Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Income Tax Expense (Benefit) for Continuing Operations

Income tax expense (benefit) for continuing operations consisted of the following:

	Successor									Predecessor
(dollars in millions)	Year Ended December 31, 2023			Year Ended December 31, 2022			September 8, 2021 to December 31, 2021			January 1, 2021 to September 7, 2021
Current:
Federal	$	—		$	—		$	—		$	—
State and local		0.5			0.6			(0.4	)		0.7
Foreign		6.0			6.4			1.6			3.1
Total current		6.5			7.0			1.2			3.8
Deferred:
Federal		(52.8	)		(37.9	)		(9.2	)		(16.1	)
State and local		(5.2	)		2.7			7.4			(3.8	)
Foreign		(1.7	)		(3.1	)		(0.7	)		(0.8	)
Total deferred		(59.7	)		(38.3	)		(2.5	)		(20.7	)
Valuation allowance		18.9			(3.8	)		(6.0	)		—
Total	$	(34.3	)	$	(35.1	)	$	(7.3	)	$	(16.9	)

Schedule of Effective Income Tax Rate Reconciliation

The following is a reconciliation of the statutory federal income tax rate with the effective tax rate for each period:

	Successor									Predecessor
	Year Ended December 31, 2023			Year Ended December 31, 2022			September 8, 2021 to December 31, 2021			January 1, 2021 to September 7, 2021
U.S. federal statutory rate		21.0	%		21.0	%		21.0	%		21.0	%
State and local income taxes, net of federal income tax		3.2			3.1			2.1			2.5
Transaction costs		—			—			(0.4	)		(4.1	)
Non-Deductible meals and entertainment		(0.3	)		(0.3	)		(0.2	)		(0.3	)
State net operating loss adjustments		(1.4	)		(4.4	)		(18.4	)		—
Change in valuation allowance, net of federal income tax		(8.3	)		2.3			17.5			—
Change in uncertain tax positions		—			—			0.1			—
Research and development credits		1.4			—			—			—
Other differences, net		(0.5	)		(0.5	)		(0.4	)		(1.9	)
Effective tax rate		15.1	%		21.2	%		21.3	%		17.2	%

Schedule of Income Tax (Benefit) Provision Charged to Continuing Operations or Accumulated Other Comprehensive Income

The income tax (benefit) provision was charged to continuing operations or accumulated other comprehensive income as follows:

	Successor									Predecessor
(dollars in millions)	Year Ended December 31, 2023			Year Ended December 31, 2022			September 8, 2021 to December 31, 2021			January 1, 2021 to September 7, 2021
Income tax (benefit) provision related to:
Continuing operations	$	(34.3	)	$	(35.1	)	$	(7.3	)	$	(16.9	)
Accumulated other comprehensive (loss) income		(0.7	)	7.6			0.8			10.8

Schedule of Deferred Tax Assets and Liabilities

The components of our deferred tax assets and liabilities were as follows:

	December 31,
(dollars in millions)	2023			2022
Deferred tax assets:
Net operating loss carryforwards	$	209.0		$	227.6
Finance and operating lease obligations		19.8			21.6
Pension and postretirement benefits		32.8			35.8
Employee benefits		3.9			4.7
Interest limitation		48.8			16.7
State tax credit		7.4			8.0
Other		30.8			23.4
Total deferred tax assets		352.5			337.8
Valuation allowance		(32.8	)		(15.7	)
Total deferred tax assets, net of valuation allowance	$	319.7		$	322.1
Deferred tax liabilities:
Property, plant and equipment and intangibles	$	(361.8	)	$	(410.5	)
Other		(9.3	)		(7.6	)
Total deferred tax liabilities		(371.1	)		(418.1	)
Net deferred tax liabilities	$	(51.4	)	$	(96.0	)

Schedule of Reconciliation of Unrecognized Tax Benefits

A reconciliation of the unrecognized tax benefits is as follows:

	Successor						Predecessor
(dollars in millions)	Year Ended December 31, 2023		Year Ended December 31, 2022		September 8, 2021 to December 31, 2021		January 1, 2021 to September 7, 2021
Balance, beginning of year	$	19.3	$	19.3	$	19.2	$	19.2
Change in tax positions for the current year		0.3		—		0.1		—
Balance, end of year	$	19.6	$	19.3	$	19.3	$	19.2