postretirement Obligations - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 03, 2021	Sep. 27, 2020	Oct. 03, 2021	Sep. 27, 2020
Pension Obligations
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 941	$ 885	$ 2,982	$ 2,709
Interest cost	1,914	2,493	5,617	7,240
Expected return on plan assets	(4,081)	(4,091)	(12,276)	(12,035)
Amortization of prior service cost	27	47	83	136
Actuarial losses (gains)	971	688	2,926	2,038
Net periodic benefit cost (income)	(228)	22	(668)	88
Other Postretirement Obligations
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	8	26	24
Interest cost	182	202	545	599
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	0	0	0	0
Actuarial losses (gains)	(5)	(19)	(16)	(57)
Net periodic benefit cost (income)	$ 185	$ 191	$ 555	$ 566