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Segment Information - Segment Information and Reconciliations to Consolidated Amounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Coal revenues	$ 861,283	$ 906,698
Other revenues	2,789	4,537
Total revenues	864,072	911,235
All Other
Segment Reporting Information [Line Items]
Coal revenues	0	19,691
Met | Operating Segments
Segment Reporting Information [Line Items]
Coal revenues	861,283	887,007
Other revenues	2,789	4,537
Total revenues	$ 864,072	$ 891,544

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