Derivatives (Effect Of Derivative Instruments Recognized In Statement Of Operations, Not Designated As Hedging Instruments) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivatives		$ 4,225	$ (3,184)
Cash receipts (payments) on derivatives settled		16,196	(22,803)
Commodity Contract
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivatives	[1]	$ 4,225	$ (3,184)

[1] Amounts settled during the periods are a gain of $16,196 and a loss of $22,803, respectively.