Description of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	May 31, 2020 USD ($) segment	May 31, 2019 USD ($)	May 31, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Number of countries in which entity operates	165
Allowance for doubtful accounts receivable	$ 19.9	$ 11.6
Capitalized computer software, net	52.3	43.9
Capitalized computer software, amortization expense	$ 22.2	25.4	$ 16.3
Useful life of intangible assets	5 years 8 months 12 days
Royalty advances, net	$ 109.5	102.9
Reporting units subject to goodwill impairment | segment	7
Advertising expense	$ 85.2	$ 106.8	$ 110.0
Minimum [Member]
Property, Plant and Equipment [Line Items]
Initial term	3 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Initial term	10 years
Building [Member]
Property, Plant and Equipment [Line Items]
Depreciable life	40 years
Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Depreciable life	25 years
Capitalized Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Depreciable life	3 years
Capitalized Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Depreciable life	7 years
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Depreciable life	10 years
Customer Lists [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life of intangible assets	5 years
Customer Lists [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life of intangible assets	10 years
Prepublication Costs [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life of intangible assets	2 years
Prepublication Costs [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life of intangible assets	5 years
Intellectual Property [Member]
Property, Plant and Equipment [Line Items]
Useful life of intangible assets	5 years
Accounting Standards Update 2018-15 [Member]
Property, Plant and Equipment [Line Items]
Capitalized costs	$ 11.9