Commitments And Contingencies (Narrative) (Details) (USD $)	12 Months Ended											1 Months Ended
	Dec. 31, 2017 BarrelsPerDay	Dec. 31, 2012 BarrelsPerDay	Dec. 31, 2011 Mcf MMcf years bbl BarrelsPerDay	Dec. 31, 2010 years Mi	Dec. 31, 2009	Dec. 31, 2011 Raton Basin [Member]	Dec. 31, 2011 Pipeline From Opal, Wyoming To Malin, Oregon [Member] Mi Mcf	Dec. 31, 2011 Lease Payments Discontinued Operations [Member]	Dec. 31, 2010 Lease Payments Discontinued Operations [Member]	Dec. 31, 2009 Lease Payments Discontinued Operations [Member]	Dec. 31, 2011 Permian Basin [Member] bbl	Jun. 30, 2010 Eagle Ford Shale [Member] Oil And Gas Production [Member]	Jun. 30, 2010 EFS Midstream [Member] years
Commitments And Contingencies [Line Items]
Current annual salaries of officers and key employees			$ 42,600,000
Lease payments associated with operating leases			26,900,000	29,500,000	30,500,000
Average gross gas volume (in MMcf/Mcf per day)							75,000
Average gross gas volumes 2012 (in Bbls per day)		7,100
Average gross gas volumes 2017 (in Bbls per day)	17,400
Average gross gas volumes 2011 (in Mcfs per day)			37,000
Average gross gas volumes 2015 (in Mcf per day)			83,500
Average gross gas volumes 2011 (in Mcf per day)			41,800
Average gross gas volumes 2020 (in Mcfs per day)			139,100			214,000
Average gross gas volumes decline in 2026 (in Mcfs per day)			133,000
Fractionation Commitments, 2011 (Bbls per day)			4,500
Fractionation Commitments, 2020 (Bbls per day)			14,900
Transportation commitments termination period					10
Number of years of oil gathering agreement				10
Number of years of gas transportation agreements			5
Pipeline length (in miles)				111			675
Income from discontinued operations, net of tax			423,152,000	134,050,000	99,716,000			513,000	7,200,000	10,700,000
Minimum transportation and fractionation commitments, 2012 (Bbls per day)			2,000								13,900
Minimum transportation and fractionation commitments, 2012 Until 2021 (Bbls per day)											16,000
Minimum transportation and fractionation commitments, 2019 until 2027 (Bbls per day)			15,000
Average fractionation commitments, NGL commencing 2014 (Bbls per day)			2,000
Average fractionation commitments, NGL, 2018 through 2023 (Bbls per day)			10,000
Average gross gas volumes mid 2016 (in Mcf per day)			9,700
Deferred gain on sale of EFS midstream													46,200,000
Revenue commitments													46,200,000
Revenue commitments													128,000,000
EFS midstream deferred gain amortization period, years													20
Transportation commitment term												$ 20
Gas gathering and processing in 2013 (in Mcfs per day)			50,000
Gas gathering and processing in 2016 (in Mcfs per day)			95,000
Gas gathering and processing in 2019 (in Mcfs per day)			70,000