XML 72 R54.htm IDEA: XBRL DOCUMENT v3.10.0.1
Derivative and Hedging Instruments (Details-5)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2018
USD ($)
counterparty
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
counterparty
Sep. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
Counterparties in net liability position or default [Abstract]          
Derivative, net liability position of counterparties $ 0   $ 0   $ 100
Number of counterparties in default | counterparty 0   0    
Commodity Derivative Contracts [Member] | Fuel For Electric Generation Purchased Power [Member]          
Realized losses (gains) on income statement [Line Items]          
Realized losses (gains) on income statement $ (145) $ 362 $ 39 $ 764  
Commodity Derivative Contracts [Member] | Cost Of Gas Sold Expense [Member]          
Realized losses (gains) on income statement [Line Items]          
Realized losses (gains) on income statement 0 18 637 227  
Financial Transmission Rights [Member] | Fuel For Electric Generation Purchased Power [Member]          
Realized losses (gains) on income statement [Line Items]          
Realized losses (gains) on income statement (150) (224) (625) (1,349)  
Financial Transmission Rights [Member] | Cost Of Gas Sold Expense [Member]          
Realized losses (gains) on income statement [Line Items]          
Realized losses (gains) on income statement 0 0 0 0  
Purchased Power Agreement [Member]          
Derivative collateral required to be posted for PPA [Abstract]          
Minimum collateral that may be required to be posted 20,000   20,000    
Maximum collateral that may be required to be posted 40,000   40,000    
Collateral posted 0   0    
Purchased Power Agreement [Member] | Fuel For Electric Generation Purchased Power [Member]          
Realized losses (gains) on income statement [Line Items]          
Realized losses (gains) on income statement 328 1,351 1,283 3,021  
Purchased Power Agreement [Member] | Cost Of Gas Sold Expense [Member]          
Realized losses (gains) on income statement [Line Items]          
Realized losses (gains) on income statement $ 0 $ 0 $ 0 $ 0