Asset Write Down (Details) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2021 USD ($) fairs $ / shares	Feb. 29, 2020 USD ($) $ / shares	Feb. 28, 2021 USD ($) fairs $ / shares	Feb. 29, 2020 USD ($) $ / shares
Asset Impairment Charges [Abstract]
Asset impairment expense	$ 8.5		$ 2.4
Right of use assets	7.0
Other long lived assets	$ 1.5
Number of book fair closed | fairs	12		12
Number of book fairs total | fairs	54		54
Impairment expense on income (loss) per basic and diluted share	$ 10.9
Asset impairments and write downs	$ 10.9	$ 40.0	$ 10.9	$ 40.0
Inventory, net of reserves		37.6		$ 37.6
Author advances		1.6
Prepublication costs		$ 0.8
Common Class A
Class of Stock [Line Items]
Impact on earnings per share (USD per share) | $ / shares	$ 0.23	$ 0.84	$ 0.23	$ 0.84