Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2018
Operating Loss Carryforwards [Line Items]
Income tax expense (benefit)	$ 16.9	$ 7.5	$ 35.3	$ (39.1)
Income tax expense as a percent of pre-tax income (loss)	24.90%	19.90%	23.00%	(36.70%)
Tax benefit due to changes in prior year tax positions			$ 1.8
Tax Cuts and Jobs Act of 2017, provisional tax expense for transition tax		$ 0.2		$ 5.3	$ 5.0
Tax Cuts and Jobs Act of 2017, provisional net benefit for re-measurement of deferred tax assets and liabilities				74.2	74.6
Tax Cuts and Jobs Act of 2017, tax expense (benefit) for transition tax	$ 0.2				(4.7)
Discrete tax charge due to re-measurement of deferred tax assets and liabilities	$ 0.2
Tax Cuts and Jobs Act of 2017, income tax benefit		(1.6)		67.6
Tax Cuts and Jobs Act of 2017, tax benefit of deferred tax assets and liabilities re-measurement		0.9
Indefinitely reinvested foreign earnings					$ 100.6
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Income tax expense (benefit)		$ 0.9		$ 1.3