Property, Plant and Equipment (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	May 31, 2022	Nov. 30, 2021	Feb. 28, 2021	Aug. 31, 2020	May 31, 2022	May 31, 2021	May 31, 2020
Property, Plant and Equipment [Line Items]
Total at cost	$ 1,011.0				$ 1,011.0	$ 1,011.2
Less: Accumulated depreciation and amortization	494.0				494.0	454.3
Property, plant and equipment, net	517.0				517.0	556.9
Depreciation and amortization expense					54.8	58.3	$ 58.3
Long-lived assets	456.7				456.7	497.5
Property, Plant and Equipment, Additions					14.4	22.4
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization	32.3				$ 32.3	$ 15.8
U.S.
Property, Plant and Equipment [Line Items]
Disclosure on Geographic Areas, Long-Lived Assets					431.3	467.8
Non-US
Property, Plant and Equipment [Line Items]
Disclosure on Geographic Areas, Long-Lived Assets					25.4	29.7
Operating Segments | Children's Book Publishing and Distribution
Property, Plant and Equipment [Line Items]
Long-lived assets	32.3				$ 32.3	$ 44.2
Property, Plant and Equipment, Additions					5.7	6.0
Operating Segments | Education Solutions
Property, Plant and Equipment [Line Items]
Long-lived assets	2.7				2.7	6.8
Property, Plant and Equipment, Additions					0.5	2.6
Operating Segments | International
Property, Plant and Equipment [Line Items]
Long-lived assets	25.0				25.0	29.4
Property, Plant and Equipment, Additions					3.9	3.4
Corporate, Non-Segment | Overhead
Property, Plant and Equipment [Line Items]
Long-lived assets	396.7				396.7	417.1
Property, Plant and Equipment, Additions					4.3	10.4
Land, Buildings and Improvements
Property, Plant and Equipment [Line Items]
Proceeds from sale of assets	5.6	$ 10.4	$ 5.1	$ 12.3
Gain (Loss) on Disposition of Property Plant Equipment	3.5	6.2	3.8	6.6
Long-lived assets	2.1	$ 4.2	$ 1.3	$ 5.7	2.1
Land
Property, Plant and Equipment [Line Items]
Total at cost	79.6				79.6	81.4
Building
Property, Plant and Equipment [Line Items]
Total at cost	232.5				232.5	244.8
Capitalized software
Property, Plant and Equipment [Line Items]
Total at cost	243.6				243.6	217.9
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Total at cost	206.5				206.5	209.4
Building and Leasehold improvements
Property, Plant and Equipment [Line Items]
Total at cost	214.9				214.9	214.4
Asset Impairment Charges					1.5
Construction in Progress
Property, Plant and Equipment [Line Items]
Total at cost	$ 33.9				$ 33.9	$ 43.3
Software
Property, Plant and Equipment [Line Items]
Asset Impairment Charges							$ 0.6