Accumulated Other Comprehensive Income (Loss) - Reclassification out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2021	Aug. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Less: Tax effect	$ 8.9	$ 12.0
Net income (loss) attributable to Scholastic Corporation	24.2	39.8
Amount reclassified from Accumulated other comprehensive income (loss) | Retirement benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of unrecognized gain (loss)	0.2	0.1
Amortization of prior service (credit) loss	(0.2)	0.0
Less: Tax effect	0.1	0.0
Net income (loss) attributable to Scholastic Corporation	$ 0.1	$ 0.1