Capital Stock and Equity Compensation (Tables)

3 Months Ended

Mar. 31, 2025

Share-Based Payment Arrangement, Noncash Expense [Abstract]

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

The components of equity compensation expense were as follows:

	Three Months Ended
(Dollars in millions)	March 31, 2025		March 31, 2024
Performance-based restricted stock units expense	$	1.8	$	1.3
Time-based restricted stock units expense	1.7		1.9
Deferred stock units expense	0.1		—
Other	—		0.3
Total equity compensation expense	$	3.6	$	3.5

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 three months ended March 31, 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	(2,218)
Awards outstanding as of March 31, 2025	190,722

A summary of activity of the outstanding time-based restricted stock units for the three months ended March 31, 2025 is presented below:

	Time-Based Restricted Stock Units
Awards outstanding as of December 31, 2024	110,745
Awards granted	88,973
Stock issued	(39,852)
Awards forfeited/cancelled	(2,339)
Awards outstanding as of March 31, 2025	157,527

A summary of activity of the outstanding deferred stock units for the three months ended March 31, 2025 is presented below:

	Deferred Stock Units
Awards outstanding as of December 31, 2024	11,900
Awards granted	536
Stock issued	(450)
Awards outstanding as of March 31, 2025	11,986