Consolidated Statements of Operations - USD ($)	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2021	Sep. 07, 2021	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenue	$ 554,400,000	$ 1,138,700,000	$ 1,817,300,000	$ 1,796,000,000
Costs and expenses
Cost of services and products, excluding items below	302,100,000	619,500,000	1,008,300,000	987,800,000
Selling, general and administrative, excluding items below	115,400,000	243,400,000	425,400,000	392,400,000
Depreciation and amortization	144,600,000	194,900,000	449,600,000	497,100,000
Loss on impairment of long-lived assets	0	0	0	2,700,000
Restructuring and severance related charges	600,000	1,200,000	13,800,000	2,000,000
Transaction and integration costs	800,000	54,800,000	2,900,000	11,300,000
Gain on sale of assets, net	0	(2,800,000)	0	0
Total operating costs and expenses	563,500,000	1,111,000,000	1,900,000,000	1,893,300,000
Operating (loss) income	(9,100,000)	27,700,000	(82,700,000)	(97,300,000)
Interest expense	28,300,000	89,100,000	161,200,000	90,100,000
Other components of pension and postretirement benefit plans expense (benefit)	(4,700,000)	6,400,000	700,000	(7,800,000)
Loss on extinguishment of debt, net	2,100,000	10,700,000	0	0
Other (income) expense, net	(300,000)	19,700,000	(17,600,000)	(13,600,000)
Loss before income taxes	(34,500,000)	(98,200,000)	(227,000,000)	(166,000,000)
Income tax benefit	(7,300,000)	(16,900,000)	(34,300,000)	(35,100,000)
Net loss	(27,200,000)	(81,300,000)	(192,700,000)	(130,900,000)
Preferred stock dividends	0	7,600,000	0	0
Net loss applicable to common shareowners	$ (27,200,000)	$ (88,900,000)	$ (192,700,000)	$ (130,900,000)