Accumulated Other Comprehensive Income (Loss) - Reclassification out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 29, 2024	Feb. 28, 2023	Feb. 29, 2024	Feb. 28, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Less: Tax effect	$ 8.1	$ 6.9	$ 7.3	$ (6.1)
Net income (loss) attributable to Scholastic Corporation	26.5	19.2	23.8	(10.6)
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)	0.4	0.2	1.0	0.4
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	$ 0.2	$ 0.0	$ 0.5	$ (0.1)