Investments - Summary of Short-term and Long-term Investments and Marketable Securities (Detail) - USD ($) $ in Thousands	1 Months Ended
Apr. 30, 2022	Jun. 30, 2022	Sep. 30, 2021
Schedule Of Held To Maturity Securities And Marketable Securities [Line Items]
Equity securities sold	$ 122,300
Total, Cost Basis		$ 468,302	$ 429,703
Total, Gross Unrealized Gains		32	1,954
Total, Gross Unrealized Losses		(7,968)	(856)
Total, Fair Value		460,366	430,801
Commercial notes (due within one year)
Schedule Of Held To Maturity Securities And Marketable Securities [Line Items]
Held to Maturity, Cost Basis		227,057	56,627
Held to Maturity, Gross Unrealized Gains		21	803
Held to Maturity, Gross Unrealized Losses		(1,588)	0
Held to Maturity, Fair Value		225,490	57,430
Commercial notes (due within one through three years)
Schedule Of Held To Maturity Securities And Marketable Securities [Line Items]
Held to Maturity, Cost Basis		165,920	195,595
Held to Maturity, Gross Unrealized Gains		0	1,151
Held to Maturity, Gross Unrealized Losses		(6,380)	(103)
Held to Maturity, Fair Value		159,540	196,643
Certificate of deposit (due within one through two years)
Schedule Of Held To Maturity Securities And Marketable Securities [Line Items]
Held to Maturity, Cost Basis			50,000
Held to Maturity, Gross Unrealized Gains			0
Held to Maturity, Gross Unrealized Losses			0
Held to Maturity, Fair Value			50,000
Certificate of deposit (due within one year)
Schedule Of Held To Maturity Securities And Marketable Securities [Line Items]
Held to Maturity, Cost Basis		50,000
Held to Maturity, Gross Unrealized Gains		0
Held to Maturity, Gross Unrealized Losses		0
Held to Maturity, Fair Value		50,000
Marketable securities
Schedule Of Held To Maturity Securities And Marketable Securities [Line Items]
Marketable Securities, Cost Basis		0	127,481
Marketable Securities, Gross Unrealized Gains		0	0
Marketable Securities, Gross Unrealized Losses		0	(753)
Marketable Securities, Fair Value		0	$ 126,728
Commercial notes (due within ninety days)
Schedule Of Held To Maturity Securities And Marketable Securities [Line Items]
Cash Equivalents, Cost Basis		25,325
Cash Equivalents, Gross Unrealized Gains		11
Cash Equivalents, Gross Unrealized Losses		0
Cash Equivalents, Fair Value		$ 25,336

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