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		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Oil And Gas Commodity Derivatives [Member]
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives		$ (1,515)		$ (3,420)
Embedded Derivative Financial Instruments [Member]
Derivative [Line Items]
Unrealized Gain (Loss) on Derivatives	$ 855	$ 311	$ 1,158	$ 1,242