XML 45 R64.htm IDEA: XBRL DOCUMENT v3.19.3
Commitments and Contingencies - Coal Supply (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2019
Jun. 30, 2019
Sep. 30, 2019
Dec. 31, 2018
Sep. 30, 2018
Jan. 31, 2016
Public Utilities, Commitments And Contingencies [Line Items]            
Other current assets $ 48,761   $ 48,761 $ 54,808    
PNM            
Public Utilities, Commitments And Contingencies [Line Items]            
Other current assets 37,213   37,213 43,516    
PNM | Loss on long-term purchase commitment | Surface            
Public Utilities, Commitments And Contingencies [Line Items]            
Final reclamation, capped amount to be collected       100,000    
Loss contingency accrual 70,600   70,600 70,100    
PNM | Loss on long-term purchase commitment | Underground            
Public Utilities, Commitments And Contingencies [Line Items]            
Loss contingency accrual 24,800   24,800 23,200    
PNM | Loss on long-term purchase commitment | San Juan Generating Station | Surface            
Public Utilities, Commitments And Contingencies [Line Items]            
Estimate of possible loss 93,600   93,600      
PNM | Loss on long-term purchase commitment | San Juan Generating Station | Underground            
Public Utilities, Commitments And Contingencies [Line Items]            
Estimate of possible loss 40,000   40,000      
Coal supply | PNM | San Juan Generating Station            
Public Utilities, Commitments And Contingencies [Line Items]            
Other current assets 26,300   26,300 26,300    
Coal supply | NM Capital | San Juan Generating Station            
Public Utilities, Commitments And Contingencies [Line Items]            
Requirement to post reclamation bonds 118,700   118,700      
Cash used to support bank letter or credit arrangement 30,300   30,300     $ 30,300
Increase in coal mine decommissioning liability | PNM            
Public Utilities, Commitments And Contingencies [Line Items]            
Regulatory disallowance, additional amount recorded   $ 300        
Increase in coal mine decommissioning liability | PNM | Underground and Surface            
Public Utilities, Commitments And Contingencies [Line Items]            
Regulatory disallowance, additional amount recorded       39,200    
Increase in coal mine decommissioning liability | PNM | Surface            
Public Utilities, Commitments And Contingencies [Line Items]            
Regulatory disallowance, additional amount recorded       29,800    
Increase in coal mine decommissioning liability | PNM | Underground            
Public Utilities, Commitments And Contingencies [Line Items]            
Regulatory disallowance, additional amount recorded       9,400    
Increase in coal mine decommissioning liability | PNM | Loss on long-term purchase commitment            
Public Utilities, Commitments And Contingencies [Line Items]            
Estimated underpaid surface mining royalties under proposed rate change         $ 2,500  
Mine Reclamation Trust | PNM            
Public Utilities, Commitments And Contingencies [Line Items]            
Required contribution to reclamation trust, current fiscal year 5,500   5,500      
Reclamation trust funding, year 2 10,200   10,200      
Reclamation trust funding, year 3 10,900   10,900      
Four Corners CSA | PNM            
Public Utilities, Commitments And Contingencies [Line Items]            
Other commitment, due in first year 2,300   2,300      
Other commitment, due in second year 2,300   2,300      
Other commitment, due in third year 1,900   1,900      
Other commitment, due in fourth year 1,900   1,900      
Other commitment, due in seventh year 1,900   1,900      
Other commitment, due in fifth year 1,900   1,900      
Other commitment, due in sixth year 1,900   1,900      
San Juan Generating Station | Loss on long-term purchase commitment | PNM            
Public Utilities, Commitments And Contingencies [Line Items]            
Annual funding post-term reclamation trust       $ 10,000    
Four Corners | Increase in coal mine decommissioning liability | PNM            
Public Utilities, Commitments And Contingencies [Line Items]            
Regulatory disallowance, additional amount recorded $ 1,100   $ 800