Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2022	Mar. 31, 2022	Sep. 30, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unrealized losses to marketable securities	$ 0.1	$ 0.2
Equity investments without readily determinable fair values	3.2	3.2
Estimated Fair Value \| Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of notes	$ 228.8	$ 228.8	$ 469.0

Amount of investment in equity security without readily determinable fair value.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117539-209714

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Amount of unrealized gain (loss) on investment in marketable security.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(c))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

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