Fee Revenue - Schedule of Disaggregation of Fee Revenue by Industry (Detail) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2025	Apr. 30, 2024	Apr. 30, 2023
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 2,761,086	$ 2,795,505	$ 2,863,836
Fee Revenue
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 2,730,088	$ 2,762,671	$ 2,835,408
Fee revenue, percentage	100.00%	100.00%	100.00%
Industrial
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 814,619	$ 813,919	$ 805,241
Fee revenue, percentage	29.90%	29.50%	28.40%
Financial Services
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 516,742	$ 491,761	$ 494,299
Fee revenue, percentage	18.90%	17.80%	17.40%
Life Sciences/Healthcare
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 475,779	$ 485,321	$ 522,372
Fee revenue, percentage	17.40%	17.60%	18.40%
Technology
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 396,027	$ 404,569	$ 483,787
Fee revenue, percentage	14.50%	14.60%	17.10%
Consumer Goods
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 349,196	$ 382,175	$ 386,409
Fee revenue, percentage	12.80%	13.80%	13.60%
Education/Non–Profit/General
Disaggregation Of Revenue [Line Items]
Fee revenue	$ 177,725	$ 184,926	$ 143,300
Fee revenue, percentage	6.50%	6.70%	5.10%