Realized And Unrealized Gain (Loss) On Derivatives

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

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- Definition

The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings.

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- Definition

Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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Amount before tax of reclassification adjustments of other comprehensive income (loss).

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

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Derivatives - Effects of derivatives on measures of financial performance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Designated as Hedging Instrument \| Coal Contract
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income			$ 4
Gains (Losses) Reclassified from Other Comprehensive Income into Income			(392)
Designated as Hedging Instrument \| Coal sales \| Coal Contract \| Revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income			500
Gains (Losses) Reclassified from Other Comprehensive Income into Income			(1,850)
Designated as Hedging Instrument \| Coal purchases \| Coal Contract \| Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income			(496)
Gains (Losses) Reclassified from Other Comprehensive Income into Income			1,458
Not Designated as Hedging Instrument \| Coal Contract \| Change in fair value of coal derivatives and coal trading activities, net
Derivative Instruments, Gain (Loss) [Line Items]
Realized and Unrealized Gain (Loss) on Derivatives			222
Unrealized Gain (Loss) on Derivatives	$ (1,274)	$ 2,392	(5,517)
Not Designated as Hedging Instrument \| Coal Contract \| Other operating (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Realized Gain (Loss) on Derivatives	(42,068)	$ (27,464)	9,258
Not Designated as Hedging Instrument \| Natural gas \| Change in fair value of coal derivatives and coal trading activities, net
Derivative Instruments, Gain (Loss) [Line Items]
Realized and Unrealized Gain (Loss) on Derivatives			76
Not Designated as Hedging Instrument \| Heating oil - diesel purchases \| Other operating (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Heating oil realized and unrealized gains and losses	$ 8,309		$ (558)