Fair Value of Financial Instruments - Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Assets
Restricted cash	$ 1.0	$ 0.9
2028 Notes
Liabilities
Debt instrument, interest rate	10.00%
2030 Notes
Liabilities
Debt instrument, interest rate	10.375%
Fair value \| Fair value, inputs, level 1
Assets
Cash and cash equivalents	$ 92.4	61.6
Restricted cash	1.0	0.9
Trade receivables	149.2	184.3
Other current assets (excluding deferred costs and right of use lease asset)	30.0	27.1
Due from related parties	6.4	85.1
Liabilities
Trade payables	63.8	81.6
Accrued expenses	65.0	68.0
Short term accrued interest and other items	29.7	30.6
Other current liabilities	47.7	84.2
Fair value \| Fair value, inputs, level 2
Liabilities
Short-term debt	121.1	134.8
Long-term debt	1,737.9	2,038.1
Carrying value
Assets
Cash and cash equivalents	92.4	61.6
Restricted cash	1.0	0.9
Trade receivables	149.2	184.3
Other current assets (excluding deferred costs and right of use lease asset)	30.0	27.1
Due from related parties	6.4	85.1
Liabilities
Trade payables	63.8	81.6
Accrued expenses	65.0	68.0
Short term accrued interest and other items	29.7	30.6
Other current liabilities	47.7	84.2
Carrying value \| Fair value, inputs, level 2
Liabilities
Short-term debt	134.7	134.7
Long-term debt	$ 1,977.6	$ 2,044.9

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Contractual interest rate for funds borrowed, under the debt agreement.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value portion of receivables, including, but not limited to, trade account receivables, note receivables, and loan receivables.

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Amount of cash restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

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Fair value portion of liabilities pertaining to principal and customer trading transactions, or which may be incurred with the objective of generating a profit from short-term fluctuations in price as part of an entity's market-making, hedging and proprietary trading. Examples include, but are not limited to, short positions in securities, derivatives and commodities.

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