Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (40.9)	$ (69.9)
Other comprehensive loss, net of tax:
Foreign currency translation loss	(2.6)	0.0
Defined benefit plans:
Amortization of prior service benefits included in net income, net of tax of ($0.1), ($0.1)	(0.1)	(0.1)
Amortization of net actuarial gain included in net income, net of tax of ($0.2), ($0.2)	(0.7)	(0.8)
Total other comprehensive loss	(3.4)	(0.9)
Total comprehensive loss	$ (44.3)	$ (70.8)