Derivative Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Summary of contracts for oil and natural gas
Fair Value of Asset (Liability)	$ 7,180
Open costless collar contracts [Member] | Oil [Member]
Summary of contracts for oil and natural gas
Fair Value of Asset (Liability)	4,997
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 20,000 Notional Amount, 85 Price Floor, 102.25 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	20,000
Price Floor	85.00
Price Ceiling	102
Fair Value of Asset (Liability)	(9)
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 20,000 Notional Amount, 85 Price Floor, 108.80 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	20,000
Price Floor	85.00
Price Ceiling	109
Fair Value of Asset (Liability)	84
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 20,000 Notional Amount, 85 Price Floor, 110.40 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	20,000
Price Floor	85.00
Price Ceiling	110
Fair Value of Asset (Liability)	94
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 20,000 Notional Amount, 90 Price Floor, 102.80 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	20,000
Price Floor	90.00
Price Ceiling	103
Fair Value of Asset (Liability)	126
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 20,000 Notional Amount, 90 Price Floor, 115 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	20,000
Price Floor	90.00
Price Ceiling	115
Fair Value of Asset (Liability)	224
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 8,000 Notional Amount, 90 Price Floor, 114 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 06/30/2014
Notional Quantity	8,000
Price Floor	90
Price Ceiling	114
Fair Value of Asset (Liability)	336
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 12,000 Notional Amount, 90 Price Floor, 115.50 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 06/30/2014
Notional Quantity	12,000
Price Floor	90.00
Price Ceiling	116
Fair Value of Asset (Liability)	513
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 15,000 Notional Amount, 85 Price Floor, 97.50 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	15,000
Price Floor	85.00
Price Ceiling	97.50
Fair Value of Asset (Liability)	248
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 30,000 Notional Amount, 85 Price Floor, 98 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	30,000
Price Floor	85.00
Price Ceiling	98.00
Fair Value of Asset (Liability)	546
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 15,000 Notional Amount, 87 Price Floor, 97 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	15,000
Price Floor	87.00
Price Ceiling	97.00
Fair Value of Asset (Liability)	349
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 20,000 Notional Amount, 88 Price Floor, 95.60 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	20,000
Price Floor	88.00
Price Ceiling	95.60
Fair Value of Asset (Liability)	444
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 20,000 Notional Amount, 90 Price Floor, 97 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	20,000
Price Floor	90.00
Price Ceiling	97.00
Fair Value of Asset (Liability)	763
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 15,000 Notional Amount, 90 Price Floor, 97.90 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	15,000
Price Floor	90.00
Price Ceiling	97.90
Fair Value of Asset (Liability)	642
Open costless collar contracts [Member] | Oil [Member] | Open Oil Collar Contract, 15,000 Notional Amount, 90 Price Floor, 98 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	15,000
Price Floor	90.00
Price Ceiling	98.00
Fair Value of Asset (Liability)	637
Open costless collar contracts [Member] | Natural Gas [Member]
Summary of contracts for oil and natural gas
Fair Value of Asset (Liability)	946
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 150,000 Notional Amount, 4.50 Price Floor, 5.75 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 07/31/2013
Notional Quantity	150,000
Price Floor	4.50
Price Ceiling	5.75
Fair Value of Asset (Liability)	119
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3 Price Floor, 3.83 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	100,000
Price Floor	3.00
Price Ceiling	3.83
Fair Value of Asset (Liability)	(57)
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3 Price Floor, 4.95 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	100,000
Price Floor	3.00
Price Ceiling	4.95
Fair Value of Asset (Liability)	9
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3 Price Floor, 4.96 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	100,000
Price Floor	3.00
Price Ceiling	4.96
Fair Value of Asset (Liability)	10
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 150,000 Notional Amount, 3 Price Floor, 4.24 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	150,000
Price Floor	3.00
Price Ceiling	4.24
Fair Value of Asset (Liability)	(25)
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.25 Price Floor, 4.41 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	100,000
Price Floor	3.25
Price Ceiling	4.41
Fair Value of Asset (Liability)	14
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.25 Price Floor, 4.44 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	100,000
Price Floor	3.25
Price Ceiling	4.44
Fair Value of Asset (Liability)	16
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.50 Price Floor, 4.37 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	100,000
Price Floor	3.50
Price Ceiling	4.37
Fair Value of Asset (Liability)	55
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 80,000 Notional Amount, 3.75 Price Floor, 4.57 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	08/01/2013 - 12/31/2013
Notional Quantity	80,000
Price Floor	3.75
Price Ceiling	4.57
Fair Value of Asset (Liability)	104
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3 Price Floor, 5.15 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	100,000
Price Floor	3.00
Price Ceiling	5.15
Fair Value of Asset (Liability)	(26)
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.25 Price Floor, 5.21 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	100,000
Price Floor	3.25
Price Ceiling	5.21
Fair Value of Asset (Liability)	45
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.25 Price Floor, 5.22 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	100,000
Price Floor	3.25
Price Ceiling	5.22
Fair Value of Asset (Liability)	45
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.25 Price Floor, 5.37 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	100,000
Price Floor	3.25
Price Ceiling	5.37
Fair Value of Asset (Liability)	64
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.25 Price Floor, 5.42 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	100,000
Price Floor	3.25
Price Ceiling	5.42
Fair Value of Asset (Liability)	68
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.50 Price Floor, 4.90 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	100,000
Price Floor	3.50
Price Ceiling	4.90
Fair Value of Asset (Liability)	98
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 100,000 Notional Amount, 3.75 Price Floor, 4.77 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2014 - 12/31/2014
Notional Quantity	100,000
Price Floor	3.75
Price Ceiling	4.77
Fair Value of Asset (Liability)	200
Open costless collar contracts [Member] | Natural Gas [Member] | Open Natural Gas Collar Contract, 200,000 Notional Amount, 3.75 Price Floor, 5.04 Price Ceiling [Member]
Summary of contracts for oil and natural gas
Calculation Period	01/01/2015 - 12/31/2015
Notional Quantity	200,000
Price Floor	3.75
Price Ceiling	5.04
Fair Value of Asset (Liability)	207
Open Swap Contracts [Member] | Oil [Member]
Summary of contracts for oil and natural gas
Fair Value of Asset (Liability)	(564)
Open Swap Contracts [Member] | Oil [Member] | Open Oil Swap Contract, 10,000 Notional Amount, 90.20 Fixed Price [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	10,000
Price Floor	90.20
Fair Value of Asset (Liability)	(295)
Open Swap Contracts [Member] | Oil [Member] | Open Oil Swap Contract, 10,000 Notional Amount, 90.65 Fixed Price [Member]
Summary of contracts for oil and natural gas
Calculation Period	07/01/2013 - 12/31/2013
Notional Quantity	10,000
Price Floor	90.65
Fair Value of Asset (Liability)	$ (269)