Derivative Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2012

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of oil derivative contracts volume and weighted average price

The following table sets forth the volumes per day in barrels ("BBLs") outstanding as of June 30, 2012 under the Company's oil derivative contracts and the weighted average oil prices per BBL for those contracts:

	Six Months Ending December 31,			Twelve Months Ending December 31,
	2012			2013		2014
Collar contracts with short puts:
Volume (BBL) (a)	51,610			67,290		40,000
Average price per BBL:
Ceiling	$	118.73		$	120.61	$	122.77
Floor	$	84.80		$	88.88	$	91.50
Short put	$	69.12		$	71.72	$	74.88
Collar contracts:
Volume (BBL)	2,000			—		—
Average price per BBL:
Ceiling	$	127.00		$	—	$	—
Floor	$	90.00		$	—	$	—
Swap contracts:
Volume (BBL) (a)	3,000			3,000		—
Average price per BBL	$	79.32		$	81.02	$	—
Rollfactor swap contracts:
Volume (BBL)	—			6,000		—
NYMEX roll price (b)	$	—		$	0.43	$	—
Basis swap contracts:
Index swap volume (BBL)	20,000			—		—
Average price per BBL (c)	$	(1.15	)	$	—	$	—

Schedule of gas volume and weighted average prices

The following table sets forth the volumes per day in millions of British thermal units ("MMBTU") outstanding as of June 30, 2012 under the Company's gas derivative contracts and the weighted average gas prices per MMBTU for those contracts:

	Six Months Ending December 31,			Twelve Months Ending December 31,
	2012			2013			2014 (a)			2015 (a)
Collar contracts with short puts:
Volume (MMBTU)	—			—			30,000			135,000
Price per MMBTU:
Ceiling	$	—		$	—		$	7.66		$	5.44
Floor	$	—		$	—		$	5.67		$	4.22
Short put	$	—		$	—		$	4.33		$	3.22
Collar contracts:
Volume (MMBTU)	65,000			150,000			80,000			50,000
Price per MMBTU:
Ceiling	$	6.60		$	6.25		$	6.39		$	7.92
Floor	$	5.00		$	5.00		$	5.00		$	5.00
Swap contracts:
Volume (MMBTU)	275,000			112,500			10,000			—
Price per MMBTU	$	4.97		$	5.62		$	6.18		$	—
Basis swap contracts:
Volume (MMBTU)	136,000			142,500			140,000			—
Price per MMBTU	$	(0.34	)	$	(0.22	)	$	(0.21	)	$	—

Schedule of marketing and basis transfer derivative contracts

The following table sets forth the contract volumes outstanding as of June 30, 2012 under the Company's marketing and basis transfer derivative contracts and the weighted average gas prices per MMBTU for those contracts:

	Six Months Ending December 31,
	2012
Average Daily Gas Production Associated with Marketing Derivatives (MMBTU):
Basis swap contracts:
Index swap volume	26,739
Price differential ($/MMBTU)	$	0.25
Average Daily Gas Production Associated with Basis Transfer Derivatives (MMBTU):
Basis swap contracts:
Short index swap volume	3,343
NGI-So Cal Border Monthly price differential to NYMEX HH ($/MMBTU)	$	0.12
Long index swap volume	$	(3,343	)
IF-HSC price differential to NYMEX HH ($/MMBTU)	$	(0.05	)

Schedule of derivative instruments

The following tables provide disclosure of the Company's derivative instruments:

Fair Value of Derivative Instruments as of June 30, 2012
	Asset Derivatives (a)			Liability Derivatives (a)
Type	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
		(in thousands)			(in thousands)
Derivatives not designated as hedging instruments
Commodity price derivatives	Derivatives - current	$	318,503	Derivatives - current	$	17,108
Interest rate derivatives	Derivatives - current	—		Derivatives - current	23,283
Commodity price derivatives	Derivatives - noncurrent	270,681		Derivatives - noncurrent	16,127
Interest rate derivatives	Derivatives - noncurrent	—		Derivatives - noncurrent	11,410
		$	589,184		$	67,928

Fair Value of Derivative Instruments as of December 31, 2011
	Asset Derivatives (a)			Liability Derivatives (a)
Type	Balance Sheet Location	Fair Value		Balance Sheet Location	Fair Value
		(in thousands)			(in thousands)
Derivatives not designated as hedging instruments
Commodity price derivatives	Derivatives - current	$	248,809	Derivatives - current	$	68,735
Interest rate derivatives	Derivatives - current	—		Derivatives - current	15,654
Commodity price derivatives	Derivatives - noncurrent	257,368		Derivatives - noncurrent	47,689
		$	506,177		$	132,078

Schedule of derivative obligations under terminated hedge arrangements

Derivatives in Cash Flow Hedging	Location of Gain/(Loss) Reclassified from	Amount of Gain/(Loss) Reclassified from AOCI into Earnings
		Three Months Ended June 30,						Six Months Ended June 30,
Relationships	AOCI into Earnings	2012			2011			2012			2011
		(in thousands)
Commodity price derivatives	Oil and gas revenue	$	(2,347	)	$	8,208		$	(3,156	)	$	16,332
Interest rate derivatives	Interest expense	—			(69		)	(1,699		)	(137		)
Total		$	(2,347	)	$	8,139		$	(4,855	)	$	16,195

		Amount of Gain (Loss) Recognized in Earnings on Derivatives
Derivatives Not Designated as Hedging	Location of Gain (Loss) Recognized in	Three Months Ended June 30,					Six Months Ended June 30,
Instruments	Earnings on Derivatives	2012			2011		2012			2011
		(in thousands)
Commodity price derivatives	Derivative gains (losses), net	$	298,471		$	214,903	$	386,601		$	(27,377	)
Interest rate derivatives	Derivative gains (losses), net	(22,659		)	14,575		(19,039		)	12,423
Total		$	275,812		$	229,478	$	367,562		$	(14,954	)

Schedule of derivative assets and liabilities by counterparty

The following table provides the Company's derivative assets and liabilities by counterparty as of June 30, 2012:

	Assets		Liabilities
	(in thousands)
JP Morgan Chase	$	119,358	$	15,217
Citibank, N.A.	87,788		438
Barclays Capital	53,131		—
BMO Financial Group	42,192		—
BNP Paribas	40,677		—
J. Aron & Company	33,071		—
Wells Fargo Bank, N.A.	31,419		20,981
Credit Suisse	29,795		—
Toronto Dominion	29,206		—
Credit Agricole	28,179		2,177
Societe Generale	24,356		—
Merrill Lynch	16,880		2,775
Morgan Stanley	16,184		885
Den Norske Bank	9,790		—
BP Corporation North America	4,040		—
Deutsche Bank	2,194		2,363
Vitol	1,345		—
Macquarie Bank	86		—
Royal Bank of Canada	—		262
UBS	—		3,337
Total	$	569,691	$	48,435