Income Taxes Income Taxes - Tax Carryforwards (Details) - Internal Revenue Service (IRS) [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 29, 2020	Dec. 27, 2020	Dec. 29, 2019
Income Tax Contingency [Line Items]
General business tax credit carryforwards			$ 128.6
Minimum [Member]
Income Tax Contingency [Line Items]
General business tax credits, estimated period of use	7 years
Minimum [Member] | Forecast [Member]
Income Tax Contingency [Line Items]
General business tax credits, estimated future tax credits		$ 50.0
Maximum [Member]
Income Tax Contingency [Line Items]
General business tax credits, estimated period of use	9 years
Maximum [Member] | Forecast [Member]
Income Tax Contingency [Line Items]
General business tax credits, estimated future tax credits		$ 80.0