v3.26.1
Segment Information (Disaggregation of Revenue) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Disaggregation of Revenue [Line Items]    
Total coal revenues $ 460,491 $ 441,451
Other revenues 6,701 7,797
Total 467,192 449,248
Metallurgical Coal [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues 408,273 421,502
Thermal Coal [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues 52,218 19,949
Australia Segment [Member] | Operating Segments [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues 252,406 266,024
Other revenues 6,682 7,253
Total 259,088 273,277
Australia Segment [Member] | Metallurgical Coal [Member] | Operating Segments [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues 209,992 250,065
Australia Segment [Member] | Thermal Coal [Member] | Operating Segments [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues 42,414 15,959
United States Segment [Member] | Operating Segments [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues 208,085 175,427
Other revenues 19 544
Total 208,104 175,971
United States Segment [Member] | Metallurgical Coal [Member] | Operating Segments [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues 198,281 171,437
United States Segment [Member] | Thermal Coal [Member] | Operating Segments [Member]    
Disaggregation of Revenue [Line Items]    
Total coal revenues $ 9,804 $ 3,990