Goodwill and Intangible Assets - Intangible Assets (Detail) - USD ($)	12 Months Ended
	Apr. 30, 2024	Apr. 30, 2023
Intangible Assets [Line Items]
Gross	$ 278,451,000	$ 278,451,000
Accumulated Amortization	(189,496,000)	(163,905,000)
Net	88,955,000	114,546,000
Exchange rate fluctuations	(122,000)	(120,000)
Amortized intangible assets, net	88,833,000	114,426,000
Intangible asset addition	0
ICS
Intangible Assets [Line Items]
Intangible asset addition		16,400,000
Salo
Intangible Assets [Line Items]
Intangible asset addition		32,000,000
Customer lists
Intangible Assets [Line Items]
Gross	192,099,000	192,099,000
Accumulated Amortization	(121,977,000)	(104,429,000)
Net	70,122,000	87,670,000
Intellectual property
Intangible Assets [Line Items]
Gross	69,100,000	69,100,000
Accumulated Amortization	(52,804,000)	(47,187,000)
Net	16,296,000	21,913,000
Trademarks
Intangible Assets [Line Items]
Gross	12,086,000	12,086,000
Accumulated Amortization	(9,549,000)	(7,123,000)
Net	2,537,000	4,963,000
Proprietary databases
Intangible Assets [Line Items]
Gross	4,256,000	4,256,000
Accumulated Amortization	(4,256,000)	(4,256,000)
Net	0	0
Non-compete agreements
Intangible Assets [Line Items]
Gross	910,000	910,000
Accumulated Amortization	(910,000)	(910,000)
Net	$ 0	$ 0