Derivative Instruments (Schedule Of Effect Of Derivatives Not Designated As Hedges On Results Of Operations) (Details) (Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Oil And Gas Commodity Derivatives [Member]
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives		$ (887)		$ (1,904)
Embedded Derivative Financial Instruments [Member]
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives	$ (1,277)	$ (2,918)	$ 303	$ 931