Commodity Derivative Contracts (Commodity Derivatives Outstanding Table) (Details)	Dec. 31, 2015 bbl / d $ / Barrel
Q1 [Member] | Enhanced Swaps | NYMEX [Member]
Derivative [Line Items]
Volume per day | bbl / d	12,000
Weighted average swap price	92.43
Weighted average sold put price	68.00
Q1 [Member] | Enhanced Swaps | LLS [Member]
Derivative [Line Items]
Volume per day | bbl / d	8,000
Weighted average swap price	94.81
Weighted average sold put price	68.50
Q1 [Member] | Three-way Collar | NYMEX [Member]
Derivative [Line Items]
Volume per day | bbl / d	10,000
Derivative, Floor Price	85.00
Derivative, Cap Price	101.25
Weighted average sold put price	68.00
Weighted average floor price	85.00
Weighted average ceiling price	99.85
Q1 [Member] | Three-way Collar | LLS [Member]
Derivative [Line Items]
Volume per day | bbl / d	6,000
Derivative, Floor Price	88.00
Derivative, Cap Price	103.15
Weighted average sold put price	68.00
Weighted average floor price	88.00
Weighted average ceiling price	102.10
Q2 [Member] | Enhanced Swaps | NYMEX [Member]
Derivative [Line Items]
Volume per day | bbl / d	2,000
Weighted average swap price	90.35
Weighted average sold put price	68.00
Q2 [Member] | Enhanced Swaps | LLS [Member]
Derivative [Line Items]
Volume per day | bbl / d	6,000
Weighted average swap price	93.38
Weighted average sold put price	70.00
Q2 [Member] | Swap | NYMEX [Member]
Derivative [Line Items]
Volume per day | bbl / d	11,500
Weighted average swap price	61.84
Q2 [Member] | Swap | LLS [Member]
Derivative [Line Items]
Volume per day | bbl / d	3,500
Weighted average swap price	64.99
Q2 [Member] | Three-way Collar | NYMEX [Member]
Derivative [Line Items]
Volume per day | bbl / d	2,000
Derivative, Floor Price	85.00
Derivative, Cap Price	95.50
Weighted average sold put price	68.00
Weighted average floor price	85.00
Weighted average ceiling price	95.50
Q2 [Member] | Three-way Collar | LLS [Member]
Derivative [Line Items]
Volume per day | bbl / d	2,000
Derivative, Floor Price	88.00
Derivative, Cap Price	98.25
Weighted average sold put price	70.00
Weighted average floor price	88.00
Weighted average ceiling price	98.25
Q2 [Member] | Collar | NYMEX [Member]
Derivative [Line Items]
Volume per day | bbl / d	5,000
Derivative, Floor Price	55.00
Derivative, Cap Price	72.25
Weighted average floor price	55.00
Weighted average ceiling price	71.01
Q2 [Member] | Collar | LLS [Member]
Derivative [Line Items]
Volume per day | bbl / d	2,000
Derivative, Floor Price	58.00
Derivative, Cap Price	73.00
Weighted average floor price	58.00
Weighted average ceiling price	73.00
Q3 [Member] | Collar | NYMEX [Member]
Derivative [Line Items]
Volume per day | bbl / d	4,500
Derivative, Floor Price	55.00
Derivative, Cap Price	72.65
Weighted average floor price	55.00
Weighted average ceiling price	71.22
Q3 [Member] | Collar | LLS [Member]
Derivative [Line Items]
Volume per day | bbl / d	3,000
Derivative, Floor Price	58.00
Derivative, Cap Price	74.30
Weighted average floor price	58.00
Weighted average ceiling price	73.85
Minimum [Member] | Q1 [Member] | Enhanced Swaps | NYMEX [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	90.65
Minimum [Member] | Q1 [Member] | Enhanced Swaps | LLS [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	93.70
Minimum [Member] | Q2 [Member] | Enhanced Swaps | NYMEX [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	90.35
Minimum [Member] | Q2 [Member] | Enhanced Swaps | LLS [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	93.30
Minimum [Member] | Q2 [Member] | Swap | NYMEX [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	60.30
Minimum [Member] | Q2 [Member] | Swap | LLS [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	64.20
Maximum [Member] | Q1 [Member] | Enhanced Swaps | NYMEX [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	93.35
Maximum [Member] | Q1 [Member] | Enhanced Swaps | LLS [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	95.45
Maximum [Member] | Q2 [Member] | Enhanced Swaps | NYMEX [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	90.35
Maximum [Member] | Q2 [Member] | Enhanced Swaps | LLS [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	93.50
Maximum [Member] | Q2 [Member] | Swap | NYMEX [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	63.75
Maximum [Member] | Q2 [Member] | Swap | LLS [Member]
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	66.15