Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Revenue	$ 272.8	$ 275.3	$ 544.4	$ 551.2
Costs and expenses
Cost of services and products, excluding items below	132.1	130.9	265.6	267.3
Selling, general and administrative, excluding items below	62.9	61.9	126.1	127.7
Depreciation and amortization	80.3	90.4	157.7	203.3
Restructuring and severance related charges	(0.3)	0.0	(0.1)	0.0
Transaction costs	0.0	0.1	0.1	0.1
Total operating costs and expenses	275.0	283.3	549.4	598.4
Operating loss	(2.2)	(8.0)	(5.0)	(47.2)
Interest expense	45.3	41.0	86.9	76.2
Other components of pension and postretirement benefit plans (benefit) expense	(1.0)	0.0	(1.5)	0.4
Other income, net	(6.5)	(27.6)	(36.5)	(24.4)
Loss from continuing operations before income taxes	(40.0)	(21.4)	(53.9)	(99.4)
Income tax (benefit) expense	(2.6)	(1.9)	31.2	(6.5)
Loss from continuing operations	(37.4)	(19.5)	(85.1)	(92.9)
Income from discontinued operations (net of tax)	3.1	9.4	9.9	12.9
Net loss	$ (34.3)	$ (10.1)	$ (75.2)	$ (80.0)