Leases - Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Leases [Abstract]
Operating lease cost	$ 14.4
Variable lease cost	0.4
Total lease cost	14.8	$ 16.1	$ 13.4
Operating cash flow payments from operating leases	14.2
Non-cash ROU assets obtained in exchange for lease obligations	$ 19.4
Weighted-average remaining lease term - operating leases	8 years 1 month 6 days
Weighted-average discount rate - operating leases	3.90%