Investments (Details) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Nov. 30, 2022	Nov. 30, 2021	May 31, 2022
Investments (Details) [Line Items]
Investments	$ 37,000,000.0	$ 39,700,000	$ 37,000,000.0	$ 39,700,000	$ 37,000,000.0
Equity method investment, impairment			0
Income from equity-method investments	1,200,000	500,000	1,300,000	1,600,000
Post-Retirement Benefits
Investments (Details) [Line Items]
Interest cost	100,000	0.0	200,000	100,000
Expected return on assets	0	0	0	0
Net amortization of prior service credit	(200,000)	(200,000)	(400,000)	(400,000)
Amortization of pension and postretirement plans	0	(0.0)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	(100,000)	(200,000)	(200,000)	(300,000)
Foreign Plan | Pension Plans
Investments (Details) [Line Items]
Interest cost	200,000	300,000	500,000	500,000
Expected return on assets	(300,000)	(300,000)	(600,000)	(600,000)
Net amortization of prior service credit	0.0	0.0	0.0	0.0
Amortization of pension and postretirement plans	100,000	200,000	200,000	400,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 0.0	200,000	$ 100,000	300,000
Children's Book Publishing and Distribution
Investments (Details) [Line Items]
Equity method ownership percentage	26.20%		26.20%
Financing and Production Company | Financing and Production Company
Investments (Details) [Line Items]
Other equity percentage			4.60%
International
Investments (Details) [Line Items]
Equity method investment	$ 31,000,000.0	33,700,000	$ 31,000,000.0	33,700,000	31,000,000.0
Children's Book Publishing and Distribution | Other Investments
Investments (Details) [Line Items]
Investments	$ 6,000,000.0	$ 6,000,000.0	$ 6,000,000.0	$ 6,000,000.0	$ 6,000,000.0