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Income Taxes (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Mar. 30, 2018 | Mar. 31, 2017 | Mar. 30, 2018 | Mar. 31, 2017 | Sep. 29, 2018
Income Tax Contingency [Line Items] |  |  |  |  |
Measurement period adjustments on effective tax rate |  |  | 1 year |  |
Provisional remeasurement income tax expense discrete benefit, deferred tax balances | $ (40.6) |  | $ 16.9 |  |
Estimated valuation allowance |  |  | $ 52.5 |  |
Effective income tax rate (percent) | 57.50% | 27.00% | 66.80% | 28.10% |
Net discrete charge of tax cuts and jobs act |  |  | $ 69.4 |  |
Decrease in unrecognized tax benefits | $ 6.7 |  | $ 6.7 |  |
Scenario, Forecast |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |
Federal statutory tax rate, percent |  |  |  |  | 24.60%

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- Definition Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (d)(3) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + Details
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