Chord Energy (CHRD) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	OAS
Entity Registrant Name	Oasis Petroleum Inc.
Entity Central Index Key	1,486,159
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		318,434,087

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 16,892	$ 16,720
Accounts receivable, net	428,184	363,580
Inventory	31,409	19,367
Prepaid expenses	6,444	7,631
Derivative instruments	0	344
Intangible assets, net	375	0
Other current assets	192	193
Total current assets	483,496	407,835
Property, plant and equipment
Oil and gas properties (successful efforts method)	8,671,144	7,838,955
Other property and equipment	1,088,781	868,746
Less: accumulated depreciation, depletion, amortization and impairment	(2,859,788)	(2,534,215)
Total property, plant and equipment, net	6,900,137	6,173,486
Derivative instruments	0	9
Long-term inventory	12,610	12,200
Other assets	20,188	21,600
Total assets	7,416,431	6,615,130
Current liabilities
Accounts payable	17,206	13,370
Revenues and production taxes payable	287,333	213,995
Accrued liabilities	307,526	236,480
Accrued interest payable	20,574	38,963
Derivative instruments	180,129	115,716
Advances from joint interest partners	3,878	4,916
Other current liabilities	40	40
Total current liabilities	816,686	623,480
Long-term debt	2,633,009	2,097,606
Deferred income taxes	230,504	305,921
Asset retirement obligations	51,357	48,511
Derivative instruments	33,017	19,851
Other liabilities	7,775	6,182
Total liabilities	3,772,348	3,101,551
Commitments and contingencies
Stockholders’ equity
Common stock, $0.01 par value: 900,000,000 and 450,000,000 shares authorized at September 30, 2018 and December 31, 2017, respectively; 320,507,783 shares issued and 318,419,144 shares outstanding at September 30, 2018 and 270,627,014 shares issued and 269,295,466 shares outstanding at December 31, 2017	3,157	2,668
Treasury stock, at cost: 2,088,639 and 1,331,548 shares at September 30, 2018 and December 31, 2017, respectively	(28,985)	(22,179)
Additional paid-in capital	3,070,642	2,677,217
Retained earnings	460,712	717,985
Oasis share of stockholders’ equity	3,505,526	3,375,691
Non-controlling interests	138,557	137,888
Total stockholders’ equity	3,644,083	3,513,579
Total liabilities and stockholders’ equity	$ 7,416,431	$ 6,615,130

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	900,000,000	450,000,000
Common stock, shares issued (in shares)	320,507,783	270,627,014
Common stock, shares outstanding (in shares)	318,419,144	269,295,466
Treasury stock, shares (in shares)	2,088,639	1,331,548

Condensed Consolidated Statemen

Condensed Consolidated Statement of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Total revenues	$ 546,448	$ 304,748	$ 1,469,001	$ 843,955
Operating expenses
Lease operating expenses	48,534	45,334	137,456	133,871
Marketing, transportation and gathering expenses	30,713	15,028	74,559	38,018
Production taxes	38,722	21,052	103,748	60,322
Depreciation, depletion and amortization	162,984	132,289	465,819	384,246
Exploration expenses	22,315	854	23,701	4,010
Impairment	0	139	384,228	6,021
General and administrative expenses	34,859	21,368	91,029	67,170
Total operating expenses	404,272	272,354	1,458,468	786,090
Gain on sale of properties	36,869	0	38,823	0
Operating income	179,045	32,394	49,356	57,865
Other income (expense)
Net gain (loss) on derivative instruments	(48,544)	(54,310)	(239,945)	52,297
Interest expense, net of capitalized interest	(39,560)	(37,389)	(117,616)	(110,548)
Loss on extinguishment of debt	(47)	0	(13,698)	0
Other income (expense)	111	(605)	146	(755)
Total other expense	(88,040)	(92,304)	(371,113)	(59,006)
Income (loss) before income taxes	91,005	(59,910)	(321,757)	(1,141)
Income tax benefit (expense)	(24,782)	18,846	75,391	470
Net income (loss) including non-controlling interests	66,223	(41,064)	(246,366)	(671)
Less: Net income attributable to non-controlling interests	3,882	150	10,907	150
Net income (loss) attributable to Oasis	$ 62,341	$ (41,214)	$ (257,273)	$ (821)
Earnings (loss) attributable to Oasis per share:
Basic (in dollars per share)	$ 0.20	$ (0.18)	$ (0.84)	$ 0
Diluted (in dollars per share)	$ 0.20	$ (0.18)	$ (0.84)	$ 0
Weighted average shares outstanding:
Basic (in shares)	313,167	233,389	305,533	233,248
Diluted (in shares)	316,387	233,389	305,533	233,248
Oil and Gas [Member]
Revenues
Total revenues	$ 452,643	$ 248,648	$ 1,212,235	$ 704,533
Purchased Oil and Gas Sales [Member]
Revenues
Total revenues	46,356	21,195	121,971	56,917
Operating expenses
Expenses	46,088	21,701	121,251	57,683
Midstream Services [Member]
Revenues
Total revenues	31,187	18,767	88,451	48,939
Operating expenses
Expenses	8,652	4,301	24,325	10,891
Well Services [Member]
Revenues
Total revenues	16,262	16,138	46,344	33,566
Operating expenses
Expenses	$ 11,405	$ 10,288	$ 32,352	$ 23,858

Condensed Consolidated Statem_2

Condensed Consolidated Statement of Changes in Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2018 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in-Capital [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]
Balance (shares) at Dec. 31, 2017		269,295	1,332
Balance at Dec. 31, 2017	$ 3,513,579	$ 2,668	$ (22,179)	$ 2,677,217	$ 717,985	$ 137,888
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Permian Basin Acquisition issuance (shares)		46,000
Permian Basin Acquisition issuance	371,220	$ 460		370,760
Other (2017 issuance of common stock and Oasis Midstream common units) (shares)		0
Other (2017 issuance of common stock and Oasis Midstream common units)	(87)	$ 0		38		(125)
Equity-based compensation (shares)		3,881
Equity-based compensation	22,936	$ 29		22,627		280
Distributions to non-controlling interest owners	(10,393)					(10,393)
Treasury stock - tax withholdings (shares)		757	757
Treasury stock - tax withholdings	(6,806)		$ (6,806)			0
Net income (loss)	(246,366)				(257,273)	10,907
Balance (shares) at Sep. 30, 2018		318,419	2,089
Balance at Sep. 30, 2018	$ 3,644,083	$ 3,157	$ (28,985)	$ 3,070,642	$ 460,712	$ 138,557

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net loss including non-controlling interests	$ (246,366)	$ (671)
Adjustments to reconcile net loss including non-controlling interests to net cash provided by operating activities:
Depreciation, depletion and amortization	465,819	384,246
Loss on extinguishment of debt	13,698	0
Gain on sale of properties	(38,823)	0
Impairment	384,228	6,021
Deferred income taxes	(75,418)	(470)
Derivative instruments	239,945	(52,297)
Equity-based compensation expenses	21,586	20,451
Deferred financing costs amortization and other	20,074	12,666
Working capital and other changes:
Change in accounts receivable, net	(61,275)	(81,022)
Change in inventory	(12,076)	(235)
Change in prepaid expenses	1,196	823
Change in other current assets	1	276
Change in long-term inventory and other assets	(490)	(12,843)
Change in accounts payable, interest payable and accrued liabilities	50,308	32,282
Change in other current liabilities	0	(10,490)
Change in other liabilities	(406)	0
Net cash provided by operating activities	762,001	298,737
Cash flows from investing activities:
Capital expenditures	(841,088)	(443,649)
Acquisitions	(579,886)	0
Proceeds from sale of properties	333,029	4,000
Costs related to sale of properties	(2,707)	0
Derivative settlements	(162,013)	(804)
Advances from joint interest partners	(1,038)	(2,502)
Net cash used in investing activities	(1,253,703)	(442,955)
Cash flows from financing activities:
Proceeds from Revolving Credit Facilities	2,499,000	764,000
Principal payments on Revolving Credit Facilities	(1,959,000)	(732,000)
Repurchase of senior unsecured notes	(423,190)	0
Proceeds from issuance of senior unsecured notes	400,000	0
Deferred financing costs	(7,650)	(96)
Proceeds from sale of Oasis Midstream common units, net of offering costs	0	115,813
Purchases of treasury stock	(6,806)	(6,182)
Distributions to non-controlling interests	(10,393)	0
Other	(87)	(55)
Net cash provided by financing activities	491,874	141,480
Increase (decrease) in cash and cash equivalents	172	(2,738)
Cash and cash equivalents:
Beginning of period	16,720	11,226
End of period	16,892	8,488
Supplemental non-cash transactions:
Change in accrued capital expenditures	79,011	63,499
Change in asset retirement obligations	2,854	3,112
Issuance of shares in connection with the Permian Basin Acquisition	371,220	0
Installment notes from acquisition	$ 0	$ 4,875

Organization and Operations of

Organization and Operations of the Company	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Organization and Operations of the Company	Organization and Operations of the Company Oasis Petroleum Inc. (together with its consolidated subsidiaries, “Oasis” or the “Company”) was originally formed in 2007 and was incorporated pursuant to the laws of the State of Delaware in 2010. The Company is an independent exploration and production company focused on the acquisition and development of onshore, unconventional oil and natural gas resources in the United S tates. Oasis Petroleum North America LLC (“OPNA”) and Oasis Petroleum Permian LLC (“ OP Permian ”) conduct the Company’s exploration and production activities and own its proved and unproved oil and natural gas properties located in the North Dakota and Montana regions of the Williston Basin and the Texas region of the Delaware Basin, respectively. The Company also operates a midstream services business through OMS Holdings LLC (“ OMS ”) and a well services business through Oasis Well Services LLC (“OWS”), both of which are separate reportable business segments that are complementary to the Company’s primary development and production activities. The midstream services business is conducted by Oasis Midstream Partners LP (“ OMP ” or “ Oasis Midstream ”), which completed an initial public offering in September 2017. The Company owns the general partner and a majority of the outstanding units of OMP .

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying condensed consolidated financial statements of the Company have not been audited by the Company’s independent registered public accounting firm, except that the Condensed Consolidated Balance Sheet at December 31, 2017 is derived from audited financial statements. Certain reclassifications of prior year balances have been made to conform such amounts to current year classifications. These reclassifications have no impact on net income. In the opinion of management, all adjustments, consisting of normal recurring adjustments necessary for the fair statement of the Company’s financial position, have been included. Management has made certain estimates and assumptions that affect reported amounts in the condensed consolidated financial statements and disclosures of contingencies. Actual results may differ from those estimates. The results for interim periods are not necessarily indicative of annual results. These interim financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain disclosures have been condensed or omitted from these financial statements. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States of America (“GAAP”) for complete consolidated financial statements and should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 (“ 2017 Annual Report”). Consolidation. The accompanying condensed consolidated financial statements of the Company include the accounts of Oasis, the accounts of wholly-owned subsidiaries, and the accounts of OMP , which is considered a variable interest entity (“ VIE ”) for which the Company is the primary beneficiary. All significant intercompany balances and transactions have been eliminated upon consolidation. Consolidated VIE . The Company has determined that the partners with equity at risk in OMP lack the authority, through voting rights or similar rights, to direct the activities that most significantly impact OMP ’s economic performance. Therefore, as the limited partners of OMP do not have substantive kick-out or substantive participating rights over OMP GP LLC (“ OMP GP ”), the general partner to OMP , OMP is a VIE . Through the Company’s ownership interest in OMP GP , the Company has the authority to direct the activities that most significantly affect economic performance and the right to receive benefits that could be potentially significant to OMP . Therefore, the Company is considered the primary beneficiary and consolidates OMP and records a non-controlling interest for the interest owned by the public as of September 30, 2018 . Risks and Uncertainties As an oil and natural gas producer, the Company’s revenue, profitability and future growth are substantially dependent upon the prevailing and future prices for oil and natural gas, which are dependent upon numerous factors beyond its control such as economic, political and regulatory developments and competition from other energy sources. The energy markets have historically been very volatile, and there can be no assurance that oil and natural gas prices will not be subject to wide fluctuations in the future. A substantial or extended decline in prices for oil and, to a lesser extent, natural gas could have a material adverse effect on the Company’s financial position, results of operations, cash flows and quantities of oil and natural gas reserves that may be economically produced. Significant Accounting Policies There have been no material changes to the Company’s critical accounting policies and estimates from those disclosed in the 2017 Annual Report, other than as noted below. Revenue recognition. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The objective of ASU 2014-09 is greater consistency and comparability across industries by using a five-step model to recognize revenue from customer contracts. ASU 2014-09 was applied on a modified retrospective basis. The adoption of ASU 2014-09 did not result in a material impact to the Company’s financial position, cash flows or results of operations. Enhanced disclosures in accordance with ASU 2014-09 have been provided in Note 3 – Revenue Recognition . Financial instruments. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”), which requires that most equity instruments be measured at fair value with subsequent changes in fair value recognized in net income. ASU 2016-01 also impacts financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. ASU 2016-01 does not apply to equity method investments or investments in consolidated subsidiaries. ASU 2016-01 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 . Statement of cash flows. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2016-15, Statement of Cash Flows (“ASU 2016-15”), which is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. ASU 2016-15 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 . Income taxes. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”), to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. ASU 2016-16 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 . In the third quarter of 2018, the Company finalized the accounting related to Accounting Standards Update No. 2018-05, Income Taxes (Topic 740) - Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 (“ASU 2018-05”). This standard amends Accounting Standards Codification 740, Income Taxes (“ASC 740”) to provide guidance on accounting for the tax effects of the Tax Cuts and Jobs Act (the “Tax Act”) pursuant to Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act ("SAB 118"). See Note 13 – Income Taxes for the total impact as a result of adoption as of September 30, 2018 . Business combinations. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2017-01, Clarifying the Definition of a Business (“ASU 2017-01”), which provides guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 requires entities to use a screen test to determine when an integrated set of assets and activities is not a business or if the integrated set of assets and activities needs to be further evaluated against the framework. ASU 2017-01 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 . Equity-based compensation. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2017-09, Scope of Modification Accounting (“ASU 2017-09”), which provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. ASU 2017-09 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 . Recent Accounting Pronouncements Leases. In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2016-02, Leases (“ASU 2016-02”), which requires a lessee to recognize lease payment obligations and a corresponding right-of-use asset to be measured at fair value on the balance sheet. ASU 2016-02 also requires certain qualitative and quantitative disclosures about the amount, timing and uncertainty of cash flows arising from leases. This standard does not apply to leases to explore for or use minerals, oil or natural gas resources, including the right to explore for those natural resources. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. In January 2018, the FASB issued Accounting Standards Update No. 2018-01, Land Easement Practical Expedient for Transition to Topic 842 , which provides an optional transition practical expedient to not evaluate under Topic 842 existing or expired land easements that were not previously accounted for as leases under Topic 840, Leases . The Company plans to elect this practical expedient. In July 2018, the FASB issued Accounting Standards Update No. 2018-11, Targeted Improvements - Lease Topic 842 , which allows entities another option for transition and also provides lessors with a practical expedient to combine lease and non-lease components. The Company will adopt the new leases standard using the required modified retrospective approach and plans to elect the option to recognize a cumulative effect adjustment of initially applying the guidance to the opening balance of retained earnings in the period of adoption, rather than recognizing in the earliest period presented. Prior period amounts will not be adjusted. The Company is in the process of analyzing its lease arrangements and is continuing to identify and put in place necessary changes to its business processes and controls to support the adoption of the new standard, including implementing a new lease accounting software to assess the portfolio of leases, assist in the quantification of the expected impact on the consolidated financial statements and facilitate the calculations of the related accounting entries and disclosures. The Company is currently evaluating the effect that adopting the new lease guidance will have on its financial position, cash flows and results of operations. Financial instruments. In August 2018, the FASB issued Accounting Standards Update No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”), which improves the effectiveness of the disclosure requirements for fair value measurements. The changes affect all companies that are required to include fair value measurement disclosures. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those years. An entity is permitted to early adopt the removed or modified disclosures upon the issuance of ASU 2018-13 and may delay adoption of the additional disclosures until their effective date. The Company does not expect the adoption of this guidance to have an impact on its financial position, cash flows or results of operations, but it may result in changes to disclosures.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition In May 2014, the FASB issued a new accounting standard related to revenue recognition, ASC 606 - Revenue from Contracts with Customers (“ASC 606”) . This standard was effective in the first quarter of 2018 and the Company adopted the new standard using the modified retrospective method. The Company applied ASC 606 to all new contracts entered into after January 1, 2018 and all existing contracts for which all (or substantially all) of the revenue has not been recognized under legacy revenue guidance as of December 31, 2017. ASC 606 supersedes previous revenue recognition requirements in ASC 605 and includes a five-step revenue recognition model to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. In accordance with the adoption of ASC 606, management evaluated its contracts with customers to apply the five-step revenue recognition model. The adoption of ASC 606 did not result in a material impact to the Company’s financial position, cash flows or results of operations. The unit of account in ASC 606 is a performance obligation, which is a promise in a contract to transfer to a customer either a distinct good or service (or bundle of goods or services) or a series of distinct goods or services provided over a period of time. ASC 606 requires that a contract’s transaction price, which is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, is to be allocated to each performance obligation in the contract based on relative standalone selling prices and recognized as revenue when (point in time) or as (over time) the performance obligation is satisfied. Exploration and production revenues Our exploration and production revenues are derived from contracts for oil, natural gas and natural gas liquids (“NGL”) sales, as described below. Generally, for the majority of these contracts: (i) each unit (barrel (“bbl”), mcf, gallon, etc.) of commodity product is a separate performance obligation, as our promise is to sell multiple distinct units of commodity product at a point in time; (ii) the transaction price principally consists of variable consideration, which amount is determinable each month end based on our right to invoice at month end for the value of commodity product sold to the customer that month; and (iii) the transaction price is allocated to each performance obligation based on the commodity product’s standalone selling price and recognized as revenue upon delivery of the commodity product, which is the point in time when the customer obtains control of the commodity product and our performance obligation is satisfied. The sales of oil, natural gas and NGLs as presented on the Company’s Condensed Consolidated Statements of Operations represent the Company’s share of revenues net of royalties and excluding revenue interests owned by others. When selling oil, natural gas and NGLs on behalf of royalty owners or working interest owners, the Company is acting as an agent and thus reports the revenue on a net basis. To the extent actual volumes and prices of oil and natural gas sales are unavailable for a given reporting period because of timing or information not received from third parties, the expected sales volumes and prices for those properties are estimated and recorded. The Company’s contracts with customers typically require payments for oil, natural gas and NGL sales within 30 days following the calendar month of delivery. Oil revenues. The Company sells a substantial majority of its oil through bulk sales at delivery points on crude oil gathering systems or directly at the wellhead to a variety of customers under short-term contracts that include a specified quantity of crude oil to be delivered and sold to the customer at a specified delivery point. The customer pays a market-based transaction price, which incorporates differentials that include, but are not limited to, transportation costs and adjustments for product quality. Natural gas revenues. The Company’s natural gas sales consist of unprocessed gas sales and residue gas sales. Unprocessed gas is sold at delivery points at or near the wellhead under various contracts, in which the customer pays a transaction price based on its sale of the bifurcated NGLs and residue gas, less any associated fees. Revenue is recorded on a net basis, with processing fees deducted within revenue rather than as a separate expense line item, as title and control transfer at the delivery point. Residue gas is sold from the tailgate of the Company’s gas processing plant located in Wild Basin or transported and sold at other downstream sales points, and the customer pays a transaction price based on a market indexed per-unit rate for the quantities sold. Purchased oil and gas sales. The Company purchases and sells crude oil and natural gas at various delivery points to a variety of customers under short-term contracts that include specified quantities of crude oil and natural gas to be sold and delivered to the customer at a specified delivery point. The Company purchases and sells crude oil and natural gas to different counterparties at market-based prices. Market-based pricing is based on the price index applicable for the location of the sale. The Company accounts for these transactions on a gross basis. NGL revenues. NGLs are sold from the Company’s gas processing plant complex located in Wild Basin or trucked and sold at other downstream locations, and the customer pays a transaction price based on a market indexed per-unit rate for the quantities sold. Prior period performance obligations. For sales of oil, purchased oil, natural gas, purchased gas and NGLs, the Company records revenue in the month production is delivered to the purchaser. However, settlement statements and payment may not be received for 30 to 90 days after the date production is delivered, and as a result, the Company is required to estimate the amount of production that was delivered to the purchaser and the price that will be received for the sale of the product. The Company records the differences between estimates and the actual amounts received for product sales once payment is received from the purchaser. Such differences have historically not been significant. The Company uses knowledge of its properties, its properties' historical performance, spot market prices and other factors as the basis for these estimates. For the three and nine months ended September 30, 2018 , revenue recognized related to performance obligations satisfied in prior reporting periods was not material. Revenues associated with contracts with customers for oil, natural gas and NGL sales were as follows for the three and nine months ended September 30, 2018 and 2017 : Exploration and Production Revenues Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Oil revenues $ 412,530 $ 221,003 $ 1,097,171 $ 623,603 Purchased oil sales 42,902 20,734 114,598 56,269 Natural gas revenues 26,181 17,037 76,201 51,689 Purchased gas sales 1,616 462 2,161 648 NGL revenues 13,932 10,607 38,863 29,241 Total exploration and production revenues $ 497,161 $ 269,843 $ 1,328,994 $ 761,450 Midstream revenues Crude oil and natural gas revenues. The Company is party to certain contracts for gas gathering, compression, processing and gas lift services, as well as crude oil gathering, stabilization, blending, storage and transportation. Under these customer contracts, the Company provides daily integrated midstream services on a stand ready basis over a period of time, which represents a single performance obligation since the customer simultaneously receives and consumes the benefits of these services on a daily basis. Satisfaction of the Company’s performance obligation is measured as each day of service is completed, which directly corresponds with its right to consideration from the customer. Revenues associated with these contracts are recognized based upon the transaction price at month-end under the right to invoice practical expedient. Payments from customers are generally received by the Company within one month after the month in which services are provided. Purchased oil sales. The Company purchases and sells crude oil at various delivery points on crude oil gathering systems to a variety of customers under short-term contracts that include a specified quantity of crude oil to be sold and delivered to the customer at a specified delivery point. The Company purchases and sells the crude oil to different counterparties at market-based prices. Market-based pricing is based on the price index applicable for the location of the sale. The Company accounts for these transactions on a gross basis. Water revenues. The Company is also party to certain contracts with customers for water services, which includes produced and flowback water gathering and disposal services and freshwater distribution services. Under its customer contracts for produced and flowback water gathering and disposal services, the Company provides daily integrated midstream services on a stand-ready basis over a period of time, which represents a single performance obligation since the customer simultaneously receives and consumes the benefits of these services on a daily basis. Satisfaction of the Company’s performance obligation is measured as each day of service is completed, which directly corresponds with its right to consideration from the customer. Revenues associated with these contracts are recognized based upon the transaction price at month-end under the right to invoice practical expedient. Payments from customers are generally received by the Company within one month after the month in which services are provided. Under its customer contracts for freshwater distribution services, the Company supplies and distributes freshwater to its customers for hydraulic fracturing and production optimization. Management has determined these contracts contain multiple distinct performance obligations since each freshwater barrel is not dependent nor highly interrelated with other barrels. Revenue associated with freshwater distribution services is recognized at a point-in-time based upon the transaction price when title, control and risk of loss transfers to the customer, which occurs at the delivery point. Payments are due from customers 30 days after receipt of invoice. Revenues associated with contracts with customers for midstream services were as follows for the three and nine months ended September 30, 2018 and 2017 : Midstream Revenues (1) Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Crude oil and natural gas revenues $ 18,188 $ 11,612 $ 54,124 $ 23,348 Purchased oil sales 1,838 — 5,212 — Water revenues 12,999 7,155 34,327 25,591 Total midstream revenues $ 33,025 $ 18,767 $ 93,663 $ 48,939 __________________ (1) Represents midstream revenues, excluding all intercompany revenues, for work performed by the midstream services business segment for the Company’s working interests that are eliminated in consolidation and are therefore not included in midstream services revenues. Well services revenues Hydraulic fracturing service revenues. Hydraulic fracturing revenue is recognized upon the completion of each hydraulic fracturing of a well. These services are composed of various components, such as personnel, equipment and hydraulic fracturing materials, but management determined that each component is not distinct, as it cannot be used on its own or together with a resource readily available to the customer. Revenue is recognized when the performance obligations of hydraulic fracturing a well in its totality are completed; generally, this is over a period of time due to all work being performed for a customer occurring on the customer’s property, where the customer has control over the work in process as it is being performed. In addition, the Company’s assets being used to perform the obligations have no alternative use at the time of performance and the Company has the right to payment for performance to date. Payments from customers are generally received by the Company within one month after the month in which services are provided. In addition, revenue from product sales to third parties is generated when OPNA requests that third-party hydraulic fracturing companies hydraulic fracture OPNA’s wells. Although the labor is provided by the third-party hydraulic fracturing company, the materials (e.g., sand, chemicals, etc.) used in the hydraulic fracturing of the wells are provided by OWS. The third-party hydraulic fracturing company or OPNA pays OWS for the materials delivered to the wells. Revenue is recognized once the performance obligations to transfer hydraulic fracturing materials are completed. Equipment rental revenues. Equipment rental revenue is generated when OPNA or a third-party hydraulic fracturing company rents equipment from OWS. This equipment is used in the preparation stage of hydraulic fracturing services or after the hydraulic fracturing services have been completed. Equipment rental revenues are calculated based on the equipment’s daily rental rate and the number of days that the equipment was rented by the customer. OWS’s performance obligation is satisfied when the entire rental period is completed. Equipment rental revenues are recognized over a period of time due to the customer simultaneously receiving and consuming the bene fits of the rental equipment provided by OWS on a daily basis. Satisfaction of the Company’s performance obligation is measured at the completion of each day’s rental period, which directly corresponds with its right to consideration from the customer. Revenues associated with these contracts are recognized at the time of invoicing for the entire rental period under the right to invoice practical expedient. Payments from customers are generally received by the Company within one month after the month in which services are provided. Revenues associated with contracts with customers for hydraulic fracturing services and equipment rental sales were as follows for the three and nine months ended September 30, 2018 and 2017 : Well Services Revenues (1) Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Hydraulic fracturing service revenues $ 14,985 $ 15,090 $ 42,801 $ 31,303 Equipment rental revenues 1,277 1,048 3,543 2,263 Total well services revenues $ 16,262 $ 16,138 $ 46,344 $ 33,566 __________________ (1) Represents well services revenues excluding all intercompany revenues for work performed by the well services business segment for the Company’s working interests that are eliminated in consolidation and are therefore not included in well services revenues. Contract balances Under the Company's customer contracts, invoicing occurs once the Company's performance obligations have been satisfied, at which point payment is unconditional. Accordingly, the Company's contracts do not give rise to contract assets or liabilities under ASC 606. Performance obligations The majority of the Company’s sales are short-term in nature with a contract term of one year or less. For those contracts, the Company utilized the practical expedient in ASC 606-10-50-14 that exempts the Company from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less. For the Company’s product sales that have a contract term greater than one year, the Company utilized the practical expedient in ASC 606-10-50-14(A) which states the Company is not required to disclose the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Under these sales contracts, each unit of product generally represents a separate performance obligation; therefore future volumes are wholly unsatisfied and disclosure of the transaction price allocated to remaining performance obligations is not required. Under the midstream services contracts, each unit of service represents a separate performance obligation and therefore performance obligations in respect of future services are wholly unsatisfied.

Inventory

Inventory	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Inventory	Inventory Crude oil inventory includes oil in tanks. Equipment and materials consist primarily of proppant, chemicals, tubular goods, well equipment to be used in future drilling or repair operations and well fracturing equipment. Crude oil inventory and equipment and materials are included in inventory on the Company’s Condensed Consolidated Balance Sheets. The minimum volume of product in a pipeline system that enables the system to operate is known as linefill and is generally not available to be withdrawn from the pipeline system until the expiration of the transportation contract. The Company owns oil linefill in third-party pipelines, which is included in long-term inventory on the Company’s Condensed Consolidated Balance Sheets. Inventory , including long-term inventory, is stated at the lower of cost and net realizable value with cost determined on an average cost method. T he Company assesses the carrying value of inventory and uses estimates and judgment when making any adjustments necessary to reduce the carrying value to net realizable value. Among the uncertainties that impact the Company’s estimates are the applicable quality and location differentials to include in the Company’s net realizable value analysis. Additionally, the Company estimates the upcoming liquidation timing of the inventory. Changes in assumptions made as to the timing of a sale can materially impact net realizable value. Total inventory consists of the following: September 30, 2018 December 31, 2017 (In thousands) Inventory Crude oil inventory $ 14,867 $ 10,427 Equipment and materials 16,542 8,940 Total inventory $ 31,409 $ 19,367 Long-term inventory Linefill in third-party pipelines $ 12,610 $ 12,200 Long-term inventory $ 12,610 $ 12,200 Total $ 44,019 $ 31,567

Accounts Receivable, Net

Accounts Receivable, Net	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Accounts Receivable, Net	Accounts Receivable, Net The following table sets forth the Company’s accounts receivable, net: September 30, 2018 December 31, 2017 (In thousands) Accounts receivable, net Trade accounts $ 277,558 $ 233,660 Joint interest accounts 94,793 73,588 Other accounts 56,779 57,905 Total 429,130 365,153 Allowance for doubtful accounts (946 ) (1,573 ) Total accounts receivable, net $ 428,184 $ 363,580

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements In accordance with the FASB’s authoritative guidance on fair value measurements, the Company’s financial assets and liabilities are measured at fair value on a recurring basis. The Company’s financial instruments, including certain cash and cash equivalents, accounts receivable, accounts payable and other payables, are carried at cost, which approximates their respective fair market values due to their short-term maturities. The Company recognizes its non-financial assets and liabilities, such as asset retirement obligations (“ARO”) and proved oil and natural gas properties upon impairment, at fair value on a non-recurring basis. As defined in the authoritative guidance, fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). To estimate fair value, the Company utilizes market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable. The authoritative guidance establishes a fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (“Level 1” measurements) and the lowest priority to unobservable inputs (“Level 3” measurements). The three levels of the fair value hierarchy are as follows: Level 1 — Unadjusted quoted prices are available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 — Pricing inputs, other than unadjusted quoted prices in active markets included in Level 1, are either directly or indirectly observable as of the reporting date. Level 2 includes those financial instruments that are valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including quoted forward prices for commodities, time value, volatility factors and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument and can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace. Level 3 — Pricing inputs are generally less observable from objective sources, requiring internally developed valuation methodologies that result in management’s best estimate of fair value. Financial Assets and Liabilities Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The following tables set forth by level, within the fair value hierarchy, the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis: Fair value at September 30, 2018 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 143 $ — $ — $ 143 Total assets $ 143 $ — $ — $ 143 Liabilities: Commodity derivative instruments (see Note 7) $ — $ 213,146 $ — $ 213,146 Total liabilities $ — $ 213,146 $ — $ 213,146 Fair value at December 31, 2017 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 142 $ — $ — $ 142 Commodity derivative instruments (see Note 7) — 353 — 353 Total assets $ 142 $ 353 $ — $ 495 Liabilities: Commodity derivative instruments (see Note 7) $ — $ 135,567 $ — $ 135,567 Total liabilities $ — $ 135,567 $ — $ 135,567 The Level 1 instruments presented in the tables above consist of money market funds included in cash and cash equivalents on the Company’s Condensed Consolidated Balance Sheets at September 30, 2018 and December 31, 2017 . The Company’s money market funds represent cash equivalents backed by the assets of high-quality major banks and financial institutions. The Company identifies the money market funds as Level 1 instruments because the money market funds have daily liquidity, quoted prices for the underlying investments can be obtained, and there are active markets for the underlying investments. The Level 2 instruments presented in the tables above consist of commodity derivative instruments, which include oil and natural gas swaps and collars. The fair values of the Company’s commodity derivative instruments are based upon a third-party preparer’s calculation using mark-to-market valuation reports provided by the Company’s counterparties for monthly settlement purposes to determine the valuation of its derivative instruments. The Company has the third-party preparer evaluate other readily available market prices for its derivative contracts, as there is an active market for these contracts. The third-party preparer performs its independent valuation using a moment matching method similar to Turnbull-Wakeman for Asian options. The significant inputs used are crude oil prices, volatility, skew, discount rate and the contract terms of the derivative instruments. The Company compares the third-party preparer’s valuation to counterparty valuation statements, investigating any significant differences, and analyzes monthly valuation changes in relation to movements in crude oil and natural gas forward price curves. The determination of the fair value for derivative instruments also incorporates a credit adjustment for non-performance risk, as required by GAAP. The Company calculates the credit adjustment for derivatives in a net asset position using current credit default swap values for each counterparty. The credit adjustment for derivatives in a net liability position is based on the Company’s market credit spread. Based on these calculations, the Company recorded an adjustment to reduce the fair value of its net derivative liability by $2.7 million and $2.8 million at September 30, 2018 and December 31, 2017 , respectively. There were no transfers between fair value levels during the nine months ended September 30, 2018 and December 31, 2017 .

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments The Company utilizes derivative financial instruments to manage risks related to changes in oil and natural gas prices. The Company’s crude oil contracts will settle monthly based on the average NYMEX West Texas Intermediate crude oil index price (“ NYMEX WTI ”), the average Intercontinental Exchange, Inc. Brent crude oil index price (“ ICE Brent ”) and the average Argus WTI Midland crude oil index price (“ Midland ”). The Company’s natural gas contracts will settle monthly based on the average NYMEX Henry Hub natural gas index price (“ NYMEX HH ”) and the average Inside FERC Northern Natural Gas Ventura natural gas index price (“ IF NNG Ventura ”). At September 30, 2018 , the Company utilized fixed price swaps, basis swaps and two-way and three-way costless collars to reduce the price volatility associated with certain of its of oil and natural gas sales. The Company’s fixed price swaps are comprised of a sold call and a purchased put established at the same price (both ceiling and floor), which the Company will receive for the volumes under contract. A basis swap transaction has an established fixed basis differential corresponding to two floating index prices. Depending on the difference of the two floating index prices in relation to the fixed basis differential, the Company either receives an amount from its counterparty, or pays an amount to its counterparty, equal to the difference multiplied by the hedged contract volume. A two-way collar is a combination of options: a sold call and a purchased put. The purchased put establishes a minimum price (floor) and the sold call establishes a maximum price (ceiling) the Company will receive for the volumes under contract. A three-way collar is a combination of options: a sold call, a purchased put and a sold put. The purchased put establishes a minimum price (floor), unless the market price falls below the sold put (sub-floor), at which point the minimum price would be the NYMEX index price plus the difference between the purchased put and the sold put strike price. The sold call establishes a maximum price (ceiling) the Company will receive for the volumes under contract. All derivative instruments are recorded on the Company’s Condensed Consolidated Balance Sheets as either assets or liabilities measured at fair value (see Note 6 – Fair Value Measurements). The Company has not designated any derivative instruments as hedges for accounting purposes and does not enter into such instruments for speculative trading purposes. If a derivative does not qualify as a hedge or is not designated as a hedge, the changes in fair value are recognized in the other income (expense) section of the Company’s Condensed Consolidated Statements of Operations as a net gain or loss on derivative instruments. The Company’s cash flow is only impacted when the actual settlements under the derivative contracts result in making a payment to or receiving a payment from the counterparty. These cash settlements represent the cumulative gains and losses on the Company’s derivative instruments and do not include a recovery of costs that were paid to acquire or modify the derivative instruments that were settled. Cash settlements are reflected as investing activities in the Company’s Condensed Consolidated Statements of Cash Flows. At September 30, 2018 , the Company had the following outstanding commodity derivative instruments: Commodity Settlement Derivative Index Volumes Weighted Average Prices Fair Value Fixed Price Swaps Basis Swaps Sub-Floor Floor Ceiling (In thousands) Crude oil 2018 Fixed price swaps NYMEX WTI 3,761,000 Bbl $ 52.95 $ (71,621 ) Crude oil 2018 Basis swaps NYMEX WTI-ICE BRENT 152,000 Bbl $ (9.84 ) 81 Crude oil 2018 Two-way collar NYMEX WTI 517,000 Bbl $ 58.74 $ 63.94 (5,171 ) Crude oil 2019 Fixed price swaps NYMEX WTI 5,613,000 Bbl $ 53.33 (99,347 ) Crude oil 2019 Basis swaps NYMEX WTI-ICE BRENT 424,000 Bbl $ (9.68 ) 408 Crude oil 2019 Two-way collar NYMEX WTI 3,223,000 Bbl $ 57.99 $ 75.46 (7,580 ) Crude oil 2019 Three-way collar NYMEX WTI 3,368,000 Bbl $ 40.54 $ 51.03 $ 68.68 (21,771 ) Crude oil 2020 Fixed price swaps NYMEX WTI 403,000 Bbl $ 53.47 (5,911 ) Crude oil 2020 Two-way collar NYMEX WTI 279,000 Bbl $ 57.78 $ 76.13 (273 ) Crude oil 2020 Three-way collar NYMEX WTI 279,000 Bbl $ 40.00 $ 50.56 $ 67.80 (1,778 ) Natural gas 2018 Fixed price swaps NYMEX HH 3,496,000 MMbtu $ 3.01 (104 ) Natural gas 2018 Basis swaps IF NNG VENTURA-NYMEX HH 1,225,000 MMbtu $ (0.05 ) (64 ) Natural gas 2019 Fixed price swaps NYMEX HH 1,896,000 MMbtu $ 2.95 16 Natural gas 2019 Basis swaps IF NNG VENTURA-NYMEX HH 2,715,000 MMbtu $ (0.05 ) (31 ) $ (213,146 ) In October 2018, the Company entered into new swaps and two-way costless collar options for crude oil and natural gas with weighted average floor prices of $64.05 per barrel and $2.88 per MMbtu , respectively. The commodity contracts included total notional amounts of 213,000 barrels, 792,000 barrels and 62,000 barrels which settle in 2018 , 2019 and 2020 , respectively, based on NYMEX WTI and 305,000 MMbtu and 1,825,000 MMbtu which settle in 2018 and 2019 , respectively, based on NYMEX HH . Additionally, the Company entered into new basis swap contracts for crude and natural gas with weighted average differential prices, which represent a reduction of $7.50 per barrel and an addition of $0.13 per MMbtu , respectively. The crude basis swap contracts include total notional amounts of 60,000 barrels and 424,000 barrels, which settle in 2018 and 2019 , respectively, based on the differential between Midland and NYMEX WTI , and the natural gas basis swap contracts include total notional amounts of 610,000 MMbtu and 1,810,000 MMbtu , which settle in 2018 and 2019 , respectively, based on the differential between IF NNG Ventura and NYMEX HH . These derivative instruments do not qualify for and were not designated as hedging instruments for accounting purposes. The following table summarizes the location and amounts of gains and losses from the Company’s commodity derivative instruments recorded in the Company’s Condensed Consolidated Statements of Operations for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, Statements of Operations Location 2018 2017 2018 2017 (In thousands) Net gain (loss) on derivative instruments $ (48,544 ) $ (54,310 ) $ (239,945 ) $ 52,297 In accordance with the FASB’s authoritative guidance on disclosures about offsetting assets and liabilities, the Company is required to disclose both gross and net information about instruments and transactions eligible for offset in the statement of financial position as well as instruments and transactions subject to an agreement similar to a master netting agreement. The Company’s derivative instruments are presented as assets and liabilities on a net basis by counterparty, as all counterparty contracts provide for net settlement. No margin or collateral balances are deposited with counterparties, and as such, gross amounts are offset to determine the net amounts presented in the Company’s Condensed Consolidated Balance Sheets. The following table summarizes the location and fair value of all outstanding commodity derivative instruments recorded in the Company’s Condensed Consolidated Balance Sheets: September 30, 2018 Commodity Balance Sheet Location Gross Recognized Liabilities Gross Amount Offset Net Recognized Fair Value Liabilities (In thousands) Derivatives liabilities: Commodity contracts Derivative instruments — current liabilities $ 184,832 $ (4,703 ) $ 180,129 Commodity contracts Derivative instruments — non-current liabilities 37,006 (3,989 ) 33,017 Total derivatives liabilities $ 221,838 $ (8,692 ) $ 213,146 December 31, 2017 Commodity Balance Sheet Location Gross Recognized Assets/Liabilities Gross Amount Offset Net Recognized Fair Value Assets/Liabilities (In thousands) Derivatives assets: Commodity contracts Derivative instruments — current assets $ 344 $ — $ 344 Commodity contracts Derivative instruments — non-current assets 9 — 9 Total derivatives assets $ 353 $ — $ 353 Derivatives liabilities: Commodity contracts Derivative instruments — current liabilities $ 117,629 $ (1,913 ) $ 115,716 Commodity contracts Derivative instruments — non-current liabilities 20,035 (184 ) 19,851 Total derivatives liabilities $ 137,664 $ (2,097 ) $ 135,567

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment The following table sets forth the Company’s property, plant and equipment: September 30, 2018 December 31, 2017 (In thousands) Proved oil and gas properties (1) $ 7,566,694 $ 7,058,782 Less: Accumulated depreciation, depletion, amortization and impairment (2,689,613 ) (2,395,153 ) Proved oil and gas properties, net 4,877,081 4,663,629 Unproved oil and gas properties 1,104,450 780,173 Other property and equipment 1,088,781 868,746 Less: Accumulated depreciation (170,175 ) (139,062 ) Other property and equipment, net 918,606 729,684 Total property, plant and equipment, net $ 6,900,137 $ 6,173,486 __________________ (1) Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $41.4 million and $39.9 million at September 30, 2018 and December 31, 2017 , respectively.

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisition	Acquisition Permian Basin Acquisition . On February 14, 2018 , the Company acquired from Forge Energy, LLC (“ Forge Energy ”) approximately 22,000 net acres in the Delaware Basin (the “ Permian Basin Acquisition ”) for aggregate consideration consisting of approximately $549.8 million in cash and 46,000,000 shares of the Company’s common stock, subject to customary post-closing adjustments (collectively, the “Purchase Price”). In connection with the closing of the Permian Basin Acquisition , the Company and Forge Energy entered into a Registration Rights Agreement that granted the equity holders of Forge Energy certain customary registration rights for the stock portion of the Purchase Price. The Company funded the cash portion of the Purchase Price with borrowings under a senior secured revolving line of credit among OPNA, as Borrower, Wells Fargo Bank, N.A., as administrative agent and the lenders party thereto (the “ Oasis Credit Facility ”), and proceeds from the Company’s December 2017 issuance of its common stock. The Permian Basin Acquisition represents the Company’s initial entry into the Delaware Basin. The assets underlying the Permian Basin Acquisition are primarily located in the Bone Spring and Wolfcamp formations of the Delaware sub-basin, across Ward, Winkler, Loving and Reeves Counties, Texas. The Permian Basin Acquisition qualified as a business combination. As such, the Company estimated the fair value of the assets acquired and liabilities assumed as of the February 14, 2018 acquisition date. The fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Fair value measurements also utilize assumptions of market participants. The Company used a discounted cash flow model and made market assumptions as to future commodity prices, projections of estimated quantities of oil and natural gas reserves, expectations for timing and amount of future development and operating costs, projections of future rates of production, expected recovery rates and risk adjusted discount rates. These assumptions represent Level 3 inputs, as further discussed under Note 6 — Fair Value Measurements . The Company recorded the assets acquired and liabilities assumed in the Permian Basin Acquisition at their estimated fair value of $921.0 million , which the Company considers to be representative of the price paid by a typical market participant. This measurement resulted in no goodwill or bargain purchase being recognized. The Permian Basin Acquisition is considered a taxable transaction; therefore, no deferred tax amounts were recognized at the acquisition date as the tax basis of the assets acquired and liabilities assumed were also recorded at fair value. The following table summarizes the consideration paid for the Company’s acquisition and the fair value of the assets acquired and liabilities assumed as of the acquisition date. At February 14, 2018 (In thousands) Consideration paid to Forge Energy: Cash $ 549,770 Common stock: 46,000,000 shares issued 371,220 $ 920,990 Recognized amounts of identifiable assets acquired and liabilities assumed: Proved developed properties $ 110,325 Proved undeveloped properties 166,552 Unproved lease acquisition costs 645,068 Inventory 293 Intangible assets 1,000 Asset retirement obligations (2,248 ) $ 920,990 The results of operations for the Permian Basin Acquisition have been included in the Company’s condensed consolidated financial statements since the February 14, 2018 closing date, including $19.4 million and $51.0 million of total revenue and $3.9 million and $14.2 million of operating income for the three and nine months ended September 30, 2018 , respectively. The Company also recorded a $1.0 million finite-lived intangible asset on the Company’s Condensed Consolidated Balance Sheets for a non-compete agreement with a one -year life. Intangible assets are amortized on a straight-line basis over the useful life, and the Company includes the amortization in depreciation, depletion and amortization expenses on the Company’s Condensed Consolidated Statements of Operations. For the three and nine months ended September 30, 2018 , amortization expense recognized for this non-compete agreement was approximately $0.3 million and $0.6 million , respectively. Summarized below are the consolidated results of operations for the three and nine months ended September 30, 2018 , on an unaudited pro forma basis, as if the acquisition and related financing had occurred on January 1, 2017. The unaudited pro forma financial information was derived from the historical consolidated statements of operations of the Company and the statement of revenues and direct operating expenses for the Permian Basin Acquisition properties, which were derived from the historical accounting records of Forge Energy . The unaudited pro forma financial information does not purport to be indicative of results of operations that would have occurred had the acquisition and related financing occurred on the basis assumed above, nor is such information indicative of the Company’s expected future results of operations. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) (In thousands) Unaudited Unaudited Revenues $ 546,449 $ 318,879 $ 1,474,530 $ 871,952 Net income (loss) attributable to Oasis 62,341 (29,717 ) (252,731 ) 22,068 Net income (loss) attributable to Oasis per share: Basic $ 0.20 $ (0.11 ) $ (0.81 ) $ 0.08 Diluted 0.20 (0.11 ) (0.81 ) 0.08 Other Delaware Acquisition . On September 12, 2018 , the Company completed the initial closing with undisclosed sellers to acquire certain exploration and production assets adjacent to the Company’s existing Delaware position (the “ Other Delaware Acquisition ”) for total cash consideration of $59.5 million . Based on the FASB’s authoritative guidance, the acquisition qualified as a business combination, and as such, the Company estimated the fair value of the assets acquired as of the acquisition date. The Company recorded the oil and gas properties acquired at their estimated fair value of $59.5 million , which the Company considers to be representative of the price paid by a typical market participant. This measurement resulted in no goodwill or bargain purchase being recognized. The results of operations for the acquisition have been included in the Company’s consolidated financial statements since the closing date. Pro forma information is not presented as the pro forma results would not be materially different from the information presented in the Company’s Consolidated Statement of Operations.

Divestitures

Divestitures	9 Months Ended
	Sep. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Divestitures	Divestitures Williston Non-Op Divestiture . On July 10, 2018 , the Company completed the initial closing for the sale of certain non-operated oil and gas properties in the Williston Basin (the “ Williston Non-Op Divestiture ”). The transaction had an effective date of March 1, 2018 , and the final closing statement will be completed in the fourth quarter of 2018. Upon the initial closing, the Company recognized a $27.5 million net gain on sale of properties, which is subject to customary closing adjustments, in its Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2018 . The divested properties were in the Company’s exploration and production segment. Foreman Butte Divestiture . On July 31, 2018 , the Company completed the initial closing for the sale of oil and gas properties and certain other property and equipment primarily located in the Foreman Butte area of the Williston Basin (the “ Foreman Butte Divestiture ”). The transaction had an effective date of March 1, 2018 , and the final closing statement will be completed in the first quarter of 2019. During the second quarter of 2018, the Company recorded an impairment loss of $383.4 million , which was included in impairment on the Company’s Condensed Consolidated Statements of Operations, to adjust the carrying value of these assets to their estimated fair value, determined based on the expected sales price as negotiated with the purchaser, less costs to sell. Upon the initial closing, the Company recognized a $10.1 million net loss on sale of properties, which is subject to customary closing adjustments, in its Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2018 . The Foreman Butte Divestiture consisted of oil and gas properties in the Company’s exploration and production segment and included certain other property and equipment in the Company’s midstream segment. Other Williston Divestiture . On August 17, 2018 , the Company completed the initial closing for the sale of additional non-strategic oil and gas properties in the Williston Basin (the “ Other Williston Divestiture ”). The transaction had an effective date of March 1, 2018 , and the final closing statement will be completed in the first quarter of 2019. Upon the initial closing, the Company recognized a $19.4 million net gain on sale of properties, which is subject to customary closing adjustments, in its Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2018 . The divested properties were in the Company’s exploration and production segment.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt The Company’s long-term debt consists of the following: September 30, 2018 December 31, 2017 (In thousands) Oasis Credit Facility $ 522,000 $ 70,000 OMP Credit Facility 166,000 78,000 Senior unsecured notes 7.25% senior unsecured notes due February 1, 2019 — 54,275 6.50% senior unsecured notes due November 1, 2021 71,835 395,501 6.875% senior unsecured notes due March 15, 2022 901,480 937,080 6.875% senior unsecured notes due January 15, 2023 366,094 366,094 6.25% senior unsecured notes due May 1, 2026 400,000 — 2.625% senior unsecured convertible notes due September 15, 2023 300,000 300,000 Total principal of senior unsecured notes 2,039,409 2,052,950 Less: unamortized deferred financing costs on senior unsecured notes (22,212 ) (22,956 ) Less: unamortized debt discount on senior unsecured convertible notes (72,188 ) (80,388 ) Total long-term debt $ 2,633,009 $ 2,097,606 The carrying amount of the Company’s long-term debt reported in the Condensed Consolidated Balance Sheet at September 30, 2018 was $2,633.0 million , which included $2,039.4 million of senior unsecured notes, reductions for the unamortized debt discount related to the equity component of the senior unsecured convertible notes and the unamortized deferred financing costs on the senior unsecured notes of $72.2 million and $22.2 million , respectively, $522.0 million of borrowings under the Oasis Credit Facility and $166.0 million of borrowings under a $250.0 million senior secured revolving credit facility among OMP , as parent, OMP Operating LLC, a subsidiary of OMP , as borrower, Wells Fargo Bank, N.A., as administrative agent and the lenders party thereto (the “ OMP Credit Facility ,” and, together with the Oasis Credit Facility , the “ Revolving Credit Facilities ”). The Revolving Credit Facilities are recorded at values that approximate fair value since their variable interest rates are tied to current market rates. The fair value of the Company’s senior unsecured notes, which are publicly traded and therefore categorized as Level 1 liabilities, was $2,172.3 million at September 30, 2018 . Senior secured revolving line of credit. The Company has the Oasis Credit Facility with an overall senior secured line of credit of $2,500.0 million as of September 30, 2018 , which has a maturity date of April 13, 2020 . The Oasis Credit Facility is restricted to a borrowing base, which is reserve-based and subject to semi-annual redeterminations on April 1 and October 1 of each year. On February 26, 2018 , the Company entered into an amendment to the Oasis Credit Facility , resulting in the aggregate elected commitment being increased from $1,150.0 million to $1,350.0 million and two new lenders being added to the bank group. On April 19, 2018 , the lenders under the Oasis Credit Facility completed their regular semi-annual redetermination of the borrowing base scheduled for April 1, 2018 , resulting in the Company entering into the Twelfth Amendment to the Second Amended and Restated Credit Agreement to the Oasis Credit Facility , which (i) reaffirmed the borrowing base and the aggregate elected commitment at $1,600.0 million and $1,350.0 million , respectively, (ii) removed the legacy anti-cash hoarding provisions, (iii) reduced the coverage threshold with respect to mortgaged properties and (iv) amended the asset sale covenant to give the Company additional flexibility to trade oil and gas properties. In addition, in connection with such amendment, OP Permian became a guarantor under the Oasis Credit Facility . On October 16, 2018 , the Company entered into a third amended and restated credit agreement (the “ Third Amended Credit Facility ”). In connection with entry into the Third Amended Credit Facility , the semi-annual redetermination of the Company’s borrowing base was completed on October 16, 2018 , which reaffirmed the borrowing base and the aggregate elected commitment at $1,600.0 million and $1,350.0 million , respectively, and the overall credit facility increased from $2,500.0 million to $3,000.0 million . Pursuant to the Third Amended Credit Facility , the credit facility was extended from April 2020 to October 2023 , provided that the Company’s 2022 and 2023 Senior Notes are retired or refinanced 90 days prior to their respective maturities. All other significant rates, terms and conditions of the Third Amended Credit Facility remained the same. The next redetermination of the Oasis Credit Facility ’s borrowing base is scheduled for April 1, 2019 . At September 30, 2018 , the Company had $522.0 million of London Interbank Offered Rate (“LIBOR”) loans at a weighted average interest rate of 3.9% and $14.0 million of outstanding letters of credit issued under the Oasis Credit Facility , resulting in an unused borrowing base committed capacity of $814.0 million . On a quarterly basis, the Company also pays a commitment fee that can range from 0.375% to 0.500% on the average amount of borrowing base capacity not utilized during the quarter and fees calculated on the average amount of letter of credit balances outstanding during the quarter. The Company was in compliance with the financial covenants of the Oasis Credit Facility as of September 30, 2018 . OMP Operating LLC revolving line of credit. Through its ownership of OMP , the Company has access to the OMP Credit Facility with a revolving line of credit of $250.0 million , which has a maturity date of September 25, 2022. On August 27, 2018, OMP entered into an amendment to its revolving credit facility to the OMP Credit Facility in order to (i) increase the aggregate amount of commitments from $200.0 million to $250.0 million , (ii) provide for the ability to further increase commitments and (iii) add six new lenders to the bank group. The OMP Credit Facility is available to fund working capital and to finance acquisitions and other capital expenditures of OMP. The OMP Credit Facility includes a letter of credit sublimit of $10.0 million and a swingline loans sublimit of $10.0 million . The borrowing capacity on the OMP Credit Facility may be increased up to $400.0 million , subject to certain conditions. Borrowings under the OMP Credit Facility bear interest at a rate per annum equal to the applicable margin (as described below) plus (i) with respect to Eurodollar Loans, the Adjusted LIBO Rate (as defined in the OMP Credit Facility ) or (ii) with respect to ABR Loans, the greatest of (A) the Prime Rate in effect on such day, (B) the Federal Funds Effective Rate in effect on such day plus 1/2 of 1.00% or (C) the Adjusted LIBO Rate for a one-month interest period on such day plus 1.00% (each as defined in the OMP Credit Facility ). The applicable margin for borrowings under the OMP Credit Facility varies from (a) in the case of Eurodollar Loans, 1.75% to 2.75% and (b) in the case of ABR Loans or swingline loans, 0.75% to 1.75% . The unused portion of the OMP Credit Facility is subject to a commitment fee ranging from 0.375% to 0.500% . The OMP Credit Facility includes certain financial covenants as of the end of each fiscal quarter, including a (i) consolidated leverage ratio, (ii) consolidated secured leverage ratio and (iii) consolidated interest coverage ratio (each covenant as described in the OMP Credit Facility ). OMP Operating LLC was in compliance with the financial covenants of the OMP Credit Facility as of September 30, 2018 . All obligations of OMP Operating LLC, as the borrower under the OMP Credit Facility , are unconditionally guaranteed on a joint and several basis by OMP, OMP Operating LLC and Bighorn DevCo LLC. At September 30, 2018 , the Company had $166.0 million of borrowings outstanding under the OMP Credit Facility . As of September 30, 2018 , the weighted average interest rate on borrowings under the OMP Credit Facility was 4.0% . Senior unsecured notes. On May 14, 2018 , the Company completed its offering of $400.0 million in aggregate principal amount of its 6.25% senior unsecured notes due 2026 (the “2026 Notes”). The Company used the net proceeds of $394.4 million from the 2026 Notes to fund the repurchase of certain outstanding senior notes (the “ Tender Offers ”), as described below. At September 30, 2018 , the Company had $1,739.4 million principal amount of senior unsecured notes outstanding with maturities ranging from November 2021 to May 2026 and coupons ranging from 6.25% to 6.875% (the “Senior Notes”). Prior to certain dates, the Company has the option to redeem some or all of the Senior Notes for cash at certain redemption prices equal to a certain percentage of their principal amount plus an applicable make-whole premium and accrued and unpaid interest to the redemption date. On May 25, 2018 , the Company completed the Tender Offers and, as a result of the Tender Offers , the Company repurchased an aggregate principal amount of $390.6 million of its outstanding Senior Notes, consisting of $31.3 million principal amount of its 7.25% senior unsecured notes due 2019 (the “2019 Notes”), $323.7 million principal amount of its 6.50% senior unsecured notes due 2021 and $35.6 million principal amount of its 6.875% senior unsecured notes due 2022 , for an aggregate cost of $402.0 million , including accrued interest and fees. On May 29, 2018 , the Company paid $23.0 million to redeem all of the remaining outstanding 2019 Notes, which payment consisted of the 100% redemption price plus all accrued and unpaid interest on the 2019 Notes. The Company financed the redemption with borrowings under the Oasis Credit Facility . As a result of the Tender Offers and the redemption, the Company recognized a pre-tax loss of $13.7 million , which was net of unamortized deferred financing costs write-offs of $4.0 million , and is reflected in loss on extinguishment of debt in the Company’s Condensed Consolidated Statements of Operations for the nine months ended September 30, 2018 . As of September 30, 2018 , no 2019 Notes remained outstanding. Senior unsecured convertible notes. At September 30, 2018 , the Company had 300.0 million of 2.625% senior unsecured convertible notes due September 2023 (the “ Senior Convertible Notes ”). The Company has the option to settle conversions of these notes with cash, shares of common stock or a combination of cash and common stock at its election. The Company’s intent is to settle the principal amount of the Senior Convertible Notes in cash upon conversion. Prior to March 15, 2023, the Senior Convertible Notes will be convertible only under the following circumstances: (i) during any calendar quarter (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (ii) during the five business day period after any five consecutive trading day period (the “Measurement Period”) in which the trading price per $1,000 principal amount of the Senior Convertible Notes for each trading day of the Measurement Period is less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; or (iii) upon the occurrence of specified corporate events, including certain distributions or a fundamental change. On or after March 15, 2023, the Senior Convertible Notes will be convertible at any time until the second scheduled trading day immediately preceding their September 15, 2023 maturity date. The Senior Convertible Notes will be convertible at an initial conversion rate of 76.3650 shares of the Company’s common stock per $1,000 principal amount of the Senior Convertible Notes, which is equivalent to an initial conversion price of approximately $13.10 . The conversion rate will be subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. In addition, following certain corporate events that occur prior to the maturity date or a notice of redemption, the Company will increase the conversion rate for a holder who elects to convert its Senior Convertible Notes in connection with such corporate event or redemption in certain circumstances. As of September 30, 2018 , none of the contingent conditions allowing holders of the Senior Convertible Notes to convert these notes had been met. Upon issuance, the Company separately accounted for the liability and equity components of the Senior Convertible Notes in accordance with Accounting Standards Codification 470-20. The liability component was recorded at the estimated fair value of a similar debt instrument without the conversion feature. The difference between the principal amount of the Senior Convertible Notes and the estimated fair value of the liability component was recorded as a debt discount and will be amortized to interest expense over the term of the notes using the effective interest method, with an effective interest rate of 8.97% per annum. The fair value of the Senior Convertible Notes as of the issuance date was estimated at $206.8 million , resulting in a debt discount at inception of $93.2 million . The equity component, representing the value of the conversion option, was computed by deducting the fair value of the liability component from the initial proceeds of the Senior Convertible Notes issuance. This equity component was recorded, net of deferred taxes and issuance costs, in additional paid-in capital and will not be remeasured as long as it continues to meet the conditions for equity classification. Interest on the Senior Notes and the Senior Convertible Notes (collectively, the “Notes”) is payable semi-annually in arrears. The Notes are guaranteed on a senior unsecured basis by the Company, along with its material subsidiaries (the “Guarantors”), which are 100% owned by the Company. These guarantees are full and unconditional and joint and several among the Guarantors, subject to certain customary release provisions. The indentures governing the Notes contain customary events of default as well as covenants that place restrictions on the Company and certain of its subsidiaries.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2018
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The following table reflects the changes in the Company’s ARO during the nine months ended September 30, 2018 : (In thousands) Balance at December 31, 2017 $ 48,799 Liabilities incurred during period 5,509 Liabilities settled during period (4,904 ) Accretion expense during period (1) 1,975 Revisions to estimates 83 Balance at September 30, 2018 $ 51,462 ___________________ (1) Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statements of Operations. At September 30, 2018 , the current portion of the total ARO balance was approximately $0.1 million and was included in accrued liabilities on the Company’s Condensed Consolidated Balance Sheets.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate for the three and nine months ended September 30, 2018 was 27.2% and 23.4% , respectively, as compared to an effective tax rate of 31.5% and 41.2% for the three and nine months ended September 30, 2017 , respectively. The effective tax rate for the three months ended September 30, 2018 was higher than the statutory federal rate of 21% primarily due to state income taxes and the impact of non-deductible executive compensation. The effective tax rate for the nine months ended September 30, 2018 was higher than the statutory rate primarily due to state income taxes and the impact of a change in the blended state rate at which the Company’s deferred taxes are recorded, partially offset by the impact of non-deductible executive compensation. The effective tax rate for the three months ended September 30, 2017 was lower than the statutory federal rate of 35% primarily due to the impact of non-deductible executive compensation and equity-based compensation shortfalls, partially offset by state income taxes. The effective tax rate for the nine months ended September 30, 2017 was higher than the statutory federal rate of 35% primarily due to state income taxes, the impact of non-deductible executive compensation and equity-based compensation windfalls, partially offset by the portion of OMP’s earnings attributable to the non-controlling public limited partners, which are not taxable to the Company. Valuation allowance. The Company had valuation allowances of $3.3 million and $1.2 million as of September 30, 2018 and December 31, 2017 , respectively, because the Company has concluded it is more likely than not that it will be unable to utilize certain state net operating loss carryforwards and charitable contribution carryforwards. As of each reporting date, the Company’s management considers new evidence, both positive and negative, which could impact management’s view with regard to future realization of deferred tax assets. During the nine months ended September 30, 2018 , the valuation allowance was increased by $2.1 million , primarily against the Company’s Montana net operating loss carryforwards, as a result of the Permian Basin Acquisition and the corresponding shift of projected future taxable income into other states. During the three months ended September 30, 2018 , there was no material change to the valuation allowance. Tax Cuts and Jobs Act. On December 22, 2017, the U.S. government enacted the Tax Act, which made broad and complex changes to the U.S. tax code. Due to the complexities involved in the accounting for the enactment of the new law, the SEC issued SAB 118, which provides guidance on the accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date to complete the accounting under ASC 740, "Income Taxes." In accordance with SAB 118, the Company was able to make reasonable estimates on certain effects of the Tax Act in the financial statements as of December 31, 2017. During the three months ended September 30, 2018 , the Company completed the accounting under the Tax Act. Based on additional guidance issued by the Internal Revenue Service regarding the grandfather provisions related to certain performance-based compensation awards outstanding as of November 2, 2017, the Company wrote off $1.9 million of deferred tax assets for which the Company will not receive a future tax deduction.

Equity-Based Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity-Based Compensation	Equity-Based Compensation Restricted stock awa rds. The Company has granted restricted stock awards to employees and directors under its Amended and Restated 2010 Long Term Incentive Plan, the majority of which vest over a three -year period. The fair value of restricted stock awards is based on the closing sales price of the Company’s common stock on the date of grant. Compensation expense is recognized ratably over the requisite service period. During the nine months ended September 30, 2018 , employees and non-employee directors of the Company were granted restricted stock awards equal to 3,511,030 shares of common stock with a $10.17 weighted average grant date per share value. Equity-based compensation expense recorded for restricted stock awards for the three and nine months ended September 30, 2018 was $5.1 million and $14.7 million , respectively, and $4.9 million and $15.2 million for the three and nine months ended September 30, 2017 , respectively. Equity-based compensation expense is included in general and administrative expenses on the Company’s Condensed Consolidated Statements of Operations. Performance share units. The Company has granted performance share units (“PSUs”) to officers of the Company under its Amended and Restated 2010 Long Term Incentive Plan. The PSUs are awards of restricted stock units, and each PSU that is earned represents the right to receive one share of the Company’s common stock. The Company accounts for PSUs as equity awards pursuant to the FASB’s authoritative guidance for share-based payments. The number of PSUs to be earned is subject to a market condition, which is based on a comparison of the total shareholder return (“TSR”) achieved with respect to shares of the Company’s common stock against the TSR achieved by a defined peer group at the end of the performance periods. Depending on the Company’s TSR performance relative to the defined peer group, award recipients will earn between 0% and 200% of the initial PSUs granted. All compensation expense related to the PSUs will be recognized if the requisite performance period is fulfilled, even if the market condition is not achieved. The aggregate grant date fair value of the market-based awards was determined using a Monte Carlo simulation model. The Monte Carlo simulation model uses assumptions regarding random projections and must be repeated numerous times to achieve a probabilistic assessment. The key valuation assumptions for the Monte Carlo model are the forecast period, initial value, stock price on the date of grant, risk-free interest rate, volatility and correlation coefficients. The risk-free interest rates are the U.S. Treasury bond rates on the date of grant that correspond to each performance period. The initial value is the average of the volume weighted average prices for the 30 trading days prior to the start of the performance cycle for the Company and each of its peers. Volatility was calculated from the daily historical returns of stock prices over a historical period for the Company and each of its peers. The correlation coefficients are measures of the strength of the linear relationship between and amongst the Company and its peers estimated based on historical stock price data. The following assumptions were used for the Monte Carlo model to determine the grant date fair value and associated equity-based compensation expense of the PSUs granted during the nine months ended September 30, 2018 : Risk-free interest rate 2.08% - 2.31% Oasis volatility 72.88 % Oasis initial value $8.82 Oasis stock price on date of grant $9.27 During the nine months ended September 30, 2018 , officers of the Company were granted 854,400 PSUs with a $12.71 weighted average grant date per unit value. Equity-based compensation expense recorded for PSUs for the three and nine months ended September 30, 2018 was $2.2 million and $6.3 million , respectively, and $1.6 million and $5.1 million for the three and nine months ended September 30, 2017 , respectively. Equity-based compensation e xpense is included in general and administrative expenses on the Company’s Condensed Consolidated Statements of Operations. OMP phantom unit awards . The Company has granted OMP phantom unit awards (collectively, the “ OMP Phantom Unit Awards ,” and each an “ OMP Phantom Unit ”) to employees under its Amended and Restated 2010 Long Term Incentive Plan in 2018, and in 2017, under OMP GP’s Oasis Midstream Partners LP 2017 Long Term Incentive Plan (“ OMP LTIP ”). Each OMP Phantom Unit represents the right to receive, upon vesting of the award, a cash payment equal to the fair market value of one OMP common unit on the day prior to the date it vests (the “Vesting Date”). Award recipients are also entitled to Distribution Equivalent Rights (“DER”) with respect to each OMP Phantom Unit received. Each DER represents the right to receive, upon vesting of the award, a cash payment equal to the value of the distributions paid on one OMP common unit between the Grant Date and the applicable Vesting Date. The OMP Phantom Unit Awards vest in equal amounts each year over a three -year period, and compensation expense will be recognized over the requisite service period and is included in general and administrative expenses on the Company’s Condensed Consolidated Statements of Operations. The OMP Phantom Unit Awards are accounted for as liability-classified awards since the awards will settle in cash, and equity-based compensation cost is accounted for under the fair value method in accordance with GAAP. Under the fair value method for liability-classified awards, compensation cost is remeasured each reporting period at fair value based upon the closing price of a publicly traded common unit. The Company will directly pay, or will reimburse OMP, for the cash settlement amount of these awards. During the nine months ended September 30, 2018 , the Company granted 87,480 OMP Phantom Unit Awards to certain employees of Oasis. Equity-based compensation expense recorded for the OMP Phantom Unit Awards for the three and nine months ended September 30, 2018 was $0.2 million and $0.4 million , respectively. The Company did not record any equity-based compensation related to the OMP Phantom Unit Awards for the three and nine months ended September 30, 2017 because these awards were first granted in the fourth quarter of 2017. OMP restricted unit awards. During the nine months ended September 30, 2018 , independent directors of OMP were granted 17,260 restricted unit awards which vest over a one -year period with a weighted average grant date fair value of $17.55 per common unit. These awards are accounted for as equity-classified awards since the awards will settle in common units upon vesting. Equity-based compensation cost is accounted for under the fair value method in accordance with GAAP. Under the fair value method for equity-classified awards, compensation cost is measured at the grant date based on the fair value of the award and is recognized over the vesting period. Compensation cost associated with these awards was approximately $0.1 million and $0.3 million for the three and nine months ended September 30, 2018 , respectively, and is included in general and administrative expenses on the Company’s Condensed Consolidated Statements of Operations.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share Basic earnings (loss) per share is computed by dividing the earnings (loss) attributable to Oasis common stockholders by the weighted average number of shares outstanding for the periods presented. The calculation of diluted earnings (loss) per share includes the potential dilutive impact of unvested restricted stock awards and contingently issuable shares related to PSUs and the Senior Convertible Notes during the periods presented, unless their effect is anti-dilutive. There are no adjustments made to the income (loss) attributable to Oasis available to common stockholders in the calculation of diluted earnings (loss) per share. The following is a calculation of the basic and diluted weighted average shares outstanding for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Basic weighted average common shares outstanding 313,167 233,389 305,533 233,248 Dilutive effect of restricted stock awards and PSUs (1) 3,220 — — — Diluted weighted average common shares outstanding 316,387 233,389 305,533 233,248 __________________ (1) No unvested stock awards were included in computing earnings (loss) per share for the nine months ended September 30, 2018 and the three and nine months ended September 30, 2017 because the effects were anti-dilutive. For the nine months ended September 30, 2018 and the three and nine months ended September 30, 2017 , the Company incurred a net loss , and therefore the diluted loss per share calculation for the period excludes the anti-dilutive effect of unvested stock awards. In addition, the Company excluded these unvested stock awards from the diluted earnings (loss) per share calculation for the three months ended September 30, 2018 because the effects were anti-dilutive based on the treasury stock method. The following is a calculation of weighted average common shares excluded from diluted earnings (loss) per share due to the anti-dilutive effect: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Restricted stock awards and PSUs 4,180 5,841 7,284 5,988 The Company issued its Senior Convertible Notes in September 2016 (see Note 11 – Long-Term Debt). The Company has the option to settle conversions of its Senior Convertible Notes with cash, shares of common stock or a combination of cash and common stock at its election. The Company’s intent is to settle the principal amount of the Senior Convertible Notes in cash upon conversion. As a result, only the amount by which the conversion value exceeds the aggregate principal amount of the notes (conversion spread) is considered in the diluted earnings per share computation under the treasury stock method. As of September 30, 2018 , the conversion value did not exceed the principal amount of the notes, and accordingly, there was no impact to diluted earnings per share for the three and nine months ended September 30, 2018 .

Business Segment Information

Business Segment Information	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Business Segment Information	Business Segment Information The Company’s exploration and production segment is engaged in the acquisition and development of oil and natural gas properties. Revenues for the exploration and production segment are derived from the sale of oil and natural gas production. The Company’s midstream services business segment (“ OMS ”) performs produced and flowback water gathering and disposal services, fresh water services, natural gas gathering and processing and crude oil gathering and transportation and other midstream services for the Company’s oil and natural gas wells operated by OPNA and other third-party operators. Revenues for the midstream segment are primarily derived from produced and flowback water pipeline transport, produced and flowback water disposal, fresh water sales, natural gas gathering and processing and crude oil gathering, blending, stabilization and transportation. The Company’s well services business segment (“OWS”) performs completion services for the Company’s oil and natural gas wells operated by OPNA. Revenues for the well services segment are derived from providing well services, product sales and equipment rentals. The revenues and expenses related to work performed by OMS and OWS for OPNA’s working interests are eliminated in consolidation, and only the revenues and expenses related to non-affiliated working interest owners are included in the Company’s Condensed Consolidated Statements of Operations. These segments represent the Company’s three operating units, each offering different products and services. The Company’s corporate activities have been allocated to the supported business segments accordingly. Management evaluates the performance of the Company’s business segments based on operating income, which is defined as segment operating revenues less operating expenses, including depreciation, depletion and amortization (“DD&A”). The following table summarizes financial information for the Company’s three business segments for the periods presented: Exploration and Production Midstream Services Well Services Eliminations Consolidated (In thousands) Three months ended September 30, 2018: Revenues from non-affiliates $ 497,161 $ 33,025 $ 16,262 $ — $ 546,448 Inter-segment revenues — 42,745 40,177 (82,922 ) — Total revenues 497,161 75,770 56,439 (82,922 ) 546,448 Operating income 146,969 31,326 9,237 (8,487 ) 179,045 Other expense (87,594 ) (367 ) (79 ) — (88,040 ) Income before income taxes including non-controlling interests $ 59,375 $ 30,959 $ 9,158 $ (8,487 ) $ 91,005 Three months ended September 30, 2017: Revenues from non-affiliates $ 269,843 $ 18,767 $ 16,138 $ — $ 304,748 Inter-segment revenues — 28,893 31,025 (59,918 ) — Total revenues 269,843 47,660 47,163 (59,918 ) 304,748 Operating income 3,484 25,194 10,802 (7,086 ) 32,394 Other income (expense) (92,319 ) (15 ) 30 — (92,304 ) Income (loss) before income taxes including non-controlling interests $ (88,835 ) $ 25,179 $ 10,832 $ (7,086 ) $ (59,910 ) Nine months ended September 30, 2018: Revenues from non-affiliates $ 1,328,994 $ 93,663 $ 46,344 $ — $ 1,469,001 Inter-segment revenues — 119,095 114,898 (233,993 ) — Total revenues 1,328,994 212,758 161,242 (233,993 ) 1,469,001 Operating income (loss) (53,159 ) 101,457 25,415 (24,357 ) 49,356 Other expense (370,311 ) (703 ) (99 ) — (371,113 ) Income (loss) before income taxes including non-controlling interests $ (423,470 ) $ 100,754 $ 25,316 $ (24,357 ) $ (321,757 ) Nine months ended September 30, 2017: Revenues from non-affiliates $ 761,450 $ 48,939 $ 33,566 $ — $ 843,955 Inter-segment revenues — 76,674 68,028 (144,702 ) — Total revenues 761,450 125,613 101,594 (144,702 ) 843,955 Operating income (loss) (12,972 ) 69,059 9,161 (7,383 ) 57,865 Other income (expense) (59,027 ) (13 ) 34 — (59,006 ) Income (loss) before income taxes including non-controlling interests $ (71,999 ) $ 69,046 $ 9,195 $ (7,383 ) $ (1,141 ) At September 30, 2018: Property, plant and equipment, net $ 6,227,767 $ 841,797 $ 41,468 $ (210,895 ) $ 6,900,137 Total assets (1) 6,675,626 867,226 49,285 (175,706 ) 7,416,431 At December 31, 2017: Property, plant and equipment, net $ 5,663,323 $ 649,923 $ 46,779 $ (186,539 ) $ 6,173,486 Total assets (1) 6,050,255 663,614 52,800 (151,539 ) 6,615,130 ___________________ (1) Intercompany receivables (payables) for all segments were reclassified to capital contributions from (distributions to) parent and not included in total assets.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Included below is a discussion of the Company’s various future commitments as of September 30, 2018 and subsequent to September 30, 2018 . The commitments under these arrangements are not recorded in the accompanying Condensed Consolidated Balance Sheets. The amounts disclosed represent undiscounted cash flows on a gross basis, and no inflation elements have been applied. Volume commitment agreements. As of September 30, 2018 and subsequent to September 30, 2018 , the Company had certain agreements with an aggregate requirement to deliver or transport a minimum quantity of approximately 50.9 MMBbl of crude oil, 43.5 MMBbl of natural gas liquids, 901.3 Bcf of natural gas and 30.8 MMBbl of water, prior to any applicable volume credits, within specified timeframes, all of which are ten years or less. The estimable future commitments under these agreements were approximately $550.5 million as of September 30, 2018 and $650.2 million subsequent to September 30, 2018 . The future commitments under certain agreements cannot be estimated as they are based on fixed differentials relative to NYMEX WTI under the agreements as compared to the differential relative to NYMEX WTI for the Williston Basin for the production month. Litigation. The Company is party to various legal and/or regulatory proceedings from time to time arising in the ordinary course of business. When the Company determines that a loss is probable of occurring and is reasonably estimable, the Company accrues an undiscounted liability for such contingencies based on its best estimate using information available at the time. The Company discloses contingencies where an adverse outcome may be material, or in the judgment of management, the matter should otherwise be disclosed. Mirada litigation. On March 23, 2017, Mirada Energy, LLC, Mirada Wild Basin Holding Company, LLC and Mirada Energy Fund I, LLC (collectively, “Mirada”) filed a lawsuit against Oasis, OPNA and Oasis Midstream Services LLC, seeking monetary damages in excess of $100 million , declaratory relief, attorneys’ fees and costs (Mirada Energy, LLC, et al. v. Oasis Petroleum North America LLC, et al.; in the 334th Judicial District Court of Harris County, Texas; Case Number 2017-19911). Mirada asserts that it is a working interest owner in certain acreage owned and operated by the Company in Wild Basin. Specifically, Mirada asserts that the Company has breached certain agreements by: (1) failing to allow Mirada to participate in the Company’s midstream operations in Wild Basin; (2) refusing to provide Mirada with information that Mirada contends is required under certain agreements and failing to provide information in a timely fashion; (3) failing to consult with Mirada and failing to obtain Mirada’s consent prior to drilling more than one well at a time in Wild Basin; and (4) overstating the estimated costs of proposed well operations in Wild Basin. Mirada seeks a declaratory judgment that the Company be removed as operator in Wild Basin at Mirada’s election and that Mirada be allowed to elect a new operator; certain agreements apply to the Company and Mirada and Wild Basin with respect to this dispute; the Company be required to provide all information within its possession regarding proposed or ongoing operations in Wild Basin; and the Company not be permitted to drill, or propose to drill, more than one well at a time in Wild Basin without obtaining Mirada’s consent. Mirada also seeks a declaratory judgment with respect to the Company’s current midstream operations in Wild Basin. Specifically, Mirada seeks a declaratory judgment that Mirada has a right to participate in the Company’s Wild Basin midstream operations, consisting of produced water disposal, crude oil gathering and gas gathering and processing; that, upon Mirada’s election to participate, Mirada is obligated to pay its proportionate costs of the Company’s midstream operations in Wild Basin; and that Mirada would then be entitled to receive a share of revenues from the midstream operations and would not be charged any amount for its use of these facilities for production from the “Contract Area.” On June 30, 2017, Mirada amended its original petition to add a claim that the Company has breached certain agreements by charging Mirada for midstream services provided by its affiliates and to seek a declaratory judgment that Mirada is entitled to be paid its share of total proceeds from the sale of hydrocarbons received by OPNA or any affiliate of OPNA without deductions for midstream services provided by OPNA or its affiliates. On February 2, 2018 and February 16, 2018, Mirada filed a second and third amended petition, respectively. In these filings, Mirada alleged new legal theories for being entitled to enforce the underlying contracts and added Bighorn DevCo LLC, Bobcat DevCo LLC and Beartooth DevCo LLC as defendants, asserting that these entities were created in bad faith in an effort to avoid contractual obligations owed to Mirada. On March 2, 2018, Mirada filed a fourth amended petition that described Mirada’s alleged ownership and assignment of interests in assets purportedly governed by agreements at issue in the lawsuit. On August 31, 2018, Mirada filed a fifth amended petition that added Oasis Midstream Partners, LP as a defendant, asserting that it was created in bad faith in an effort to avoid contractual obligations owed to Mirada. The Company believes that Mirada’s claims are without merit, that the Company has complied with its obligations under the applicable agreements and that some of Mirada’s claims are grounded in agreements that do not apply to the Company. The Company filed answers denying all of Mirada’s claims and intends and continues to vigorously defend against Mirada’s claims. OMP has not yet filed an answer because it has not yet been served with process. Discovery is ongoing, and each of the parties has made a number of procedural filings and motions, and additional filings and motions can be expected over the course of the claim. Trial is currently scheduled for May 2019. However, the Company cannot predict or guarantee the ultimate outcome or resolution of such matter. If such matter were to be determined adversely to the Company’s interests, or if the Company were forced to settle such matter for a significant amount, such resolution or settlement could have a material adverse effect on the Company’s business, financial condition, results of operations or cash flows. Such an adverse determination could materially impact the Company’s ability to operate its properties in Wild Basin or develop its identified drilling locations in Wild Basin on its current development schedule. A determination that Mirada has a right to participate in the Company’s midstream operations could materially reduce the interests of the Company in their current assets and future midstream opportunities and related revenues in Wild Basin. In addition, the Company has agreed to indemnify OMP for any losses resulting from this litigation under the omnibus agreement it entered into with OMP at the time of OMP’s initial public offering.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information The Notes (see Note 11 – Long-Term Debt ) are guaranteed on a senior unsecured basis by the Guarantors, which are 100% owned by the Company. These guarantees are full and unconditional and joint and several among the Guarantors. Certain of the Company’s operating units, including OMP, which is accounted for on a consolidated basis, do not guarantee the Notes (“Non-Guarantor Subsidiaries”). The following financial information reflects consolidating financial information of the parent company, Oasis Petroleum Inc. (“Issuer”), its Guarantors on a combined basis and the Non-Guarantor Subsidiaries on a combined basis, prepared on the equity basis of accounting. The information is presented in accordance with the requirements of Rule 3-10 under the SEC’s Regulation S-X. The financial information may not necessarily be indicative of results of operations, cash flows or financial position had the Guarantors operated as independent entities. The Company has not presented separate financial and narrative information for each of the Guarantors because it believes such financial and narrative information would not provide any additional information that would be material in evaluating the sufficiency of the Guarantors. Condensed Consolidating Balance Sheet September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands, except share data) ASSETS Current assets Cash and cash equivalents $ 170 $ 11,732 $ 4,990 $ — $ 16,892 Accounts receivable, net — 423,130 5,054 — 428,184 Accounts receivable - affiliates 653,255 66,153 72,896 (792,304 ) — Inventory — 31,409 — — 31,409 Prepaid expenses 617 5,731 96 — 6,444 Intangible assets, net — 375 — — 375 Other current assets — 192 — — 192 Total current assets 654,042 538,722 83,036 (792,304 ) 483,496 Property, plant and equipment Oil and gas properties (successful efforts method) — 8,679,662 — (8,518 ) 8,671,144 Other property and equipment — 212,257 876,534 (10 ) 1,088,781 Less: accumulated depreciation, depletion, amortization and impairment — (2,805,233 ) (54,555 ) — (2,859,788 ) Total property, plant and equipment, net — 6,086,686 821,979 (8,528 ) 6,900,137 Investments in and advances to subsidiaries 4,653,951 515,997 — (5,169,948 ) — Deferred income taxes 209,919 — — (209,919 ) — Long-term inventory — 12,610 — — 12,610 Other assets — 18,207 1,981 — 20,188 Total assets $ 5,517,912 $ 7,172,222 $ 906,996 $ (6,180,699 ) $ 7,416,431 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities Accounts payable $ — $ 17,182 $ 24 $ — $ 17,206 Accounts payable - affiliates 41,213 726,151 24,940 (792,304 ) — Revenues and production taxes payable — 286,897 436 — 287,333 Accrued liabilities 56 248,097 59,373 — 307,526 Accrued interest payable 19,855 547 172 — 20,574 Derivative instruments — 180,129 — — 180,129 Advances from joint interest partners — 3,878 — — 3,878 Other current liabilities — 40 — — 40 Total current liabilities 61,124 1,462,921 84,945 (792,304 ) 816,686 Long-term debt 1,945,009 522,000 166,000 — 2,633,009 Deferred income taxes — 440,423 — (209,919 ) 230,504 Asset retirement obligations — 49,860 1,497 — 51,357 Derivative instruments — 33,017 — — 33,017 Other liabilities — 7,775 — — 7,775 Total liabilities 2,006,133 2,515,996 252,442 (1,002,223 ) 3,772,348 Stockholders’ equity Capital contributions from affiliates — 3,271,788 202,007 (3,473,795 ) — Common stock, $0.01 par value: 900,000,000 shares authorized; 320,507,783 shares issued and 318,419,144 shares outstanding 3,157 — — — 3,157 Treasury stock, at cost: 2,088,639 shares (28,985 ) — — — (28,985 ) Additional paid-in-capital 3,070,642 9,141 — (9,141 ) 3,070,642 Retained earnings 466,965 1,236,740 46,413 (1,289,406 ) 460,712 Oasis share of stockholders’ equity 3,511,779 4,517,669 248,420 (4,772,342 ) 3,505,526 Non-controlling interests — 138,557 406,134 (406,134 ) 138,557 Total stockholders’ equity 3,511,779 4,656,226 654,554 (5,178,476 ) 3,644,083 Total liabilities and stockholders’ equity $ 5,517,912 $ 7,172,222 $ 906,996 $ (6,180,699 ) $ 7,416,431 Condensed Consolidating Balance Sheet December 31, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands, except share data) ASSETS Current assets Cash and cash equivalents $ 178 $ 15,659 $ 883 $ — $ 16,720 Accounts receivable, net — 362,746 834 — 363,580 Accounts receivable - affiliates 425,668 46,020 85,818 (557,506 ) — Inventory — 19,367 — — 19,367 Prepaid expenses 267 6,586 778 — 7,631 Derivative instruments — 344 — — 344 Other current assets — 193 — — 193 Total current assets 426,113 450,915 88,313 (557,506 ) 407,835 Property, plant and equipment Oil and gas properties (successful efforts method) — 7,840,921 — (1,966 ) 7,838,955 Other property and equipment — 214,818 653,928 — 868,746 Less: accumulated depreciation, depletion, amortization and impairment — (2,499,867 ) (34,348 ) — (2,534,215 ) Total property, plant and equipment, net — 5,555,872 619,580 (1,966 ) 6,173,486 Investments in and advances to subsidiaries 4,790,976 422,132 — (5,213,108 ) — Derivative instruments — 9 — — 9 Deferred income taxes 183,568 — — (183,568 ) — Long-term inventory — 12,200 — — 12,200 Other assets — 19,587 2,013 — 21,600 Total assets $ 5,400,657 $ 6,460,715 $ 709,906 $ (5,956,148 ) $ 6,615,130 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities Accounts payable $ — $ 13,370 $ — $ — $ 13,370 Accounts payable - affiliates 34,382 511,486 11,638 (557,506 ) — Revenues and production taxes payable — 213,995 — — 213,995 Accrued liabilities 216 177,446 58,818 — 236,480 Accrued interest payable 38,796 53 114 — 38,963 Derivative instruments — 115,716 — — 115,716 Advances from joint interest partners — 4,916 — — 4,916 Other current liabilities — 40 — — 40 Total current liabilities 73,394 1,037,022 70,570 (557,506 ) 623,480 Long-term debt 1,949,606 70,000 78,000 — 2,097,606 Deferred income taxes — 489,489 — (183,568 ) 305,921 Asset retirement obligations — 47,195 1,316 — 48,511 Derivative instruments — 19,851 — — 19,851 Other liabilities — 6,182 — — 6,182 Total liabilities 2,023,000 1,669,739 149,886 (741,074 ) 3,101,551 Stockholders’ equity Capital contributions from affiliates — 3,264,691 234,935 (3,499,626 ) — Common stock, $0.01 par value: 450,000,000 shares authorized; 270,627,014 shares issued and 269,295,466 shares outstanding 2,668 — — — 2,668 Treasury stock, at cost: 1,331,548 shares (22,179 ) — — — (22,179 ) Additional paid-in-capital 2,677,217 8,922 — (8,922 ) 2,677,217 Retained earnings 719,951 1,379,475 11,639 (1,393,080 ) 717,985 Oasis share of stockholders’ equity 3,377,657 4,653,088 246,574 (4,901,628 ) 3,375,691 Non-controlling interests — 137,888 313,446 (313,446 ) 137,888 Total stockholders’ equity 3,377,657 4,790,976 560,020 (5,215,074 ) 3,513,579 Total liabilities and stockholders’ equity $ 5,400,657 $ 6,460,715 $ 709,906 $ (5,956,148 ) $ 6,615,130 Condensed Consolidating Statement of Operations Three Months Ended September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 452,643 $ — $ — $ 452,643 Purchased oil and gas sales — 46,356 — — 46,356 Midstream revenues — 765 71,467 (41,045 ) 31,187 Well services revenues — 16,262 — — 16,262 Total revenues — 516,026 71,467 (41,045 ) 546,448 Operating expenses Lease operating expenses — 63,099 — (14,565 ) 48,534 Midstream operating expenses — 528 19,816 (11,692 ) 8,652 Well services operating expenses — 11,405 — — 11,405 Marketing, transportation and gathering expenses — 36,839 — (6,126 ) 30,713 Purchased oil and gas expenses — 46,148 — (60 ) 46,088 Production taxes — 38,722 — — 38,722 Depreciation, depletion and amortization — 159,843 7,189 (4,048 ) 162,984 Exploration expenses — 22,315 — — 22,315 General and administrative expenses 7,486 24,627 5,449 (2,703 ) 34,859 Total operating expenses 7,486 403,526 32,454 (39,194 ) 404,272 Gain on sale of properties — 36,869 — — 36,869 Operating income (loss) (7,486 ) 149,369 39,013 (1,851 ) 179,045 Other income (expense) Equity in earnings of subsidiaries 96,555 38,835 — (135,390 ) — Net loss on derivative instruments — (48,544 ) — — (48,544 ) Interest expense, net of capitalized interest (32,836 ) (6,561 ) (163 ) — (39,560 ) Loss on extinguishment of debt (47 ) — — — (47 ) Other income (expense) — 126 (15 ) — 111 Total other income (expense) 63,672 (16,144 ) (178 ) (135,390 ) (88,040 ) Income before income taxes 56,186 133,225 38,835 (137,241 ) 91,005 Income tax benefit (expense) 6,155 (30,937 ) — — (24,782 ) Net income including non-controlling interests 62,341 102,288 38,835 (137,241 ) 66,223 Less: Net income attributable to non-controlling interests — 3,882 26,459 (26,459 ) 3,882 Net income attributable to Oasis $ 62,341 $ 98,406 $ 12,376 $ (110,782 ) $ 62,341 Condensed Consolidating Statement of Operations Three Months Ended September 30, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 248,648 $ — $ — $ 248,648 Purchased oil and gas sales — 21,195 — — 21,195 Midstream revenues — 15,828 2,939 — 18,767 Well services revenues — 16,138 — — 16,138 Total revenues — 301,809 2,939 — 304,748 Operating expenses Lease operating expenses — 45,334 — — 45,334 Midstream operating expenses — 3,621 680 — 4,301 Well services operating expenses — 10,288 — — 10,288 Marketing, transportation and gathering expenses — 15,028 — — 15,028 Purchased oil and gas expenses — 21,701 — — 21,701 Production taxes — 21,052 — — 21,052 Depreciation, depletion and amortization — 132,035 254 — 132,289 Exploration expenses — 854 — — 854 Impairment — 139 — — 139 General and administrative expenses 6,775 14,212 381 — 21,368 Total operating expenses 6,775 264,264 1,315 — 272,354 Operating income (loss) (6,775 ) 37,545 1,624 — 32,394 Other income (expense) Equity in earnings (loss) of subsidiaries (13,599 ) 1,605 — 11,994 — Net loss on derivative instruments — (54,310 ) — — (54,310 ) Interest expense, net of capitalized interest (32,894 ) (4,476 ) (19 ) — (37,389 ) Other income (expense) 2 (607 ) — — (605 ) Total other expense (46,491 ) (57,788 ) (19 ) 11,994 (92,304 ) Income (loss) before income taxes (53,266 ) (20,243 ) 1,605 11,994 (59,910 ) Income tax benefit 12,052 6,794 — — 18,846 Net income (loss) including non-controlling interests (41,214 ) (13,449 ) 1,605 11,994 (41,064 ) Less: Net income attributable to non-controlling interests — 150 1,112 (1,112 ) 150 Net income (loss) attributable to Oasis $ (41,214 ) $ (13,599 ) $ 493 $ 13,106 $ (41,214 ) Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 1,212,235 $ — $ — $ 1,212,235 Purchased oil and gas sales — 121,971 — — 121,971 Midstream revenues — 2,832 199,446 (113,827 ) 88,451 Well services revenues — 46,344 — — 46,344 Total revenues — 1,383,382 199,446 (113,827 ) 1,469,001 Operating expenses Lease operating expenses — 176,413 — (38,957 ) 137,456 Midstream operating expenses — 2,054 53,266 (30,995 ) 24,325 Well services operating expenses — 32,352 — — 32,352 Marketing, transportation and gathering expenses — 92,164 — (17,605 ) 74,559 Purchased oil and gas expenses — 121,311 — (60 ) 121,251 Production taxes — 103,748 — — 103,748 Depreciation, depletion and amortization — 456,624 20,212 (11,017 ) 465,819 Exploration expenses — 23,701 — — 23,701 Impairment — 384,228 — — 384,228 General and administrative expenses 22,214 60,259 17,496 (8,940 ) 91,029 Total operating expenses 22,214 1,452,854 90,974 (107,574 ) 1,458,468 Gain on sale of properties — 38,823 — — 38,823 Operating income (loss) (22,214 ) (30,649 ) 108,472 (6,253 ) 49,356 Other income (expense) Equity in earnings (loss) of subsidiaries (149,295 ) 107,849 — 41,446 — Net loss on derivative instruments — (239,945 ) — — (239,945 ) Interest expense, net of capitalized interest (98,417 ) (18,591 ) (608 ) — (117,616 ) Loss on extinguishment of debt (13,698 ) — — — (13,698 ) Other income (expense) — 161 (15 ) — 146 Total other expense (261,410 ) (150,526 ) (623 ) 41,446 (371,113 ) Income (loss) before income taxes (283,624 ) (181,175 ) 107,849 35,193 (321,757 ) Income tax benefit 26,351 49,040 — — 75,391 Net income (loss) including non-controlling interests (257,273 ) (132,135 ) 107,849 35,193 (246,366 ) Less: Net income attributable to non-controlling interests — 10,907 73,075 (73,075 ) 10,907 Net income (loss) attributable to Oasis $ (257,273 ) $ (143,042 ) $ 34,774 $ 108,268 $ (257,273 ) Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 704,533 $ — $ — $ 704,533 Purchased oil and gas sales — 56,917 — — 56,917 Midstream revenues — 46,000 2,939 — 48,939 Well services revenues — 33,566 — — 33,566 Total revenues — 841,016 2,939 — 843,955 Operating expenses Lease operating expenses — 133,871 — — 133,871 Midstream operating expenses — 10,211 680 — 10,891 Well services operating expenses — 23,858 — — 23,858 Marketing, transportation and gathering expenses — 38,018 — — 38,018 Purchased oil and gas expenses — 57,683 — — 57,683 Production taxes — 60,322 — — 60,322 Depreciation, depletion and amortization — 383,992 254 — 384,246 Exploration expenses — 4,010 — — 4,010 Impairment — 6,021 — — 6,021 General and administrative expenses 21,374 45,415 381 — 67,170 Total operating expenses 21,374 763,401 1,315 — 786,090 Operating income (loss) (21,374 ) 77,615 1,624 — 57,865 Other income (expense) Equity in earnings of subsidiaries 74,379 1,605 — (75,984 ) — Net gain on derivative instruments — 52,297 — — 52,297 Interest expense, net of capitalized interest (98,751 ) (11,778 ) (19 ) — (110,548 ) Other income (expense) 2 (757 ) — — (755 ) Total other income (expense) (24,370 ) 41,367 (19 ) (75,984 ) (59,006 ) Income (loss) before income taxes (45,744 ) 118,982 1,605 (75,984 ) (1,141 ) Income tax benefit (expense) 44,923 (44,453 ) — — 470 Net income (loss) including non-controlling interests (821 ) 74,529 1,605 (75,984 ) (671 ) Less: Net income attributable to non-controlling interests — 150 1,112 (1,112 ) 150 Net income (loss) attributable to Oasis $ (821 ) $ 74,379 $ 493 $ (74,872 ) $ (821 ) Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Cash flows from operating activities: Net income (loss) including non-controlling interests $ (257,273 ) $ (132,135 ) $ 107,849 $ 35,193 $ (246,366 ) Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities: Equity in earnings (loss) of subsidiaries 149,295 (107,849 ) — (41,446 ) — Depreciation, depletion and amortization — 456,624 20,212 (11,017 ) 465,819 Loss on extinguishment of debt 13,698 — — — 13,698 Gain on sale of properties — (38,823 ) — — (38,823 ) Impairment — 384,228 — — 384,228 Deferred income taxes (26,351 ) (49,067 ) — — (75,418 ) Derivative instruments — 239,945 — — 239,945 Equity-based compensation expenses 20,292 1,014 280 — 21,586 Deferred financing costs amortization and other 11,955 7,884 235 — 20,074 Working capital and other changes: Change in accounts receivable (227,589 ) (77,231 ) 8,747 234,798 (61,275 ) Change in inventory — (12,076 ) — — (12,076 ) Change in prepaid expenses (350 ) 864 682 — 1,196 Change in other current assets — 1 — — 1 Change in long-term inventory and other assets — (490 ) — — (490 ) Change in accounts payable, interest payable and accrued liabilities (12,270 ) 278,481 18,895 (234,798 ) 50,308 Change in other liabilities — (406 ) — — (406 ) Net cash provided by (used in) operating activities (328,593 ) 950,964 156,900 (17,270 ) 762,001 Cash flows from investing activities: Capital expenditures — (621,269 ) (219,819 ) — (841,088 ) Acquisitions — (579,886 ) — — (579,886 ) Proceeds from sale of properties — 333,029 — — 333,029 Costs related to sale of properties — (2,707 ) — — (2,707 ) Derivative settlements — (162,013 ) — — (162,013 ) Advances from joint interest partners — (1,038 ) — — (1,038 ) Net cash used in investing activities — (1,033,884 ) (219,819 ) — (1,253,703 ) Cash flows from financing activities: Proceeds from Revolving Credit Facilities — 2,376,000 123,000 — 2,499,000 Principal payments on Revolving Credit Facilities — (1,924,000 ) (35,000 ) — (1,959,000 ) Repurchase of senior unsecured notes (423,190 ) — — — (423,190 ) Proceeds from issuance of senior unsecured convertible notes 400,000 — — — 400,000 Deferred financing costs (7,058 ) (261 ) (331 ) — (7,650 ) Purchases of treasury stock (6,806 ) — — — (6,806 ) Distributions to non-controlling interests — 92,672 (103,065 ) — (10,393 ) Investment in subsidiaries / capital contributions from parent 365,601 (465,293 ) 82,422 17,270 — Other 38 (125 ) — — (87 ) Net cash provided by financing activities 328,585 78,993 67,026 17,270 491,874 Increase (decrease) in cash and cash equivalents (8 ) (3,927 ) 4,107 — 172 Cash and cash equivalents at beginning of period 178 15,659 883 — 16,720 Cash and cash equivalents at end of period $ 170 $ 11,732 $ 4,990 $ — $ 16,892 Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Cash flows from operating activities: Net income (loss) including non-controlling interests $ (821 ) $ 74,529 $ 1,605 $ (75,984 ) $ (671 ) Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities: Equity in earnings of subsidiaries (74,379 ) (1,605 ) — 75,984 — Depreciation, depletion and amortization — 383,992 254 — 384,246 Impairment — 6,021 — — 6,021 Deferred income taxes (44,923 ) 44,453 — — (470 ) Derivative instruments — (52,297 ) — — (52,297 ) Equity-based compensation expenses 19,740 711 — — 20,451 Deferred financing costs amortization and other 11,399 1,260 7 — 12,666 Working capital and other changes: Change in accounts receivable 115,996 (87,610 ) (5,630 ) (103,778 ) (81,022 ) Change in inventory — (235 ) — — (235 ) Change in prepaid expenses (190 ) 1,013 — — 823 Change in other current assets — 276 — — 276 Change in long-term inventory and other assets — (12,843 ) — — (12,843 ) Change in accounts payable, interest payable and accrued liabilities (12,571 ) (62,542 ) 3,617 103,778 32,282 Change in other current liabilities — (10,490 ) — — (10,490 ) Net cash provided by operating activities 14,251 284,633 (147 ) — 298,737 Cash flows from investing activities: Capital expenditures — (443,649 ) — — (443,649 ) Proceeds from sale of properties — 4,000 — — 4,000 Derivative settlements — (804 ) — — (804 ) Advances from joint interest partners — (2,502 ) — — (2,502 ) Net cash used in investing activities — (442,955 ) — — (442,955 ) Cash flows from financing activities: Proceeds from Oasis Credit Facility — 764,000 — — 764,000 Principal payments on Oasis Credit Facility — (732,000 ) — — (732,000 ) Deferred financing costs — 1,858 (1,954 ) — (96 ) Proceeds from issuance of Oasis Midstream common units, net of offering costs — — 115,813 — 115,813 Purchases of treasury stock (6,182 ) — — — (6,182 ) Investment in subsidiaries / capital contributions from parent (8,002 ) 121,714 (113,712 ) — — Other (55 ) — — — (55 ) Net cash provided by (used in) financing activities (14,239 ) 155,572 147 — 141,480 Increase (decrease) in cash and cash equivalents 12 (2,750 ) — — (2,738 ) Cash and cash equivalents at beginning of period 166 11,060 — — 11,226 Cash and cash equivalents at end of period $ 178 $ 8,310 $ — $ — $ 8,488

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated the period after the balance sheet date, noting no subsequent events or transactions that required recognition or disclosure in the financial statements, other than as previously disclosed.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of the Company have not been audited by the Company’s independent registered public accounting firm, except that the Condensed Consolidated Balance Sheet at December 31, 2017 is derived from audited financial statements. Certain reclassifications of prior year balances have been made to conform such amounts to current year classifications. These reclassifications have no impact on net income. In the opinion of management, all adjustments, consisting of normal recurring adjustments necessary for the fair statement of the Company’s financial position, have been included. Management has made certain estimates and assumptions that affect reported amounts in the condensed consolidated financial statements and disclosures of contingencies. Actual results may differ from those estimates. The results for interim periods are not necessarily indicative of annual results. These interim financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain disclosures have been condensed or omitted from these financial statements. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States of America (“GAAP”) for complete consolidated financial statements and should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 (“ 2017 Annual Report”).
Consolidation	Consolidation. The accompanying condensed consolidated financial statements of the Company include the accounts of Oasis, the accounts of wholly-owned subsidiaries, and the accounts of OMP , which is considered a variable interest entity (“ VIE ”) for which the Company is the primary beneficiary. All significant intercompany balances and transactions have been eliminated upon consolidation.
Consolidated VIE	Consolidated VIE . The Company has determined that the partners with equity at risk in OMP lack the authority, through voting rights or similar rights, to direct the activities that most significantly impact OMP ’s economic performance. Therefore, as the limited partners of OMP do not have substantive kick-out or substantive participating rights over OMP GP LLC (“ OMP GP ”), the general partner to OMP , OMP is a VIE . Through the Company’s ownership interest in OMP GP , the Company has the authority to direct the activities that most significantly affect economic performance and the right to receive benefits that could be potentially significant to OMP . Therefore, the Company is considered the primary beneficiary and consolidates OMP and records a non-controlling interest for the interest owned by the public as of September 30, 2018 .
Risks and Uncertainties	Risks and Uncertainties As an oil and natural gas producer, the Company’s revenue, profitability and future growth are substantially dependent upon the prevailing and future prices for oil and natural gas, which are dependent upon numerous factors beyond its control such as economic, political and regulatory developments and competition from other energy sources. The energy markets have historically been very volatile, and there can be no assurance that oil and natural gas prices will not be subject to wide fluctuations in the future. A substantial or extended decline in prices for oil and, to a lesser extent, natural gas could have a material adverse effect on the Company’s financial position, results of operations, cash flows and quantities of oil and natural gas reserves that may be economically produced.
Revenue Recognition	Revenue recognition. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The objective of ASU 2014-09 is greater consistency and comparability across industries by using a five-step model to recognize revenue from customer contracts. ASU 2014-09 was applied on a modified retrospective basis. The adoption of ASU 2014-09 did not result in a material impact to the Company’s financial position, cash flows or results of operations. Enhanced disclosures in accordance with ASU 2014-09 have been provided in Note 3 – Revenue Recognition . In May 2014, the FASB issued a new accounting standard related to revenue recognition, ASC 606 - Revenue from Contracts with Customers (“ASC 606”) . This standard was effective in the first quarter of 2018 and the Company adopted the new standard using the modified retrospective method. The Company applied ASC 606 to all new contracts entered into after January 1, 2018 and all existing contracts for which all (or substantially all) of the revenue has not been recognized under legacy revenue guidance as of December 31, 2017. ASC 606 supersedes previous revenue recognition requirements in ASC 605 and includes a five-step revenue recognition model to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. In accordance with the adoption of ASC 606, management evaluated its contracts with customers to apply the five-step revenue recognition model. The adoption of ASC 606 did not result in a material impact to the Company’s financial position, cash flows or results of operations. The unit of account in ASC 606 is a performance obligation, which is a promise in a contract to transfer to a customer either a distinct good or service (or bundle of goods or services) or a series of distinct goods or services provided over a period of time. ASC 606 requires that a contract’s transaction price, which is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, is to be allocated to each performance obligation in the contract based on relative standalone selling prices and recognized as revenue when (point in time) or as (over time) the performance obligation is satisfied. Exploration and production revenues Our exploration and production revenues are derived from contracts for oil, natural gas and natural gas liquids (“NGL”) sales, as described below. Generally, for the majority of these contracts: (i) each unit (barrel (“bbl”), mcf, gallon, etc.) of commodity product is a separate performance obligation, as our promise is to sell multiple distinct units of commodity product at a point in time; (ii) the transaction price principally consists of variable consideration, which amount is determinable each month end based on our right to invoice at month end for the value of commodity product sold to the customer that month; and (iii) the transaction price is allocated to each performance obligation based on the commodity product’s standalone selling price and recognized as revenue upon delivery of the commodity product, which is the point in time when the customer obtains control of the commodity product and our performance obligation is satisfied. The sales of oil, natural gas and NGLs as presented on the Company’s Condensed Consolidated Statements of Operations represent the Company’s share of revenues net of royalties and excluding revenue interests owned by others. When selling oil, natural gas and NGLs on behalf of royalty owners or working interest owners, the Company is acting as an agent and thus reports the revenue on a net basis. To the extent actual volumes and prices of oil and natural gas sales are unavailable for a given reporting period because of timing or information not received from third parties, the expected sales volumes and prices for those properties are estimated and recorded. The Company’s contracts with customers typically require payments for oil, natural gas and NGL sales within 30 days following the calendar month of delivery. Oil revenues. The Company sells a substantial majority of its oil through bulk sales at delivery points on crude oil gathering systems or directly at the wellhead to a variety of customers under short-term contracts that include a specified quantity of crude oil to be delivered and sold to the customer at a specified delivery point. The customer pays a market-based transaction price, which incorporates differentials that include, but are not limited to, transportation costs and adjustments for product quality. Natural gas revenues. The Company’s natural gas sales consist of unprocessed gas sales and residue gas sales. Unprocessed gas is sold at delivery points at or near the wellhead under various contracts, in which the customer pays a transaction price based on its sale of the bifurcated NGLs and residue gas, less any associated fees. Revenue is recorded on a net basis, with processing fees deducted within revenue rather than as a separate expense line item, as title and control transfer at the delivery point. Residue gas is sold from the tailgate of the Company’s gas processing plant located in Wild Basin or transported and sold at other downstream sales points, and the customer pays a transaction price based on a market indexed per-unit rate for the quantities sold. Purchased oil and gas sales. The Company purchases and sells crude oil and natural gas at various delivery points to a variety of customers under short-term contracts that include specified quantities of crude oil and natural gas to be sold and delivered to the customer at a specified delivery point. The Company purchases and sells crude oil and natural gas to different counterparties at market-based prices. Market-based pricing is based on the price index applicable for the location of the sale. The Company accounts for these transactions on a gross basis. NGL revenues. NGLs are sold from the Company’s gas processing plant complex located in Wild Basin or trucked and sold at other downstream locations, and the customer pays a transaction price based on a market indexed per-unit rate for the quantities sold. Prior period performance obligations. For sales of oil, purchased oil, natural gas, purchased gas and NGLs, the Company records revenue in the month production is delivered to the purchaser. However, settlement statements and payment may not be received for 30 to 90 days after the date production is delivered, and as a result, the Company is required to estimate the amount of production that was delivered to the purchaser and the price that will be received for the sale of the product. The Company records the differences between estimates and the actual amounts received for product sales once payment is received from the purchaser. Such differences have historically not been significant. The Company uses knowledge of its properties, its properties' historical performance, spot market prices and other factors as the basis for these estimates. For the three and nine months ended September 30, 2018 , revenue recognized related to performance obligations satisfied in prior reporting periods was not material. Revenues associated with contracts with customers for oil, natural gas and NGL sales were as follows for the three and nine months ended September 30, 2018 and 2017 : Exploration and Production Revenues Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Oil revenues $ 412,530 $ 221,003 $ 1,097,171 $ 623,603 Purchased oil sales 42,902 20,734 114,598 56,269 Natural gas revenues 26,181 17,037 76,201 51,689 Purchased gas sales 1,616 462 2,161 648 NGL revenues 13,932 10,607 38,863 29,241 Total exploration and production revenues $ 497,161 $ 269,843 $ 1,328,994 $ 761,450 Midstream revenues Crude oil and natural gas revenues. The Company is party to certain contracts for gas gathering, compression, processing and gas lift services, as well as crude oil gathering, stabilization, blending, storage and transportation. Under these customer contracts, the Company provides daily integrated midstream services on a stand ready basis over a period of time, which represents a single performance obligation since the customer simultaneously receives and consumes the benefits of these services on a daily basis. Satisfaction of the Company’s performance obligation is measured as each day of service is completed, which directly corresponds with its right to consideration from the customer. Revenues associated with these contracts are recognized based upon the transaction price at month-end under the right to invoice practical expedient. Payments from customers are generally received by the Company within one month after the month in which services are provided. Purchased oil sales. The Company purchases and sells crude oil at various delivery points on crude oil gathering systems to a variety of customers under short-term contracts that include a specified quantity of crude oil to be sold and delivered to the customer at a specified delivery point. The Company purchases and sells the crude oil to different counterparties at market-based prices. Market-based pricing is based on the price index applicable for the location of the sale. The Company accounts for these transactions on a gross basis. Water revenues. The Company is also party to certain contracts with customers for water services, which includes produced and flowback water gathering and disposal services and freshwater distribution services. Under its customer contracts for produced and flowback water gathering and disposal services, the Company provides daily integrated midstream services on a stand-ready basis over a period of time, which represents a single performance obligation since the customer simultaneously receives and consumes the benefits of these services on a daily basis. Satisfaction of the Company’s performance obligation is measured as each day of service is completed, which directly corresponds with its right to consideration from the customer. Revenues associated with these contracts are recognized based upon the transaction price at month-end under the right to invoice practical expedient. Payments from customers are generally received by the Company within one month after the month in which services are provided. Under its customer contracts for freshwater distribution services, the Company supplies and distributes freshwater to its customers for hydraulic fracturing and production optimization. Management has determined these contracts contain multiple distinct performance obligations since each freshwater barrel is not dependent nor highly interrelated with other barrels. Revenue associated with freshwater distribution services is recognized at a point-in-time based upon the transaction price when title, control and risk of loss transfers to the customer, which occurs at the delivery point. Payments are due from customers 30 days after receipt of invoice. Revenues associated with contracts with customers for midstream services were as follows for the three and nine months ended September 30, 2018 and 2017 : Midstream Revenues (1) Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Crude oil and natural gas revenues $ 18,188 $ 11,612 $ 54,124 $ 23,348 Purchased oil sales 1,838 — 5,212 — Water revenues 12,999 7,155 34,327 25,591 Total midstream revenues $ 33,025 $ 18,767 $ 93,663 $ 48,939 __________________ (1) Represents midstream revenues, excluding all intercompany revenues, for work performed by the midstream services business segment for the Company’s working interests that are eliminated in consolidation and are therefore not included in midstream services revenues. Well services revenues Hydraulic fracturing service revenues. Hydraulic fracturing revenue is recognized upon the completion of each hydraulic fracturing of a well. These services are composed of various components, such as personnel, equipment and hydraulic fracturing materials, but management determined that each component is not distinct, as it cannot be used on its own or together with a resource readily available to the customer. Revenue is recognized when the performance obligations of hydraulic fracturing a well in its totality are completed; generally, this is over a period of time due to all work being performed for a customer occurring on the customer’s property, where the customer has control over the work in process as it is being performed. In addition, the Company’s assets being used to perform the obligations have no alternative use at the time of performance and the Company has the right to payment for performance to date. Payments from customers are generally received by the Company within one month after the month in which services are provided. In addition, revenue from product sales to third parties is generated when OPNA requests that third-party hydraulic fracturing companies hydraulic fracture OPNA’s wells. Although the labor is provided by the third-party hydraulic fracturing company, the materials (e.g., sand, chemicals, etc.) used in the hydraulic fracturing of the wells are provided by OWS. The third-party hydraulic fracturing company or OPNA pays OWS for the materials delivered to the wells. Revenue is recognized once the performance obligations to transfer hydraulic fracturing materials are completed. Equipment rental revenues. Equipment rental revenue is generated when OPNA or a third-party hydraulic fracturing company rents equipment from OWS. This equipment is used in the preparation stage of hydraulic fracturing services or after the hydraulic fracturing services have been completed. Equipment rental revenues are calculated based on the equipment’s daily rental rate and the number of days that the equipment was rented by the customer. OWS’s performance obligation is satisfied when the entire rental period is completed. Equipment rental revenues are recognized over a period of time due to the customer simultaneously receiving and consuming the bene fits of the rental equipment provided by OWS on a daily basis. Satisfaction of the Company’s performance obligation is measured at the completion of each day’s rental period, which directly corresponds with its right to consideration from the customer. Revenues associated with these contracts are recognized at the time of invoicing for the entire rental period under the right to invoice practical expedient. Payments from customers are generally received by the Company within one month after the month in which services are provided. Revenues associated with contracts with customers for hydraulic fracturing services and equipment rental sales were as follows for the three and nine months ended September 30, 2018 and 2017 : Well Services Revenues (1) Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Hydraulic fracturing service revenues $ 14,985 $ 15,090 $ 42,801 $ 31,303 Equipment rental revenues 1,277 1,048 3,543 2,263 Total well services revenues $ 16,262 $ 16,138 $ 46,344 $ 33,566 __________________ (1) Represents well services revenues excluding all intercompany revenues for work performed by the well services business segment for the Company’s working interests that are eliminated in consolidation and are therefore not included in well services revenues. Contract balances Under the Company's customer contracts, invoicing occurs once the Company's performance obligations have been satisfied, at which point payment is unconditional. Accordingly, the Company's contracts do not give rise to contract assets or liabilities under ASC 606. Performance obligations The majority of the Company’s sales are short-term in nature with a contract term of one year or less. For those contracts, the Company utilized the practical expedient in ASC 606-10-50-14 that exempts the Company from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less. For the Company’s product sales that have a contract term greater than one year, the Company utilized the practical expedient in ASC 606-10-50-14(A) which states the Company is not required to disclose the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Under these sales contracts, each unit of product generally represents a separate performance obligation; therefore future volumes are wholly unsatisfied and disclosure of the transaction price allocated to remaining performance obligations is not required. Under the midstream services contracts, each unit of service represents a separate performance obligation and therefore performance obligations in respect of future services are wholly unsatisfied.
Financial Instruments	Financial instruments. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”), which requires that most equity instruments be measured at fair value with subsequent changes in fair value recognized in net income. ASU 2016-01 also impacts financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. ASU 2016-01 does not apply to equity method investments or investments in consolidated subsidiaries. ASU 2016-01 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 .
Statement of Cash Flows	Statement of cash flows. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2016-15, Statement of Cash Flows (“ASU 2016-15”), which is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. ASU 2016-15 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 .
Income Taxes	Income taxes. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2016-16, Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”), to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. ASU 2016-16 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 . In the third quarter of 2018, the Company finalized the accounting related to Accounting Standards Update No. 2018-05, Income Taxes (Topic 740) - Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 (“ASU 2018-05”). This standard amends Accounting Standards Codification 740, Income Taxes (“ASC 740”) to provide guidance on accounting for the tax effects of the Tax Cuts and Jobs Act (the “Tax Act”) pursuant to Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act ("SAB 118"). See Note 13 – Income Taxes for the total impact as a result of adoption as of September 30, 2018 .
Business Combinations	Business combinations. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2017-01, Clarifying the Definition of a Business (“ASU 2017-01”), which provides guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. ASU 2017-01 requires entities to use a screen test to determine when an integrated set of assets and activities is not a business or if the integrated set of assets and activities needs to be further evaluated against the framework. ASU 2017-01 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 .
Equity-based Compensation	Equity-based compensation. In the first quarter of 2018, the Company adopted Accounting Standards Update No. 2017-09, Scope of Modification Accounting (“ASU 2017-09”), which provides guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. ASU 2017-09 was applied on a prospective basis and prior periods were not retrospectively adjusted. There was no material impact as a result of adoption as of September 30, 2018 .
Recent Accounting Pronouncements	Recent Accounting Pronouncements Leases. In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2016-02, Leases (“ASU 2016-02”), which requires a lessee to recognize lease payment obligations and a corresponding right-of-use asset to be measured at fair value on the balance sheet. ASU 2016-02 also requires certain qualitative and quantitative disclosures about the amount, timing and uncertainty of cash flows arising from leases. This standard does not apply to leases to explore for or use minerals, oil or natural gas resources, including the right to explore for those natural resources. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. In January 2018, the FASB issued Accounting Standards Update No. 2018-01, Land Easement Practical Expedient for Transition to Topic 842 , which provides an optional transition practical expedient to not evaluate under Topic 842 existing or expired land easements that were not previously accounted for as leases under Topic 840, Leases . The Company plans to elect this practical expedient. In July 2018, the FASB issued Accounting Standards Update No. 2018-11, Targeted Improvements - Lease Topic 842 , which allows entities another option for transition and also provides lessors with a practical expedient to combine lease and non-lease components. The Company will adopt the new leases standard using the required modified retrospective approach and plans to elect the option to recognize a cumulative effect adjustment of initially applying the guidance to the opening balance of retained earnings in the period of adoption, rather than recognizing in the earliest period presented. Prior period amounts will not be adjusted. The Company is in the process of analyzing its lease arrangements and is continuing to identify and put in place necessary changes to its business processes and controls to support the adoption of the new standard, including implementing a new lease accounting software to assess the portfolio of leases, assist in the quantification of the expected impact on the consolidated financial statements and facilitate the calculations of the related accounting entries and disclosures. The Company is currently evaluating the effect that adopting the new lease guidance will have on its financial position, cash flows and results of operations. Financial instruments. In August 2018, the FASB issued Accounting Standards Update No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”), which improves the effectiveness of the disclosure requirements for fair value measurements. The changes affect all companies that are required to include fair value measurement disclosures. ASU 2018-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those years. An entity is permitted to early adopt the removed or modified disclosures upon the issuance of ASU 2018-13 and may delay adoption of the additional disclosures until their effective date. The Company does not expect the adoption of this guidance to have an impact on its financial position, cash flows or results of operations, but it may result in changes to disclosures.
Inventory	Inventory , including long-term inventory, is stated at the lower of cost and net realizable value with cost determined on an average cost method. T he Company assesses the carrying value of inventory and uses estimates and judgment when making any adjustments necessary to reduce the carrying value to net realizable value. Among the uncertainties that impact the Company’s estimates are the applicable quality and location differentials to include in the Company’s net realizable value analysis. Additionally, the Company estimates the upcoming liquidation timing of the inventory. Changes in assumptions made as to the timing of a sale can materially impact net realizable value.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2018
Exploration and Production [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	Revenues associated with contracts with customers for oil, natural gas and NGL sales were as follows for the three and nine months ended September 30, 2018 and 2017 : Exploration and Production Revenues Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Oil revenues $ 412,530 $ 221,003 $ 1,097,171 $ 623,603 Purchased oil sales 42,902 20,734 114,598 56,269 Natural gas revenues 26,181 17,037 76,201 51,689 Purchased gas sales 1,616 462 2,161 648 NGL revenues 13,932 10,607 38,863 29,241 Total exploration and production revenues $ 497,161 $ 269,843 $ 1,328,994 $ 761,450
Midstream Services [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	Revenues associated with contracts with customers for midstream services were as follows for the three and nine months ended September 30, 2018 and 2017 : Midstream Revenues (1) Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Crude oil and natural gas revenues $ 18,188 $ 11,612 $ 54,124 $ 23,348 Purchased oil sales 1,838 — 5,212 — Water revenues 12,999 7,155 34,327 25,591 Total midstream revenues $ 33,025 $ 18,767 $ 93,663 $ 48,939 __________________ (1) Represents midstream revenues, excluding all intercompany revenues, for work performed by the midstream services business segment for the Company’s working interests that are eliminated in consolidation and are therefore not included in midstream services revenues.
Well Services [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	Revenues associated with contracts with customers for hydraulic fracturing services and equipment rental sales were as follows for the three and nine months ended September 30, 2018 and 2017 : Well Services Revenues (1) Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Hydraulic fracturing service revenues $ 14,985 $ 15,090 $ 42,801 $ 31,303 Equipment rental revenues 1,277 1,048 3,543 2,263 Total well services revenues $ 16,262 $ 16,138 $ 46,344 $ 33,566 __________________ (1) Represents well services revenues excluding all intercompany revenues for work performed by the well services business segment for the Company’s working interests that are eliminated in consolidation and are therefore not included in well services revenues.

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Components of Inventory	Total inventory consists of the following: September 30, 2018 December 31, 2017 (In thousands) Inventory Crude oil inventory $ 14,867 $ 10,427 Equipment and materials 16,542 8,940 Total inventory $ 31,409 $ 19,367 Long-term inventory Linefill in third-party pipelines $ 12,610 $ 12,200 Long-term inventory $ 12,610 $ 12,200 Total $ 44,019 $ 31,567
Components of Long-term Inventory	Total inventory consists of the following: September 30, 2018 December 31, 2017 (In thousands) Inventory Crude oil inventory $ 14,867 $ 10,427 Equipment and materials 16,542 8,940 Total inventory $ 31,409 $ 19,367 Long-term inventory Linefill in third-party pipelines $ 12,610 $ 12,200 Long-term inventory $ 12,610 $ 12,200 Total $ 44,019 $ 31,567

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Schedule of Accounts Receivable, Net	The following table sets forth the Company’s accounts receivable, net: September 30, 2018 December 31, 2017 (In thousands) Accounts receivable, net Trade accounts $ 277,558 $ 233,660 Joint interest accounts 94,793 73,588 Other accounts 56,779 57,905 Total 429,130 365,153 Allowance for doubtful accounts (946 ) (1,573 ) Total accounts receivable, net $ 428,184 $ 363,580

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Hierarchy of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables set forth by level, within the fair value hierarchy, the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis: Fair value at September 30, 2018 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 143 $ — $ — $ 143 Total assets $ 143 $ — $ — $ 143 Liabilities: Commodity derivative instruments (see Note 7) $ — $ 213,146 $ — $ 213,146 Total liabilities $ — $ 213,146 $ — $ 213,146 Fair value at December 31, 2017 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 142 $ — $ — $ 142 Commodity derivative instruments (see Note 7) — 353 — 353 Total assets $ 142 $ 353 $ — $ 495 Liabilities: Commodity derivative instruments (see Note 7) $ — $ 135,567 $ — $ 135,567 Total liabilities $ — $ 135,567 $ — $ 135,567

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Commodity Derivative Instruments	At September 30, 2018 , the Company had the following outstanding commodity derivative instruments: Commodity Settlement Derivative Index Volumes Weighted Average Prices Fair Value Fixed Price Swaps Basis Swaps Sub-Floor Floor Ceiling (In thousands) Crude oil 2018 Fixed price swaps NYMEX WTI 3,761,000 Bbl $ 52.95 $ (71,621 ) Crude oil 2018 Basis swaps NYMEX WTI-ICE BRENT 152,000 Bbl $ (9.84 ) 81 Crude oil 2018 Two-way collar NYMEX WTI 517,000 Bbl $ 58.74 $ 63.94 (5,171 ) Crude oil 2019 Fixed price swaps NYMEX WTI 5,613,000 Bbl $ 53.33 (99,347 ) Crude oil 2019 Basis swaps NYMEX WTI-ICE BRENT 424,000 Bbl $ (9.68 ) 408 Crude oil 2019 Two-way collar NYMEX WTI 3,223,000 Bbl $ 57.99 $ 75.46 (7,580 ) Crude oil 2019 Three-way collar NYMEX WTI 3,368,000 Bbl $ 40.54 $ 51.03 $ 68.68 (21,771 ) Crude oil 2020 Fixed price swaps NYMEX WTI 403,000 Bbl $ 53.47 (5,911 ) Crude oil 2020 Two-way collar NYMEX WTI 279,000 Bbl $ 57.78 $ 76.13 (273 ) Crude oil 2020 Three-way collar NYMEX WTI 279,000 Bbl $ 40.00 $ 50.56 $ 67.80 (1,778 ) Natural gas 2018 Fixed price swaps NYMEX HH 3,496,000 MMbtu $ 3.01 (104 ) Natural gas 2018 Basis swaps IF NNG VENTURA-NYMEX HH 1,225,000 MMbtu $ (0.05 ) (64 ) Natural gas 2019 Fixed price swaps NYMEX HH 1,896,000 MMbtu $ 2.95 16 Natural gas 2019 Basis swaps IF NNG VENTURA-NYMEX HH 2,715,000 MMbtu $ (0.05 ) (31 ) $ (213,146 )
Gains and Losses from Commodity Derivative Instruments	The following table summarizes the location and amounts of gains and losses from the Company’s commodity derivative instruments recorded in the Company’s Condensed Consolidated Statements of Operations for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, Statements of Operations Location 2018 2017 2018 2017 (In thousands) Net gain (loss) on derivative instruments $ (48,544 ) $ (54,310 ) $ (239,945 ) $ 52,297
Summary of Gross and Net Information about Commodity Derivative Assets	The following table summarizes the location and fair value of all outstanding commodity derivative instruments recorded in the Company’s Condensed Consolidated Balance Sheets: September 30, 2018 Commodity Balance Sheet Location Gross Recognized Liabilities Gross Amount Offset Net Recognized Fair Value Liabilities (In thousands) Derivatives liabilities: Commodity contracts Derivative instruments — current liabilities $ 184,832 $ (4,703 ) $ 180,129 Commodity contracts Derivative instruments — non-current liabilities 37,006 (3,989 ) 33,017 Total derivatives liabilities $ 221,838 $ (8,692 ) $ 213,146 December 31, 2017 Commodity Balance Sheet Location Gross Recognized Assets/Liabilities Gross Amount Offset Net Recognized Fair Value Assets/Liabilities (In thousands) Derivatives assets: Commodity contracts Derivative instruments — current assets $ 344 $ — $ 344 Commodity contracts Derivative instruments — non-current assets 9 — 9 Total derivatives assets $ 353 $ — $ 353 Derivatives liabilities: Commodity contracts Derivative instruments — current liabilities $ 117,629 $ (1,913 ) $ 115,716 Commodity contracts Derivative instruments — non-current liabilities 20,035 (184 ) 19,851 Total derivatives liabilities $ 137,664 $ (2,097 ) $ 135,567
Summary of Gross and Net Information about Commodity Derivative Liabilities	The following table summarizes the location and fair value of all outstanding commodity derivative instruments recorded in the Company’s Condensed Consolidated Balance Sheets: September 30, 2018 Commodity Balance Sheet Location Gross Recognized Liabilities Gross Amount Offset Net Recognized Fair Value Liabilities (In thousands) Derivatives liabilities: Commodity contracts Derivative instruments — current liabilities $ 184,832 $ (4,703 ) $ 180,129 Commodity contracts Derivative instruments — non-current liabilities 37,006 (3,989 ) 33,017 Total derivatives liabilities $ 221,838 $ (8,692 ) $ 213,146 December 31, 2017 Commodity Balance Sheet Location Gross Recognized Assets/Liabilities Gross Amount Offset Net Recognized Fair Value Assets/Liabilities (In thousands) Derivatives assets: Commodity contracts Derivative instruments — current assets $ 344 $ — $ 344 Commodity contracts Derivative instruments — non-current assets 9 — 9 Total derivatives assets $ 353 $ — $ 353 Derivatives liabilities: Commodity contracts Derivative instruments — current liabilities $ 117,629 $ (1,913 ) $ 115,716 Commodity contracts Derivative instruments — non-current liabilities 20,035 (184 ) 19,851 Total derivatives liabilities $ 137,664 $ (2,097 ) $ 135,567

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	The following table sets forth the Company’s property, plant and equipment: September 30, 2018 December 31, 2017 (In thousands) Proved oil and gas properties (1) $ 7,566,694 $ 7,058,782 Less: Accumulated depreciation, depletion, amortization and impairment (2,689,613 ) (2,395,153 ) Proved oil and gas properties, net 4,877,081 4,663,629 Unproved oil and gas properties 1,104,450 780,173 Other property and equipment 1,088,781 868,746 Less: Accumulated depreciation (170,175 ) (139,062 ) Other property and equipment, net 918,606 729,684 Total property, plant and equipment, net $ 6,900,137 $ 6,173,486 __________________ (1) Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $41.4 million and $39.9 million at September 30, 2018 and December 31, 2017 , respectively.

Acquisition Acquisition (Tables

Acquisition Acquisition (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Purchase Price Allocation	The following table summarizes the consideration paid for the Company’s acquisition and the fair value of the assets acquired and liabilities assumed as of the acquisition date. At February 14, 2018 (In thousands) Consideration paid to Forge Energy: Cash $ 549,770 Common stock: 46,000,000 shares issued 371,220 $ 920,990 Recognized amounts of identifiable assets acquired and liabilities assumed: Proved developed properties $ 110,325 Proved undeveloped properties 166,552 Unproved lease acquisition costs 645,068 Inventory 293 Intangible assets 1,000 Asset retirement obligations (2,248 ) $ 920,990
Pro Forma Information	Summarized below are the consolidated results of operations for the three and nine months ended September 30, 2018 , on an unaudited pro forma basis, as if the acquisition and related financing had occurred on January 1, 2017. The unaudited pro forma financial information was derived from the historical consolidated statements of operations of the Company and the statement of revenues and direct operating expenses for the Permian Basin Acquisition properties, which were derived from the historical accounting records of Forge Energy . The unaudited pro forma financial information does not purport to be indicative of results of operations that would have occurred had the acquisition and related financing occurred on the basis assumed above, nor is such information indicative of the Company’s expected future results of operations. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) (In thousands) Unaudited Unaudited Revenues $ 546,449 $ 318,879 $ 1,474,530 $ 871,952 Net income (loss) attributable to Oasis 62,341 (29,717 ) (252,731 ) 22,068 Net income (loss) attributable to Oasis per share: Basic $ 0.20 $ (0.11 ) $ (0.81 ) $ 0.08 Diluted 0.20 (0.11 ) (0.81 ) 0.08

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	The Company’s long-term debt consists of the following: September 30, 2018 December 31, 2017 (In thousands) Oasis Credit Facility $ 522,000 $ 70,000 OMP Credit Facility 166,000 78,000 Senior unsecured notes 7.25% senior unsecured notes due February 1, 2019 — 54,275 6.50% senior unsecured notes due November 1, 2021 71,835 395,501 6.875% senior unsecured notes due March 15, 2022 901,480 937,080 6.875% senior unsecured notes due January 15, 2023 366,094 366,094 6.25% senior unsecured notes due May 1, 2026 400,000 — 2.625% senior unsecured convertible notes due September 15, 2023 300,000 300,000 Total principal of senior unsecured notes 2,039,409 2,052,950 Less: unamortized deferred financing costs on senior unsecured notes (22,212 ) (22,956 ) Less: unamortized debt discount on senior unsecured convertible notes (72,188 ) (80,388 ) Total long-term debt $ 2,633,009 $ 2,097,606

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2018
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Changes in Asset Retirement Obligations	The following table reflects the changes in the Company’s ARO during the nine months ended September 30, 2018 : (In thousands) Balance at December 31, 2017 $ 48,799 Liabilities incurred during period 5,509 Liabilities settled during period (4,904 ) Accretion expense during period (1) 1,975 Revisions to estimates 83 Balance at September 30, 2018 $ 51,462 ___________________ (1) Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statements of Operations.

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Based Compensation Assumptions	The following assumptions were used for the Monte Carlo model to determine the grant date fair value and associated equity-based compensation expense of the PSUs granted during the nine months ended September 30, 2018 : Risk-free interest rate 2.08% - 2.31% Oasis volatility 72.88 % Oasis initial value $8.82 Oasis stock price on date of grant $9.27

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of Weighted-Average Number of Shares Outstanding	The following is a calculation of the basic and diluted weighted average shares outstanding for the three and nine months ended September 30, 2018 and 2017 : Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Basic weighted average common shares outstanding 313,167 233,389 305,533 233,248 Dilutive effect of restricted stock awards and PSUs (1) 3,220 — — — Diluted weighted average common shares outstanding 316,387 233,389 305,533 233,248 __________________ (1) No unvested stock awards were included in computing earnings (loss) per share for the nine months ended September 30, 2018 and the three and nine months ended September 30, 2017 because the effects were anti-dilutive.
Schedule of Common Shares Excluded From Diluted Earnings (Loss) per Share Calculation	The following is a calculation of weighted average common shares excluded from diluted earnings (loss) per share due to the anti-dilutive effect: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 (In thousands) Restricted stock awards and PSUs 4,180 5,841 7,284 5,988

Business Segment Information (T

Business Segment Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Summarized Financial Information of Segments	The following table summarizes financial information for the Company’s three business segments for the periods presented: Exploration and Production Midstream Services Well Services Eliminations Consolidated (In thousands) Three months ended September 30, 2018: Revenues from non-affiliates $ 497,161 $ 33,025 $ 16,262 $ — $ 546,448 Inter-segment revenues — 42,745 40,177 (82,922 ) — Total revenues 497,161 75,770 56,439 (82,922 ) 546,448 Operating income 146,969 31,326 9,237 (8,487 ) 179,045 Other expense (87,594 ) (367 ) (79 ) — (88,040 ) Income before income taxes including non-controlling interests $ 59,375 $ 30,959 $ 9,158 $ (8,487 ) $ 91,005 Three months ended September 30, 2017: Revenues from non-affiliates $ 269,843 $ 18,767 $ 16,138 $ — $ 304,748 Inter-segment revenues — 28,893 31,025 (59,918 ) — Total revenues 269,843 47,660 47,163 (59,918 ) 304,748 Operating income 3,484 25,194 10,802 (7,086 ) 32,394 Other income (expense) (92,319 ) (15 ) 30 — (92,304 ) Income (loss) before income taxes including non-controlling interests $ (88,835 ) $ 25,179 $ 10,832 $ (7,086 ) $ (59,910 ) Nine months ended September 30, 2018: Revenues from non-affiliates $ 1,328,994 $ 93,663 $ 46,344 $ — $ 1,469,001 Inter-segment revenues — 119,095 114,898 (233,993 ) — Total revenues 1,328,994 212,758 161,242 (233,993 ) 1,469,001 Operating income (loss) (53,159 ) 101,457 25,415 (24,357 ) 49,356 Other expense (370,311 ) (703 ) (99 ) — (371,113 ) Income (loss) before income taxes including non-controlling interests $ (423,470 ) $ 100,754 $ 25,316 $ (24,357 ) $ (321,757 ) Nine months ended September 30, 2017: Revenues from non-affiliates $ 761,450 $ 48,939 $ 33,566 $ — $ 843,955 Inter-segment revenues — 76,674 68,028 (144,702 ) — Total revenues 761,450 125,613 101,594 (144,702 ) 843,955 Operating income (loss) (12,972 ) 69,059 9,161 (7,383 ) 57,865 Other income (expense) (59,027 ) (13 ) 34 — (59,006 ) Income (loss) before income taxes including non-controlling interests $ (71,999 ) $ 69,046 $ 9,195 $ (7,383 ) $ (1,141 ) At September 30, 2018: Property, plant and equipment, net $ 6,227,767 $ 841,797 $ 41,468 $ (210,895 ) $ 6,900,137 Total assets (1) 6,675,626 867,226 49,285 (175,706 ) 7,416,431 At December 31, 2017: Property, plant and equipment, net $ 5,663,323 $ 649,923 $ 46,779 $ (186,539 ) $ 6,173,486 Total assets (1) 6,050,255 663,614 52,800 (151,539 ) 6,615,130 ___________________ (1) Intercompany receivables (payables) for all segments were reclassified to capital contributions from (distributions to) parent and not included in total assets.

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands, except share data) ASSETS Current assets Cash and cash equivalents $ 170 $ 11,732 $ 4,990 $ — $ 16,892 Accounts receivable, net — 423,130 5,054 — 428,184 Accounts receivable - affiliates 653,255 66,153 72,896 (792,304 ) — Inventory — 31,409 — — 31,409 Prepaid expenses 617 5,731 96 — 6,444 Intangible assets, net — 375 — — 375 Other current assets — 192 — — 192 Total current assets 654,042 538,722 83,036 (792,304 ) 483,496 Property, plant and equipment Oil and gas properties (successful efforts method) — 8,679,662 — (8,518 ) 8,671,144 Other property and equipment — 212,257 876,534 (10 ) 1,088,781 Less: accumulated depreciation, depletion, amortization and impairment — (2,805,233 ) (54,555 ) — (2,859,788 ) Total property, plant and equipment, net — 6,086,686 821,979 (8,528 ) 6,900,137 Investments in and advances to subsidiaries 4,653,951 515,997 — (5,169,948 ) — Deferred income taxes 209,919 — — (209,919 ) — Long-term inventory — 12,610 — — 12,610 Other assets — 18,207 1,981 — 20,188 Total assets $ 5,517,912 $ 7,172,222 $ 906,996 $ (6,180,699 ) $ 7,416,431 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities Accounts payable $ — $ 17,182 $ 24 $ — $ 17,206 Accounts payable - affiliates 41,213 726,151 24,940 (792,304 ) — Revenues and production taxes payable — 286,897 436 — 287,333 Accrued liabilities 56 248,097 59,373 — 307,526 Accrued interest payable 19,855 547 172 — 20,574 Derivative instruments — 180,129 — — 180,129 Advances from joint interest partners — 3,878 — — 3,878 Other current liabilities — 40 — — 40 Total current liabilities 61,124 1,462,921 84,945 (792,304 ) 816,686 Long-term debt 1,945,009 522,000 166,000 — 2,633,009 Deferred income taxes — 440,423 — (209,919 ) 230,504 Asset retirement obligations — 49,860 1,497 — 51,357 Derivative instruments — 33,017 — — 33,017 Other liabilities — 7,775 — — 7,775 Total liabilities 2,006,133 2,515,996 252,442 (1,002,223 ) 3,772,348 Stockholders’ equity Capital contributions from affiliates — 3,271,788 202,007 (3,473,795 ) — Common stock, $0.01 par value: 900,000,000 shares authorized; 320,507,783 shares issued and 318,419,144 shares outstanding 3,157 — — — 3,157 Treasury stock, at cost: 2,088,639 shares (28,985 ) — — — (28,985 ) Additional paid-in-capital 3,070,642 9,141 — (9,141 ) 3,070,642 Retained earnings 466,965 1,236,740 46,413 (1,289,406 ) 460,712 Oasis share of stockholders’ equity 3,511,779 4,517,669 248,420 (4,772,342 ) 3,505,526 Non-controlling interests — 138,557 406,134 (406,134 ) 138,557 Total stockholders’ equity 3,511,779 4,656,226 654,554 (5,178,476 ) 3,644,083 Total liabilities and stockholders’ equity $ 5,517,912 $ 7,172,222 $ 906,996 $ (6,180,699 ) $ 7,416,431 Condensed Consolidating Balance Sheet December 31, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands, except share data) ASSETS Current assets Cash and cash equivalents $ 178 $ 15,659 $ 883 $ — $ 16,720 Accounts receivable, net — 362,746 834 — 363,580 Accounts receivable - affiliates 425,668 46,020 85,818 (557,506 ) — Inventory — 19,367 — — 19,367 Prepaid expenses 267 6,586 778 — 7,631 Derivative instruments — 344 — — 344 Other current assets — 193 — — 193 Total current assets 426,113 450,915 88,313 (557,506 ) 407,835 Property, plant and equipment Oil and gas properties (successful efforts method) — 7,840,921 — (1,966 ) 7,838,955 Other property and equipment — 214,818 653,928 — 868,746 Less: accumulated depreciation, depletion, amortization and impairment — (2,499,867 ) (34,348 ) — (2,534,215 ) Total property, plant and equipment, net — 5,555,872 619,580 (1,966 ) 6,173,486 Investments in and advances to subsidiaries 4,790,976 422,132 — (5,213,108 ) — Derivative instruments — 9 — — 9 Deferred income taxes 183,568 — — (183,568 ) — Long-term inventory — 12,200 — — 12,200 Other assets — 19,587 2,013 — 21,600 Total assets $ 5,400,657 $ 6,460,715 $ 709,906 $ (5,956,148 ) $ 6,615,130 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities Accounts payable $ — $ 13,370 $ — $ — $ 13,370 Accounts payable - affiliates 34,382 511,486 11,638 (557,506 ) — Revenues and production taxes payable — 213,995 — — 213,995 Accrued liabilities 216 177,446 58,818 — 236,480 Accrued interest payable 38,796 53 114 — 38,963 Derivative instruments — 115,716 — — 115,716 Advances from joint interest partners — 4,916 — — 4,916 Other current liabilities — 40 — — 40 Total current liabilities 73,394 1,037,022 70,570 (557,506 ) 623,480 Long-term debt 1,949,606 70,000 78,000 — 2,097,606 Deferred income taxes — 489,489 — (183,568 ) 305,921 Asset retirement obligations — 47,195 1,316 — 48,511 Derivative instruments — 19,851 — — 19,851 Other liabilities — 6,182 — — 6,182 Total liabilities 2,023,000 1,669,739 149,886 (741,074 ) 3,101,551 Stockholders’ equity Capital contributions from affiliates — 3,264,691 234,935 (3,499,626 ) — Common stock, $0.01 par value: 450,000,000 shares authorized; 270,627,014 shares issued and 269,295,466 shares outstanding 2,668 — — — 2,668 Treasury stock, at cost: 1,331,548 shares (22,179 ) — — — (22,179 ) Additional paid-in-capital 2,677,217 8,922 — (8,922 ) 2,677,217 Retained earnings 719,951 1,379,475 11,639 (1,393,080 ) 717,985 Oasis share of stockholders’ equity 3,377,657 4,653,088 246,574 (4,901,628 ) 3,375,691 Non-controlling interests — 137,888 313,446 (313,446 ) 137,888 Total stockholders’ equity 3,377,657 4,790,976 560,020 (5,215,074 ) 3,513,579 Total liabilities and stockholders’ equity $ 5,400,657 $ 6,460,715 $ 709,906 $ (5,956,148 ) $ 6,615,130
Condensed Consolidating Statement of Operations	Condensed Consolidating Statement of Operations Three Months Ended September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 452,643 $ — $ — $ 452,643 Purchased oil and gas sales — 46,356 — — 46,356 Midstream revenues — 765 71,467 (41,045 ) 31,187 Well services revenues — 16,262 — — 16,262 Total revenues — 516,026 71,467 (41,045 ) 546,448 Operating expenses Lease operating expenses — 63,099 — (14,565 ) 48,534 Midstream operating expenses — 528 19,816 (11,692 ) 8,652 Well services operating expenses — 11,405 — — 11,405 Marketing, transportation and gathering expenses — 36,839 — (6,126 ) 30,713 Purchased oil and gas expenses — 46,148 — (60 ) 46,088 Production taxes — 38,722 — — 38,722 Depreciation, depletion and amortization — 159,843 7,189 (4,048 ) 162,984 Exploration expenses — 22,315 — — 22,315 General and administrative expenses 7,486 24,627 5,449 (2,703 ) 34,859 Total operating expenses 7,486 403,526 32,454 (39,194 ) 404,272 Gain on sale of properties — 36,869 — — 36,869 Operating income (loss) (7,486 ) 149,369 39,013 (1,851 ) 179,045 Other income (expense) Equity in earnings of subsidiaries 96,555 38,835 — (135,390 ) — Net loss on derivative instruments — (48,544 ) — — (48,544 ) Interest expense, net of capitalized interest (32,836 ) (6,561 ) (163 ) — (39,560 ) Loss on extinguishment of debt (47 ) — — — (47 ) Other income (expense) — 126 (15 ) — 111 Total other income (expense) 63,672 (16,144 ) (178 ) (135,390 ) (88,040 ) Income before income taxes 56,186 133,225 38,835 (137,241 ) 91,005 Income tax benefit (expense) 6,155 (30,937 ) — — (24,782 ) Net income including non-controlling interests 62,341 102,288 38,835 (137,241 ) 66,223 Less: Net income attributable to non-controlling interests — 3,882 26,459 (26,459 ) 3,882 Net income attributable to Oasis $ 62,341 $ 98,406 $ 12,376 $ (110,782 ) $ 62,341 Condensed Consolidating Statement of Operations Three Months Ended September 30, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 248,648 $ — $ — $ 248,648 Purchased oil and gas sales — 21,195 — — 21,195 Midstream revenues — 15,828 2,939 — 18,767 Well services revenues — 16,138 — — 16,138 Total revenues — 301,809 2,939 — 304,748 Operating expenses Lease operating expenses — 45,334 — — 45,334 Midstream operating expenses — 3,621 680 — 4,301 Well services operating expenses — 10,288 — — 10,288 Marketing, transportation and gathering expenses — 15,028 — — 15,028 Purchased oil and gas expenses — 21,701 — — 21,701 Production taxes — 21,052 — — 21,052 Depreciation, depletion and amortization — 132,035 254 — 132,289 Exploration expenses — 854 — — 854 Impairment — 139 — — 139 General and administrative expenses 6,775 14,212 381 — 21,368 Total operating expenses 6,775 264,264 1,315 — 272,354 Operating income (loss) (6,775 ) 37,545 1,624 — 32,394 Other income (expense) Equity in earnings (loss) of subsidiaries (13,599 ) 1,605 — 11,994 — Net loss on derivative instruments — (54,310 ) — — (54,310 ) Interest expense, net of capitalized interest (32,894 ) (4,476 ) (19 ) — (37,389 ) Other income (expense) 2 (607 ) — — (605 ) Total other expense (46,491 ) (57,788 ) (19 ) 11,994 (92,304 ) Income (loss) before income taxes (53,266 ) (20,243 ) 1,605 11,994 (59,910 ) Income tax benefit 12,052 6,794 — — 18,846 Net income (loss) including non-controlling interests (41,214 ) (13,449 ) 1,605 11,994 (41,064 ) Less: Net income attributable to non-controlling interests — 150 1,112 (1,112 ) 150 Net income (loss) attributable to Oasis $ (41,214 ) $ (13,599 ) $ 493 $ 13,106 $ (41,214 ) Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 1,212,235 $ — $ — $ 1,212,235 Purchased oil and gas sales — 121,971 — — 121,971 Midstream revenues — 2,832 199,446 (113,827 ) 88,451 Well services revenues — 46,344 — — 46,344 Total revenues — 1,383,382 199,446 (113,827 ) 1,469,001 Operating expenses Lease operating expenses — 176,413 — (38,957 ) 137,456 Midstream operating expenses — 2,054 53,266 (30,995 ) 24,325 Well services operating expenses — 32,352 — — 32,352 Marketing, transportation and gathering expenses — 92,164 — (17,605 ) 74,559 Purchased oil and gas expenses — 121,311 — (60 ) 121,251 Production taxes — 103,748 — — 103,748 Depreciation, depletion and amortization — 456,624 20,212 (11,017 ) 465,819 Exploration expenses — 23,701 — — 23,701 Impairment — 384,228 — — 384,228 General and administrative expenses 22,214 60,259 17,496 (8,940 ) 91,029 Total operating expenses 22,214 1,452,854 90,974 (107,574 ) 1,458,468 Gain on sale of properties — 38,823 — — 38,823 Operating income (loss) (22,214 ) (30,649 ) 108,472 (6,253 ) 49,356 Other income (expense) Equity in earnings (loss) of subsidiaries (149,295 ) 107,849 — 41,446 — Net loss on derivative instruments — (239,945 ) — — (239,945 ) Interest expense, net of capitalized interest (98,417 ) (18,591 ) (608 ) — (117,616 ) Loss on extinguishment of debt (13,698 ) — — — (13,698 ) Other income (expense) — 161 (15 ) — 146 Total other expense (261,410 ) (150,526 ) (623 ) 41,446 (371,113 ) Income (loss) before income taxes (283,624 ) (181,175 ) 107,849 35,193 (321,757 ) Income tax benefit 26,351 49,040 — — 75,391 Net income (loss) including non-controlling interests (257,273 ) (132,135 ) 107,849 35,193 (246,366 ) Less: Net income attributable to non-controlling interests — 10,907 73,075 (73,075 ) 10,907 Net income (loss) attributable to Oasis $ (257,273 ) $ (143,042 ) $ 34,774 $ 108,268 $ (257,273 ) Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 704,533 $ — $ — $ 704,533 Purchased oil and gas sales — 56,917 — — 56,917 Midstream revenues — 46,000 2,939 — 48,939 Well services revenues — 33,566 — — 33,566 Total revenues — 841,016 2,939 — 843,955 Operating expenses Lease operating expenses — 133,871 — — 133,871 Midstream operating expenses — 10,211 680 — 10,891 Well services operating expenses — 23,858 — — 23,858 Marketing, transportation and gathering expenses — 38,018 — — 38,018 Purchased oil and gas expenses — 57,683 — — 57,683 Production taxes — 60,322 — — 60,322 Depreciation, depletion and amortization — 383,992 254 — 384,246 Exploration expenses — 4,010 — — 4,010 Impairment — 6,021 — — 6,021 General and administrative expenses 21,374 45,415 381 — 67,170 Total operating expenses 21,374 763,401 1,315 — 786,090 Operating income (loss) (21,374 ) 77,615 1,624 — 57,865 Other income (expense) Equity in earnings of subsidiaries 74,379 1,605 — (75,984 ) — Net gain on derivative instruments — 52,297 — — 52,297 Interest expense, net of capitalized interest (98,751 ) (11,778 ) (19 ) — (110,548 ) Other income (expense) 2 (757 ) — — (755 ) Total other income (expense) (24,370 ) 41,367 (19 ) (75,984 ) (59,006 ) Income (loss) before income taxes (45,744 ) 118,982 1,605 (75,984 ) (1,141 ) Income tax benefit (expense) 44,923 (44,453 ) — — 470 Net income (loss) including non-controlling interests (821 ) 74,529 1,605 (75,984 ) (671 ) Less: Net income attributable to non-controlling interests — 150 1,112 (1,112 ) 150 Net income (loss) attributable to Oasis $ (821 ) $ 74,379 $ 493 $ (74,872 ) $ (821 )
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2018 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Cash flows from operating activities: Net income (loss) including non-controlling interests $ (257,273 ) $ (132,135 ) $ 107,849 $ 35,193 $ (246,366 ) Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities: Equity in earnings (loss) of subsidiaries 149,295 (107,849 ) — (41,446 ) — Depreciation, depletion and amortization — 456,624 20,212 (11,017 ) 465,819 Loss on extinguishment of debt 13,698 — — — 13,698 Gain on sale of properties — (38,823 ) — — (38,823 ) Impairment — 384,228 — — 384,228 Deferred income taxes (26,351 ) (49,067 ) — — (75,418 ) Derivative instruments — 239,945 — — 239,945 Equity-based compensation expenses 20,292 1,014 280 — 21,586 Deferred financing costs amortization and other 11,955 7,884 235 — 20,074 Working capital and other changes: Change in accounts receivable (227,589 ) (77,231 ) 8,747 234,798 (61,275 ) Change in inventory — (12,076 ) — — (12,076 ) Change in prepaid expenses (350 ) 864 682 — 1,196 Change in other current assets — 1 — — 1 Change in long-term inventory and other assets — (490 ) — — (490 ) Change in accounts payable, interest payable and accrued liabilities (12,270 ) 278,481 18,895 (234,798 ) 50,308 Change in other liabilities — (406 ) — — (406 ) Net cash provided by (used in) operating activities (328,593 ) 950,964 156,900 (17,270 ) 762,001 Cash flows from investing activities: Capital expenditures — (621,269 ) (219,819 ) — (841,088 ) Acquisitions — (579,886 ) — — (579,886 ) Proceeds from sale of properties — 333,029 — — 333,029 Costs related to sale of properties — (2,707 ) — — (2,707 ) Derivative settlements — (162,013 ) — — (162,013 ) Advances from joint interest partners — (1,038 ) — — (1,038 ) Net cash used in investing activities — (1,033,884 ) (219,819 ) — (1,253,703 ) Cash flows from financing activities: Proceeds from Revolving Credit Facilities — 2,376,000 123,000 — 2,499,000 Principal payments on Revolving Credit Facilities — (1,924,000 ) (35,000 ) — (1,959,000 ) Repurchase of senior unsecured notes (423,190 ) — — — (423,190 ) Proceeds from issuance of senior unsecured convertible notes 400,000 — — — 400,000 Deferred financing costs (7,058 ) (261 ) (331 ) — (7,650 ) Purchases of treasury stock (6,806 ) — — — (6,806 ) Distributions to non-controlling interests — 92,672 (103,065 ) — (10,393 ) Investment in subsidiaries / capital contributions from parent 365,601 (465,293 ) 82,422 17,270 — Other 38 (125 ) — — (87 ) Net cash provided by financing activities 328,585 78,993 67,026 17,270 491,874 Increase (decrease) in cash and cash equivalents (8 ) (3,927 ) 4,107 — 172 Cash and cash equivalents at beginning of period 178 15,659 883 — 16,720 Cash and cash equivalents at end of period $ 170 $ 11,732 $ 4,990 $ — $ 16,892 Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2017 Parent/ Combined Combined Non-guarantor Subsidiaries Intercompany Consolidated (In thousands) Cash flows from operating activities: Net income (loss) including non-controlling interests $ (821 ) $ 74,529 $ 1,605 $ (75,984 ) $ (671 ) Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities: Equity in earnings of subsidiaries (74,379 ) (1,605 ) — 75,984 — Depreciation, depletion and amortization — 383,992 254 — 384,246 Impairment — 6,021 — — 6,021 Deferred income taxes (44,923 ) 44,453 — — (470 ) Derivative instruments — (52,297 ) — — (52,297 ) Equity-based compensation expenses 19,740 711 — — 20,451 Deferred financing costs amortization and other 11,399 1,260 7 — 12,666 Working capital and other changes: Change in accounts receivable 115,996 (87,610 ) (5,630 ) (103,778 ) (81,022 ) Change in inventory — (235 ) — — (235 ) Change in prepaid expenses (190 ) 1,013 — — 823 Change in other current assets — 276 — — 276 Change in long-term inventory and other assets — (12,843 ) — — (12,843 ) Change in accounts payable, interest payable and accrued liabilities (12,571 ) (62,542 ) 3,617 103,778 32,282 Change in other current liabilities — (10,490 ) — — (10,490 ) Net cash provided by operating activities 14,251 284,633 (147 ) — 298,737 Cash flows from investing activities: Capital expenditures — (443,649 ) — — (443,649 ) Proceeds from sale of properties — 4,000 — — 4,000 Derivative settlements — (804 ) — — (804 ) Advances from joint interest partners — (2,502 ) — — (2,502 ) Net cash used in investing activities — (442,955 ) — — (442,955 ) Cash flows from financing activities: Proceeds from Oasis Credit Facility — 764,000 — — 764,000 Principal payments on Oasis Credit Facility — (732,000 ) — — (732,000 ) Deferred financing costs — 1,858 (1,954 ) — (96 ) Proceeds from issuance of Oasis Midstream common units, net of offering costs — — 115,813 — 115,813 Purchases of treasury stock (6,182 ) — — — (6,182 ) Investment in subsidiaries / capital contributions from parent (8,002 ) 121,714 (113,712 ) — — Other (55 ) — — — (55 ) Net cash provided by (used in) financing activities (14,239 ) 155,572 147 — 141,480 Increase (decrease) in cash and cash equivalents 12 (2,750 ) — — (2,738 ) Cash and cash equivalents at beginning of period 166 11,060 — — 11,226 Cash and cash equivalents at end of period $ 178 $ 8,310 $ — $ — $ 8,488

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenues	$ 546,448	$ 304,748	$ 1,469,001	$ 843,955
Performance obligation satisfaction period			The majority of the Company’s sales are short-term in nature with a contract term of one year or less. For those contracts, the Company utilized the practical expedient in ASC 606-10-50-14 that exempts the Company from disclosure of the transaction price allocated to remaining performance obligations if the performance obligation is part of a contract that has an original expected duration of one year or less. For the Company’s product sales that have a contract term greater than one year, the Company utilized the practical expedient in ASC 606-10-50-14(A) which states the Company is not required to disclose the transaction price allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. Under these sales contracts, each unit of product generally represents a separate performance obligation; therefore future volumes are wholly unsatisfied and disclosure of the transaction price allocated to remaining performance obligations is not required. Under the midstream services contracts, each unit of service represents a separate performance obligation and therefore performance obligations in respect of future services are wholly unsatisfied.
Exploration and Production [Member]
Disaggregation of Revenue [Line Items]
Total revenues	497,161	269,843	$ 1,328,994	761,450
Exploration and Production [Member] | Oil Production [Member]
Disaggregation of Revenue [Line Items]
Total revenues	412,530	221,003	1,097,171	623,603
Exploration and Production [Member] | Purchased Oil Sales [Member]
Disaggregation of Revenue [Line Items]
Total revenues	42,902	20,734	114,598	56,269
Exploration and Production [Member] | Natural Gas, Production [Member]
Disaggregation of Revenue [Line Items]
Total revenues	26,181	17,037	76,201	51,689
Exploration and Production [Member] | Purchased Gas Sales [Member]
Disaggregation of Revenue [Line Items]
Total revenues	1,616	462	2,161	648
Exploration and Production [Member] | Natural Gas Liquid Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	13,932	10,607	38,863	29,241
Midstream Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	75,770	47,660	212,758	125,613
Well Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	56,439	47,163	161,242	101,594
Operating Segments [Member] | Exploration and Production [Member]
Disaggregation of Revenue [Line Items]
Total revenues	497,161	269,843	1,328,994	761,450
Operating Segments [Member] | Midstream Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	33,025	18,767	93,663	48,939
Operating Segments [Member] | Midstream Services [Member] | Purchased Oil Sales [Member]
Disaggregation of Revenue [Line Items]
Total revenues	1,838	0	5,212	0
Operating Segments [Member] | Midstream Services [Member] | Crude Oil and Natural Gas Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	18,188	11,612	54,124	23,348
Operating Segments [Member] | Midstream Services [Member] | Water Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	12,999	7,155	34,327	25,591
Operating Segments [Member] | Well Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	16,262	16,138	46,344	33,566
Operating Segments [Member] | Well Services [Member] | Hydraulic Fracturing Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	14,985	15,090	42,801	31,303
Operating Segments [Member] | Well Services [Member] | Equipment Rental Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 1,277	$ 1,048	$ 3,543	$ 2,263

Inventory- Schedule of Inventor

Inventory- Schedule of Inventory (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory
Crude oil inventory	$ 14,867	$ 10,427
Equipment and materials	16,542	8,940
Total inventory	31,409	19,367
Long-term inventory
Linefill in third-party pipelines	12,610	12,200
Long-term inventory	12,610	12,200
Total	$ 44,019	$ 31,567

Accounts Receivable, Net (Detai

Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	$ 429,130	$ 365,153
Allowance for Doubtful Accounts Receivable, Current	(946)	(1,573)
Accounts Receivable, Net, Current	428,184	363,580
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	277,558	233,660
Joint Interest Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	94,793	73,588
Other Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	$ 56,779	$ 57,905

Fair Value Measurements - Hiera

Fair Value Measurements - Hierarchy of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Total assets	$ 143	$ 495
Liabilities:
Total liabilities	213,146	135,567
Money market funds [Member]
Assets:
Total assets	143	142
Commodity derivative instruments [Member]
Assets:
Total assets		353
Liabilities:
Total liabilities	213,146	135,567
Level 1 [Member]
Assets:
Total assets	143	142
Liabilities:
Total liabilities	0	0
Level 1 [Member] | Money market funds [Member]
Assets:
Total assets	143	142
Level 1 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets		0
Liabilities:
Total liabilities	0	0
Level 2 [Member]
Assets:
Total assets	0	353
Liabilities:
Total liabilities	213,146	135,567
Level 2 [Member] | Money market funds [Member]
Assets:
Total assets	0	0
Level 2 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets		353
Liabilities:
Total liabilities	213,146	135,567
Level 3 [Member]
Assets:
Total assets	0	0
Liabilities:
Total liabilities	0	0
Level 3 [Member] | Money market funds [Member]
Assets:
Total assets	0	0
Level 3 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets		0
Liabilities:
Total liabilities	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Derivative credit risk valuation adjustment, derivative liabilities	$ 2.7	$ 2.8

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Outstanding Commodity Derivative Instruments (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Oct. 31, 2018MMBTU$ / bbl$ / MMBTUbbl	Sep. 30, 2018USD ($)MMBTU$ / bbl$ / MMBTUbbl
Derivative [Line Items]
Fair value asset | $		$ (213,146)
Crude Oil [Member] | 2018 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		3,761,000
Average swap price (in dollars per barrel)		52.95
Fair value asset | $		$ (71,621)
Crude Oil [Member] | 2018 Basis Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		152,000
Average swap price (in dollars per barrel)		9.84
Fair value asset | $		$ 81
Crude Oil [Member] | 2018 Two-way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		517,000
Average floor price (in dollars per barrel)		58.74
Average ceiling price (in dollars per barrel)		63.94
Fair value asset | $		$ (5,171)
Crude Oil [Member] | 2019 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		5,613,000
Average swap price (in dollars per barrel)		53.33
Fair value asset | $		$ (99,347)
Crude Oil [Member] | 2019 Basis Swaps [Member] [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		424,000
Average swap price (in dollars per barrel)		9.68
Fair value asset | $		$ 408
Crude Oil [Member] | 2019 Two-way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		3,223,000
Average floor price (in dollars per barrel)		57.99
Average ceiling price (in dollars per barrel)		75.46
Fair value asset | $		$ (7,580)
Crude Oil [Member] | 2019 Three-way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		3,368,000
Average sub-floor price (in dollars per barrel)		40.54
Average floor price (in dollars per barrel)		51.03
Average ceiling price (in dollars per barrel)		68.68
Fair value asset | $		$ (21,771)
Crude Oil [Member] | 2020 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		403,000
Average swap price (in dollars per barrel)		53.47
Fair value asset | $		$ (5,911)
Crude Oil [Member] | 2020 Two-way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		279,000
Average floor price (in dollars per barrel)		57.78
Average ceiling price (in dollars per barrel)		76.13
Fair value asset | $		$ (273)
Crude Oil [Member] | 2020 Three-way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl		279,000
Average sub-floor price (in dollars per barrel)		40
Average floor price (in dollars per barrel)		50.56
Average ceiling price (in dollars per barrel)		67.80
Fair value asset | $		$ (1,778)
Natural Gas [Member] | 2018 Swaps [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU		3,496,000
Average swap price (in dollars per barrel) | $ / MMBTU		3.01
Fair value asset | $		$ (104)
Natural Gas [Member] | 2018 Basis Swaps [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU		1,225,000
Average swap price (in dollars per barrel)		0.05
Fair value asset | $		$ (64)
Natural Gas [Member] | 2019 Swaps [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU		1,896,000
Average swap price (in dollars per barrel) | $ / MMBTU		2.95
Fair value asset | $		$ 16
Natural Gas [Member] | 2019 Basis Swaps [Member] [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU		2,715,000
Average swap price (in dollars per barrel)		0.05
Fair value asset | $		$ (31)
Subsequent Event [Member] | Crude Oil [Member]
Derivative [Line Items]
Average floor price (in dollars per barrel)	64.05
Addition (reduction) in weighted average differential prices	(7.50)
Subsequent Event [Member] | Crude Oil [Member] | 2018 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl	213,000
Subsequent Event [Member] | Crude Oil [Member] | 2018 Basis Swaps [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	60,000
Subsequent Event [Member] | Crude Oil [Member] | 2019 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl	792,000
Subsequent Event [Member] | Crude Oil [Member] | 2019 Basis Swaps [Member] [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	424,000
Subsequent Event [Member] | Crude Oil [Member] | 2020 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in Bbls) | bbl	62,000
Subsequent Event [Member] | Natural Gas [Member]
Derivative [Line Items]
Average floor price (in dollars per barrel) | $ / MMBTU	2.88
Addition (reduction) in weighted average differential prices | $ / MMBTU	0.13
Subsequent Event [Member] | Natural Gas [Member] | 2018 Basis Swaps [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	610,000
Subsequent Event [Member] | Natural Gas [Member] | 2018 Two-way Collars [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	305,000
Subsequent Event [Member] | Natural Gas [Member] | 2019 Basis Swaps [Member] [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	1,810,000
Subsequent Event [Member] | Natural Gas [Member] | 2019 Two-way Collars [Member]
Derivative [Line Items]
Total notional amount of natural gas (in MMBtu) | MMBTU	1,825,000

Derivative Instruments - Realiz

Derivative Instruments - Realized and Unrealized Gains and Losses from Commodity Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net gain (loss) on derivative instruments	$ (48,544)	$ (54,310)	$ (239,945)	$ 52,297

Derivative Instruments - Sche_2

Derivative Instruments - Schedule of Location and Fair Value of Outstanding Commodity Derivative Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative asset, gross amounts recognized		$ 353
Derivative liability, gross amount recognized	$ 221,838	137,664
Derivative asset, gross amounts offset		0
Derivative liability, gross amounts offset	(8,692)	(2,097)
Derivative asset, net asset		353
Derivative liability, net liability	213,146	135,567
Commodity derivative instruments [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, gross amounts recognized		344
Derivative asset, gross amounts offset		0
Derivative asset, net asset		344
Commodity derivative instruments [Member] | Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, gross amounts recognized		9
Derivative asset, gross amounts offset		0
Derivative asset, net asset		9
Commodity derivative instruments [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	184,832	117,629
Derivative liability, gross amounts offset	(4,703)	(1,913)
Derivative liability, net liability	180,129	115,716
Commodity derivative instruments [Member] | Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	37,006	20,035
Derivative liability, gross amounts offset	(3,989)	(184)
Derivative liability, net liability	$ 33,017	$ 19,851

Property, Plant and Equipment -

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Proved oil and gas properties	$ 7,566,694	$ 7,058,782
Less: Accumulated depreciation, depletion, amortization and impairment	(2,689,613)	(2,395,153)
Proved oil and gas properties, net	4,877,081	4,663,629
Unproved oil and gas properties	1,104,450	780,173
Other property and equipment	1,088,781	868,746
Less: Accumulated depreciation	(170,175)	(139,062)
Other property and equipment, net	918,606	729,684
Total property, plant and equipment, net	$ 6,900,137	$ 6,173,486

Property, Plant and Equipment P

Property, Plant and Equipment Property, Plant and Equipment - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Proved Oil And Gas Properties [Member]
Business Acquisition [Line Items]
Estimate of future asset retirement costs	$ 41.4	$ 39.9

Acquisition - Additional Inform

Acquisition - Additional Information (Details) a in Thousands, $ in Thousands	Sep. 12, 2018USD ($)	Feb. 14, 2018USD ($)ashares	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Permian Basin Acquisition [Member]
Business Acquisition [Line Items]
Net acres acquired | a		22
Cash		$ 549,770
Aggregate consideration paid in shares (shares) | shares		46,000,000
Consideration paid to Forge Energy		$ 920,990
Actual total revenue of acquiree included in condensed financials			$ 19,400	$ 51,000
Actual operating income of acquiree included in condensed financials			3,900	14,200
Finite lived intangible asset		$ 1,000
Other Delaware Acquisition [Member]
Business Acquisition [Line Items]
Consideration paid to Forge Energy	$ 59,500
Noncompete Agreements [Member] | Permian Basin Acquisition [Member]
Business Acquisition [Line Items]
Useful life of acquired intangible asset		1 year
Amortization of Intangible Assets			$ 300	$ 600

Acquisition - Price Allocation

Acquisition - Price Allocation (Details) - USD ($) $ in Thousands	Feb. 14, 2018	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Common stock: 46,000,000 shares issued		$ 371,220	$ 0
Permian Basin Acquisition [Member]
Business Acquisition [Line Items]
Cash	$ 549,770
Common stock: 46,000,000 shares issued	$ 371,220
Common stock shares issued (shares)	46,000,000
Consideration paid to Forge Energy:	$ 920,990
Proved developed properties	110,325
Proved undeveloped properties	166,552
Unproved lease acquisition costs	645,068
Inventory	293
Intangible assets	1,000
Asset retirement obligations	$ (2,248)

Acquisition - Pro-Forma Informa

Acquisition - Pro-Forma Information (Details) - Permian Basin Acquisition [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Revenues	$ 546,449	$ 318,879	$ 1,474,530	$ 871,952
Net income (loss) attributable to Oasis	$ 62,341	$ (29,717)	$ (252,731)	$ 22,068
Basic (in usd per share)	$ 0.20	$ (0.11)	$ (0.81)	$ 0.08
Diluted (in usd per share)	$ 0.20	$ (0.11)	$ (0.81)	$ 0.08

Divestitures (Details)

Divestitures (Details) - Held for Sale [Member] - USD ($) $ in Millions	Aug. 17, 2018	Jul. 31, 2018	Jul. 10, 2018	Jun. 30, 2018
Williston Non-Op Divestiture [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain (loss) on sale of properties			$ 27.5
Foreman Butte Divestiture [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain (loss) on sale of properties		$ (10.1)
Impairment loss recorded				$ 383.4
Other WIlliston Divestiture [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain (loss) on sale of properties	$ 19.4

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2018	May 25, 2018	Dec. 31, 2017	Sep. 30, 2016
Debt Instrument [Line Items]
Total long-term debt	$ 2,633,009		$ 2,097,606
Line of Credit [Member] | Revolving Credit Facility [Member] | Senior Secured Revolving Line of Credit [Member]
Debt Instrument [Line Items]
Total principal of senior unsecured notes and revolving line of credit	522,000		70,000
Line of Credit [Member] | Revolving Credit Facility [Member] | OMP Revolving Line of Credit [Member]
Debt Instrument [Line Items]
Total principal of senior unsecured notes and revolving line of credit	166,000		78,000
Senior Notes [Member]
Debt Instrument [Line Items]
Total principal of senior unsecured notes and revolving line of credit	2,039,409		2,052,950
Less: unamortized deferred financing costs on senior unsecured notes	$ (22,212)		(22,956)
Senior Notes [Member] | 7.25% senior unsecured notes due February 1, 2019 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	7.25%	7.25%
Total principal of senior unsecured notes and revolving line of credit	$ 0		54,275
Senior Notes [Member] | 6.50% senior unsecured notes due November 1, 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.50%	6.50%
Total principal of senior unsecured notes and revolving line of credit	$ 71,835		395,501
Senior Notes [Member] | 6.875% senior unsecured notes due March 15, 2022 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.875%	6.875%
Total principal of senior unsecured notes and revolving line of credit	$ 901,480		937,080
Senior Notes [Member] | 6.875% senior unsecured notes due January 15, 2023 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.875%
Total principal of senior unsecured notes and revolving line of credit	$ 366,094		366,094
Senior Notes [Member] | 6.25% senior unsecured notes due May 1, 2026 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.25%
Total principal of senior unsecured notes and revolving line of credit	$ 400,000		0
Senior Notes [Member] | 2.625% senior convertible notes due September 15, 2023 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	2.625%
Total principal of senior unsecured notes and revolving line of credit	$ 300,000		300,000
Less: unamortized debt discount on senior unsecured convertible notes	$ (72,188)		$ (80,388)	$ (93,200)

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details)	May 29, 2018USD ($)	May 14, 2018USD ($)	Sep. 30, 2018USD ($)$ / shares	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)day$ / shares	Sep. 30, 2017USD ($)	Oct. 16, 2018USD ($)	Jun. 30, 2018USD ($)	May 25, 2018USD ($)	Apr. 19, 2018USD ($)	Feb. 26, 2018USD ($)	Dec. 31, 2017USD ($)	Apr. 10, 2017USD ($)	Sep. 30, 2016USD ($)
Debt Instrument [Line Items]
Total long-term debt			$ 2,633,009,000		$ 2,633,009,000							$ 2,097,606,000
Payment to redeem outstanding notes					423,190,000	$ 0
Loss on extinguishment of debt			(47,000)	$ 0	(13,698,000)	$ 0
Write-off of deferred financing costs					$ 4,000,000
Ownership percentage, guarantors (as percent)					100.00%
Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, fair value			2,172,300,000		$ 2,172,300,000
Amended Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, remaining borrowing capacity			814,000,000		814,000,000
Swingline Loan [Member] | The Credit Agreement [Member]
Debt Instrument [Line Items]
Credit facility borrowing base			10,000,000		10,000,000
Line of Credit [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding			14,000,000		14,000,000
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility amount			$ 2,500,000,000		$ 2,500,000,000
Credit facility borrowing base										$ 1,600,000,000
Line of credit facility, current borrowing capacity										$ 1,350,000,000	$ 1,350,000,000		$ 1,150,000,000
Weighted average interest rate (as percent)			4.00%		4.00%
Line of Credit [Member] | Revolving Credit Facility [Member] | Senior Secured Revolving Line of Credit [Member]
Debt Instrument [Line Items]
Long-term debt, gross			$ 522,000,000		$ 522,000,000							70,000,000
Weighted average interest rate (as percent)			3.90%		3.90%
Line of Credit [Member] | Revolving Credit Facility [Member] | OMP Revolving Line of Credit [Member]
Debt Instrument [Line Items]
Long-term debt, gross			$ 166,000,000		$ 166,000,000							78,000,000
Credit facility borrowing base			250,000,000		250,000,000			$ 200,000,000
Senior Notes [Member]
Debt Instrument [Line Items]
Debt issuance costs			22,212,000		22,212,000							22,956,000
Long-term debt, gross			2,039,409,000		2,039,409,000							2,052,950,000
Aggregate principal amount repurchased									$ 390,600,000
Debt Instrument, Repurchase Amount									$ 402,000,000
Senior Notes [Member] | Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Total long-term debt			2,039,400,000		2,039,400,000
Senior Notes [Member] | 2026 Notes [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)		6.25%
Net proceeds from debt issuance		$ 394,400,000
Debt issued		$ 400,000,000
Senior Notes [Member] | Notes [Member]
Debt Instrument [Line Items]
Unsecured debt			$ 1,739,400,000		$ 1,739,400,000
Senior Notes [Member] | Notes [Member] | Minimum [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)			6.25%		6.25%
Senior Notes [Member] | Notes [Member] | Maximum [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)			6.875%		6.875%
Senior Notes [Member] | 7.25% senior unsecured notes due February 1, 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, gross			$ 0		$ 0							54,275,000
Stated interest rate (as percent)			7.25%		7.25%				7.25%
Debt issued									$ 31,300,000
Payment to redeem outstanding notes	$ 23,000,000
Debt redemption price (percent)	100.00%
Senior Notes [Member] | 6.50% senior unsecured notes due November 1, 2021 [Member]
Debt Instrument [Line Items]
Long-term debt, gross			$ 71,835,000		$ 71,835,000							395,501,000
Stated interest rate (as percent)			6.50%		6.50%				6.50%
Debt issued									$ 323,700,000
Senior Notes [Member] | 6.875% senior unsecured notes due March 15, 2022 [Member]
Debt Instrument [Line Items]
Long-term debt, gross			$ 901,480,000		$ 901,480,000							937,080,000
Stated interest rate (as percent)			6.875%		6.875%				6.875%
Debt issued									$ 35,600,000
Senior Notes [Member] | 6.875% senior unsecured notes due January 15, 2023 [Member]
Debt Instrument [Line Items]
Long-term debt, gross			$ 366,094,000		$ 366,094,000							366,094,000
Stated interest rate (as percent)			6.875%		6.875%
Senior Notes [Member] | 2.625% senior convertible notes due September 15, 2023 [Member]
Debt Instrument [Line Items]
Debt discount			$ 72,188,000		$ 72,188,000							80,388,000		$ 93,200,000
Long-term debt, gross			$ 300,000,000		$ 300,000,000							$ 300,000,000
Stated interest rate (as percent)			2.625%		2.625%
Debt issued			$ 300,000,000		$ 300,000,000
Debt conversion rate per $1000 principal (in shares per $1000)					0.0763650
Debt conversion price (in dollars per share) | $ / shares			$ 13.10		$ 13.10
Debt instrument effective interest rate (percent)														8.97%
Estimated fair value of debt														$ 206,800,000
Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Commitment fee percentage			0.375%
Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Commitment fee percentage			0.50%
Debt Conversion Scenario 1 [Member] | Senior Notes [Member] | 2.625% senior convertible notes due September 15, 2023 [Member]
Debt Instrument [Line Items]
Number of trading days | day					20
Number of consecutive trading days | day					30
Stock price relative to conversion price (percent)					130.00%
Debt Conversion Scenario 2 [Member] | Senior Notes [Member] | 2.625% senior convertible notes due September 15, 2023 [Member]
Debt Instrument [Line Items]
Number of trading days | day					5
Number of consecutive trading days | day					5
Stock price relative to product of sale price and conversion rate (percent)					98.00%
OMP Operating, LLC [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Credit facility borrowing base			$ 10,000,000		$ 10,000,000
OMP Operating, LLC [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity subject to certain conditions			$ 400,000,000		$ 400,000,000
OMP Operating, LLC [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Commitment fee percentage					0.375%
OMP Operating, LLC [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Commitment fee percentage					0.50%
OMP Operating, LLC [Member] | ABR Loans [Member] | Revolving Credit Facility [Member] | Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Spread on variable rate					0.50%
OMP Operating, LLC [Member] | ABR Loans [Member] | Revolving Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Spread on variable rate					1.00%
OMP Operating, LLC [Member] | Eurodollar Loans [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on variable rate					1.75%
OMP Operating, LLC [Member] | Eurodollar Loans [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on variable rate					2.75%
OMP Operating, LLC [Member] | ABR Loans or Swingline Loans [Member] | Revolving Credit Facility [Member] | Federal Funds Effective Swap Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on variable rate					0.75%
OMP Operating, LLC [Member] | ABR Loans or Swingline Loans [Member] | Revolving Credit Facility [Member] | Federal Funds Effective Swap Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on variable rate					1.75%
OMP Operating, LLC [Member] | ABR Loans or Swingline Loans [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on variable rate					0.75%
OMP Operating, LLC [Member] | ABR Loans or Swingline Loans [Member] | Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread on variable rate					1.75%
Subsequent Event [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility amount							$ 3,000,000,000

Asset Retirement Obligations -

Asset Retirement Obligations - Schedule of Changes in Asset Retirement Obligations (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
December 31, 2017	$ 48,799
Liabilities incurred during period	5,509
Liabilities settled during period	(4,904)
Accretion expense during period	1,975
Liabilities held for sale	83
September 30, 2018	$ 51,462

Asset Retirement Obligations _2

Asset Retirement Obligations - Additional Information (Details) $ in Millions	Sep. 30, 2018USD ($)
Asset Retirement Obligation Disclosure [Abstract]
Total asset retirement obligations, current portion	$ 0.1

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate (as percent)	27.20%	31.50%	23.40%	41.20%
Valuation allowance on carryforwards	$ 3.3		$ 3.3		$ 1.2
Increase in valuation allowance			$ 2.1
Deferred tax asset written off	$ 1.9

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Details) $ / shares in Units, $ in Thousands	Oct. 19, 2017	Sep. 25, 2017$ / shares	Sep. 30, 2018shares	Sep. 30, 2018USD ($)shares	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)day$ / sharesshares	Sep. 30, 2017USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expenses | $						$ 21,586	$ 20,451
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period						3 years
Stock granted (in shares) | shares						3,511,030
Granted, weighted average grant date fair value per unit (in usd per share) | $ / shares						$ 10.17
Equity-based compensation expenses | $				$ 5,100	$ 4,900	$ 14,700	15,200
Performance Share Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted (in shares) | shares						854,400
Granted, weighted average grant date fair value per unit (in usd per share) | $ / shares						$ 12.71
Equity-based compensation expenses | $				$ 2,200	$ 1,600	$ 6,300	$ 5,100
Right to received shares of common stock (in shares) | shares			1	1		1
Number of trading days | day						30
Performance Share Unit Awards [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU granted percentage of earnings (as a percent)						0.00%
Performance Share Unit Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSU granted percentage of earnings (as a percent)						200.00%
Oasis Midstream Partners, LP [Member] | Phantom Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted (in shares) | shares						87,480
Equity-based compensation expenses | $				$ 200		$ 400
Vesting period	3 years
OMP General Partner LLC [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted (in shares) | shares			17,260
Granted, weighted average grant date fair value per unit (in usd per share) | $ / shares		$ 17.55
Equity-based compensation expenses | $				$ 100		$ 300
Vesting period		1 year

Equity-Based Compensation - Sum

Equity-Based Compensation - Summary of Assumptions (Details) - Performance Share Units [Member] - $ / shares	9 Months Ended
	Sep. 30, 2018	Jan. 24, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Oasis stock price volatility (as percent)	72.88%
Oasis initial value (usd per share)	$ 8.82
Oasis stock price on date of grant (usd per share)		$ 9.27
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate (as percent)	2.08%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate (as percent)	2.31%

Earnings (Loss) Per Share - Sch

Earnings (Loss) Per Share - Schedule of Weighted-Average Number of Shares Outstanding (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Basic weighted average common shares outstanding (in shares)	313,167	233,389	305,533	233,248
Diluted weighted average common shares outstanding (in shares)	316,387	233,389	305,533	233,248
Stock Awards and PSUs [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Dilution effect of stock awards at end of period (in shares)	3,220	0	0	0

Earnings (Loss) Per Share - S_2

Earnings (Loss) Per Share - Schedule of Common Shares Excluded from Diluted Earnings (Loss) per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive stock-based compensation awards (in shares)	4,180,000	5,841,000	7,284,000	5,988,000
Unvested Stock Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive stock-based compensation awards (in shares)		0	0

Business Segment Information -

Business Segment Information - Additional Information (Details)	9 Months Ended
	Sep. 30, 2018Segment
Segment Reporting [Abstract]
Number of current operating units	3

Business Segment Information _2

Business Segment Information - Summarized Financial Information of Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues from non-affiliates	$ 546,448	$ 304,748	$ 1,469,001	$ 843,955
Operating income	179,045	32,394	49,356	57,865
Other income (expense)	(88,040)	(92,304)	(371,113)	(59,006)
Income (loss) before income taxes	91,005	(59,910)	(321,757)	(1,141)
Property, plant and equipment, net	6,900,137		6,900,137		$ 6,173,486
Total assets	7,416,431		7,416,431		6,615,130
Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	497,161	269,843	1,328,994	761,450
Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	75,770	47,660	212,758	125,613
Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	56,439	47,163	161,242	101,594
Operating Segments [Member] | Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	497,161	269,843	1,328,994	761,450
Operating income	146,969	3,484	(53,159)	(12,972)
Other income (expense)	(87,594)	(92,319)	(370,311)	(59,027)
Income (loss) before income taxes	59,375	(88,835)	(423,470)	(71,999)
Property, plant and equipment, net	6,227,767		6,227,767		5,663,323
Total assets	6,675,626		6,675,626		6,050,255
Operating Segments [Member] | Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	33,025	18,767	93,663	48,939
Operating income	31,326	25,194	101,457	69,059
Other income (expense)	(367)	(15)	(703)	(13)
Income (loss) before income taxes	30,959	25,179	100,754	69,046
Property, plant and equipment, net	841,797		841,797		649,923
Total assets	867,226		867,226		663,614
Operating Segments [Member] | Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	16,262	16,138	46,344	33,566
Operating income	9,237	10,802	25,415	9,161
Other income (expense)	(79)	30	(99)	34
Income (loss) before income taxes	9,158	10,832	25,316	9,195
Property, plant and equipment, net	41,468		41,468		46,779
Total assets	49,285		49,285		52,800
Segment Reconciling Items [Member] | Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	0	0	0	0
Segment Reconciling Items [Member] | Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	42,745	28,893	119,095	76,674
Segment Reconciling Items [Member] | Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	40,177	31,025	114,898	68,028
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	(82,922)	(59,918)	(233,993)	(144,702)
Operating income	(8,487)	(7,086)	(24,357)	(7,383)
Other income (expense)	0	0	0	0
Income (loss) before income taxes	(8,487)	$ (7,086)	(24,357)	$ (7,383)
Property, plant and equipment, net	(210,895)		(210,895)		(186,539)
Total assets	$ (175,706)		$ (175,706)		$ (151,539)

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) bbl in Millions, Mcf in Millions	Mar. 23, 2017USD ($)	Nov. 06, 2018USD ($)bblMcf	Sep. 30, 2018USD ($)bblMcf
Loss Contingencies [Line Items]
Estimable future commitments under agreements | $			$ 550,500,000
Mirada Litigation [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Damages sought (in excess of) | $	$ 100,000,000
Crude Oil [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported			50.9
Natural Gas Liquids [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported			43.5
Natural Gas [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported | Mcf			901.3
Produced Water [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported			30.8
Subsequent Event [Member]
Loss Contingencies [Line Items]
Estimable future commitments under agreements | $		$ 650,200,000
Subsequent Event [Member] | Crude Oil [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported		50.9
Subsequent Event [Member] | Natural Gas Liquids [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported		43.5
Subsequent Event [Member] | Natural Gas [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported | Mcf		901.3
Subsequent Event [Member] | Produced Water [Member]
Loss Contingencies [Line Items]
Minimum quantity to be delivered or transported		30.8

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information - Additional Information (Details)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Ownership percentage, guarantors (as percent)	100.00%

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 16,892	$ 16,720	$ 8,488	$ 11,226
Accounts receivable, net	428,184	363,580
Accounts receivable - affiliates	0	0
Inventory	31,409	19,367
Prepaid expenses	6,444	7,631
Derivative instruments	0	344
Intangible assets, net	375	0
Other current assets	192	193
Total current assets	483,496	407,835
Property, plant and equipment
Oil and gas properties (successful efforts method)	8,671,144	7,838,955
Other property and equipment	1,088,781	868,746
Less: accumulated depreciation, depletion, amortization and impairment	(2,859,788)	(2,534,215)
Total property, plant and equipment, net	6,900,137	6,173,486
Investments in and advances to subsidiaries	0	0
Derivative instruments	0	9
Deferred income taxes	0	0
Long-term inventory	12,610	12,200
Other assets	20,188	21,600
Total assets	7,416,431	6,615,130
Current liabilities
Accounts payable	17,206	13,370
Accounts payable - affiliates	0	0
Revenues and production taxes payable	287,333	213,995
Accrued liabilities	307,526	236,480
Accrued interest payable	20,574	38,963
Derivative instruments	180,129	115,716
Advances from joint interest partners	3,878	4,916
Other current liabilities	40	40
Total current liabilities	816,686	623,480
Long-term debt	2,633,009	2,097,606
Deferred income taxes	230,504	305,921
Asset retirement obligations	51,357	48,511
Derivative instruments	33,017	19,851
Other liabilities	7,775	6,182
Total liabilities	3,772,348	3,101,551
Stockholders’ equity
Capital contributions from affiliates	0	0
Common stock, $0.01 par value: 450,000,000 shares authorized; 320,010,501 shares issued and 317,987,427 shares outstanding at June 30, 2018 and 270,627,014 shares issued and 269,295,466 shares outstanding at December 31, 2017	3,157	2,668
Treasury stock, at cost: 2,023,074 and 1,331,548 shares at June 30, 2018 and December 31, 2017, respectively	(28,985)	(22,179)
Additional paid-in capital	3,070,642	2,677,217
Retained earnings	460,712	717,985
Oasis share of stockholders’ equity	3,505,526	3,375,691
Non-controlling interests	138,557	137,888
Total stockholders’ equity	3,644,083	3,513,579
Total liabilities and stockholders’ equity	7,416,431	6,615,130
Intercompany Eliminations [Member]
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Accounts receivable - affiliates	(792,304)	(557,506)
Inventory	0	0
Prepaid expenses	0	0
Derivative instruments		0
Intangible assets, net	0
Other current assets	0	0
Total current assets	(792,304)	(557,506)
Property, plant and equipment
Oil and gas properties (successful efforts method)	(8,518)	(1,966)
Other property and equipment	(10)	0
Less: accumulated depreciation, depletion, amortization and impairment	0	0
Total property, plant and equipment, net	(8,528)	(1,966)
Investments in and advances to subsidiaries	(5,169,948)	(5,213,108)
Derivative instruments		0
Deferred income taxes	(209,919)	(183,568)
Long-term inventory	0	0
Other assets	0	0
Total assets	(6,180,699)	(5,956,148)
Current liabilities
Accounts payable	0	0
Accounts payable - affiliates	(792,304)	(557,506)
Revenues and production taxes payable	0	0
Accrued liabilities	0	0
Accrued interest payable	0	0
Derivative instruments	0	0
Advances from joint interest partners	0	0
Other current liabilities	0	0
Total current liabilities	(792,304)	(557,506)
Long-term debt	0	0
Deferred income taxes	(209,919)	(183,568)
Asset retirement obligations	0	0
Derivative instruments	0	0
Other liabilities	0	0
Total liabilities	(1,002,223)	(741,074)
Stockholders’ equity
Capital contributions from affiliates	(3,473,795)	(3,499,626)
Common stock, $0.01 par value: 450,000,000 shares authorized; 320,010,501 shares issued and 317,987,427 shares outstanding at June 30, 2018 and 270,627,014 shares issued and 269,295,466 shares outstanding at December 31, 2017	0	0
Treasury stock, at cost: 2,023,074 and 1,331,548 shares at June 30, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	(9,141)	(8,922)
Retained earnings	(1,289,406)	(1,393,080)
Oasis share of stockholders’ equity	(4,772,342)	(4,901,628)
Non-controlling interests	(406,134)	(313,446)
Total stockholders’ equity	(5,178,476)	(5,215,074)
Total liabilities and stockholders’ equity	(6,180,699)	(5,956,148)
Non-Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents	4,990	883	0	0
Accounts receivable, net	5,054	834
Accounts receivable - affiliates	72,896	85,818
Inventory	0	0
Prepaid expenses	96	778
Derivative instruments		0
Intangible assets, net	0
Other current assets	0	0
Total current assets	83,036	88,313
Property, plant and equipment
Oil and gas properties (successful efforts method)	0	0
Other property and equipment	876,534	653,928
Less: accumulated depreciation, depletion, amortization and impairment	(54,555)	(34,348)
Total property, plant and equipment, net	821,979	619,580
Investments in and advances to subsidiaries	0	0
Derivative instruments		0
Deferred income taxes	0	0
Long-term inventory	0	0
Other assets	1,981	2,013
Total assets	906,996	709,906
Current liabilities
Accounts payable	24	0
Accounts payable - affiliates	24,940	11,638
Revenues and production taxes payable	436	0
Accrued liabilities	59,373	58,818
Accrued interest payable	172	114
Derivative instruments	0	0
Advances from joint interest partners	0	0
Other current liabilities	0	0
Total current liabilities	84,945	70,570
Long-term debt	166,000	78,000
Deferred income taxes	0	0
Asset retirement obligations	1,497	1,316
Derivative instruments	0	0
Other liabilities	0	0
Total liabilities	252,442	149,886
Stockholders’ equity
Capital contributions from affiliates	202,007	234,935
Common stock, $0.01 par value: 450,000,000 shares authorized; 320,010,501 shares issued and 317,987,427 shares outstanding at June 30, 2018 and 270,627,014 shares issued and 269,295,466 shares outstanding at December 31, 2017	0	0
Treasury stock, at cost: 2,023,074 and 1,331,548 shares at June 30, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	0	0
Retained earnings	46,413	11,639
Oasis share of stockholders’ equity	248,420	246,574
Non-controlling interests	406,134	313,446
Total stockholders’ equity	654,554	560,020
Total liabilities and stockholders’ equity	906,996	709,906
Parent/Issuer [Member]
Current assets
Cash and cash equivalents	170	178	178	166
Accounts receivable, net	0	0
Accounts receivable - affiliates	653,255	425,668
Inventory	0	0
Prepaid expenses	617	267
Derivative instruments		0
Intangible assets, net	0
Other current assets	0	0
Total current assets	654,042	426,113
Property, plant and equipment
Oil and gas properties (successful efforts method)	0	0
Other property and equipment	0	0
Less: accumulated depreciation, depletion, amortization and impairment	0	0
Total property, plant and equipment, net	0	0
Investments in and advances to subsidiaries	4,653,951	4,790,976
Derivative instruments		0
Deferred income taxes	209,919	183,568
Long-term inventory	0	0
Other assets	0	0
Total assets	5,517,912	5,400,657
Current liabilities
Accounts payable	0	0
Accounts payable - affiliates	41,213	34,382
Revenues and production taxes payable	0	0
Accrued liabilities	56	216
Accrued interest payable	19,855	38,796
Derivative instruments	0	0
Advances from joint interest partners	0	0
Other current liabilities	0	0
Total current liabilities	61,124	73,394
Long-term debt	1,945,009	1,949,606
Deferred income taxes	0	0
Asset retirement obligations	0	0
Derivative instruments	0	0
Other liabilities	0	0
Total liabilities	2,006,133	2,023,000
Stockholders’ equity
Capital contributions from affiliates	0	0
Common stock, $0.01 par value: 450,000,000 shares authorized; 320,010,501 shares issued and 317,987,427 shares outstanding at June 30, 2018 and 270,627,014 shares issued and 269,295,466 shares outstanding at December 31, 2017	3,157	2,668
Treasury stock, at cost: 2,023,074 and 1,331,548 shares at June 30, 2018 and December 31, 2017, respectively	(28,985)	(22,179)
Additional paid-in capital	3,070,642	2,677,217
Retained earnings	466,965	719,951
Oasis share of stockholders’ equity	3,511,779	3,377,657
Non-controlling interests	0	0
Total stockholders’ equity	3,511,779	3,377,657
Total liabilities and stockholders’ equity	5,517,912	5,400,657
Combined Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents	11,732	15,659	$ 8,310	$ 11,060
Accounts receivable, net	423,130	362,746
Accounts receivable - affiliates	66,153	46,020
Inventory	31,409	19,367
Prepaid expenses	5,731	6,586
Derivative instruments		344
Intangible assets, net	375
Other current assets	192	193
Total current assets	538,722	450,915
Property, plant and equipment
Oil and gas properties (successful efforts method)	8,679,662	7,840,921
Other property and equipment	212,257	214,818
Less: accumulated depreciation, depletion, amortization and impairment	(2,805,233)	(2,499,867)
Total property, plant and equipment, net	6,086,686	5,555,872
Investments in and advances to subsidiaries	515,997	422,132
Derivative instruments		9
Deferred income taxes	0	0
Long-term inventory	12,610	12,200
Other assets	18,207	19,587
Total assets	7,172,222	6,460,715
Current liabilities
Accounts payable	17,182	13,370
Accounts payable - affiliates	726,151	511,486
Revenues and production taxes payable	286,897	213,995
Accrued liabilities	248,097	177,446
Accrued interest payable	547	53
Derivative instruments	180,129	115,716
Advances from joint interest partners	3,878	4,916
Other current liabilities	40	40
Total current liabilities	1,462,921	1,037,022
Long-term debt	522,000	70,000
Deferred income taxes	440,423	489,489
Asset retirement obligations	49,860	47,195
Derivative instruments	33,017	19,851
Other liabilities	7,775	6,182
Total liabilities	2,515,996	1,669,739
Stockholders’ equity
Capital contributions from affiliates	3,271,788	3,264,691
Common stock, $0.01 par value: 450,000,000 shares authorized; 320,010,501 shares issued and 317,987,427 shares outstanding at June 30, 2018 and 270,627,014 shares issued and 269,295,466 shares outstanding at December 31, 2017	0	0
Treasury stock, at cost: 2,023,074 and 1,331,548 shares at June 30, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	9,141	8,922
Retained earnings	1,236,740	1,379,475
Oasis share of stockholders’ equity	4,517,669	4,653,088
Non-controlling interests	138,557	137,888
Total stockholders’ equity	4,656,226	4,790,976
Total liabilities and stockholders’ equity	$ 7,172,222	$ 6,460,715

Condensed Consolidating Finan_5

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet - Additional Information (Details) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	900,000,000	450,000,000
Common stock, shares issued (in shares)	320,507,783	270,627,014
Common stock, shares outstanding (in shares)	318,419,144	269,295,466
Treasury stock, shares (in shares)	2,088,639	1,331,548

Condensed Consolidating Finan_6

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Total revenues	$ 546,448	$ 304,748	$ 1,469,001	$ 843,955
Operating expenses
Lease operating expenses	48,534	45,334	137,456	133,871
Marketing, transportation and gathering expenses	30,713	15,028	74,559	38,018
Production taxes	38,722	21,052	103,748	60,322
Depreciation, depletion and amortization	162,984	132,289	465,819	384,246
Exploration expenses	22,315	854	23,701	4,010
Impairment	0	139	384,228	6,021
General and administrative expenses	34,859	21,368	91,029	67,170
Total operating expenses	404,272	272,354	1,458,468	786,090
Gain on sale of properties	36,869	0	38,823	0
Operating income	179,045	32,394	49,356	57,865
Other income (expense)
Equity In Earnings In Subsidiaries	0	0	0	0
Net gain (loss) on derivative instruments	(48,544)	(54,310)	(239,945)	52,297
Interest expense, net of capitalized interest	(39,560)	(37,389)	(117,616)	(110,548)
Loss on extinguishment of debt	(47)	0	(13,698)	0
Other income (expense)	111	(605)	146	(755)
Total other expense	(88,040)	(92,304)	(371,113)	(59,006)
Income (loss) before income taxes	91,005	(59,910)	(321,757)	(1,141)
Income tax benefit (expense)	(24,782)	18,846	75,391	470
Net loss including non-controlling interests	66,223	(41,064)	(246,366)	(671)
Less: Net income attributable to non-controlling interests	3,882	150	10,907	150
Net income (loss) attributable to Oasis	62,341	(41,214)	(257,273)	(821)
Intercompany Eliminations [Member]
Revenues
Total revenues	(41,045)	0	(113,827)	0
Operating expenses
Lease operating expenses	(14,565)	0	(38,957)	0
Marketing, transportation and gathering expenses	(6,126)	0	(17,605)	0
Production taxes	0	0	0	0
Depreciation, depletion and amortization	(4,048)	0	(11,017)	0
Exploration expenses	0	0	0	0
Impairment		0	0	0
General and administrative expenses	(2,703)	0	(8,940)	0
Total operating expenses	(39,194)	0	(107,574)	0
Gain on sale of properties	0		0
Operating income	(1,851)	0	(6,253)	0
Other income (expense)
Equity In Earnings In Subsidiaries	(135,390)	11,994	41,446	(75,984)
Net gain (loss) on derivative instruments	0	0	0	0
Interest expense, net of capitalized interest	0	0	0	0
Loss on extinguishment of debt	0		0
Other income (expense)	0	0	0	0
Total other expense	(135,390)	11,994	41,446	(75,984)
Income (loss) before income taxes	(137,241)	11,994	35,193	(75,984)
Income tax benefit (expense)	0	0	0	0
Net loss including non-controlling interests	(137,241)	11,994	35,193	(75,984)
Less: Net income attributable to non-controlling interests	(26,459)	(1,112)	(73,075)	(1,112)
Net income (loss) attributable to Oasis	(110,782)	13,106	108,268	(74,872)
Parent/Issuer [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Lease operating expenses	0	0	0	0
Marketing, transportation and gathering expenses	0	0	0	0
Production taxes	0	0	0	0
Depreciation, depletion and amortization	0	0	0	0
Exploration expenses	0	0	0	0
Impairment		0	0	0
General and administrative expenses	7,486	6,775	22,214	21,374
Total operating expenses	7,486	6,775	22,214	21,374
Gain on sale of properties	0		0
Operating income	(7,486)	(6,775)	(22,214)	(21,374)
Other income (expense)
Equity In Earnings In Subsidiaries	96,555	(13,599)	(149,295)	74,379
Net gain (loss) on derivative instruments	0	0	0	0
Interest expense, net of capitalized interest	(32,836)	(32,894)	(98,417)	(98,751)
Loss on extinguishment of debt	(47)		(13,698)
Other income (expense)	0	2	0	2
Total other expense	63,672	(46,491)	(261,410)	(24,370)
Income (loss) before income taxes	56,186	(53,266)	(283,624)	(45,744)
Income tax benefit (expense)	6,155	12,052	26,351	44,923
Net loss including non-controlling interests	62,341	(41,214)	(257,273)	(821)
Less: Net income attributable to non-controlling interests	0	0	0	0
Net income (loss) attributable to Oasis	62,341	(41,214)	(257,273)	(821)
Combined Guarantor Subsidiaries [Member]
Revenues
Total revenues	516,026	301,809	1,383,382	841,016
Operating expenses
Lease operating expenses	63,099	45,334	176,413	133,871
Marketing, transportation and gathering expenses	36,839	15,028	92,164	38,018
Production taxes	38,722	21,052	103,748	60,322
Depreciation, depletion and amortization	159,843	132,035	456,624	383,992
Exploration expenses	22,315	854	23,701	4,010
Impairment		139	384,228	6,021
General and administrative expenses	24,627	14,212	60,259	45,415
Total operating expenses	403,526	264,264	1,452,854	763,401
Gain on sale of properties	36,869		38,823
Operating income	149,369	37,545	(30,649)	77,615
Other income (expense)
Equity In Earnings In Subsidiaries	38,835	1,605	107,849	1,605
Net gain (loss) on derivative instruments	(48,544)	(54,310)	(239,945)	52,297
Interest expense, net of capitalized interest	(6,561)	(4,476)	(18,591)	(11,778)
Loss on extinguishment of debt	0		0
Other income (expense)	126	(607)	161	(757)
Total other expense	(16,144)	(57,788)	(150,526)	41,367
Income (loss) before income taxes	133,225	(20,243)	(181,175)	118,982
Income tax benefit (expense)	(30,937)	6,794	49,040	(44,453)
Net loss including non-controlling interests	102,288	(13,449)	(132,135)	74,529
Less: Net income attributable to non-controlling interests	3,882	150	10,907	150
Net income (loss) attributable to Oasis	98,406	(13,599)	(143,042)	74,379
Non-Guarantor Subsidiaries [Member]
Revenues
Total revenues	71,467	2,939	199,446	2,939
Operating expenses
Lease operating expenses	0	0	0	0
Marketing, transportation and gathering expenses	0	0	0	0
Production taxes	0	0	0	0
Depreciation, depletion and amortization	7,189	254	20,212	254
Exploration expenses	0	0	0	0
Impairment		0	0	0
General and administrative expenses	5,449	381	17,496	381
Total operating expenses	32,454	1,315	90,974	1,315
Gain on sale of properties	0		0
Operating income	39,013	1,624	108,472	1,624
Other income (expense)
Equity In Earnings In Subsidiaries	0	0	0	0
Net gain (loss) on derivative instruments	0	0	0	0
Interest expense, net of capitalized interest	(163)	(19)	(608)	(19)
Loss on extinguishment of debt	0		0
Other income (expense)	(15)	0	(15)	0
Total other expense	(178)	(19)	(623)	(19)
Income (loss) before income taxes	38,835	1,605	107,849	1,605
Income tax benefit (expense)	0	0	0	0
Net loss including non-controlling interests	38,835	1,605	107,849	1,605
Less: Net income attributable to non-controlling interests	26,459	1,112	73,075	1,112
Net income (loss) attributable to Oasis	12,376	493	34,774	493
Oil and Gas [Member]
Revenues
Total revenues	452,643	248,648	1,212,235	704,533
Oil and Gas [Member] | Intercompany Eliminations [Member]
Revenues
Total revenues	0	0	0	0
Oil and Gas [Member] | Parent/Issuer [Member]
Revenues
Total revenues	0	0	0	0
Oil and Gas [Member] | Combined Guarantor Subsidiaries [Member]
Revenues
Total revenues	452,643	248,648	1,212,235	704,533
Oil and Gas [Member] | Non-Guarantor Subsidiaries [Member]
Revenues
Total revenues	0	0	0	0
Purchased Oil and Gas Sales [Member]
Revenues
Total revenues	46,356	21,195	121,971	56,917
Operating expenses
Expenses	46,088	21,701	121,251	57,683
Purchased Oil and Gas Sales [Member] | Intercompany Eliminations [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Expenses	(60)	0	(60)	0
Purchased Oil and Gas Sales [Member] | Parent/Issuer [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Expenses	0	0	0	0
Purchased Oil and Gas Sales [Member] | Combined Guarantor Subsidiaries [Member]
Revenues
Total revenues	46,356	21,195	121,971	56,917
Operating expenses
Expenses	46,148	21,701	121,311	57,683
Purchased Oil and Gas Sales [Member] | Non-Guarantor Subsidiaries [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Expenses	0	0	0	0
Midstream Services [Member]
Revenues
Total revenues	31,187	18,767	88,451	48,939
Operating expenses
Expenses	8,652	4,301	24,325	10,891
Midstream Services [Member] | Intercompany Eliminations [Member]
Revenues
Total revenues	(41,045)	0	(113,827)	0
Operating expenses
Expenses	(11,692)	0	(30,995)	0
Midstream Services [Member] | Parent/Issuer [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Expenses	0	0	0	0
Midstream Services [Member] | Combined Guarantor Subsidiaries [Member]
Revenues
Total revenues	765	15,828	2,832	46,000
Operating expenses
Expenses	528	3,621	2,054	10,211
Midstream Services [Member] | Non-Guarantor Subsidiaries [Member]
Revenues
Total revenues	71,467	2,939	199,446	2,939
Operating expenses
Expenses	19,816	680	53,266	680
Well Services [Member]
Revenues
Total revenues	16,262	16,138	46,344	33,566
Operating expenses
Expenses	11,405	10,288	32,352	23,858
Well Services [Member] | Intercompany Eliminations [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Expenses	0	0	0	0
Well Services [Member] | Parent/Issuer [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Expenses	0	0	0	0
Well Services [Member] | Combined Guarantor Subsidiaries [Member]
Revenues
Total revenues	16,262	16,138	46,344	33,566
Operating expenses
Expenses	11,405	10,288	32,352	23,858
Well Services [Member] | Non-Guarantor Subsidiaries [Member]
Revenues
Total revenues	0	0	0	0
Operating expenses
Expenses	$ 0	$ 0	$ 0	$ 0

Condensed Consolidating Finan_7

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income (loss)	$ 66,223	$ (41,064)	$ (246,366)	$ (671)
Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	0	0	0	0
Depreciation, depletion and amortization	162,984	132,289	465,819	384,246
Loss on extinguishment of debt	47	0	13,698	0
Gain on sale of properties	(36,869)	0	(38,823)	0
Impairment	0	139	384,228	6,021
Deferred income taxes			(75,418)	(470)
Derivative instruments	48,544	54,310	239,945	(52,297)
Equity-based compensation expenses			21,586	20,451
Deferred financing costs amortization and other			20,074	12,666
Working capital and other changes:
Change in accounts receivable			(61,275)	(81,022)
Change in inventory			(12,076)	(235)
Change in prepaid expenses			1,196	823
Change in other current assets			1	276
Change in long-term inventory and other assets			(490)	(12,843)
Change in accounts payable, interest payable and accrued liabilities			50,308	32,282
Change in other current liabilities			0	(10,490)
Change in other liabilities			(406)	0
Net cash provided by operating activities			762,001	298,737
Cash flows from investing activities:
Capital expenditures			(841,088)	(443,649)
Acquisitions			(579,886)	0
Proceeds from sale of properties			333,029	4,000
Costs related to sale of properties			(2,707)	0
Derivative settlements			(162,013)	(804)
Advances from joint interest partners			(1,038)	(2,502)
Net cash used in investing activities			(1,253,703)	(442,955)
Cash flows from financing activities:
Proceeds from Revolving Credit Facilities			2,499,000	764,000
Principal payments on revolving credit facility			(1,959,000)	(732,000)
Repurchase of senior unsecured notes			(423,190)	0
Proceeds from issuance of senior unsecured notes			400,000	0
Deferred financing costs			(7,650)	(96)
Proceeds from issuance of Oasis Midstream common units, net of offering costs			0	115,813
Purchases of treasury stock			(6,806)	(6,182)
Distributions to non-controlling interests			(10,393)	0
Investment in / capital contributions from subsidiaries			0	0
Other			(87)	(55)
Net cash provided by financing activities			491,874	141,480
Increase (decrease) in cash and cash equivalents			172	(2,738)
Beginning of period			16,720	11,226
End of period	16,892	8,488	16,892	8,488
Intercompany Eliminations [Member]
Cash flows from operating activities:
Net income (loss)	(137,241)	11,994	35,193	(75,984)
Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	135,390	(11,994)	(41,446)	75,984
Depreciation, depletion and amortization	(4,048)	0	(11,017)	0
Loss on extinguishment of debt	0		0
Gain on sale of properties	0		0
Impairment		0	0	0
Deferred income taxes			0	0
Derivative instruments	0	0	0	0
Equity-based compensation expenses			0	0
Deferred financing costs amortization and other			0	0
Working capital and other changes:
Change in accounts receivable			234,798	(103,778)
Change in inventory			0	0
Change in prepaid expenses			0	0
Change in other current assets			0	0
Change in long-term inventory and other assets			0	0
Change in accounts payable, interest payable and accrued liabilities			(234,798)	103,778
Change in other current liabilities				0
Change in other liabilities			0
Net cash provided by operating activities			(17,270)	0
Cash flows from investing activities:
Capital expenditures			0	0
Acquisitions			0
Proceeds from sale of properties			0	0
Costs related to sale of properties			0
Derivative settlements			0	0
Advances from joint interest partners			0	0
Net cash used in investing activities			0	0
Cash flows from financing activities:
Proceeds from Revolving Credit Facilities			0	0
Principal payments on revolving credit facility			0	0
Repurchase of senior unsecured notes			0
Proceeds from issuance of senior unsecured notes			0
Deferred financing costs			0	0
Proceeds from issuance of Oasis Midstream common units, net of offering costs				0
Purchases of treasury stock			0	0
Distributions to non-controlling interests			0
Investment in / capital contributions from subsidiaries			17,270	0
Other			0	0
Net cash provided by financing activities			17,270	0
Increase (decrease) in cash and cash equivalents			0	0
Beginning of period			0	0
End of period	0	0	0	0
Parent/Issuer [Member]
Cash flows from operating activities:
Net income (loss)	62,341	(41,214)	(257,273)	(821)
Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	(96,555)	13,599	149,295	(74,379)
Depreciation, depletion and amortization	0	0	0	0
Loss on extinguishment of debt	47		13,698
Gain on sale of properties	0		0
Impairment		0	0	0
Deferred income taxes			(26,351)	(44,923)
Derivative instruments	0	0	0	0
Equity-based compensation expenses			20,292	19,740
Deferred financing costs amortization and other			11,955	11,399
Working capital and other changes:
Change in accounts receivable			(227,589)	115,996
Change in inventory			0	0
Change in prepaid expenses			(350)	(190)
Change in other current assets			0	0
Change in long-term inventory and other assets			0	0
Change in accounts payable, interest payable and accrued liabilities			(12,270)	(12,571)
Change in other current liabilities				0
Change in other liabilities			0
Net cash provided by operating activities			(328,593)	14,251
Cash flows from investing activities:
Capital expenditures			0	0
Acquisitions			0
Proceeds from sale of properties			0	0
Costs related to sale of properties			0
Derivative settlements			0	0
Advances from joint interest partners			0	0
Net cash used in investing activities			0	0
Cash flows from financing activities:
Proceeds from Revolving Credit Facilities			0	0
Principal payments on revolving credit facility			0	0
Repurchase of senior unsecured notes			(423,190)
Proceeds from issuance of senior unsecured notes			400,000
Deferred financing costs			(7,058)	0
Proceeds from issuance of Oasis Midstream common units, net of offering costs				0
Purchases of treasury stock			(6,806)	(6,182)
Distributions to non-controlling interests			0
Investment in / capital contributions from subsidiaries			365,601	(8,002)
Other			38	(55)
Net cash provided by financing activities			328,585	(14,239)
Increase (decrease) in cash and cash equivalents			(8)	12
Beginning of period			178	166
End of period	170	178	170	178
Combined Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net income (loss)	102,288	(13,449)	(132,135)	74,529
Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	(38,835)	(1,605)	(107,849)	(1,605)
Depreciation, depletion and amortization	159,843	132,035	456,624	383,992
Loss on extinguishment of debt	0		0
Gain on sale of properties	(36,869)		(38,823)
Impairment		139	384,228	6,021
Deferred income taxes			(49,067)	44,453
Derivative instruments	48,544	54,310	239,945	(52,297)
Equity-based compensation expenses			1,014	711
Deferred financing costs amortization and other			7,884	1,260
Working capital and other changes:
Change in accounts receivable			(77,231)	(87,610)
Change in inventory			(12,076)	(235)
Change in prepaid expenses			864	1,013
Change in other current assets			1	276
Change in long-term inventory and other assets			(490)	(12,843)
Change in accounts payable, interest payable and accrued liabilities			278,481	(62,542)
Change in other current liabilities				(10,490)
Change in other liabilities			(406)
Net cash provided by operating activities			950,964	284,633
Cash flows from investing activities:
Capital expenditures			(621,269)	(443,649)
Acquisitions			(579,886)
Proceeds from sale of properties			333,029	4,000
Costs related to sale of properties			(2,707)
Derivative settlements			(162,013)	(804)
Advances from joint interest partners			(1,038)	(2,502)
Net cash used in investing activities			(1,033,884)	(442,955)
Cash flows from financing activities:
Proceeds from Revolving Credit Facilities			2,376,000	764,000
Principal payments on revolving credit facility			(1,924,000)	(732,000)
Repurchase of senior unsecured notes			0
Proceeds from issuance of senior unsecured notes			0
Deferred financing costs			(261)	1,858
Proceeds from issuance of Oasis Midstream common units, net of offering costs				0
Purchases of treasury stock			0	0
Distributions to non-controlling interests			92,672
Investment in / capital contributions from subsidiaries			(465,293)	121,714
Other			(125)	0
Net cash provided by financing activities			78,993	155,572
Increase (decrease) in cash and cash equivalents			(3,927)	(2,750)
Beginning of period			15,659	11,060
End of period	11,732	8,310	11,732	8,310
Non-Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net income (loss)	38,835	1,605	107,849	1,605
Adjustments to reconcile net income (loss) including non-controlling interests to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	0	0	0	0
Depreciation, depletion and amortization	7,189	254	20,212	254
Loss on extinguishment of debt	0		0
Gain on sale of properties	0		0
Impairment		0	0	0
Deferred income taxes			0	0
Derivative instruments	0	0	0	0
Equity-based compensation expenses			280	0
Deferred financing costs amortization and other			235	7
Working capital and other changes:
Change in accounts receivable			8,747	(5,630)
Change in inventory			0	0
Change in prepaid expenses			682	0
Change in other current assets			0	0
Change in long-term inventory and other assets			0	0
Change in accounts payable, interest payable and accrued liabilities			18,895	3,617
Change in other current liabilities				0
Change in other liabilities			0
Net cash provided by operating activities			156,900	(147)
Cash flows from investing activities:
Capital expenditures			(219,819)	0
Acquisitions			0
Proceeds from sale of properties			0	0
Costs related to sale of properties			0
Derivative settlements			0	0
Advances from joint interest partners			0	0
Net cash used in investing activities			(219,819)	0
Cash flows from financing activities:
Proceeds from Revolving Credit Facilities			123,000	0
Principal payments on revolving credit facility			(35,000)	0
Repurchase of senior unsecured notes			0
Proceeds from issuance of senior unsecured notes			0
Deferred financing costs			(331)	(1,954)
Proceeds from issuance of Oasis Midstream common units, net of offering costs				115,813
Purchases of treasury stock			0	0
Distributions to non-controlling interests			(103,065)
Investment in / capital contributions from subsidiaries			82,422	(113,712)
Other			0	0
Net cash provided by financing activities			67,026	147
Increase (decrease) in cash and cash equivalents			4,107	0
Beginning of period			883	0
End of period	$ 4,990	$ 0	$ 4,990	$ 0