Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Nov. 30, 2022	Nov. 30, 2021
Disaggregation of Revenue [Line Items]
Revenues	$ 587.9	$ 524.2	$ 850.8	$ 784.0
Children's Book Publishing and Distribution
Disaggregation of Revenue [Line Items]
Revenues	418.3	352.5	543.0	468.3
Children's Book Publishing and Distribution | Book Clubs - U.S.
Disaggregation of Revenue [Line Items]
Revenues	57.6	51.9	63.9	58.7
Children's Book Publishing and Distribution | Book Fairs - U.S.
Disaggregation of Revenue [Line Items]
Revenues	240.8	176.2	269.1	192.2
Children's Book Publishing and Distribution | Trade - U.S.
Disaggregation of Revenue [Line Items]
Revenues	107.9	109.4	184.1	189.5
Children's Book Publishing and Distribution | Trade - International
Disaggregation of Revenue [Line Items]
Revenues	12.0	15.0	25.9	27.9
Education
Disaggregation of Revenue [Line Items]
Revenues	80.0	79.5	153.2	159.6
International
Disaggregation of Revenue [Line Items]
Revenues	89.6	92.2	154.6	156.1
International | Major Markets
Disaggregation of Revenue [Line Items]
Revenues	77.1	78.8	130.5	126.3
International | Other Markets
Disaggregation of Revenue [Line Items]
Revenues	$ 12.5	$ 13.4	$ 24.1	$ 29.8