Deferred Client Conversion and Start-up Costs - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred client conversion and start-up costs	$ 930.6		$ 930.6		$ 937.0
Deferred client conversion and start-up costs	921.4		921.4		925.4
Other start-up costs	9.2		9.2		$ 11.5
Amortization of deferred sales commissions and set-up costs	$ 32.2	$ 24.1	$ 64.4	$ 48.0