Derivative Instruments (Tables)

3 Months Ended

Mar. 31, 2013

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Commodity Derivative Positions

The following table sets forth our commodity derivative positions as of March 31, 2013:

		Average
		Volume Per	Weighted Average Price				Fair Value
	Instrument	Day	Floor/Swap		Ceiling		Asset		Liability
Crude Oil:		(barrels)	($/barrel)
Second quarter 2013	Collars	1,900	$	90.00	$	99.17	$	—	$	164
Third quarter 2013	Collars	1,900	$	90.00	$	99.17	—		235
Fourth quarter 2013	Collars	1,900	$	90.00	$	99.17	—		81
Second quarter 2013	Swaps	3,750	$	101.26			1,460		173
Third quarter 2013	Swaps	4,000	$	98.43			1,038		550
Fourth quarter 2013	Swaps	4,000	$	98.43			1,355		357
First quarter 2014	Swaps	4,000	$	95.27			1,093		720
Second quarter 2014	Swaps	4,000	$	95.27			1,312		519
Third quarter 2014	Swaps	3,500	$	94.43			1,096		347
Fourth quarter 2014	Swaps	3,500	$	94.43			1,199		210
First quarter 2014	Swaptions	1,812	$	100.00			—		281
Second quarter 2014	Swaptions	1,812	$	100.00			—		280
Third quarter 2014	Swaptions	1,812	$	100.00			—		280
Fourth quarter 2014	Swaptions	1,812	$	100.00			—		280
Natural Gas:		(in MMBtu)	($/MMBtu)
Second quarter 2013	Collars	10,000	$	3.50	$	4.30	—		34
Third quarter 2013	Collars	10,000	$	3.50	$	4.30	—		125
Fourth quarter 2013	Collars	15,000	$	3.67	$	4.37	15		222
First quarter 2014	Collars	5,000	$	4.00	$	4.50	—		58
Second quarter 2013	Swaps	15,000	$	3.92			13		151
Third quarter 2013	Swaps	15,000	$	3.92			—		271
Fourth quarter 2013	Swaps	10,000	$	4.04			—		160
First quarter 2014	Swaps	5,000	$	4.05			—		145
Second quarter 2014	Swaps	10,000	$	4.03			—		53
Third quarter 2014	Swaps	10,000	$	4.03			—		105
Settlements to be received in subsequent period							954		—

Impact of Derivative Activities on Condensed Consolidated Statements of Income

The impact of our derivatives activities on income is included in the Derivatives caption on our Condensed Consolidated Statements of Operations. The following table summarizes the effects of our derivative activities for the periods presented:

	Three Months Ended March 31,
	2013			2012
Impact by contract type:
Commodity contracts	$	(7,761	)	$	294
Interest rate contracts	—			(599		)
	$	(7,761	)	$	(305	)
Realized and unrealized impact:
Cash received for:
Commodity contract settlements	$	3,557		$	7,981
Interest rate contract settlements	—			—
	3,557			7,981
Unrealized losses attributable to:
Commodity contracts	(11,318		)	(7,687		)
Interest rate contracts	—			(599		)
	(11,318		)	(8,286		)
	$	(7,761	)	$	(305	)

Fair Value of Derivative Instruments on Condensed Consolidated Balance Sheets

The following table summarizes the fair values of our derivative instruments, as well as the locations of these instruments, on our Condensed Consolidated Balance Sheets as of the dates presented:

		Fair Values as of
		March 31, 2013				December 31, 2012
		Derivative		Derivative		Derivative		Derivative
Type	Balance Sheet Location	Assets		Liabilities		Assets		Liabilities
Commodity contracts	Derivative assets/liabilities - current	$	5,900	$	4,539	$	11,292	$	—
Interest rate contracts	Derivative assets/liabilities - current	—		—		—		—
		5,900		4,539		11,292		—
Commodity contracts	Derivative assets/liabilities - noncurrent	3,608		1,235		5,181		1,421
Interest rate contracts	Derivative assets/liabilities - noncurrent	—		—		—		—
		3,608		1,235		5,181		1,421
		$	9,508	$	5,774	$	16,473	$	1,421