Subsequent Events (Tables)

9 Months Ended

Sep. 30, 2012

Subsequent Event [Line Items]

Notional Volumes Of Commodity Derivative Contracts

Commodity	Index		Oct 1 - Dec 31, 2012		2013		2014		2015		2016		2017
Oil positions:
Swaps
Hedged Volume (Bbls/d)	WTI		5,872		6,543		5,661		4,540		2,480		3,730
Average price ($/Bbls)		$	100.34	$	99.75	$	97.91	$	96.87	$	92.07	$	87.57
Collars
Hedged Volume (Bbls/d)	WTI						425		1,025		1,500
Average floor price ($/Bbls)						$	90.00	$	90.00	$	80.00
Average ceiling price ($/Bbls)						$	106.50	$	110.00	$	102.00
Natural gas positions:
Swaps
Hedged Volume (MMBtu/d)	Henry Hub		30,213		29,674		25,907		6,520		11,350		10,445
Average price ($/MMBtu)		$	5.89	$	6.07	$	6.23	$	5.43	$	4.27	$	4.47
Basis Swaps
Hedged Volume (MMBtu/d)	Henry Hub		20,709		18,466		17,066		14,400
Average price ($/MMBtu)		$	(0.15)	$	(0.17)	$	(0.19)	$	(0.19)
Collars
Hedged Volume (MMBtu/d)	Henry Hub		2,609		2,466		4,966		18,000
Average floor price ($/MMBtu)		$	6.50	$	6.50	$	5.74	$	5.00
Average ceiling price ($/MMBtu)		$	8.60	$	8.65	$	7.51	$	7.48
Puts
Hedged Volume (MMBtu/d)	Henry Hub								420		11,350		10,445
Average price ($/MMBtu)								$	4.00	$	4.00	$	4.00

Subsequent Event [Member]

Subsequent Event [Line Items]

Notional Volumes Of Commodity Derivative Contracts

Commodity	Index		2013		2014		2015		2016		2017
Oil positions:
Swaps
Hedged Volume (Bbls/d)	WTI		627		1,000		931		868		817
Average price ($/Bbls)		$	88.20	$	87.53	$	85.65	$	84.65	$	84.35
Natural gas positions:
Swaps
Hedged Volume (MMBtu/d)	Henry Hub		767		715		671
Average price ($/MMBtu)		$	3.99	$	4.27	$	4.43
Collars
Hedged Volume (MMBtu/d)	Henry Hub								630		595
Average floor price ($/MMBtu)								$	4.00	$	4.00
Average ceiling price ($/MMBtu)								$	5.55	$	6.15