Equity Investments - Investment in ATC (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Investments In ATC [Roll Forward]
Equity Investment Balance as of December 31, 2023	$ 331.2
Cash Investments	1.6	$ 0.8
Equity Earnings	5.5	6.0
Equity Investment Balance as of March 31, 2024	333.1
Net Loss Attributable to Non-Controlling Interest	(13.7)	$ (20.6)
ATC
Investments In ATC [Roll Forward]
Equity Investment Balance as of December 31, 2023	179.7
Cash Investments	1.6
Equity Earnings	5.7
Distributed earnings	(4.6)
Amortization of the Remeasurement of Deferred Income Taxes	0.3
Equity Investment Balance as of March 31, 2024	182.7
Nobles 2
Investments In ATC [Roll Forward]
Equity Investment Balance as of December 31, 2023	151.5
Equity Earnings	(0.2)
Distributed earnings	(0.9)
Equity Investment Balance as of March 31, 2024	150.4
Net Loss Attributable to Non-Controlling Interest	$ 3.0

Amortization From The Remeasurement Of Deferred Income Taxes For Equity Method Investments

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- Definition

Investments In ATC

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Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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- Definition

Amount of Net Income (Loss) attributable to noncontrolling interest.

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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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