Capital Stock and Equity Compensation (Tables)

6 Months Ended

Jun. 30, 2025

Share-Based Payment Arrangement, Noncash Expense [Abstract]

Schedule of Stockholders Equity

(Dollars in millions, except shares and per share amounts)
Period	Total Number of Shares Purchased	Average Price Paid per Share		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs	Approximate Dollar Value of Shares that May Yet be Purchased under the Plans or Programs
April 1, 2025 to April 30, 2025	—	$	—	—	$	104.2
May 1, 2025 to May 31, 2025	406,560	$	63.09	406,560	$	77.4
June 1, 2025 to June 30, 2025	19,430	$	66.01	19,430	$	76.1

Schedule of Share-Based Payment Arrangement, Expensed and Capitalized, Amount

The components of equity compensation expense were as follows:

	Three Months Ended				Six Months Ended
(Dollars in millions)	June 30, 2025		June 30, 2024		June 30, 2025		June 30, 2024
Performance-based restricted stock units expense	$	2.1	$	2.0	$	3.9	$	3.3
Time-based restricted stock units expense	1.8		2.1		3.5		4.0
Deferred stock units expense	0.1		1.3		0.2		1.3
Other	0.3		(0.1)		0.3		0.2
Total equity compensation expense	$	4.3	$	5.3	$	7.9	$	8.8

Schedule of Weighted-Average Assumptions Used

The following table sets forth the assumptions used in the Monte Carlo calculation for each material award granted in 2025 and 2024:

	February 26, 2025	February 19, 2024	February 13, 2024
Expected volatility	45.6%	46.3%	46.2%
Expected term (in years)	2.9	2.9	2.9
Risk-free interest rate	4.28%	4.35%	4.35%

Schedule of Restricted Stock and Restricted Stock Activity

A summary of activity of the outstanding performance-based restricted stock units for the six months ended June 30, 2025 is presented below:

	Performance-Based Restricted Stock Units
Awards outstanding as of December 31, 2024	109,106
Awards granted	83,834
Stock issued	—
Awards forfeited/cancelled	(5,069)
Awards outstanding as of June 30, 2025	187,871

A summary of activity of the outstanding time-based restricted stock units for the six months ended June 30, 2025 is presented below:

	Time-Based Restricted Stock Units
Awards outstanding as of December 31, 2024	110,745
Awards granted	88,973
Stock issued	(47,882)
Awards forfeited/cancelled	(5,244)
Awards outstanding as of June 30, 2025	146,592

A summary of activity of the outstanding deferred stock units for the six months ended June 30, 2025 is presented below:

	Deferred Stock Units
Awards outstanding as of December 31, 2024	11,900
Awards granted	22,616
Stock issued	(10,950)
Awards outstanding as of June 30, 2025	23,566