Employee Stock Award and Benefit Plans - Stock Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Share-based Payment Arrangement [Abstract]
Share-based payment arrangement, amount capitalized	$ 6.7	$ 4.8
Employee service share-based compensation, allocation of Recognized period costs, amortized amount	5.3	4.8
Employee service share-based compensation, allocation of recognized period costs, remaining	2.8	1.5
Share-based payment arrangement, nonvested award, cost not yet recognized, amount	$ 37.7
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition	1 year 6 months
Discrete tax benefit, provision income taxes related to share-based compensation	$ 0.9	$ 2.5	$ 12.8