Supplemental Oil And Gas Disclosures (Schedule Of Proved Developed And Undeveloped Oil And Gas Reserve Quantities) (Details)	12 Months Ended
	Dec. 31, 2013 bbl	Dec. 31, 2012 bbl	Dec. 31, 2011 bbl
Oil [Member] (bbls)
Reserve Quantities [Line Items]
Beginning of year	21,998,000	20,255,000	17,494,000
Revision of previous estimates	(2,113,000)	(1,747,000)	374,000	[1]
Extensions and discoveries	4,678,000	5,014,000	3,477,000
Infill reserves in existing proved fields	2,299,000	4,196,000	1,229,000
Purchases of minerals in place	0	2,830,000	192,000
Production	(3,360,000)	(3,279,000)	(2,511,000)
Sales	(1,737,000)	(5,271,000)	0
End of Year	21,765,000	21,998,000	20,255,000
Beginning of year, developed	16,441,000	15,618,000	12,773,000
End of year, developed	15,594,000	16,441,000	15,618,000
Beginning of year, undeveloped	5,557,000	4,637,000	4,721,000
End of year, undeveloped	6,171,000	5,557,000	4,637,000
Natural Gas Liquids [Member] (bbls)
Reserve Quantities [Line Items]
Beginning of year	35,166,000	22,087,000	16,117,000
Revision of previous estimates	836,000	(2,682,000)	2,112,000	[1]
Extensions and discoveries	7,273,000	4,819,000	3,924,000
Infill reserves in existing proved fields	1,945,000	3,018,000	1,780,000
Purchases of minerals in place	0	11,098,000	393,000
Production	(3,914,000)	(2,796,000)	(2,239,000)
Sales	(101,000)	(378,000)	0
End of Year	41,205,000	35,166,000	22,087,000
Beginning of year, developed	25,657,000	16,649,000	12,088,000
End of year, developed	30,437,000	25,657,000	16,649,000
Beginning of year, undeveloped	9,509,000	5,438,000	4,029,000
End of year, undeveloped	10,768,000	9,509,000	5,438,000
Natural Gas [Member] (Mcf)
Reserve Quantities [Line Items]
Beginning of year	555,647,000	442,135,000	420,486,000
Revision of previous estimates	2,421,000	(55,110,000)	(30,510,000)	[1]
Extensions and discoveries	68,611,000	54,761,000	39,836,000
Infill reserves in existing proved fields	21,573,000	25,057,000	15,592,000
Purchases of minerals in place	11,000	141,494,000	40,835,000
Production	(56,757,000)	(48,930,000)	(44,104,000)
Sales	(9,722,000)	(3,760,000)	0
End of Year	581,784,000	555,647,000	442,135,000
Beginning of year, developed	452,844,000	372,311,000	346,928,000
End of year, developed	464,234,000	452,844,000	372,311,000
Beginning of year, undeveloped	102,803,000	69,824,000	73,558,000
End of year, undeveloped	117,550,000	102,803,000	69,824,000

[1] Natural gas revisions of previous estimates decreased primarily due to a decline in natural gas prices.