XML 44 R34.htm IDEA: XBRL DOCUMENT v3.23.2
Business Segments (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2023
Jun. 30, 2022
Jun. 30, 2023
Jun. 30, 2022
Segment Reporting Information [Line Items]        
Revenues $ 61,350 $ 61,369 $ 111,491 $ 116,392
Operating profit (loss) 1,750 29,683 3,564 44,627
Expenditures for property, plant and equipment and acquisition of mineral interests 6,256 20,269 14,135 24,918
Depreciation, depletion and amortization 7,090 6,488 14,109 12,615
Operating segments | Coal Mining        
Segment Reporting Information [Line Items]        
Revenues 26,343 26,602 46,996 47,564
Operating profit (loss) (4,675) 21,175 (4,362) 28,527
Expenditures for property, plant and equipment and acquisition of mineral interests 1,032 6,280 3,718 8,000
Depreciation, depletion and amortization 4,348 4,388 8,588 8,426
Operating segments | NAMining        
Segment Reporting Information [Line Items]        
Revenues 21,716 22,814 42,349 44,218
Operating profit (loss) 2,214 1,257 3,044 2,528
Expenditures for property, plant and equipment and acquisition of mineral interests 4,507 6,561 8,930 8,381
Depreciation, depletion and amortization 1,855 1,493 3,741 2,960
Operating segments | Minerals Management        
Segment Reporting Information [Line Items]        
Revenues 9,171 11,962 17,456 24,716
Operating profit (loss) 7,289 13,073 13,333 24,701
Expenditures for property, plant and equipment and acquisition of mineral interests 638 116 982 949
Depreciation, depletion and amortization 749 543 1,560 1,121
Unallocated Items        
Segment Reporting Information [Line Items]        
Revenues 4,628 617 5,819 809
Operating profit (loss) (3,065) (5,952) (8,418) (11,391)
Expenditures for property, plant and equipment and acquisition of mineral interests 79 7,312 505 7,588
Depreciation, depletion and amortization 138 64 220 108
Eliminations        
Segment Reporting Information [Line Items]        
Revenues (508) (626) (1,129) (915)
Operating profit (loss) $ (13) $ 130 $ (33) $ 262