XML 91 R65.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value of Derivative and Other Financial Instruments, Statement of Earnings Information (Details) (Commodity Contract [Member], Economic hedges [Member], USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) $ 5,084us-gaap_DerivativeGainLossOnDerivativeNet $ 2,836us-gaap_DerivativeGainLossOnDerivativeNet $ 5,708us-gaap_DerivativeGainLossOnDerivativeNet
Electric operating revenues [Member]
     
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) 4,491us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesMember
1,727us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesMember
6,168us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_SalesMember
Cost of energy [Member]
     
Derivative Instruments, Gain (Loss) [Line Items]      
Gain (loss) $ 593us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
$ 1,109us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
$ (460)us-gaap_DerivativeGainLossOnDerivativeNet
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis
= us-gaap_FairValueHedgingMember
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember