Significant Accounting Policies - New Accounting Pronouncements (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2017	Sep. 29, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Expected tax benefit increase with comparable increase in deferred tax asset	$ 6.1
New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase to the opening balance of retained earnings, net	$ 19.8
Decrease in income tax provision due to adoption of ASU No. 2016-9		$ 12.8
Increase to weighted average diluted shares outstanding		71,010