Supplemental Oil And Gas Disclosures (Schedule Of Proved Developed And Undeveloped Oil And Gas Reserve Quantities) (Details) bbl in Thousands, Mcf in Thousands, MBoe in Thousands	12 Months Ended
	Dec. 31, 2019 MBoe bbl Mcf		Dec. 31, 2018 MBoe bbl Mcf		Dec. 31, 2017 MBoe bbl Mcf
Proved developed and undeveloped reserves:
Beginning of year (MBoe) | MBoe	159,681		149,774		117,774
Revision of previous estimate (MBoe) | MBoe	(68,366)	[1]	(4,165)	[2]	11,444
Extension and discovery (MBoe) | MBoe	3,015	[1]	21,033		14,975
Infill reserves in existing proved fields (MBoe) | MBoe	1,506		8,656		16,123
Purchase of mineral in place (MBoe) | MBoe	503		2,707		5,768
Production (MBoe) | MBoe	(16,825)		(17,070)		(15,996)
Sales (MBoe) | MBoe	(7,590)		(1,254)		(314)
End of year (MBoe) | MBoe	71,924		159,681		149,774
Proved developed reserves:
Beginning of year (MBoe) | MBoe	111,576		112,961		99,079
End of year (MBoe) | MBoe	71,924		111,576		112,961
Proved undeveloped reserves
Beginning of year (MBoe) | MBoe	48,105		36,813		18,695
End of year (MBoe) | MBoe	0		48,105		36,813
Oil (bbls)
Proved developed and undeveloped reserves:
Beginning of year	22,558		19,513		15,696
Revision of previous estimates	(8,263)	[1]	180	[2]	730
Extensions and discoveries	703	[1]	3,250		2,235
Infill reserves in existing proved fields	271		1,898		1,632
Purchases of minerals in place	183		701		2,019
Production	(3,208)		(2,874)		(2,715)
Sales	(48)		(110)		(84)
End of year	12,196		22,558		19,513
Proved developed reserves:
Beginning of year	15,192		14,862		12,724
End of year	12,196		15,192		14,862
Proved undeveloped reserves
Beginning of year	7,366		4,651		2,972
End of year	0		7,366		4,651
Natural Gas Liquids (bbls)
Proved developed and undeveloped reserves:
Beginning of year	47,796		45,486		34,482
Revision of previous estimates	(20,961)	[1]	(1,368)	[2]	4,325
Extensions and discoveries	845	[1]	5,149		4,520
Infill reserves in existing proved fields	434		2,795		5,779
Purchases of minerals in place	101		856		1,197
Production	(4,773)		(4,925)		(4,737)
Sales	(412)		(197)		(80)
End of year	23,030		47,796		45,486
Proved developed reserves:
Beginning of year	33,515		33,358		28,502
End of year	23,030		33,515		33,358
Proved undeveloped reserves
Beginning of year	14,281		12,128		5,980
End of year	0		14,281		12,128
Natural gas (Mcf)
Proved developed and undeveloped reserves:
Beginning of year | Mcf	535,963		508,650		405,579
Revision of previous estimates | Mcf	(234,852)	[1]	(17,859)	[2]	38,330
Extensions and discoveries | Mcf	8,798	[1]	75,806		49,321
Infill reserves in existing proved fields | Mcf	4,806		23,778		52,270
Purchases of minerals in place | Mcf	1,316		6,897		15,313
Production | Mcf	(53,064)		(55,627)		(51,260)
Sales | Mcf	(42,780)		(5,682)		(903)
End of year | Mcf	220,187		535,963		508,650
Proved developed reserves:
Beginning of year | Mcf	377,216		388,446		347,121
End of year | Mcf	220,187		377,216		388,446
Proved undeveloped reserves
Beginning of year | Mcf	158,747		120,204		58,458
End of year | Mcf	0		158,747		120,204

[1] Revisions of previous estimates and extensions and discoveries decreased primarily due to the removal of proved undeveloped reserves due to uncertainty regarding our ability to finance the development of our proved undeveloped reserves over a five-year period and from lower commodity prices.

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