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Inventory	12 Months Ended
Inventory	Dec. 31, 2019
Inventory [Abstract]
Inventory	(3) INVENTORY Inventory is valued at lower of average cost or net realizable value (NRV). As of December 31, 2019, and December 31, 2018, coal inventory includes NRV adjustments of $2.0 million and $1.3 million, respectively.