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Derivatives and Fair Value Measurements - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) $ / $	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) $ / $	Jun. 30, 2023 USD ($)	Jun. 30, 2024 AUD ($) $ / $	Dec. 31, 2023 USD ($)
Derivatives, Fair Value [Line Items]
Unobservable Measurement Input, Uncertainty, Description			10
Asset impairment	$ 0.0	$ 0.0	$ 0.0	$ 2.0
Fair Value, Inputs, Level 1, 2 and 3
Derivatives, Fair Value [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Notional amount					$ 455,000,000.0
Foreign Exchange Contract [Member] \| Minimum
Derivatives, Fair Value [Line Items]
Derivative, exchange rate cap (in dollars per share) \| $ / $	0.70		0.70		0.70
Foreign Exchange Contract [Member] \| Maximum
Derivatives, Fair Value [Line Items]
Derivative, exchange rate cap (in dollars per share) \| $ / $	0.71		0.71		0.71
Foreign Exchange Contract [Member] \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 2.2		$ 2.2			$ 6.2
Coal derivative contracts related to forecasted sales
Derivatives, Fair Value [Line Items]
Notional amount					$ 0
Foreign Exchange Option
Derivatives, Fair Value [Line Items]
Notional amount					$ 507,000,000
Derivative, Floor Price					0.59
Derivative, Cap Price					0.72