Service Revenue (Summary of Changes in Deferred Revenue Related to Material Rights Performance Obligations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 29, 2024	Feb. 28, 2023	Feb. 29, 2024	Feb. 28, 2023
Revenue from Contract with Customer [Abstract]
Balance, beginning of period	$ 69.8	$ 55.2	$ 62.0	$ 48.9
Deferral of revenue	12.4	10.9	36.3	31.0
Recognition of unearned revenue	(8.9)	(7.6)	25.0	(21.4)
Balance, end of period	$ 73.3	$ 58.5	$ 73.3	$ 58.5