Pension and Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2018	Apr. 02, 2017	Dec. 31, 2017
Defined Benefit Plan Plan Amendment [Abstract]
Defined Benefit Plan Accumulated Benefit Obligation Increase For Plan Amendment	$ 35,192
Date of resolution approval plan termination	February 2018
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 685	$ 952
Interest cost	4,016	4,725
Expected return on assets	(5,205)	(6,281)
Net amortization and deferrals	2,977	2,694
Net periodic benefit cost	2,473	2,090
Contributions to defined benefit pension plans	280
Expected fiscal year defined benefit pension plan contributions	$ 1,300
Weighted average discount rate	3.20%		3.70%
Postretirement [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 188	172
Interest cost	292	295
Expected return on assets	0	0
Net amortization and deferrals	42	0
Net periodic benefit cost	$ 522	$ 467