Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 07, 2021	Sep. 30, 2022	Sep. 07, 2021	Sep. 30, 2022
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (5.0)	$ (73.7)	$ (26.6)	$ (81.3)	$ (94.6)
Other comprehensive (loss) income, net of tax:
Foreign currency translation (loss) gain	(1.2)	(1.4)	(5.9)	1.2	(7.2)
Cash flow hedges:
Unrealized loss on cash flow hedges arising during the period, net of tax of ($0.2), $0.0	0.0	(0.6)	0.0	(0.1)	0.0
Reclassification adjustment for net losses included in net income, net of tax of $4.7, $5.8	0.0	16.2	0.0	19.7	0.0
Defined benefit plans:
Net (loss) gain arising from remeasurement during the period, net of tax of ($0.3), ($0.7), $1.8	0.0	0.0	(0.8)	6.0	(2.1)
Amortization of prior service benefits included in net income, net of tax of ($0.1), ($0.4)	0.0	(0.3)	0.0	(1.3)	0.0
Amortization of net actuarial loss included in net income, net of tax of $1.0, $3.6	0.0	3.1	0.0	12.0	0.0
Total other comprehensive (loss) income	(1.2)	17.0	(6.7)	37.5	(9.3)
Total comprehensive loss	$ (6.2)	$ (56.7)	$ (33.3)	$ (43.8)	$ (103.9)