Summary of Significant Accounting Policies - Amount of loss recognized in other comprehensive income, net of taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 29, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Notional amount	$ 1,000.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2.3	$ 3.1
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(0.5)	(8.0)
Accumulated other comprehensive Income loss Hedge	(0.9)	(2.7)	$ 2.2
Interest Rate Swap [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.0	0.0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(27.6)	3.5	0.0
Accumulated other comprehensive Income loss Hedge	(24.1)	3.5	$ 0.0
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 0.0	$ 0.0