Postretirement Benefits Amounts Recognized in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 30, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ 1,265	$ 1,617
Net gain	(1,826)	(2,928)
Deferred Tax Assets, Other Comprehensive Loss	140	326
Accumulated other comprehensive income	(646)	(1,210)
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization, Next Fiscal Year	113
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Amortization, Next Fiscal Year	(350)
Other Comprehensive Income (Loss) [Member]
Defined Benefit Plan Disclosure [Line Items]
Deferred Tax Assets, Other Comprehensive Loss	$ (85)	$ 101