Inventories - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Inventory Disclosure [Abstract]
Provision for excess and obsolete inventories, excluding write-down to net realizable value	$ 22.6	$ 28.5	$ 9.4
Provision to write-down to net realizable value	$ (4.2)	$ 4.4	$ 0.0