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Business Segments (Concentration Risk) (Details) - Percentage of Consolidated Revenue - Customer concentration risk
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Coal Mining customer | Coal Mining customer    
Segment Reporting Information [Line Items]    
Percentage of Consolidated Revenue 39.00% 43.00%
NAMining customer | NAMining customer    
Segment Reporting Information [Line Items]    
Percentage of Consolidated Revenue 17.00% 19.00%