Commodity Derivative Contracts (Commodity Derivatives Outstanding Table) (Details) - Year 2017	Mar. 31, 2017 bbl / d $ / Barrel
Swap | Q2 | NYMEX
Derivative [Line Items]
Volume per day | bbl / d	22,000
Weighted average swap price	43.99
Swap | Q2 | NYMEX | Minimum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	41.20
Swap | Q2 | NYMEX | Maximum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	46.50
Swap | Q2 | LLS
Derivative [Line Items]
Volume per day | bbl / d	7,000
Weighted average swap price	45.35
Swap | Q2 | LLS | Minimum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	42.65
Swap | Q2 | LLS | Maximum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	46.65
Collar | Q4 | NYMEX
Derivative [Line Items]
Volume per day | bbl / d	1,000
Derivative, Floor Price	40.00
Derivative, Cap Price	70.00
Weighted average floor price	40.00
Weighted average ceiling price	70.00
Three-way Collar | Q3 | NYMEX
Derivative [Line Items]
Volume per day | bbl / d	14,500
Derivative, Floor Price	40.00
Derivative, Cap Price	70.25
Weighted average sold put price	30.00
Weighted average floor price	40.00
Weighted average ceiling price	69.09
Three-way Collar | Q3 | LLS
Derivative [Line Items]
Volume per day | bbl / d	2,000
Derivative, Floor Price	41.00
Derivative, Cap Price	69.25
Weighted average sold put price	31.00
Weighted average floor price	41.00
Weighted average ceiling price	69.25
Three-way Collar | Q4 | NYMEX
Derivative [Line Items]
Volume per day | bbl / d	11,000
Derivative, Floor Price	40.00
Derivative, Cap Price	70.20
Weighted average sold put price	30.00
Weighted average floor price	40.00
Weighted average ceiling price	69.67
Three-way Collar | Q4 | LLS
Derivative [Line Items]
Volume per day | bbl / d	1,000
Derivative, Floor Price	41.00
Derivative, Cap Price	70.25
Weighted average sold put price	31.00
Weighted average floor price	41.00
Weighted average ceiling price	70.25