Leases - Summary of lease cost (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022
Leases [Abstract]
Operating lease cost	$ 2.8	$ 2.5
Short-term lease cost	0.9	0.8
Variable lease cost	0.0	0.2
Sublease income	(0.2)	(0.2)
Total lease cost	3.5	3.3
Operating cash flow payments from operating leases	3.1	2.8
Non-cash ROU assets obtained in exchange for lease obligations	$ 0.2	$ 0.2
Weighted-average remaining lease term - operating leases	8 years 4 months 24 days		8 years 6 months
Weighted-average discount rate - operating leases	3.70%		3.70%