Financial Instruments - Financial Instruments and Balance Sheet Classification (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2024	Jul. 31, 2023	Apr. 30, 2024
Fair Value Measurement
Assets, fair value	$ 905,605		$ 1,195,001
Balance Sheet Classification
Cash and Cash Equivalents	633,376		941,005
Marketable Securities, Current	40,626		42,742
Marketable Securities, Non- current	231,195		211,681
Income Taxes & Other Receivables	408
Other Accrued Liabilities			(427)
Mutual funds
Balance Sheet Classification
Obligations for which assets are held in trust	214,500		198,600
Unvested obligations under deferred compensation plans	16,700		22,400
Gain on marketable securities	14,200	$ 12,800
Fair Value, Inputs, Level 2
Fair Value Measurement
Cost	39,203		38,550
Unrealized Gains	54		4
Unrealized Losses	(19)		(55)
Fair Value	39,238		38,499
Balance Sheet Classification
Cash and Cash Equivalents	0		3,932
Marketable Securities, Current	28,124		25,414
Marketable Securities, Non- current	11,114		9,153
Income Taxes & Other Receivables	0
Other Accrued Liabilities			0
Fair Value, Inputs, Level 2 | Foreign currency forward contracts
Fair Value Measurement
Foreign currency forward contracts, fair value	408		(427)
Balance Sheet Classification
Cash and Cash Equivalents	0		0
Marketable Securities, Current	0		0
Marketable Securities, Non- current	0		0
Income Taxes & Other Receivables	408
Other Accrued Liabilities			(427)
Fair Value, Inputs, Level 2 | Commercial paper
Fair Value Measurement
Cost	12,163		16,873
Unrealized Gains	0		1
Unrealized Losses	(9)		(19)
Fair Value	12,154		16,855
Balance Sheet Classification
Cash and Cash Equivalents	0		3,932
Marketable Securities, Current	12,154		12,923
Marketable Securities, Non- current	0		0
Income Taxes & Other Receivables	0
Other Accrued Liabilities			0
Fair Value, Inputs, Level 2 | Corporate notes/bonds
Fair Value Measurement
Cost	20,173		17,322
Unrealized Gains	52		3
Unrealized Losses	(7)		(27)
Fair Value	20,218		17,298
Balance Sheet Classification
Cash and Cash Equivalents	0		0
Marketable Securities, Current	10,600		10,050
Marketable Securities, Non- current	9,618		7,248
Income Taxes & Other Receivables	0
Other Accrued Liabilities			0
Fair Value, Inputs, Level 2 | U.S. Treasury and Agency Securities
Fair Value Measurement
Cost	6,867		4,355
Unrealized Gains	2		0
Unrealized Losses	(3)		(9)
Fair Value	6,866		4,346
Balance Sheet Classification
Cash and Cash Equivalents	0		0
Marketable Securities, Current	5,370		2,441
Marketable Securities, Non- current	1,496		1,905
Income Taxes & Other Receivables	0
Other Accrued Liabilities			0
Fair Value, Inputs, Level 1 | Mutual funds
Fair Value Measurement
Equity securities, fair value	232,583		219,856
Balance Sheet Classification
Cash and Cash Equivalents	0		0
Marketable Securities, Current	12,502		17,328
Marketable Securities, Non- current	220,081		202,528
Income Taxes & Other Receivables	0
Other Accrued Liabilities			0
Fair Value, Inputs, Level 1 | Equity investments
Fair Value Measurement
Equity securities, fair value	232,583		219,856
Balance Sheet Classification
Cash and Cash Equivalents	0		0
Marketable Securities, Current	12,502		17,328
Marketable Securities, Non- current	220,081		202,528
Income Taxes & Other Receivables	0
Other Accrued Liabilities			0
Fair Value, Inputs, Level 1 | Cash
Fair Value Measurement
Cash and cash equivalents, fair value	540,650		790,938
Balance Sheet Classification
Cash and Cash Equivalents	540,650		790,938
Marketable Securities, Current	0		0
Marketable Securities, Non- current	0		0
Income Taxes & Other Receivables	0
Other Accrued Liabilities			0
Fair Value, Inputs, Level 1 | Money market funds
Fair Value Measurement
Cash and cash equivalents, fair value	92,726		146,135
Balance Sheet Classification
Cash and Cash Equivalents	92,726		146,135
Marketable Securities, Current	0		0
Marketable Securities, Non- current	0		0
Income Taxes & Other Receivables	$ 0
Other Accrued Liabilities			$ 0