Other Financial Data (Details) - Schedule of Other Financial Data Other Than Accumulated Other Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Schedule of Other Financial Data Other Than Accumulated Other Comprehensive Income [Abstract]
Advertising expense	$ 110.0	$ 121.0	$ 127.3
Amortization of prepublication and production costs	21.8	23.3	26.4
Foreign currency transaction gain (loss)	0.0	1.0	(0.5)
Purchases related to contractual commitments for minimum print quantities	$ 0.0	$ 0.0	$ 0.0