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Inventory	3 Months Ended
Inventory	Mar. 31, 2020
Inventory [Abstract]
Inventory	(3)INVENTORY Inventory is valued at lower of average cost or net realizable value (NRV). As of March 31, 2020, and December 31, 2019, coal inventory includes NRV adjustments of $1.1 million and $2.0 million, respectively.