Postretirement Benefits Amounts Recognized in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ 913	$ 1,265
Net gain	210	(1,826)
Accumulated other comprehensive income	622	(646)
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	(340)
Other Comprehensive Income (Loss) [Member]
Defined Benefit Plan Disclosure [Line Items]
Deferred Tax Assets, Other Comprehensive Loss	$ (501)	$ (85)

Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses in other comprehensive income.

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Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount of cost (credit) included in accumulated other comprehensive (income) loss expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position.

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