Other Comprehensive Income (Loss) (Components And Allocated Tax Effects Of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Other Comprehensive Income (Loss) Components and Tax Effects [Line Items]
Net Unrealized Gain (Loss) on Marketable Securities before Taxes	$ (63)	$ 25	$ 5	$ 36
Net unrealized gain (loss) on hedging instruments	(5,809)	34,315	(25,128)	121,398
Net change in pension and other post-retirement benefit obligation	0	0	0	(89)
Other comprehensive income (loss)	(5,872)	34,340	(25,123)	121,345
Less other comprehensive income attributable to noncontrolling interest	135	(453)	(319)	(395)
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Stockholders	(6,007)	34,793	(24,804)	121,740
Net Unrealized Gain (loss) on Marketable Securities, Tax	(25)	17	2	14
Net unrealized gain (loss) on hedging instruments, tax expense (benefit)	(2,300)	13,400	(9,602)	47,143
Net change in Pension and Other Postretirement Benefit Plans, Tax				(35)
Other comprehensive income, tax expense	(2,325)	13,417	(9,600)	47,122
Other Comprehensive Income (Loss), Tax, Portion Attributable to Stockholders	(2,325)	13,417	(9,600)	47,122
Net unrealized gain (loss) on marketable securities, after tax	(38)	8	3	22
Net unrealized gain (loss) on hedging instruments, after tax	(3,509)	20,915	(15,526)	74,255
Net Change in Pension and Other Post-retirement Benefit Obligations, After Tax				(54)
Other comprehensive income (loss), net of tax	(3,547)	20,923	(15,523)	74,223
Less other comprehensive income attributable to noncontrolling interest, after tax	135	(453)	(319)	(395)
Other Comprehensive Income (Loss) Portion Attributable to Stockholders	$ (3,682)	$ 21,376	$ (15,204)	$ 74,618