Concentration of Credit Risk and Major Customers (Tables)

12 Months Ended

Dec. 31, 2019

Risks and Uncertainties [Abstract]

Schedule of Concentration of Credit Risk

Concentration of credit risk is summarized below:

	December 31,
	2019		2018
Thermal coal utilities	$	58,557	$	61,218
Coal exporters and distributors	73,416		22,972
Steel and coke producers	—		661
Other	1,815		2,738
Total Trade Receivables	133,788		87,589
Less: Allowance for doubtful accounts	2,100		—
Total Trade Receivables, net of Allowance	$	131,688	$	87,589