Segment Information (Details) - Schedule of segment reporting information $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Feb. 29, 2020 USD ($)	Feb. 28, 2019 segment	May 31, 2020 USD ($) segment	May 31, 2019 USD ($)	May 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			3
Revenues			$ 1,487.1	$ 1,653.9	$ 1,628.4
Bad debts			15.6	7.0	9.5
Depreciation and amortization			90.2	81.7	66.0
Asset impairments and write downs	$ 40.0		40.6	0.9	11.2
Segment operating income (loss)			(88.5)	25.0	55.6
Segment assets			2,033.6	1,878.5	1,825.4
Goodwill			124.9	125.2	119.2
Expenditures for long-lived assets including royalty advances			140.6	185.1	197.6
Long-lived assets			867.8	864.3	820.0
Children's Book Publishing and Distribution [Member]
Segment Reporting Information [Line Items]
Revenues			847.4	987.4	970.2
Education [Member]
Segment Reporting Information [Line Items]
Revenues			287.1	297.3	288.6
International
Segment Reporting Information [Line Items]
Revenues			352.6	369.2	369.6
Operating Segments [Member] | Children's Book Publishing and Distribution [Member]
Segment Reporting Information [Line Items]
Revenues			875.4	990.3	970.2
Bad debts			5.8	3.8	4.4
Depreciation and amortization			26.5	23.7	23.3
Asset impairments and write downs			0.0	0.0	0.2
Segment operating income (loss)			23.6	82.9	105.8
Segment assets			523.7	523.4	434.8
Goodwill			46.9	47.0	40.9
Expenditures for long-lived assets including royalty advances			49.5	71.4	58.6
Long-lived assets			169.6	175.0	151.2
Number of Operating Segments | segment		3
Operating Segments [Member] | Education [Member]
Segment Reporting Information [Line Items]
Revenues			287.3	297.4	288.6
Bad debts			2.5	1.4	1.4
Depreciation and amortization			13.0	9.5	7.4
Asset impairments and write downs			0.0	0.0	0.0
Segment operating income (loss)			29.9	30.6	33.9
Segment assets			223.4	214.7	202.4
Goodwill			68.1	68.2	68.3
Expenditures for long-lived assets including royalty advances			20.1	22.6	19.2
Long-lived assets			123.8	116.3	101.8
Number of Operating Segments | segment		3
Operating Segments [Member] | Overhead [Member]
Segment Reporting Information [Line Items]
Revenues			0.0	0.0	0.0
Bad debts			0.0	0.0	0.0
Depreciation and amortization			43.4	41.7	29.1
Asset impairments and write downs			40.0	0.9	11.0
Segment operating income (loss)			(135.5)	(102.3)	(101.8)
Segment assets			1,012.7	887.6	927.9
Goodwill			0.0	0.0	0.0
Expenditures for long-lived assets including royalty advances			49.0	77.6	104.5
Long-lived assets			499.8	507.7	492.7
Operating Segments [Member] | Total Domestic [Member]
Segment Reporting Information [Line Items]
Revenues			1,162.7	1,287.7	1,258.8
Bad debts			8.3	5.2	5.8
Depreciation and amortization			82.9	74.9	59.8
Asset impairments and write downs			40.0	0.9	11.2
Segment operating income (loss)			(82.0)	11.2	37.9
Segment assets			1,759.8	1,625.7	1,565.1
Goodwill			115.0	115.2	109.2
Expenditures for long-lived assets including royalty advances			118.6	171.6	182.3
Long-lived assets			793.2	799.0	745.7
Operating Segments [Member] | International
Segment Reporting Information [Line Items]
Revenues			324.4	366.2	369.6
Bad debts			7.3	1.8	3.7
Depreciation and amortization			7.3	6.8	6.2
Asset impairments and write downs			0.6	0.0	0.0
Segment operating income (loss)			(6.5)	13.8	17.7
Segment assets			273.8	252.8	260.3
Goodwill			9.9	10.0	10.0
Expenditures for long-lived assets including royalty advances			22.0	13.5	15.3
Long-lived assets			74.6	65.3	74.3
Expenditures for long-lived assets			17.3	8.2	10.0
Long-lived assets			$ 43.8	$ 35.9	$ 36.8
Number of Operating Segments | segment		3