Segment Information, Other Significant Reconciling Items by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Segment Information [Abstract]
Expenditures for long lived assets	$ (115,201)	$ (101,593)	$ (150,728)
Depreciation and amortization	175,127	161,155	153,989
Operating Segments [Member]
Segment Information [Abstract]
Depreciation and amortization	163,433	147,132	140,191
Operating Segments [Member] | Research Publishing & Platforms [Member]
Segment Information [Abstract]
Expenditures for long lived assets	(16,329)	(12,928)	(24,961)
Depreciation and amortization	69,495	60,889	54,805
Operating Segments [Member] | Academic & Professional Learning [Member]
Segment Information [Abstract]
Expenditures for long lived assets	(38,229)	(32,337)	(43,625)
Depreciation and amortization	69,807	68,126	72,274
Operating Segments [Member] | Education Services [Member]
Segment Information [Abstract]
Expenditures for long lived assets	(613)	(3,160)	(5,991)
Depreciation and amortization	24,131	18,117	13,112
Corporate [Member]
Segment Information [Abstract]
Expenditures for long lived assets	(60,030)	(53,168)	(76,151)
Depreciation and amortization	$ 11,694	$ 14,023	$ 13,798