Accumulated Other Comprehensive Income (Loss) - Reclassification out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2025	Feb. 29, 2024	Feb. 28, 2025	Feb. 29, 2024
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Less: Tax effect	$ 24.8	$ 8.1	$ 32.9	$ 7.3
Net income (loss) attributable to Scholastic Corporation			17.3	23.8
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	0.4	1.0	1.0
Amortization of prior service (credit) loss	(0.3)	(0.3)	(0.7)	(0.7)
Less: Tax effect	0.1	0.1	0.2	0.2
Net income (loss) attributable to Scholastic Corporation	$ 0.1	$ 0.2	$ 0.5	$ 0.5