The agreed purchase price per MMBtu.

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Agreement termination notice period.

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Services Agreement Renewal Term

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Represents the term of agreement.

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Asset Fee

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Represents the assumption of capital commitments in a joint venture.

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Cash outflow for earnout payments to related parties.

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The fee amount per volume that the entity agreed to pay under the long-term purchase commitment.

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Proceeds from gathering and processing agreement.

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It represents amount of proceeds from the transportation agreement .

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Per day energy measure of interests in proved developed reserves of crude oil, including condensate and natural gas liquids, natural gas, synthetic oil and gas, or other nonrenewable natural resource that is intended to be upgraded into synthetic oil and gas.

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Value of properties held, percentage.

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Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Area spaced or assigned to productive wells in which a working interest is owned.

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Fractional interest owned based on working interests or other economic arrangements of area spaced or assigned to productive wells.

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Volume that must be purchased within the specified time period of the agreement to avoid penalties or unfavorable effects on pricing, among other adverse consequences.

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Period covered by the long-term purchase commitment, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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Amount paid to managing member or general partner, affiliate of managing member or general partner, or affiliate of limited liability company (LLC) or limited partnership (LP) for administrative services provided to the LLC or LP, for example, but not limited to, salaries, rent, or overhead costs.

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The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

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The total number of producing oil wells and oil wells capable of production, in which the entity owns a fractional working interest.

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Receivables to be collected from (obligations owed to) related parties, net as of the balance sheet date within one year where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.

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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.

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Related Party Transactions (Details) $ in Millions				1 Months Ended			3 Months Ended	12 Months Ended
Related Party Transactions (Details) $ in Millions	Sep. 01, 2017 $ / MMBTU	Nov. 22, 2016 USD ($)	Jul. 05, 2016 USD ($)	Sep. 30, 2017 item	Nov. 30, 2016 USD ($) item shares	Jul. 31, 2016 USD ($)	Mar. 31, 2018 USD ($) a $ / bbl $ / Mcf Mcf bbl	Dec. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Related parties, net receivable							$ 6.1	$ 13.1
Related parties, net payable							$ 6.9	10.4
Proved developed reserves (in mmcf/d) \| item				400
Agreed purchase price \| $ / MMBTU	0.22
Ownership by related parties (as a percentage)							15.00%
Sanchez Energy
Related Party Transaction [Line Items]
Payments to acquire interest in joint venture					$ 25.0
Assumption of capital commitments in joint venture					$ 24.2
SP Holdings
Related Party Transaction [Line Items]
Quarterly fee (as a percent)							0.375%
Maximum asset acquisition, disposition and financing fee (as a percent)							2.00%
Agreement term (in years)							10 years
Services Agreement renewal term							10 years
Agreement notice period							180 days
Administrative fee paid							$ 2.3
Carnero Processing Joint Venture
Related Party Transaction [Line Items]
Ownership interest (as a percent)		50.00%			50.00%
Payments to acquire interest in joint venture		$ 55.5			$ 55.5		0.2
Assumption of capital commitments in joint venture		$ 24.5			$ 24.5
Carnero Gathering, Joint Venture
Related Party Transaction [Line Items]
Ownership interest (as a percent)			50.00%			50.00%
Payments to acquire interest in joint venture			$ 37.0			$ 37.0	46.4
Assumption of capital commitments in joint venture			$ 7.4			$ 7.4
Carnero Gathering, Joint Venture \| Sanchez Energy
Related Party Transaction [Line Items]
Earnout payments to related parties							$ 0.1
Targa
Related Party Transaction [Line Items]
Ownership interest (as a percent)					50.00%
Eagle Ford \| Sanchez Energy
Related Party Transaction [Line Items]
Acres dedicated for gathering \| a							487,000
Net acres assembled \| a							285,000
Acquisition of Wellbore Interests \| Sanchez Energy
Related Party Transaction [Line Items]
Producing wellbores \| item					23
Acquisition of Working Interests \| Sanchez Energy
Related Party Transaction [Line Items]
Producing wellbores \| item					11
Western Catarina Midstream \| Sanchez Energy
Related Party Transaction [Line Items]
Agreement term (in years)							15 years
Acres dedicated for gathering \| a							35,000
Gathering Agreement delivery commitment period							5 years
Proceeds from gathering and processing agreement							$ 14.0	$ 12.6
Western Catarina Midstream \| Sanchez Energy \| Oil reserves
Related Party Transaction [Line Items]
Gathering Agreement minimum quarterly volume delivery commitment \| bbl							10,200
Gathering and processing fees (in dollars per volume) \| $ / bbl							0.96
Western Catarina Midstream \| Sanchez Energy \| Natural gas
Related Party Transaction [Line Items]
Gathering Agreement minimum quarterly volume delivery commitment \| Mcf							142,000
Gathering and processing fees (in dollars per volume) \| $ / Mcf							0.74
Western Catarina Midstream \| SN Catarina \| Oil reserves
Related Party Transaction [Line Items]
Proceeds from transportation agreement							$ 0.5
Common units \| Sanchez Energy
Related Party Transaction [Line Items]
Shares repurchased \| shares					2,272,727
Common units \| Sanchez Energy \| Executive Chairman
Related Party Transaction [Line Items]
Ownership by related parties (as a percentage)							6.80%
Common units \| Sanchez Energy \| Chief Executive Officer
Related Party Transaction [Line Items]
Ownership by related parties (as a percentage)							3.00%
Common units \| Sanchez Energy \| President
Related Party Transaction [Line Items]
Ownership by related parties (as a percentage)							1.20%