Fair Value Measurements (Schedule Of Quantitative Information About Unobservable Inputs) (Details) - Level 3 $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) $ / Unit
Crude Oil | Collar
Derivative assets, Fair Value | $	$ 3,893	[1]
Derivatives assets, Valuation Technique(s)	Discounted cash flow	[1]
Unobservable Input	Forward commodity price curve	[1]
Crude Oil | Three-way collar
Derivative assets, Fair Value | $	$ 3,470	[1]
Derivatives assets, Valuation Technique(s)	Discounted cash flow	[1]
Unobservable Input	Forward commodity price curve	[1]
Crude Oil | Minimum | Collar
Derivative, Forward Price	0.4
Crude Oil | Minimum | Three-way collar
Derivative, Forward Price	0.4
Crude Oil | Maximum | Collar
Derivative, Forward Price	55.05
Crude Oil | Maximum | Three-way collar
Derivative, Forward Price	71.66
Natural gas | Collar
Derivative assets, Fair Value | $	$ 1,000	[1]
Derivatives assets, Valuation Technique(s)	Discounted cash flow	[1]
Unobservable Input	Forward commodity price curve	[1]
Natural gas | Three-way collar
Derivative assets, Fair Value | $	$ 731	[1]
Derivatives assets, Valuation Technique(s)	Discounted cash flow	[1]
Unobservable Input	Forward commodity price curve	[1]
Natural gas | Minimum | Collar
Derivative, Forward Price	0.4
Natural gas | Minimum | Three-way collar
Derivative, Forward Price	0.4
Natural gas | Maximum | Collar
Derivative, Forward Price	1.26
Natural gas | Maximum | Three-way collar
Derivative, Forward Price	1.93

[1] The commodity contracts detailed in this category include non-exchange-traded crude oil and natural gas collars and three-way collars that are valued based on NYMEX. The forward pricing range represents the low and high price expected to be received within the settlement period.