Goodwill And Intangible Assets (Schedule Of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018
Goodwill [Roll Forward]
Goodwill before impairment losses, beginning balance	$ 540,168	$ 523,504
Accumulated impairment losses, beginning balance	(32,297)	(32,297)
Goodwill, beginning balance	507,871	491,207
Acquisitions	13,656	15,983
Disposals and foreign currency changes, net	(1,590)	681
Impairments	0	0
Goodwill before impairment losses, ending balance	552,234	540,168
Accumulated impairment losses, ending balance	(32,297)	(32,297)
Goodwill, ending balance	$ 519,937	$ 507,871