Employee Benefit Plans (Components of Net Periodic Benefit Cost (Credit)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 05, 2020	Mar. 31, 2019
Defined Benefit Pension Benefits [Member]
Components of net periodic benefit cost (credit)
Service cost	$ 1,907	$ 1,633
Interest cost	3,144	4,159
Expected return on plan assets	(5,384)	(6,176)
Amortization of prior service	0	(39)
Net periodic benefit cost (credit)	(333)	(423)
Postretirement Medical Benefits [Member]
Components of net periodic benefit cost (credit)
Service cost	18	22
Interest cost	24	29
Expected return on plan assets	(347)	(294)
Amortization of prior service	0	0
Net periodic benefit cost (credit)	(305)	$ (243)
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 2,100