Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2024

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Equipment

For financial reporting purposes, provisions for depreciation are calculated on a straight-line basis over the following estimated useful lives of the underlying assets:

Property, Plant and Equipment Classification	Estimated Useful Lives
Buildings and improvements	30-40 years
Machinery and equipment	5-15 years
Office equipment	3-10 years

The “Property, plant and equipment, net” line item in the consolidated statements of financial position, as of December 31, 2024 and 2023, consisted of the following:

(Dollars in millions)	2024		2023
Land and improvements	$	16.1	$	16.8
Buildings and improvements	189.3		177.2
Machinery and equipment	367.6		343.0
Office equipment	69.1		70.7
Property plant and equipment, gross	642.1		607.7
Accumulated depreciation	(390.8)		(385.7)
Property, plant and equipment, net	251.3		222.0
Construction in process	113.8		144.3
Total property, plant and equipment, net	$	365.1	$	366.3

The depreciation expense and impairment charges related to property, plant and equipment in 2024, 2023 and 2022, were as follows:

(Dollars in millions)	2024		2023		2022
Depreciation expense	$	37.0	$	37.7	$	29.5
Impairment charges	$	7.9	$	—	$	47.2