Leases - Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 12.4	$ 14.4
Short-term lease cost	2.9	0.0
Variable lease cost	0.2	0.4
Sublease income	(0.7)	0.0
Total lease cost	14.8	14.8	$ 16.1
Operating cash flow payments from operating leases	13.1	14.2
Non-cash ROU assets obtained in exchange for lease obligations	$ 2.0	$ 19.4
Weighted-average remaining lease term - operating leases	8 years 4 months 24 days	8 years 1 month 6 days
Weighted-average discount rate - operating leases	4.00%	3.90%