Pension And Other Postretirement Benefits (Schedule Of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net Unfunded Status of Plans [Roll Forward]
Net funded status before tax adjustments	$ (62,743)	$ (64,463)	$ (91,182)		$ (91,182)
Service cost	(2,079)	(2,078)	(2,079)	$ (1,808)	(6,236)	$ (5,423)
Interest cost	(7,411)	(7,408)	(7,408)	(7,788)	(22,227)	(23,365)
Expected return on assets	11,204	11,206	11,206	10,474	33,616	31,420
Actuarial valuation adjustment	108
Employer contributions during quarter	146		25,000
Net funded status before tax adjustments	(60,775)	(62,743)	(64,463)		(60,775)
Regulatory Assets Related to Pensions [Roll Forward]
Amortization of prior service cost	(1,217)			(1,214)	(3,650)	(3,640)
Amortization of net actuarial loss	(3,470)			(2,428)	(10,420)	(7,283)
ASC 715 settlement accounting re-actuarial valuation - supplemental plan(2)	(206)			$ 0	(206)	$ 0
Pension Plan [Member]
Net Unfunded Status of Plans [Roll Forward]
Actuarial valuation adjustment	(108)
Regulatory Assets Related to Pensions [Roll Forward]
Regulatory assets before tax adjustments	227,508	232,200	236,891		236,891
Amortization of prior service cost	(1,217)	(1,217)	(1,216)
Amortization of net actuarial loss	(3,470)	(3,475)	(3,475)
ASC 715 settlement accounting re-actuarial valuation - supplemental plan(2)	(206)
Regulatory assets before tax adjustments	$ 222,507	$ 227,508	$ 232,200		$ 222,507