Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
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-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Goodwill and Other Intangibles - Schedule of goodwill by segment (Details) - USD ($) $ in Millions	May 31, 2022	May 31, 2021	May 31, 2020
Goodwill and Other Intangibles (Details) [Line Items]
Goodwill	$ 125.3	$ 126.3	$ 124.9
Operating Segments \| Children's Book Publishing and Distribution
Goodwill and Other Intangibles (Details) [Line Items]
Goodwill	47.0	47.8
Operating Segments \| Education Solutions
Goodwill and Other Intangibles (Details) [Line Items]
Goodwill	68.3	68.5
Operating Segments \| International
Goodwill and Other Intangibles (Details) [Line Items]
Goodwill	$ 10.0	$ 10.0