Derivatives And Fair Value Measurements (Estimated Fair Value Of Derivative Instruments) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 0	$ 120,176
Noncurrent derivative assets	0	29,391
Asset Derivatives [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets	0	201,363
Liability Derivatives [Member]
Derivatives, Fair Value [Line Items]
Total derivative liabilities	0	51,796
Not Designated as Hedging Instrument [Member] | Asset Derivatives [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	0	120,176
Noncurrent derivative assets	0	81,187
Not Designated as Hedging Instrument [Member] | Liability Derivatives [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	0	0
Noncurrent derivative assets	$ 0	$ 51,796