Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income tax provision	$ 9.3	$ 10.6	$ 56.4	$ 45.8
Earnings before income taxes	$ 21.4	$ 65.5	$ 140.3	$ 199.9
Effective tax rate	42.90%	16.20%	40.20%	22.90%
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Federal statutory income tax rate			35.00%
Newly enacted federal tax rate	21.00%		21.00%
Fiscal 2018 blended tax rate	24.50%		24.50%
Income tax provision	$ 9.3	$ 10.6	$ 56.4	$ 45.8
US Tax Act
Income Tax Disclosure [Abstract]
Income tax provision			17.4
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Transition tax, repatriation of foreign earnings, provision			94.2
Tax benefit, re-rate of DTAs for Tax Act			(76.8)
Income tax provision			$ 17.4