Fair Value (Reconciliation For All Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Significant Unobservable Inputs (Level 3)) (Details) - Level 3 [Member] - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ (2,976,000)	$ (5,262,000)
Gain (Loss) Included in Earnings	0	0
Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Included in regulatory assets/liabilities	485,000	7,959,000
Purchases	0	0
Issuances	0	0
Settlements	238,000	(5,413,000)
Transfers, Net	0	0
Ending Balance	(2,253,000)	(2,716,000)
Natural Gas Exchange Agreements [Member]
Fair Value Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(2,976,000)	(2,774,000)
Gain (Loss) Included in Earnings	0	0
Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Included in regulatory assets/liabilities	485,000	8,977,000
Purchases	0	0
Issuances	0	0
Settlements	238,000	(8,307,000)
Transfers, Net	0	0
Ending Balance	(2,253,000)	(2,104,000)
Power Exchange Agreements [Member]
Fair Value Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	0	(2,488,000)
Gain (Loss) Included in Earnings	0	0
Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Included in regulatory assets/liabilities	0	(1,018,000)
Purchases	0	0
Issuances	0	0
Settlements	0	2,894,000
Transfers, Net	0	0
Ending Balance	$ 0	$ (612,000)