XML 12 R43.htm IDEA: XBRL DOCUMENT v3.20.1
Palo Verde Generating Station (Narrative) (Details) - USD ($)
$ in Thousands
3 Months Ended
Apr. 20, 2020
Oct. 31, 2019
Mar. 31, 2020
Mar. 31, 2019
Jointly Owned Utility Plant Interests [Line Items]        
Increase (Decrease) in Deferred Fuel Costs     $ 6,174 $ (12,799)
Suit Against Department of Energy for Spent Fuel | Palo Verde Participants        
Jointly Owned Utility Plant Interests [Line Items]        
Legal Settlement Extension     3 years  
Litigation, Claim Amount   $ 16,000    
Subsequent Event | Suit Against Department of Energy for Spent Fuel | Palo Verde Generating Station        
Jointly Owned Utility Plant Interests [Line Items]        
Proceeds from Legal Settlements $ 2,400      
Increase (Decrease) in Deferred Fuel Costs $ (900)