XML 143 R118.htm IDEA: XBRL DOCUMENT v3.10.0.1
Regulatory and Rate Matters - TNMP Narrative (Details)
$ in Thousands
 1 Months Ended 12 Months Ended
Jan. 25, 2019
USD ($)
Nov. 02, 2018
USD ($)
May 30, 2018
USD ($)
Mar. 13, 2017
USD ($)
Jul. 31, 2011
USD ($)
Dec. 31, 2018
USD ($)
advanced_meter
Dec. 31, 2017
USD ($)
Public Utilities, General Disclosures [Line Items]              
Unrecovered investment revenue     $ 21,800        
Net increase in regulatory liabilities           $ 7,175 $ 548,952
Texas-New Mexico Power Company              
Public Utilities, General Disclosures [Line Items]              
Regulatory liabilities           180,929 180,662
Net increase in regulatory liabilities           (4,069) 146,451
Refund of regulatory liability to customers             37,800
Net regulatory assets           $ 1,600  
CTC Funding amount interest minimum           15.00%  
Adjustment for collection of amortization       $ 1,100      
Reduction to revenue           $ 5,400  
Texas-New Mexico Power Company | 2018 TNMP Rate Case              
Public Utilities, General Disclosures [Line Items]              
Requested rate increase (decrease)   $ 10,000 $ 25,900        
Requested return on equity   9.65% 10.50%        
Requested cost of debt, percentage   6.44% 7.20%        
Requested debt capital structure, percentage   55.00% 50.00%        
Requested equity capital structure, percentage   45.00% 50.00%        
New rate rider recovery, amount     $ 7,700        
Regulatory liabilities             146,500
Net increase in regulatory liabilities             $ 14,400
Refund of federal income tax rates period             5 years
Investments excluded from rate, amount   $ 10,600          
Texas-New Mexico Power Company | Advanced Meter System Deployment and Surcharge Request              
Public Utilities, General Disclosures [Line Items]              
Revenue from AMS rider             $ 21,800
Approved deployment costs         $ 113,400    
Period of time to collect deployment costs through surcharge period         12 years    
Number of advanced meters installed | advanced_meter           242,000  
Texas-New Mexico Power Company | Transmission Cost of Service Rates | Subsequent Event              
Public Utilities, General Disclosures [Line Items]              
Requested rate increase (decrease) $ 111,800            
Requested increase in annual transmission service revenue $ 14,300