Income Taxes (Details) - USD ($) $ in Millions			3 Months Ended
	Dec. 22, 2017	Dec. 21, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Corporate tax rate (as a percentage)	21.00%	35.00%
Blended effective tax rate (as a percentage)			24.53%
Tax benefit relating to adjustment in corporate tax rate			$ (3.5)
Tax benefit relating to adjustment to ATM credits	$ (1.7)
Expected effective tax rate (as a percent)			(5.80%)
Change in tax rate, income tax benefit			$ (5.2)