Fair Value Measurements (Schedule Of Quantitative Information About Unobservable Inputs) (Details) - Level 3 [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($) $ / Unit
Oil [Member] | Three-way collar [Member]
Derivative fair value | $	$ 2,270	[1]
Unobservable Input	Forward commodity price curve
Oil [Member] | Three-way collar [Member] | Minimum [Member]
Forward commodity price curve	0
Oil [Member] | Three-way collar [Member] | Maximum [Member]
Forward commodity price curve	11.80
Natural Gas [Member] | Collar [Member]
Derivative fair value | $	$ 441	[1]
Unobservable Input	Forward commodity price curve
Natural Gas [Member] | Collar [Member] | Minimum [Member]
Forward commodity price curve	0
Natural Gas [Member] | Collar [Member] | Maximum [Member]
Forward commodity price curve	2.430

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