v3.19.3
Derivative Financial Instruments (Schedule of Derivative Offset Amounts) (Details) - USD ($)
$ in Thousands
Sep. 30, 2019
Dec. 31, 2018
Derivative [Line Items]    
Energy commodity derivatives deposits $ 21,811 $ 0
Exchange Traded [Member]    
Derivative [Line Items]    
Derivative Asset, Fair Value, Gross Asset 16,978 62,166
Derivative Liability, Fair Value, Gross Liability (12,139) (7,155)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral 4,839 55,011
Derivative, Collateral, Right to Reclaim Cash   (37,328)
Energy commodity derivatives deposits 21,811  
Amount After Offset [1] $ 26,650 $ 17,683
[1]
Amount represents the maximum loss we would incur if all of our counterparties failed to perform on their derivative contracts.