Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Income Taxes [Line Items]
Federal tax rate	21.00%	21.00%	21.00%
Effective tax rate	27.30%	23.30%	23.60%
Unrecognized tax benefits that would impact effective tax rate	$ 1.7	$ 1.8	$ 1.7
Earliest Tax Year [Member] \| PENNSYLVANIA
Income Taxes [Line Items]
Open Tax Year	2016
Latest Tax Year [Member] \| PENNSYLVANIA
Income Taxes [Line Items]
Open Tax Year	2020
Federal [Member]
Income Taxes [Line Items]
Income Taxes Paid	$ 33.5	11.3	4.5
State [Member]
Income Taxes [Line Items]
Income Taxes Paid	8.8	$ 2.8	$ 2.1
Operating Loss Carryforwards	$ 72.0

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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Tax year that remains open to examination under enacted tax laws, in CCYY format.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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Income Taxes [Line Items]

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