XML 234 R87.htm IDEA: XBRL DOCUMENT v3.22.4
Business Segments (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Segment Reporting Information [Line Items]    
Revenues $ 241,719 $ 191,846
Operating profit (loss) 69,986 55,410
Expenditures for property, plant and equipment and acquisition of mineral interests 54,447 44,561
Depreciation, depletion and amortization 26,816 23,085
Operating Segments | Coal Mining customer    
Segment Reporting Information [Line Items]    
Revenues 95,204 82,831
Operating profit (loss) 38,309 45,784
Expenditures for property, plant and equipment and acquisition of mineral interests 14,853 16,830
Depreciation, depletion and amortization 17,074 16,510
Operating Segments | NAMining customer    
Segment Reporting Information [Line Items]    
Revenues 85,664 78,944
Operating profit (loss) 2,202 3,384
Expenditures for property, plant and equipment and acquisition of mineral interests 13,203 21,100
Depreciation, depletion and amortization 6,457 4,574
Operating Segments | Minerals Management    
Segment Reporting Information [Line Items]    
Revenues 60,242 31,003
Operating profit (loss) 52,214 26,080
Expenditures for property, plant and equipment and acquisition of mineral interests 13,388 6,423
Depreciation, depletion and amortization 3,026 1,858
Unallocated Items    
Segment Reporting Information [Line Items]    
Revenues 2,952 4,695
Operating profit (loss) (23,233) (19,553)
Expenditures for property, plant and equipment and acquisition of mineral interests 13,003 208
Depreciation, depletion and amortization 259 143
Eliminations    
Segment Reporting Information [Line Items]    
Revenues (2,343) (5,627)
Operating profit (loss) $ 494 $ (285)