Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Pension Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Service cost	$ 0	$ 24
Interest cost	1,467	1,493
Expected return on plan assets	(2,076)	(2,289)
Amortization of net (gain) loss	530	349
Net periodic benefit income	(79)	(423)
Other Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Service cost	64	60
Interest cost	153	148
Amortization of prior service credit	(226)	(226)
Amortization of net (gain) loss	(8)	18
Net periodic benefit income	$ (17)	$ 0