Goodwill - Summary of Changes in Goodwill (Details) - USD ($)	3 Months Ended	12 Months Ended
Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning balance		$ 64,315,000	$ 163,246,000
Adjustments			(2,000)
Goodwill impairment	$ (98,900,000)	0	(98,929,000)	$ (10,396,000)
Ending balance	$ 64,315,000	$ 64,315,000	$ 64,315,000	$ 163,246,000

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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