Accumulated Other Comprehensive Income (Loss) - Reclassification out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Less: Tax effect	$ (24.6)	$ (25.5)	$ (0.8)	$ (13.0)
Net income (loss) attributable to Scholastic Corporation	(76.9)	(75.3)	(2.7)	(29.8)
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)	0.3	0.1	0.6	0.2
Amortization of prior service (credit) loss	(0.2)	(0.2)	(0.4)	(0.4)
Less: Tax effect	0.0	0.0	0.1	0.1
Net income (loss) attributable to Scholastic Corporation	$ 0.1	$ (0.1)	$ 0.3	$ (0.1)