Derivatives And Fair Value Measurements (Estimated Fair Value Of Derivative Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 86,003	$ 113,367
Noncurrent derivative assets	75,328	105,270
Noncurrent derivative liabilities	3,172	17,485
Asset Derivatives [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets	161,854	221,001
Liability Derivatives [Member]
Derivatives, Fair Value [Line Items]
Total derivative liabilities	3,695	19,849
Not Designated as Hedging Instrument [Member] \| Asset Derivatives [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	86,003	113,367
Noncurrent derivative assets	75,403	107,542
Current derivative liabilities	0	0
Noncurrent derivative liabilities	448	92
Not Designated as Hedging Instrument [Member] \| Liability Derivatives [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	0	0
Noncurrent derivative assets	75	2,272
Current derivative liabilities	0	0
Noncurrent derivative liabilities	$ 3,620	$ 17,577

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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