Accrued Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jun. 30, 2017
Accrued Liabilities, Current [Abstract]
Accrued compensation and benefits	$ 83.3	$ 59.1
Accrued postretirement benefits	15.4	15.5
Accrued interest expense	10.4	11.2
Deferred revenue	10.4	9.8
Accrued pension liabilities	3.3	3.3
Accrued income taxes	1.4	5.1
Derivative financial instruments	0.0	13.1
Other	24.4	22.8
Total accrued liabilities	$ 148.6	$ 139.9