Derivative Instruments and Hedging Activities (Details)	3 Months Ended
	Mar. 31, 2015
Crude Oil Commodity Contract [Member] | Swaps - NYMEX WTI 2015
Derivative [Line Items]
Settlement Period	2015
Index	NYMEX WTI
Bbls Per Day	27,000
Weighted Average Fixed Price	88.80
Crude Oil Commodity Contract [Member] | Swaps - Dated Brent 2015
Derivative [Line Items]
Settlement Period	2015
Index	Dated Brent
Bbls Per Day	8,000
Weighted Average Fixed Price	100.31
Crude Oil Commodity Contract [Member] | Two Way Collars - NYMEX WTI 2015
Derivative [Line Items]
Settlement Period	2015
Index	NYMEX WTI
Bbls Per Day	5,000
Weighted Average Floor Price	50.00
Weighted Average Ceiling Price	64.94
Crude Oil Commodity Contract [Member] | Three Way Collars - NYMEX WTI 2015
Derivative [Line Items]
Settlement Period	2015
Index	NYMEX WTI
Bbls Per Day	20,000
Weighted Average Short Put Price	70.50
Weighted Average Floor Price	87.55
Weighted Average Ceiling Price	94.41
Crude Oil Commodity Contract [Member] | Three Way Collars - Dated Brent 2015
Derivative [Line Items]
Settlement Period	2015
Index	Dated Brent
Bbls Per Day	13,000
Weighted Average Short Put Price	76.92
Weighted Average Floor Price	96.00
Weighted Average Ceiling Price	108.49
Crude Oil Commodity Contract [Member] | Swaps - NYMEX WTI 2016
Derivative [Line Items]
Settlement Period	2016
Index	NYMEX WTI
Bbls Per Day	6,000
Weighted Average Fixed Price	87.95
Crude Oil Commodity Contract [Member] | Swaps - Dated Brent 2016
Derivative [Line Items]
Settlement Period	2016
Index	Dated Brent
Bbls Per Day	9,000
Weighted Average Fixed Price	97.96
Crude Oil Commodity Contract [Member] | Three Way Collars - NYMEX WTI 2016
Derivative [Line Items]
Settlement Period	2016
Index	NYMEX WTI
Bbls Per Day	6,000
Weighted Average Short Put Price	61.00
Weighted Average Floor Price	72.50
Weighted Average Ceiling Price	86.37
Crude Oil Commodity Contract [Member] | Three Way Collars - Dated Brent 2016
Derivative [Line Items]
Settlement Period	2016
Index	Dated Brent
Bbls Per Day	8,000
Weighted Average Short Put Price	72.50
Weighted Average Floor Price	86.25
Weighted Average Ceiling Price	101.79
Natural Gas Commodity Contract | Swaps - NYMEX HH 2015
Derivative [Line Items]
Settlement Period	2015
Index	NYMEX HH
Bbls Per Day	140,000
Weighted Average Fixed Price	4.30
Natural Gas Commodity Contract | Three Way Collars - NYMEX HH 2015
Derivative [Line Items]
Settlement Period	2015
Index	NYMEX HH
Bbls Per Day	150,000
Weighted Average Short Put Price	3.58
Weighted Average Floor Price	4.25
Weighted Average Ceiling Price	5.04
Natural Gas Commodity Contract | Swaps - NYMEX HH 2016
Derivative [Line Items]
Settlement Period	2016
Index	NYMEX HH
Bbls Per Day	40,000	[1]
Weighted Average Fixed Price	3.60	[1]
Natural Gas Commodity Contract | Two Way Collars - NYMEX HH 2016
Derivative [Line Items]
Settlement Period	2016
Index	NYMEX HH
Bbls Per Day	30,000
Weighted Average Floor Price	3.00
Weighted Average Ceiling Price	3.50
Natural Gas Commodity Contract | Three Way Collars - NYMEX HH 2016
Derivative [Line Items]
Settlement Period	2016
Index	NYMEX HH
Bbls Per Day	60,000
Weighted Average Short Put Price	2.88
Weighted Average Floor Price	3.50
Weighted Average Ceiling Price	4.03
Natural Gas Commodity Contract | Swaps - NYMEX HH Extension
Derivative [Line Items]
Bbls Per Day	30,000
Natural Gas Commodity Contract | Swaps - NYMEX HH Increase
Derivative [Line Items]
Bbls Per Day	30,000
Weighted Average Fixed Price	3.50	[1]

[1] (1) We have entered into natural gas derivative contracts which give counterparties the option to extend for an additional 12-month period. Options covering a notional volume of 30,000 MMBtu/d are exercisable on December 22 and 23, 2016. If the counterparties exercise all such options, the notional volume of our existing natural gas derivative contracts will increase by 30,000 MMBtu/d at an average price of $3.50 per MMBtu for each month during the period January 1, 2017 through December 31, 2017.