XML 50 R39.htm IDEA: XBRL DOCUMENT v3.24.1.u1
Revenue - Performance Obligations (Details)
$ in Thousands
Mar. 31, 2024
USD ($)
Disaggregation of Revenue [Line Items]  
Estimated coal revenues $ 85,016
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01  
Disaggregation of Revenue [Line Items]  
Estimated coal revenues $ 85,016
Estimated coal revenues, satisfaction period 9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01  
Disaggregation of Revenue [Line Items]  
Estimated coal revenues $ 0
Estimated coal revenues, satisfaction period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01  
Disaggregation of Revenue [Line Items]  
Estimated coal revenues $ 0
Estimated coal revenues, satisfaction period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01  
Disaggregation of Revenue [Line Items]  
Estimated coal revenues $ 0
Estimated coal revenues, satisfaction period 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01  
Disaggregation of Revenue [Line Items]  
Estimated coal revenues $ 0
Estimated coal revenues, satisfaction period 1 year