Deferred Client Conversion and Start-Up Costs - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred client conversion and start-up costs	$ 882.0		$ 892.1
Deferred client conversion and start-up costs	875.2		884.5
Other start-up costs	6.8		$ 7.6
Amortization of deferred sales commissions costs	$ 36.6	$ 32.2