Long-term Debt (Tables)

3 Months Ended

Mar. 31, 2024

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

The Company’s total indebtedness as of March 31, 2024 and December 31, 2023 consisted of the following:

Debt Instrument (defined below, as applicable)	March 31, 2024		December 31, 2023
	(Dollars in millions)
3.250% Convertible Senior Notes due March 2028 (2028 Convertible Notes)	$	320.0	$	320.0
Finance lease obligations	25.3		22.3
Less: Debt issuance costs	(7.6)		(8.1)
	337.7		334.2
Less: Current portion of long-term debt	14.4		13.5
Long-term debt	$	323.3	$	320.7

Schedule of Interest Charges

Additionally, the table sets forth the amount of cash paid for interest and the amount of non-cash interest expense primarily related to the amortization of debt issuance costs.

	Three Months Ended March 31,
	2024		2023
	(Dollars in millions)
2028 Convertible Notes	$	2.6	$	2.6
Finance lease obligations	0.4		0.5
Financial assurance instruments	8.8		12.0
Amortization of debt issuance costs	1.2		1.6
Other	1.7		1.7
Interest expense	$	14.7	$	18.4
Cash paid for interest	$	11.5	$	19.1
Non-cash interest expense	$	1.3	$	1.6