Changes in Accumulated Other Comprehensive Income/(Loss) by Component - Summary of Changes in Accumulated Balances for Each Component of Accumulated Other Comprehensive Income/(Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Balance	$ 1,125.4	$ 1,122.6	$ 1,127.5	$ 1,094.3
Other comprehensive income/(loss) before reclassifications	0.1	5.1	2.9	(10.7)
Amounts reclassified from accumulated other comprehensive income/(loss)	0.4	0.0	1.1	0.0
Balance	1,202.5	1,265.6	1,202.5	1,265.6
Foreign Currency Translation
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Balance	(55.5)	(59.3)	(58.3)
Other comprehensive income/(loss) before reclassifications	0.1	4.9	2.9	(11.2)
Amounts reclassified from accumulated other comprehensive income/(loss)	0.0	0.0	0.0	0.0
Balance	(55.4)	(54.5)	(55.4)	(54.5)
Pension and Post- Retirement Liabilities
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Balance	(12.2)	(9.8)	(12.9)
Other comprehensive income/(loss) before reclassifications	0.0	0.2	0.0	0.6
Amounts reclassified from accumulated other comprehensive income/(loss)	0.4	0.0	1.1	0.0
Balance	(11.9)	(9.7)	(11.9)	(9.7)
Accumulated Other Comprehensive Income (Loss)
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Balance	(67.7)	(69.2)	(71.2)	(51.9)
Balance	$ (67.2)	$ (64.1)	$ (67.2)	$ (64.1)