Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Pension Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Service cost	$ 0	$ 0
Interest cost	858	1,467
Expected return on plan assets	(1,495)	(2,076)
Amortization of net gain	460	530
Net periodic benefit income	(177)	(79)
Other Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Service cost	61	64
Interest cost	109	153
Amortization of prior service credit	(226)	(226)
Amortization of net gain	(53)	(8)
Net periodic benefit income	$ (109)	$ (17)