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Business Segments (Concentration Risk) (Details) - Percentage of Consolidated Revenue - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Utility Coal Mining customer \| Utility Coal Mining customer
Segment Reporting Information [Line Items]
Percentage of Consolidated Revenue (percent)	32.00%	29.00%
Contract Mining customer \| Contract Mining customer
Segment Reporting Information [Line Items]
Percentage of Consolidated Revenue (percent)	25.00%	24.00%
Contract Mining customer \| Contract Mining customer
Segment Reporting Information [Line Items]
Percentage of Consolidated Revenue (percent)	10.00%	11.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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