Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net loss	$ (129.3)	$ (192.7)	$ (130.9)
Other comprehensive income (loss), net of tax:
Foreign currency translation (loss) gain	(6.5)	2.6	(6.2)
Accumulated foreign currency translation loss divested of in discontinued operations	11.5	0.0	0.0
Defined benefit plans:
Net gain arising from remeasurement during the period, net of tax of $2.6, $0.7, $7.8	8.1	10.5	25.1
Amortization of prior service benefits included in net income, net of tax of ($0.2), ($0.2)	(0.6)	(0.6)	0.0
Amortization of net actuarial gain included in net income, net of tax of ($1.0), ($1.2), ($0.2)	(3.0)	(3.8)	(0.6)
Reclassification adjustment for pension settlement benefits included in net income, net of tax of ($0.8)	(2.7)	0.0	0.0
Total other comprehensive income	6.8	8.7	18.3
Comprehensive loss	$ (122.5)	$ (184.0)	$ (112.6)