Goodwill And Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Schedule Of Goodwill And Intangible Assets [Line Items]
Amortization expense	$ 19.2	$ 16.3	$ 13.5
Amortizable intangible assets fully amortization year	2032
Consulting
Schedule Of Goodwill And Intangible Assets [Line Items]
Impairment of intangible assets			77.0
Digital
Schedule Of Goodwill And Intangible Assets [Line Items]
Impairment of intangible assets			29.6
General and Administrative Expenses
Schedule Of Goodwill And Intangible Assets [Line Items]
Impairment of intangible assets			$ 106.6
Pivot Leadership
Schedule Of Goodwill And Intangible Assets [Line Items]
Tax deductible goodwill	$ 6.6	7.2
Acquired Companies
Schedule Of Goodwill And Intangible Assets [Line Items]
Tax deductible goodwill	$ 24.5	34.9
Acquired Companies | IP
Schedule Of Goodwill And Intangible Assets [Line Items]
Intangibles assets		$ 36.0
Weighted average useful life		7 years
Acquired Companies | Customer Relationships
Schedule Of Goodwill And Intangible Assets [Line Items]
Intangibles assets		$ 6.2
Weighted average useful life		10 years
Acquired Companies | Trade Names
Schedule Of Goodwill And Intangible Assets [Line Items]
Intangibles assets		$ 3.2
Weighted average useful life		9 years