Revenues - Deferred Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2026	Aug. 31, 2025	May 31, 2026
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 173.7	$ 184.7	$ 181.9
Contract with customer, liability, revenue recognized	39.6	37.0
Book fairs incentive credits
Deferred Revenue Arrangement [Line Items]
Deferred revenue	108.5	104.0	127.2
Magazines+ subscriptions
Deferred Revenue Arrangement [Line Items]
Deferred revenue	12.2	19.3	3.6
U.S. digital subscriptions
Deferred Revenue Arrangement [Line Items]
Deferred revenue	6.9	12.3	6.6
U.S. Education-related
Deferred Revenue Arrangement [Line Items]
Deferred revenue	5.3	7.0	5.7
Entertainment-related (2)
Deferred Revenue Arrangement [Line Items]
Deferred revenue	9.7	12.8	10.9
Stored value programs
Deferred Revenue Arrangement [Line Items]
Deferred revenue	23.3	22.8	22.5
Other
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 7.8	$ 6.5	$ 5.4