Goodwill and Intangible Assets, Goodwill (Details) $ in Thousands	3 Months Ended
	Jul. 31, 2021 USD ($)
Activity in Goodwill by Segment [Roll Forward]
Balance, beginning of period	$ 1,304,340	[1]
Foreign translation adjustment	(2,741)
Balance, end of period	1,301,599
Goodwill impairment	110,000
Research Publishing & Platforms [Member]
Activity in Goodwill by Segment [Roll Forward]
Balance, beginning of period	619,203	[1]
Foreign translation adjustment	(763)
Balance, end of period	618,440
Academic & Professional Learning [Member]
Activity in Goodwill by Segment [Roll Forward]
Balance, beginning of period	512,512	[1]
Foreign translation adjustment	(1,884)
Balance, end of period	510,628
Education Services [Member]
Activity in Goodwill by Segment [Roll Forward]
Balance, beginning of period	172,625	[1]
Foreign translation adjustment	(94)
Balance, end of period	$ 172,531

[1] The Education Services goodwill balance as of April 30, 2021 includes a cumulative pretax noncash goodwill impairment of $110.0 million.