Derivative Activities (Notional Volumes Of Commodity Derivative Contracts) (Details)	Jun. 30, 2012
Oil Positions [Member] | Jul 1 - Dec 31, 2012 [Member] | WTI [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	5,872
Average price	100.34
Oil Positions [Member] | 2013 [Member] | WTI [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	6,543
Average price	99.75
Oil Positions [Member] | 2014 [Member] | WTI [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	5,661
Average price	97.91
Oil Positions [Member] | 2014 [Member] | WTI [Member] | Collars [Member]
Derivative [Line Items]
Hedged volume per day	425
Average floor price	90.00
Average ceiling price	106.50
Oil Positions [Member] | 2015 [Member] | WTI [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	4,540
Average price	96.87
Oil Positions [Member] | 2015 [Member] | WTI [Member] | Collars [Member]
Derivative [Line Items]
Hedged volume per day	1,025
Average floor price	90.00
Average ceiling price	110.00
Oil Positions [Member] | 2016 [Member] | WTI [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	2,480
Average price	92.07
Oil Positions [Member] | 2016 [Member] | WTI [Member] | Collars [Member]
Derivative [Line Items]
Hedged volume per day	1,500
Average floor price	80.00
Average ceiling price	102.00
Oil Positions [Member] | 2017 [Member] | WTI [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	3,730
Average price	87.57
Natural Gas Positions [Member] | Jul 1 - Dec 31, 2012 [Member] | NYMEX [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	30,267
Average price	5.83
Natural Gas Positions [Member] | Jul 1 - Dec 31, 2012 [Member] | NYMEX [Member] | Basis Swaps [Member]
Derivative [Line Items]
Hedged volume per day	20,709
Average price	(0.15)
Natural Gas Positions [Member] | Jul 1 - Dec 31, 2012 [Member] | Henry Hub [Member] | Collars [Member]
Derivative [Line Items]
Hedged volume per day	2,609
Average floor price	6.50
Average ceiling price	8.60
Natural Gas Positions [Member] | 2013 [Member] | NYMEX [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	29,674
Average price	6.07
Natural Gas Positions [Member] | 2013 [Member] | NYMEX [Member] | Basis Swaps [Member]
Derivative [Line Items]
Hedged volume per day	18,466
Average price	(0.17)
Natural Gas Positions [Member] | 2013 [Member] | Henry Hub [Member] | Collars [Member]
Derivative [Line Items]
Hedged volume per day	2,466
Average floor price	6.50
Average ceiling price	8.65
Natural Gas Positions [Member] | 2014 [Member] | NYMEX [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	25,907
Average price	6.23
Natural Gas Positions [Member] | 2014 [Member] | NYMEX [Member] | Basis Swaps [Member]
Derivative [Line Items]
Hedged volume per day	17,066
Average price	(0.19)
Natural Gas Positions [Member] | 2014 [Member] | Henry Hub [Member] | Collars [Member]
Derivative [Line Items]
Hedged volume per day	4,966
Average floor price	5.74
Average ceiling price	7.51
Natural Gas Positions [Member] | 2015 [Member] | NYMEX [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	6,520
Average price	5.43
Natural Gas Positions [Member] | 2015 [Member] | NYMEX [Member] | Basis Swaps [Member]
Derivative [Line Items]
Hedged volume per day	14,400
Average price	(0.19)
Natural Gas Positions [Member] | 2015 [Member] | Henry Hub [Member] | Collars [Member]
Derivative [Line Items]
Hedged volume per day	18,000
Average floor price	5.00
Average ceiling price	7.48
Natural Gas Positions [Member] | 2015 [Member] | Henry Hub [Member] | Put [Member]
Derivative [Line Items]
Hedged volume per day	420
Average price	4.0
Natural Gas Positions [Member] | 2016 [Member] | NYMEX [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	11,350
Average price	4.27
Natural Gas Positions [Member] | 2016 [Member] | Henry Hub [Member] | Put [Member]
Derivative [Line Items]
Hedged volume per day	11,350
Average price	4.0
Natural Gas Positions [Member] | 2017 [Member] | NYMEX [Member] | Swaps [Member]
Derivative [Line Items]
Hedged volume per day	10,445
Average price	4.47
Natural Gas Positions [Member] | 2017 [Member] | Henry Hub [Member] | Put [Member]
Derivative [Line Items]
Hedged volume per day	10,445
Average price	4.0