Discontinued Operations - Income from Discontinued Operations (Net of Tax) on Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense (benefit)			$ 18.0
Net income from discontinued operations	$ 3.1	$ 9.4	9.9	$ 12.9
Disposal Group [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	176.7	186.7	361.0	364.0
Cost of services and products, excluding items below	123.9	122.2	246.2	243.3
Selling, general and administrative, excluding items below	40.9	40.4	84.8	80.0
Depreciation and amortization	0.0	21.2	5.7	41.6
Restructuring and severance related charges	1.9	1.2	2.3	1.4
Transaction costs	6.2	0.0	10.3	0.0
Total operating costs and expenses	172.9	185.0	349.3	366.3
Operating income (loss)	3.8	1.7	11.7	(2.3)
Interest expense	0.3	0.2	0.7	0.5
Other (income) expense, net	(0.4)	0.5	(1.3)	0.4
Income (loss) before income taxes	3.9	1.0	12.3	(3.2)
Income tax expense (benefit)	0.8	(8.4)	2.4	(16.1)
Net income from discontinued operations	$ 3.1	$ 9.4	$ 9.9	$ 12.9