Leases - Components of Lease Expense (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	7 Months Ended	9 Months Ended
	Aug. 11, 2023	Sep. 30, 2023	Sep. 30, 2022	Aug. 11, 2023	Sep. 30, 2022
Lessee, Lease, Description [Line Items]
Operating lease expense		$ 8.2
Finance lease expense
Amortization of ROU lease assets		0.6
Interest on lease liabilities		0.1
Variable lease expense		$ 1.0
Predecessor
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 7.5		$ 18.7	$ 41.9	$ 57.7
Finance lease expense
Amortization of ROU lease assets	0.8		1.1	2.4	3.0
Interest on lease liabilities	0.2		0.2	0.5	0.5
Variable lease expense	$ 0.9		$ 1.7	$ 5.2	$ 7.5