Segment Information - Schedule of segment reporting information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 29, 2024 USD ($)	Feb. 28, 2023 USD ($)	Feb. 29, 2024 USD ($) segment	Feb. 28, 2023 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			3
Revenues	$ 323.7	$ 324.9	$ 1,114.8	$ 1,175.7
Total Revenues excluding rental income	321.2	324.9	1,107.5	1,175.7
Segment operating income (loss)	(34.9)	(27.7)	$ (32.7)	14.3
Children's Book Publishing & Distribution
Segment Reporting Information [Line Items]
Number of operating segments | segment			2
Revenues	193.6	204.0	$ 689.2	747.0
Education
Segment Reporting Information [Line Items]
Number of operating segments | segment			1
Revenues	68.5	70.0	$ 215.5	223.2
International
Segment Reporting Information [Line Items]
Number of operating segments | segment			3
Revenues	59.1	50.9	$ 202.8	205.5
Operating Segments | Children's Book Publishing & Distribution
Segment Reporting Information [Line Items]
Revenues	193.6	204.0	689.2	747.0
Segment operating income (loss)	(0.8)	1.9	68.5	85.0
Operating Segments | Education
Segment Reporting Information [Line Items]
Revenues	68.5	70.0	215.5	223.2
Segment operating income (loss)	(0.8)	0.7	(13.7)	3.4
Operating Segments | International
Segment Reporting Information [Line Items]
Revenues	59.1	50.9	202.8	205.5
Segment operating income (loss)	(5.9)	(9.0)	(6.1)	(5.8)
Operating Segments | Overhead
Segment Reporting Information [Line Items]
Segment operating income (loss)	$ (27.4)	$ (21.3)	$ (81.4)	$ (68.3)