Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2020
Operating loss carryforwards disclosures
Deferred income taxes	$ (3.1)	$ (33.6)	$ (0.4)
Deferred tax assets, operating loss carryforwards, subject to expiration	338.6
Amount of future tax benefits	11.0
Increase (decrease) in valuation allowance	3.9
Operating loss carryforward, income tax benefit	0.0
Unrecognized tax benefits	0.0	$ 0.0	$ 0.0
United Kingdom
Operating loss carryforwards disclosures
Deferred tax assets, operating loss carryforwards, not subject to expiration	9.1
Deferred income taxes	3.5
Singapore
Operating loss carryforwards disclosures
Deferred tax assets, operating loss carryforwards, not subject to expiration	1.7
Deferred income taxes	0.0
Operating Loss Carryforward, Expired
Operating loss carryforwards disclosures
Increase (decrease) in valuation allowance	(4.0)
Operating Losses, Jurisdictions Without Tax Benefits
Operating loss carryforwards disclosures
Increase (decrease) in valuation allowance	$ 0.1