Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Contingency [Line Items]
Provisional income tax benefit			$ 4.5
Income tax expense	$ 9.7	$ 5.9	15.6	$ 4.0
Pre-tax income	27.2	$ 16.1	60.0	$ 4.8
Valuation allowance	3.2		3.2			$ 3.1
Increase in uncertain tax positions			1.4
Interest and penalties	3.8		3.8			$ 1.8
Reductions due to the statute of limitations expiration			$ (0.4)
Foreign operations
Income Tax Contingency [Line Items]
Increase in uncertain tax positions	2.3
Increase of deferred tax assets related to income tax-related uncertainties	$ 1.8
Forecast
Income Tax Contingency [Line Items]
Federal income tax rate					24.50%