Concentration of Credit Risk and Major Customers - Schedule of Concentration of Credit Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Concentration Risk [Line Items]
Accounts receivables, before allowance for credit loss	$ 159,858	$ 108,696
Less: Allowance for credit losses	(1,731)	(4,597)
Total Trade Receivables, net	158,127	104,099
Accounts Receivable | Customer Concentration Risk | Electric coal utilities
Concentration Risk [Line Items]
Accounts receivables, before allowance for credit loss	82,608	41,582
Accounts Receivable | Customer Concentration Risk | Coal exporters and industrial customers
Concentration Risk [Line Items]
Accounts receivables, before allowance for credit loss	51,548	53,949
Accounts Receivable | Customer Concentration Risk | Steel and coke producers
Concentration Risk [Line Items]
Accounts receivables, before allowance for credit loss	24,230	11,560
Accounts Receivable | Customer Concentration Risk | Other
Concentration Risk [Line Items]
Accounts receivables, before allowance for credit loss	$ 1,472	$ 1,605