Leases - Components of Lease Costs (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2021
Lease, Cost [Abstract]
Operating lease cost	$ 13.9	$ 58.6	$ 54.0	$ 53.3
Finance lease cost - amortization	2.1	13.8	9.9	5.4
Finance lease cost - interest	0.1	1.4	0.6	0.4
Variable lease cost	7.1	31.7	31.9	34.0
Short-term lease cost	$ 2.5	$ 11.1	$ 11.1	$ 9.5

Amount of interest expense on finance lease liability.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479589/842-20-55-53

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479041/842-20-45-4

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147478964/842-20-50-4

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- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

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- References

No definition available.

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- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

+ References

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- Definition

Amount of short-term lease cost, excluding expense for lease with term of one month or less.

+ References

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- Definition

Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

+ References

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