Stockholders' Equity And Stock-Based Compensation Stockholders' Equity And Stock- Based Compensation - Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions									12 Months Ended
		Dec. 04, 2019	Nov. 14, 2019	Aug. 20, 2019	Aug. 01, 2019	May 22, 2019	May 01, 2019	Jan. 30, 2019	Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
Dividends Payable [Line Items]
Cash dividend declared per common share					$ 0.19		$ 0.19	$ 0.19	$ 0.79	$ 0.67	$ 0.58
Dividends				$ 19.2		$ 19.3		$ 19.5
Subsequent Event [Member]
Dividends Payable [Line Items]
Cash dividend declared per common share	[1]		$ 0.22
Dividends	[1]	$ 22.0

[1] The dividend payment amount is estimated based on the number of shares of our Class A and Class B common stock that we estimate will be outstanding as of the Record Date.