Commodity Derivative Contracts (Commodity Derivatives Outstanding Table) (Details)	Sep. 30, 2017 bbl / d $ / Barrel
Swap \| Year 2017 \| Q4 \| NYMEX
Derivative [Line Items]
Volume per day \| bbl / d	12,000
Weighted average swap price	49.76
Swap \| Year 2017 \| Q4 \| NYMEX \| Minimum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	48.40
Swap \| Year 2017 \| Q4 \| NYMEX \| Maximum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	50.13
Swap \| Year 2018 \| NYMEX
Derivative [Line Items]
Volume per day \| bbl / d	15,500
Weighted average swap price	50.13
Swap \| Year 2018 \| NYMEX \| Minimum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	50.00
Swap \| Year 2018 \| NYMEX \| Maximum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	50.40
Three-way Collar \| Year 2017 \| Q4 \| NYMEX
Derivative [Line Items]
Volume per day \| bbl / d	14,000
Derivative, Floor Price	40.00
Derivative, Cap Price	70.20
Weighted average sold put price	31.07
Weighted average floor price	41.07
Weighted average ceiling price	65.79
Three-way Collar \| Year 2017 \| 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
Three-way Collar \| Year 2018 \| NYMEX
Derivative [Line Items]
Volume per day \| bbl / d	15,000
Derivative, Floor Price	45.00
Derivative, Cap Price	56.60
Weighted average sold put price	36.50
Weighted average floor price	46.50
Weighted average ceiling price	53.88
Collar \| Year 2017 \| 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
Basis Swap \| Year 2017 \| December \| LLS
Derivative [Line Items]
Volume per day \| bbl / d	5,000
Weighted average swap price	4.15
Basis Swap \| Year 2017 \| December \| LLS \| Minimum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	4.15
Basis Swap \| Year 2017 \| December \| LLS \| Maximum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	4.15
Basis Swap \| Year 2018 \| Q1-Q2 \| LLS
Derivative [Line Items]
Volume per day \| bbl / d	2,500
Weighted average swap price	3.13
Basis Swap \| Year 2018 \| Q1-Q2 \| LLS \| Minimum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	3.13
Basis Swap \| Year 2018 \| Q1-Q2 \| LLS \| Maximum
Derivative [Line Items]
Derivative, Swap Type, Fixed Price	3.15

- Definition

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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- Definition

The average cap rate on a group of price risk derivatives such as caps or collars. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract.

+ References

No definition available.

+ Details

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- Definition

The average floor rate on a group of price risk derivatives such as floors or collars. A payment or receipt is triggered if the market rate falls below the floor rate on the contract.

+ References

No definition available.

+ Details

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- Definition

The average strike price on the group of price risk option contracts such as put options or call options.

+ References

No definition available.

+ Details

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- Definition

The cap rate on a price risk derivative such as a cap or collar. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract.

+ References

No definition available.

+ Details

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- Definition

Floor rate on a price risk derivative such as a floor or a collar. A payment or receipt is triggered if the market rate falls below the floor rate on the contract.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Average fixed price related to the group of price risk swap derivatives.

+ References

No definition available.

+ Details

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- Definition

Fixed price related to the price risk swap derivative.

+ References

No definition available.

+ Details

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