Collateralized Long term Debt, Percent of Reserve Value of Oil and Natural Gas Properties

No definition available.

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Convertible, Threshold Percentage of Stock Price to Product of Stock Sale Price and Conversion Rate

+ References

No definition available.

+ Details

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Namespace Prefix:	oas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument, Covenant, Maximum Consolidated Total Leverage Ratio

+ References

No definition available.

+ Details

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Namespace Prefix:	oas_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument, Covenants, Aggregate Elected Commitment Amount, Threshold

+ References

No definition available.

+ Details

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Namespace Prefix:	oas_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Maximum Borrowing Capacity, Accordian Feature

+ References

No definition available.

+ Details

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Namespace Prefix:	oas_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum current ratio as required by the entity's debt agreement.

+ References

No definition available.

+ Details

Name:	oas_MinimumCurrentRatio
Namespace Prefix:	oas_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum ratio of consolidated EBITDAX to consolidated Interest Expense as required by the entity's debt agreement.

+ References

No definition available.

+ Details

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Namespace Prefix:	oas_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

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-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
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+ Details

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Period Type:	instant

- Definition

Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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- Definition

Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Minimum percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion.

+ References

No definition available.

+ Details

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- Definition

Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature.

+ References

No definition available.

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Period Type:	instant

- 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

No definition available.

+ Details

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Period Type:	duration

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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-Section 50
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-Subparagraph e
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Period Type:	duration

- Definition

Fair value amount of debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Amount, after accumulated amortization, of debt discount.

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for a specific purpose other than for financing goods acquired for inventory or imminent delivery to a customer.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

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- Definition

The cash outflow to repay long-term debt that is not secured by collateral. Excludes repayments of tax exempt unsecured debt.

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

+ References

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Period Type:	instant

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

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Long-Term Debt - Additional Information (Detail)			3 Months Ended	12 Months Ended
Long-Term Debt - Additional Information (Detail)	May 29, 2018 USD ($)	May 14, 2018 USD ($)	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2018 USD ($) day $ / shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Nov. 19, 2018 USD ($)	Oct. 16, 2018 USD ($)	Aug. 27, 2018 USD ($)	Jun. 30, 2018 USD ($)	May 25, 2018 USD ($)	Apr. 19, 2018 USD ($)	Feb. 26, 2018 USD ($)	Apr. 10, 2017 USD ($)
Debt Instrument [Line Items]
Long-term debt			$ 2,735,276,000	$ 2,735,276,000	$ 2,097,606,000
Total long-term debt			2,735,276,000	2,735,276,000	2,097,606,000
Less: unamortized deferred financing costs on senior unsecured notes			$ 31,200,000	$ 31,200,000
Minimum reserve value of oil and natural gas properties (percent)			90.00%	90.00%
Aggregate cost of debt repurchased				$ 423,340,000	0	$ 435,907,000
Gain (loss) on debt repurchase				(13,848,000)	0	4,741,000
Write off of deferred finance costs				4,000,000
Amortization of deferred financing costs				7,600,000	7,000,000	9,800,000
Senior unsecured notes
Debt Instrument [Line Items]
Less: unamortized deferred financing costs on senior unsecured notes			$ 20,865,000	20,865,000	22,956,000
Total principal of senior unsecured notes			2,039,409,000	2,039,409,000	$ 2,052,950,000
Face amount of repurchased debt											$ 390,600,000
Debt repurchased											$ 402,000,000
Revolving credit facility
Debt Instrument [Line Items]
Debt, weighted average interest rate					3.10%
Line of credit \| Letter of Credit
Debt Instrument [Line Items]
Outstanding letters of credit			$ 14,000,000	$ 14,000,000	$ 10,500,000
Line of credit \| Revolving credit facility
Debt Instrument [Line Items]
Line of credit sublimit								$ 1,600,000,000				$ 1,600,000,000
Line of credit facility, capacity available for specific purpose other than for trade purchases								3,000,000,000				2,500,000,000
Current borrowing base								$ 1,350,000,000				$ 1,350,000,000	$ 1,350,000,000	$ 1,150,000,000
Debt, weighted average interest rate			4.20%	4.20%	3.20%
Write off of deferred finance costs				$ 289,410.602981102	$ 1,800,000
Unsecured Senior Notes
Debt Instrument [Line Items]
Long-term debt, fair value			$ 1,830,400,000	1,830,400,000
Unsecured Senior Notes \| Senior unsecured notes
Debt Instrument [Line Items]
Total long-term debt			2,039,400,000	2,039,400,000
7.25% senior unsecured notes due February 1, 2019 \| Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes			0	0	54,275,000
Senior unsecured notes stated interest rate (percent)											7.25%
Senior unsecured debt principal amount											$ 31,300,000
Aggregate cost of debt repurchased	$ 23,000,000
Debt redemption price (percent)	100.00%
6.50% senior unsecured notes due November 1, 2021 \| Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes			71,835,000	71,835,000	395,501,000
Senior unsecured notes stated interest rate (percent)											6.50%
Senior unsecured debt principal amount											$ 323,700,000
Amended credit facility
Debt Instrument [Line Items]
Letter of credit unused borrowing base capacity			868,000,000	$ 868,000,000	1,069,500,000
Amended credit facility \| Current ratio
Debt Instrument [Line Items]
Minimum current ratio				1.0
Aggregate elected commitment threshold			0.85	$ 0.85
Amended credit facility \| Minimum \| EBITDAX
Debt Instrument [Line Items]
Minimum debt to EBITDAX ratio				2.5
The Credit Agreement \| Bridge Loan
Debt Instrument [Line Items]
Line of credit sublimit			10,000,000	$ 10,000,000
OMP Credit Facility \| Revolving credit facility
Debt Instrument [Line Items]
Less: unamortized deferred financing costs on senior unsecured notes			2,400,000	2,400,000
OMP Credit Facility \| Line of credit \| Revolving credit facility
Debt Instrument [Line Items]
Total principal of senior unsecured notes			318,000,000	318,000,000	78,000,000
Unused borrowing capacity			82,000,000	82,000,000
Line of credit sublimit							$ 400,000,000		$ 250,000,000	$ 200,000,000
Notes \| Senior unsecured notes
Debt Instrument [Line Items]
Senior unsecured notes outstanding			$ 1,739,400,000	$ 1,739,400,000
Notes \| Senior unsecured notes \| Minimum
Debt Instrument [Line Items]
Senior unsecured notes stated interest rate (percent)			6.25%	6.25%
Notes \| Senior unsecured notes \| Maximum
Debt Instrument [Line Items]
Senior unsecured notes stated interest rate (percent)			6.875%	6.875%
2026 Notes \| Senior unsecured notes
Debt Instrument [Line Items]
Senior unsecured notes stated interest rate (percent)		6.25%
Senior unsecured debt principal amount		$ 400,000,000
Proceeds from debt issuance		$ 394,400,000
6.875% senior unsecured notes due March 15, 2022 \| Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes			$ 901,480,000	$ 901,480,000	937,080,000
Senior unsecured notes stated interest rate (percent)											6.875%
Senior unsecured debt principal amount											$ 35,600,000
6.875% senior unsecured notes and 2.625% senior unsecured notes \| Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes			666,100,000	666,100,000
6.25% senior unsecured notes due May 1, 2026 \| Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes			400,000,000	400,000,000
2022 Notes and 2023 Notes \| Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes			1,267,600,000	1,267,600,000
6.875% senior unsecured notes due January 15, 2023 \| Senior unsecured notes
Debt Instrument [Line Items]
Total principal of senior unsecured notes			366,094,000	366,094,000	366,094,000
2.625% senior unsecured convertible notes due September 15, 2023 \| Senior unsecured notes
Debt Instrument [Line Items]
Debt discount at inception			69,268,000	69,268,000	80,388,000
Total principal of senior unsecured notes			$ 300,000,000	$ 300,000,000	300,000,000
Senior unsecured notes stated interest rate (percent)			2.625%	2.625%
Senior unsecured debt principal amount			$ 300,000,000	$ 300,000,000
Initial conversion rate (shares per $1000 principal)				76.365
Debt conversion rate (in usd per share) \| $ / shares			$ 13.10	$ 13.10
Oasis Credit Facility \| Line of credit \| Revolving credit facility
Debt Instrument [Line Items]
Total principal of senior unsecured notes			$ 468,000,000	$ 468,000,000	70,000,000
Debt, weighted average interest rate			4.20%	4.20%
Oasis Credit Facility \| Revolving credit facility
Debt Instrument [Line Items]
Less: unamortized deferred financing costs on senior unsecured notes			$ 7,900,000	$ 7,900,000
Gain on Extinguishment of Debt \| Purchased Notes \| Senior unsecured notes
Debt Instrument [Line Items]
Write off of deferred finance costs					$ 0	$ 6,400,000
Debt Conversion Scenario 1 \| Amended credit facility \| Current ratio
Debt Instrument [Line Items]
EBITDAX ratio				4.25
Debt Conversion Scenario 1 \| 2.625% senior unsecured convertible notes due September 15, 2023 \| Senior unsecured notes
Debt Instrument [Line Items]
Number of trading days \| day				20
Number of consecutive trading days \| day				30
Conversion price, percentage of stock price trigger (percent)				130.00%
Debt Conversion Scenario 2 \| Amended credit facility \| Current ratio
Debt Instrument [Line Items]
EBITDAX ratio				4.0
Debt Conversion Scenario 2 \| 2.625% senior unsecured convertible notes due September 15, 2023 \| Senior unsecured notes
Debt Instrument [Line Items]
Number of trading days \| day				5
Number of consecutive trading days \| day				5
Percentage of stock price to product of stock sale price and conversion rate (percent)				98.00%
LIBOR \| Revolving credit facility \| Minimum
Debt Instrument [Line Items]
Loan term				1 month
Commitment fee of borrowing base capacity not utilized, percentage			0.375%
LIBOR \| Revolving credit facility \| Maximum
Debt Instrument [Line Items]
Loan term				6 months
Commitment fee of borrowing base capacity not utilized, percentage			0.50%
OMP Operating, LLC \| Letter of Credit
Debt Instrument [Line Items]
Line of credit sublimit			$ 10,000,000	$ 10,000,000
OMP Operating, LLC \| Revolving credit facility
Debt Instrument [Line Items]
Line of credit, sublimit increase allowed subject to certain conditions							$ 600,000,000
OMP Operating, LLC \| Federal Funds Effective Swap Rate \| ABR Loans \| Revolving credit facility
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)				0.50%
OMP Operating, LLC \| Federal Funds Effective Swap Rate \| ABR Loans or Swingline Loans \| Revolving credit facility \| Minimum
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)				0.75%
OMP Operating, LLC \| Federal Funds Effective Swap Rate \| ABR Loans or Swingline Loans \| Revolving credit facility \| Maximum
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)				1.75%
OMP Operating, LLC \| LIBOR \| ABR Loans \| Revolving credit facility
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)				1.00%