Assets Held For Sale And Discontinued Operations (Schedule Of The Amounts In Net Loss From Discontinued Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets Held For Sale And Discontinued Operations [Abstract]
Revenues									$ 30	$ 23	$ 5
Production costs and taxes									(315)	(260)	(167)
Depreciation, depletion, and amortization									(223)	(176)	(421)
Impairment									(5,242)		(4,957)
Deferred income tax benefit									1,419	127	1,884
Current income tax benefit									20
Net loss from discontinued operations, net of income tax	$ (4,105)	$ (60)	$ (65)	$ (81)	$ (93)	$ (51)	$ (60)	$ (82)	$ (4,311)	$ (286)	$ (3,656)