Revenue Recognition, Contracts with Customers, Description of Revenue Generating Activities (Details)	12 Months Ended
	Apr. 30, 2020 Performanceobligation Institution
Description of Revenue Generating Activities [Abstract]
Number of academic institutions | Institution	700
Journals Subscriptions [Member]
Description of Revenue Generating Activities [Abstract]
Number of performance obligations | Performanceobligation	2
Duration of contract	1 year
Test Preparation and Certification [Member]
Description of Revenue Generating Activities [Abstract]
Duration of contract	3 years
Professional Assessment [Member]
Description of Revenue Generating Activities [Abstract]
Duration of contract	1 year
Minimum [Member] | Publishing Technology Services [Member]
Description of Revenue Generating Activities [Abstract]
Duration of contract	2 years
Minimum [Member] | Education Services [Member]
Description of Revenue Generating Activities [Abstract]
Duration of contract	7 years
Maximum [Member] | Publishing Technology Services [Member]
Description of Revenue Generating Activities [Abstract]
Duration of contract	5 years
Maximum [Member] | Education Services [Member]
Description of Revenue Generating Activities [Abstract]
Duration of contract	10 years