Chord Energy (CHRD) 10-Q 5 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
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 Common Stock, Shares Outstanding		139,117,892

Condensed Consolidated Balance

Condensed Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 12,265	$ 45,811
Accounts receivable — oil and gas revenues	101,977	130,934
Accounts receivable — joint interest partners	96,205	175,537
Inventory	12,929	21,354
Prepaid expenses	8,517	14,273
Derivative instruments	130,747	302,159
Other current assets	1,010	6,539
Total current assets	363,650	696,607
Property, plant and equipment
Oil and gas properties (successful efforts method)	6,337,945	5,966,140
Other property and equipment	436,052	313,439
Less: accumulated depreciation, depletion, amortization and impairment	(1,466,422)	(1,092,793)
Total property, plant and equipment, net	5,307,575	5,186,786
Derivative instruments	4,699	13,348
Deferred financing costs and other assets	49,184	41,671
Total assets	5,725,108	5,938,412
Current liabilities
Accounts payable	19,505	20,958
Revenues and production taxes payable	152,585	209,890
Accrued liabilities	177,134	410,379
Accrued interest payable	24,650	49,786
Deferred income taxes	35,027	97,499
Advances from joint interest partners	5,377	6,616
Other current liabilities	1,655	0
Total current liabilities	415,933	795,128
Long-term debt	2,380,000	2,700,000
Deferred income taxes	571,412	526,770
Asset retirement obligations	44,975	42,097
Derivative instruments	90	0
Other liabilities	3,216	2,116
Total liabilities	$ 3,415,626	$ 4,066,111
Commitments and contingencies
Stockholders’ equity
Common stock, $0.01 par value: 300,000,000 shares authorized; 139,603,486 shares issued and 139,111,585 shares outstanding at September 30, 2015 and 101,627,296 shares issued and 101,341,619 shares outstanding at December 31, 2014	$ 1,376	$ 1,001
Treasury stock, at cost: 491,901 and 285,677 shares at September 30, 2015 and December 31, 2014, respectively	(13,442)	(10,671)
Additional paid-in capital	1,490,995	1,007,202
Retained earnings	830,553	874,769
Total stockholders’ equity	2,309,482	1,872,301
Total liabilities and stockholders’ equity	$ 5,725,108	$ 5,938,412

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheet (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	139,603,486	101,627,296
Common stock, shares, outstanding	139,111,585	101,341,619
Treasury stock, shares	491,901	285,677

Condensed Consolidated Statemen

Condensed Consolidated Statement of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues
Oil and gas revenues	$ 175,270	$ 344,706	$ 563,239	$ 1,030,735
Well services and midstream revenues	21,965	23,953	44,429	59,821
Total revenues	197,235	368,659	607,668	1,090,556
Operating expenses
Lease operating expenses	35,670	44,361	112,556	124,903
Well services and midstream operating expenses	10,023	14,922	19,370	34,611
Marketing, transportation and gathering expenses	8,465	7,306	23,313	19,606
Production taxes	16,676	34,584	53,915	100,880
Depreciation, depletion and amortization	123,734	106,972	361,430	295,520
Exploration expenses	327	1,100	2,252	1,955
Rig termination	0	0	3,895	0
Impairment of oil and gas properties	80	1,439	24,917	2,243
General and administrative expenses	22,358	23,915	67,190	68,186
Total operating expenses	217,333	234,599	668,838	647,904
Gain on sale of properties	172	43	172	187,076
Operating income (loss)	(19,926)	134,103	(60,998)	629,728
Other income (expense)
Net gain on derivative instruments	103,637	103,426	111,285	20,253
Interest expense, net of capitalized interest	(36,513)	(39,420)	(112,702)	(118,568)
Other income (expense)	249	(38)	370	250
Total other income (expense)	67,373	63,968	(1,047)	(98,065)
Income (loss) before income taxes	47,447	198,071	(62,045)	531,663
Income tax benefit (expense)	(20,392)	(76,484)	17,829	(201,290)
Net income (loss)	$ 27,055	$ 121,587	$ (44,216)	$ 330,373
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.20	$ 1.22	$ (0.35)	$ 3.32
Diluted (in dollars per share)	$ 0.20	$ 1.21	$ (0.35)	$ 3.29
Weighted average shares outstanding:
Basic (in shares)	137,014	99,715	127,827	99,647
Diluted (in shares)	137,014	100,306	127,827	100,356

Condensed Consolidated Stateme5

Condensed Consolidated Statement of Changes in Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2015 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in-Capital [Member]	Retained Earnings [Member]
Balance, shares at Dec. 31, 2014		101,342	286
Balance at Dec. 31, 2014	$ 1,872,301	$ 1,001	$ (10,671)	$ 1,007,202	$ 874,769
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	462,833	$ 368		462,465
Issuance of common stock, shares		36,800
Stock-based compensation	21,335			21,335
Stock-based compensation, shares		1,176
Vesting of restricted shares	0	$ 7		(7)
Treasury stock – tax withholdings	(2,771)		$ (2,771)
Treasury stock - tax withholdings, shares		(206)	206
Net loss	(44,216)				(44,216)
Balance, shares at Sep. 30, 2015		139,112	492
Balance at Sep. 30, 2015	$ 2,309,482	$ 1,376	$ (13,442)	$ 1,490,995	$ 830,553

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income (loss)	$ (44,216)	$ 330,373
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	361,430	295,520
Gain on sale of properties	(172)	(187,076)
Impairment of oil and gas properties	24,917	2,243
Deferred income taxes	(17,829)	197,548
Derivative instruments	(111,285)	(20,253)
Stock-based compensation expenses	19,629	15,755
Deferred financing costs amortization and other	7,468	5,209
Working capital and other changes:
Change in accounts receivable	108,309	(62,581)
Change in inventory	8,425	(4,089)
Change in prepaid expenses	638	(3,179)
Change in other current assets	5,529	(1,581)
Change in other assets	0	(3,069)
Change in accounts payable and accrued liabilities	(84,133)	108,788
Change in other current liabilities	1,655	0
Change in other liabilities	(28)	(116)
Net cash provided by operating activities	280,337	673,492
Cash flows from investing activities:
Capital expenditures	(740,633)	(998,889)
Proceeds from sale of properties	78	324,938
Costs related to sale of properties	0	(2,337)
Derivative settlements	291,436	(24,773)
Advances from joint interest partners	(1,239)	(6,053)
Net cash used in investing activities	(450,358)	(707,114)
Cash flows from financing activities:
Proceeds from sale of common stock	462,833	0
Proceeds from revolving credit facility	618,000	370,000
Principal payments on revolving credit facility	(938,000)	(355,570)
Deferred financing costs	(3,587)	(99)
Purchases of treasury stock	(2,771)	(5,240)
Other	0	(176)
Net cash provided by financing activities	136,475	8,915
Decrease in cash and cash equivalents	(33,546)	(24,707)
Cash and cash equivalents:
Beginning of period	45,811	91,901
End of period	12,265	67,194
Supplemental non-cash transactions:
Change in accrued capital expenditures	(233,913)	99,103
Change in asset retirement obligations	$ 3,405	$ 5,134

Organization and Operations of

Organization and Operations of the Company	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Organization and Operations of the Company	Organization and Operations of the Company Organization Oasis Petroleum Inc. (together with its subsidiaries, “Oasis” or the “Company”) was formed on February 25, 2010, pursuant to the laws of the State of Delaware, to become a holding company for Oasis Petroleum LLC (“OP LLC”), the Company’s predecessor, which was formed as a Delaware limited liability company on February 26, 2007. In connection with its initial public offering in June 2010 and related corporate reorganization, the Company acquired all of the outstanding membership interests in OP LLC in exchange for shares of the Company’s common stock. Oasis Petroleum North America LLC (“OPNA”), a Delaware limited liability company formed in 2007, conducts the Company’s domestic oil and natural gas exploration and production activities. In 2011, the Company formed Oasis Well Services LLC (“OWS”), a Delaware limited liability company, to provide well services to OPNA, and Oasis Petroleum Marketing LLC (“OPM”), a Delaware limited liability company, to provide marketing services to OPNA. In 2013, the Company formed Oasis Midstream Services LLC (“OMS”), a Delaware limited liability company, to provide midstream services to OPNA. Nature of Business The Company is an independent exploration and production company focused on the acquisition and development of unconventional oil and natural gas resources in the Williston Basin. The Company’s proved and unproved oil and natural gas properties are located in the North Dakota and Montana areas of the Williston Basin and are owned by OPNA. The Company also operates an oil and gas marketing business (OPM), a well services business (OWS) and a midstream services business (OMS), all of which are complementary to its primary development and production activities. Both OWS and OMS are separate reportable business segments, while OPM is included in the Company’s exploration and production segment.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
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 include the accounts of Oasis and its wholly-owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. 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, 2014 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 presentation, 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, 2014 (“ 2014 Annual Report”). 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. Crude oil prices declined significantly in the latter part of 2014 and have remained low while experiencing high volatility in 2015. As a result of lower oil prices, the Company significantly decreased its 2015 capital expenditures as compared to 2014 and is currently concentrating its drilling activities in certain areas that are the most economic in the Williston Basin. An extended period of low prices for oil 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 2014 Annual Report. Recent Accounting Pronouncements Revenue recognition. In May 2014, the Financial Accounting Standards Board (“FASB”) issued 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 also contains some new disclosure requirements under GAAP. In August 2015, the FASB issued Accounting Standards Update No. 2015-14, Deferral of the Effective Date (“ASU 2015-14”). ASU 2015-14 defers the effective date of the new revenue standard by one year, making it effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations. Going concern. In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”). ASU 2014-15 codifies in GAAP management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. ASU 2014-15 is effective for the annual reporting period ending after December 15, 2016 and for annual periods and interim periods thereafter. The adoption of this guidance will not impact the Company’s financial position, cash flows or results of operations, but could result in additional disclosures. Extraordinary items. In January 2015, the FASB issued Accounting Standards Update No. 2015-01, Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items (“ASU 2015-01”). ASU 2015-01 removes the concept of extraordinary items from GAAP. Under existing guidance, an entity is required to separately disclose extraordinary items, net of tax, in the income statement after income from continuing operations if an event or transaction is of an unusual nature and occurs infrequently. This separate, net-of-tax presentation will no longer be allowed. ASU 2015-01 is effective for fiscal years beginning after December 15, 2015, including interim periods within those years. The Company does not expect the adoption of this guidance to have a material impact on its financial position, cash flows or results of operations. Debt issuance costs. In April 2015, the FASB issued Accounting Standards Update No. 2015-03, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). ASU 2015-03 requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability, consistent with the presentation of debt discount, but it does not affect the recognition or measurement of debt issuance costs. ASU 2015-03 is effective for fiscal years beginning after December 15, 2015, including interim periods within those years, and should be applied on a retrospective basis for all prior periods presented. The Company expects that the adoption of this guidance will only impact the presentation of its balance sheet. As of September 30, 2015 and December 31, 2014, the Company had capitalized, unamortized debt issuance costs associated with debt liabilities other than line-of-credit arrangements of $25.9 million and $29.3 million , respectively, included in deferred financing costs and other assets on its Condensed Consolidated Balance Sheet. In August 2015, the FASB issued Accounting Standards Update No. 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements (“ASU 2015-15”), which confirms that line-of-credit arrangements are not in the scope of ASU 2015-03. ASU 2015-15 states that, for debt issuance costs related to line-of-credit arrangements, the SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs ratably over the term of the line-of-credit arrangement, regardless of whether there are outstanding borrrowings under the line-of-credit arrangement. Inventory. In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Simplifying the Measurement of Inventory (“ASU 2015-11”). ASU 2015-11 changes the inventory measurement principle from lower of cost or market to lower of cost and net realizable value for entities using the first-in, first out (FIFO) or average cost methods. ASU 2015-11 is effective for fiscal years beginning after December 15, 2016, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations. Business combinations. In September 2015, the FASB issued Accounting Standards Update No. 2015-16, Simplifying the Accounting for Measurement-Period Adjustments (“ASU 2015-16”), which eliminates the requirement for an acquirer in a business combination to restate prior period financial statements for measurement period adjustments. ASU 2015-16 requires that the cumulative impact of measurement period adjustments on current and prior periods be recognized in the reporting period in which the adjustment amount is determined. ASU 2015-16 is effective for fiscal years beginning after December 15, 2015, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations.

Inventory

Inventory	9 Months Ended
	Sep. 30, 2015
Inventory Disclosure [Abstract]
Inventory	Inventory 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 includes oil in tank and linefill. Inventory is stated at the lower of cost or market value with cost determined on an average cost method. Inventory consists of the following: September 30, 2015 December 31, 2014 (In thousands) Equipment and materials $ 5,569 $ 14,225 Crude oil inventory 7,360 7,129 Total inventory $ 12,929 $ 21,354

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2015
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, 2015 December 31, 2014 (In thousands) Proved oil and gas properties (1) $ 5,669,125 $ 5,156,875 Less: Accumulated depreciation, depletion, amortization and impairment (1,393,283 ) (1,043,121 ) Proved oil and gas properties, net 4,275,842 4,113,754 Unproved oil and gas properties 668,820 809,265 Total oil and gas properties, net 4,944,662 4,923,019 Other property and equipment 436,052 313,439 Less: Accumulated depreciation (73,139 ) (49,672 ) Other property and equipment, net 362,913 263,767 Total property, plant and equipment, net $ 5,307,575 $ 5,186,786 __________________ (1) Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $38.4 million and $36.9 million at September 30, 2015 and December 31, 2014 , respectively. Impairment. As a result of expiring leases and periodic assessments of unproved properties, the Company recorded non-cash impairment charges on its unproved oil and natural gas properties of $0.1 million and $24.9 million for the three and nine months ended September 30, 2015 , respectively, and $1.4 million and $2.2 million for the three and nine months ended September 30, 2014 , respectively. The impairment charges for the nine months ended September 30, 2015 included $16.4 million related to acreage expiring in future periods because there were no current plans to drill or extend the leases prior to their expiration. For the three months ended September 30, 2015 and the three and nine months ended September 30, 2014 , the Company did not record similar impairment charges based on its ability to actively manage and prioritize its capital expenditures to drill leases and to make payments to extend leases that would have otherwise expired. No impairment charges on proved oil and gas properties were recorded for the three and nine months ended September 30, 2015 or 2014 . Divestiture. On March 5, 2014, the Company completed the sale of certain non-operated properties in and around its Sanish position for cash proceeds of $324.9 million , which included customary post close adjustments. The Company recognized a $187.0 million gain on sale of properties in its Consolidated Statement of Operations for the year ended December 31, 2014.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2015
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 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 As required, 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: At fair value as of September 30, 2015 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 742 $ — $ — $ 742 Commodity derivative instruments (see Note 6) — 135,446 — 135,446 Total assets $ 742 $ 135,446 $ — $ 136,188 Liabilities: Commodity derivative instruments (see Note 6) $ — $ 90 $ — $ 90 Total liabilities $ — $ 90 $ — $ 90 At fair value as of December 31, 2014 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 742 $ — $ — $ 742 Commodity derivative instruments (see Note 6) — 315,507 — 315,507 Total assets $ 742 $ 315,507 $ — $ 316,249 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 Sheet at September 30, 2015 and December 31, 2014 . 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 collars and swaps. 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. However, the Company does not have access to the specific proprietary valuation models or inputs used by its counterparties or third-party preparer. 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 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 asset by $0.2 million and $0.6 million at September 30, 2015 and December 31, 2014 , respectively. Fair Value of Other Financial Instruments The Company’s financial instruments, including certain cash and cash equivalents, accounts receivable and accounts payable, are carried at cost, which approximates fair value due to the short-term maturity of these instruments. At September 30, 2015 , the Company’s cash equivalents were all Level 1 assets. The carrying amount of the Company’s long-term debt reported in the Condensed Consolidated Balance Sheet at September 30, 2015 was $2,380.0 million , which includes $2,200.0 million of senior unsecured notes and $180.0 million of borrowings under the revolving credit facility (see Note 7 – Long-Term Debt). The fair value of the Company’s senior unsecured notes, which are publicly traded and therefore categorized as Level 1 liabilities, was $1,771.3 million at September 30, 2015 . Non-Financial Assets and Liabilities Asset retirement obligations. The carrying amount of ARO in the Company’s Condensed Consolidated Balance Sheet at September 30, 2015 was $45.6 million (see Note 8 – Asset Retirement Obligations). The Company determines its ARO by calculating the present value of estimated cash flows related to the liability. Estimating the future ARO requires management to make estimates and judgments regarding the timing and existence of a liability, as well as what constitutes adequate restoration when considering current regulatory requirements. Inherent in the fair value calculation are numerous assumptions and judgments, including the ultimate costs, inflation factors, credit adjusted discount rates, timing of settlement and changes in the legal, regulatory, environmental and political environments. These assumptions represent Level 3 inputs. To the extent future revisions to these assumptions impact the fair value of the existing ARO liability, a corresponding adjustment is made to the related asset. Impairment. The Company reviews its proved oil and natural gas properties for impairment whenever events and circumstances indicate that a decline in the recoverability of their carrying value may have occurred. The Company estimates the expected undiscounted future cash flows of its proved oil and natural gas properties then compares such undiscounted future cash flows to the carrying amount of the proved oil and natural gas properties to determine if the carrying amount is recoverable. If the carrying amount exceeds the estimated undiscounted future cash flows, the Company will adjust the carrying amount of the oil and natural gas properties to fair value. The factors used to determine fair value are subject to management’s judgment and expertise and include, but are not limited to, recent sales prices of comparable properties, the present value of future cash flows, net of estimated operating and development costs using estimates of proved reserves, future commodity pricing, future production estimates, anticipated capital expenditures and various discount rates commensurate with the risk and current market conditions associated with realizing the expected cash flows projected. These assumptions represent Level 3 inputs. No impairment charges on proved oil and natural gas properties were recorded for the three and nine months ended September 30, 2015 or 2014 .

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2015
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 prices. As of September 30, 2015 , the Company utilized two-way costless collar options and swaps to reduce the volatility of oil prices on a significant portion of its future expected oil production. 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 swap is a sold call and a purchased put established at the same price (both ceiling and floor). All derivative instruments are recorded on the Company’s Condensed Consolidated Balance Sheet as either assets or liabilities measured at fair value (see Note 5 – 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 Statement 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 Statement of Cash Flows. As of September 30, 2015 , the Company had the following outstanding commodity derivative instruments, all of which settle monthly based on the average WTI: Settlement Period Derivative Instrument Total Notional Amount of Oil Weighted Average Prices Fair Value Swap Floor Ceiling (Barrels) ($/Barrel) (In thousands) 2015 Two-way collars 455,000 $ 86.00 $ 103.42 $ 18,790 2015 Swaps 2,093,000 $ 73.35 57,933 2016 Two-way collars 155,000 $ 86.00 $ 103.42 6,133 2016 Swaps 5,643,000 $ 57.75 51,499 2017 Swaps 372,000 $ 53.84 1,001 $ 135,356 The following table summarizes the location and fair value of all outstanding commodity derivative instruments recorded in the Company’s Condensed Consolidated Balance Sheet for the periods presented: Fair Value Asset (Liability) Commodity Balance Sheet Location September 30, 2015 December 31, 2014 (In thousands) Crude oil Derivative instruments — current assets $ 130,747 $ 302,159 Crude oil Derivative instruments — non-current assets 4,699 13,348 Crude oil Derivative instruments — non-current liabilities (90 ) — Total derivative instruments $ 135,356 $ 315,507 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 Statement of Operations for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, Statement of Operations Location 2015 2014 2015 2014 (In thousands) Net gain on derivative instruments $ 103,637 $ 103,426 $ 111,285 $ 20,253 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 Sheet. The following tables summarize gross and net information about the Company’s commodity derivative instruments for the periods presented: Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet (In thousands) As of September 30, 2015 $ 153,394 $ (17,948 ) $ 135,446 As of December 31, 2014 331,121 (15,614 ) 315,507 Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet (In thousands) As of September 30, 2015 $ 18,038 $ (17,948 ) $ 90 As of December 31, 2014 15,614 (15,614 ) —

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Senior unsecured notes. During 2013, the Company issued $1,000.0 million of 6.875% senior unsecured notes due March 15, 2022 (the “2022 Notes”), which resulted in aggregate net proceeds to the Company of $983.6 million . The Company used the proceeds from the 2022 Notes to fund the acquisition of oil and gas properties. During 2011 and 2012, the Company issued $400.0 million of 7.25% senior unsecured notes due February 1, 2019 (the “2019 Notes”), $400.0 million of 6.5% senior unsecured notes due November 1, 2021 (the “2021 Notes”) and $400.0 million of 6.875% senior unsecured notes due January 15, 2023 (the “2023 Notes”), which resulted in aggregate net proceeds to the Company of $1,175.8 million . The Company used the proceeds from these notes to fund its exploration, development and acquisition program and for general corporate purposes. Interest on the 2019 Notes, the 2021 Notes, the 2022 Notes and the 2023 Notes (collectively, the “Notes”) is payable semi-annually in arrears. The Notes were issued under indentures containing provisions that are substantially the same, as amended and supplemented by supplemental indentures (collectively, the “Indentures”), among the Company, along with its material subsidiaries (the “Guarantors”), and U.S. Bank National Association, as trustee. The Notes are guaranteed on a senior unsecured basis by the Company’s 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, as follows: • in connection with any sale or other disposition of all or substantially all of the assets of that Guarantor (including by way of merger or consolidation) to a person that is not (either before or after giving effect to such transaction) the Company or a Restricted Subsidiary (as defined in the Indentures) of the Company; • in connection with any sale or other disposition of the capital stock of that Guarantor (including by way of merger or consolidation) to a person that is not (either before or after giving effect to such transaction) the Company or a Restricted Subsidiary of the Company, such that, immediately after giving effect to such transaction, such Guarantor would no longer constitute a subsidiary of the Company; • if the Company designates any Restricted Subsidiary that is a Guarantor to be an unrestricted subsidiary in accordance with the Indenture; • upon legal defeasance or satisfaction and discharge of the Indenture; or • upon the liquidation or dissolution of a Guarantor, provided no event of default occurs under the Indentures as a result thereof. Prior to certain dates, the Company has certain options to redeem up to 35% of the Notes at a certain redemption price based on a percentage of the principal amount, plus accrued and unpaid interest to the redemption date, with the proceeds of certain equity offerings so long as the redemption occurs within 180 days of completing such equity offering and at least 65% of the aggregate principal amount of the Notes remains outstanding after such redemption. Prior to certain dates, the Company has the option to redeem some or all of the 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. The Company estimates that the fair value of these redemption options is immaterial at September 30, 2015 and December 31, 2014 . The Indentures restrict the Company’s ability and the ability of certain of its subsidiaries to: (i) incur additional debt or enter into sale and leaseback transactions; (ii) pay distributions on, redeem or repurchase equity interests; (iii) make certain investments; (iv) incur liens; (v) enter into transactions with affiliates; (vi) merge or consolidate with another company; and (vii) transfer and sell assets. These covenants are subject to certain exceptions and qualifications. If at any time when the Notes are rated investment grade by both Moody’s Investors Service, Inc. and Standard & Poor’s Ratings Services and no Default (as defined in the Indentures) has occurred and is continuing, many of such covenants will terminate and the Company and its subsidiaries will cease to be subject to such covenants. The Indentures contain customary events of default, including: • default in any payment of interest on any Note when due, continued for 30 days; • default in the payment of principal or premium, if any, on any Note when due; • failure by the Company to comply with its other obligations under the Indentures, in certain cases subject to notice and grace periods; • payment defaults and accelerations with respect to other indebtedness of the Company and its Restricted Subsidiaries in the aggregate principal amount of $10.0 million or more; • certain events of bankruptcy, insolvency or reorganization of the Company or a Significant Subsidiary (as defined in the Indentures) or group of Restricted Subsidiaries that, taken together, would constitute a Significant Subsidiary; • failure by the Company or any Significant Subsidiary or group of Restricted Subsidiaries that, taken together, would constitute a Significant Subsidiary to pay certain final judgments aggregating in excess of $10.0 million within 60 days; and • any guarantee of the Notes by a Guarantor ceases to be in full force and effect, is declared null and void in a judicial proceeding or is denied or disaffirmed by its maker. Senior secured revolving line of credit. On April 5, 2013, the Company, as parent, and OPNA, as borrower, entered into a second amended and restated credit agreement (the “Second Amended Credit Facility”), which had a maturity date of April 5, 2018 . The Second Amended Credit Facility is restricted to the borrowing base, which is reserve-based and subject to semi-annual redeterminations on April 1 and October 1 of each year. On April 13, 2015, the Company entered into its third amendment to the Second Amended Credit Facility (the “Third Amendment”), which extended the maturity date of the Second Amended Credit Facility to April 13, 2020, provided that the 2019 Notes are retired or refinanced 90 days prior to their maturity. In connection with the Third Amendment, the lenders under the Second Amended Credit Facility (the “Lenders”) completed their regular semi-annual redetermination of the borrowing base scheduled for April 1, 2015, resulting in a borrowing base decrease from $2,000.0 million to $1,700.0 million . The Company increased the Lenders’ aggregate elected commitment from $1,500.0 million to $1,525.0 million . The Lenders’ aggregate commitment can be increased to the full $1,700.0 million borrowing base by increasing the commitment of one or more Lenders. The Third Amendment also increased the Lenders in the bank group to 18 financial institutions supporting the Company’s borrowing base facility. The overall senior secured line of credit under the Second Amended Credit Facility is $2,500.0 million as of September 30, 2015 . Borrowings under the Second Amended Credit Facility are collateralized by perfected first priority liens and security interests on substantially all of the Company’s assets, including mortgage liens on oil and natural gas properties having at least 80% of the reserve value as determined by reserve reports. Borrowings under the Second Amended Credit Facility are subject to varying rates of interest based on (1) the total outstanding borrowings (including the value of all outstanding letters of credit) in relation to the borrowing base and (2) whether the loan is a London interbank offered rate (“LIBOR”) loan or a domestic bank prime interest rate loan (defined in the Second Amended Credit Facility as an Alternate Based Rate or “ABR” loan). As of September 30, 2015 , any outstanding LIBOR and ABR loans bore their respective interest rates plus the applicable margin indicated in the following table: Ratio of Total Outstanding Borrowings to Borrowing Base Applicable Margin for LIBOR Loans Applicable Margin for ABR Loans Less than .25 to 1 1.50 % 0.00 % Greater than or equal to .25 to 1 but less than .50 to 1 1.75 % 0.25 % Greater than or equal to .50 to 1 but less than .75 to 1 2.00 % 0.50 % Greater than or equal to .75 to 1 but less than .90 to 1 2.25 % 0.75 % Greater than or equal to .90 to 1 2.50 % 1.00 % An ABR loan may be repaid at any time before the scheduled maturity of the Second Amended Credit Facility upon the Company providing advance notification to the Lenders. Interest is paid quarterly on ABR loans based on the number of days an ABR loan is outstanding as of the last business day in March, June, September and December. The Company has the option to convert an ABR loan to a LIBOR-based loan upon providing advance notification to the Lenders. The minimum available loan term is one month and the maximum loan term is six months for LIBOR-based loans. Interest for LIBOR loans is paid upon maturity of the loan term. Interim interest is paid every three months for LIBOR loans that have loan terms greater than three months in duration. At the end of a LIBOR loan term, the Second Amended Credit Facility allows the Company to elect to repay the borrowing, continue a LIBOR loan with the same or a differing loan term or convert the borrowing to an ABR loan. On a quarterly basis, the Company pays a 0.375% (as of September 30, 2015 ) annualized commitment fee 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. As of September 30, 2015 , the Second Amended Credit Facility contained covenants that included, among others: • a prohibition against incurring debt, subject to permitted exceptions; • a prohibition against making dividends, distributions and redemptions, subject to permitted exceptions; • a prohibition against making investments, loans and advances, subject to permitted exceptions; • restrictions on creating liens and leases on the assets of the Company and its subsidiaries, subject to permitted exceptions; • restrictions on merging and selling assets outside the ordinary course of business; • restrictions on use of proceeds, investments, transactions with affiliates or change of principal business; • a provision limiting oil and natural gas derivative financial instruments; • a requirement that the Company maintain a ratio of consolidated EBITDAX (as defined in the Second Amended Credit Facility) to consolidated Interest Expense (as defined in the Second Amended Credit Facility) of no less than 2.5 to 1.0 for the four quarters ended on the last day of each quarter; and • a requirement that the Company maintain a Current Ratio (as defined in the Second Amended Credit Facility) of consolidated current assets (including unused borrowing base capacity and with exclusions as described in the Second Amended Credit Facility) to consolidated current liabilities (with exclusions as described in the Second Amended Credit Facility) of no less than 1.0 to 1.0 as of the last day of any fiscal quarter. The Second Amended Credit Facility contains customary events of default. If an event of default occurs and is continuing, the Lenders may declare all amounts outstanding under the Second Amended Credit Facility to be immediately due and payable. As of September 30, 2015 , the Company had $180.0 million of LIBOR loans and $5.2 million of outstanding letters of credit issued under the Second Amended Credit Facility, resulting in an unused borrowing base committed capacity of $1,339.8 million . As of September 30, 2015 and December 31, 2014 , the weighted average interest rate on borrowings outstanding under the Second Amended Credit Facility was 1.7% and 1.9% , respectively. The Company was in compliance with the financial covenants of the Second Amended Credit Facility as of September 30, 2015 . Deferred financing costs. As of September 30, 2015 , the Company had $33.6 million of deferred financing costs related to the Notes and the Second Amended Credit Facility. The deferred financing costs are included in deferred financing costs and other assets on the Company’s Condensed Consolidated Balance Sheet at September 30, 2015 and are being amortized over the respective terms of the Notes and the Second Amended Credit Facility. Amortization of deferred financing costs recorded for the three and nine months ended September 30, 2015 was $1.6 million and $5.5 million , respectively, and $1.6 million and $4.8 million for the three and nine months ended September 30, 2014 , respectively. These costs are included in interest expense on the Company’s Condensed Consolidated Statement of Operations.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2015
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, 2015 : (In thousands) Balance at December 31, 2014 $ 42,549 Liabilities incurred during period 1,233 Liabilities settled during period (112 ) Accretion expense during period (1) 1,654 Revisions to estimates 241 Balance at September 30, 2015 $ 45,565 ___________________ (1) Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statement of Operations. At September 30, 2015 , the current portion of the total ARO balance was approximately $0.6 million and is included in accrued liabilities on the Company’s Condensed Consolidated Balance Sheet.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate for the three and nine months ended September 30, 2015 was 43.0% and 28.7% , respectively. The Company’s effective tax rate for the three and nine months ended September 30, 2014 was 38.6% and 37.9% , respectively. While the 2014 rates were consistent with the statutory tax rate applicable to the U.S. and the blended state rate for the states in which the Company conducts business, the effective tax rate was higher for the three months ended September 30, 2015 due to lower pre-tax income and the impact of permanent differences, while the effective tax rate was lower for the nine months ended September 30, 2015 due to the Company’s pre-tax loss and the impact of permanent differences. The permanent differences were primarily between compensation amounts expensed for book purposes versus the amounts deductible for income tax purposes related to stock-based compensation vestings during the three and nine months ended September 30, 2015 at stock prices lower than the grant date values. The impact of these permanent differences was partially offset by a reduction in the North Dakota statutory tax rate in the second quarter of 2015. The Company had deferred tax assets for its federal and state tax loss carryforwards at September 30, 2015 recorded in deferred income taxes. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. As of September 30, 2015, management determined that a valuation allowance was not required for the tax loss carryforwards as they are expected to be fully utilized before expiration. As of September 30, 2015, the Company did not have any uncertain tax positions requiring adjustments to its tax liability.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Restricted stock awards. 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 grants 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. For the nine months ended September 30, 2015 , the Company assumed annual forfeiture rates by employee group ranging from 0% to 16.9% based on the Company’s forfeiture history for this type of award. During the nine months ended September 30, 2015 , employees and non-employee directors of the Company were granted restricted stock awards equal to 1,234,320 shares of common stock with a $ 13.08 weighted average grant date per share value. Stock-based compensation expense recorded for restricted stock awards for the three and nine months ended September 30, 2015 was $5.0 million and $16.8 million , respectively, and $5.2 million and $13.4 million for the three and nine months ended September 30, 2014 , respectively. Stock-based compensation expense is included in general and administrative expenses on the Company’s Condensed Consolidated Statement 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. For the nine months ended September 30, 2015 , the Company assumed annual forfeiture rates by employee group ranging from 2.4% to 4.9% based on the Company’s forfeiture history for the officer employee groups receiving PSUs. During the nine months ended September 30, 2015 , officers of the Company were granted 425,590 PSUs with an $ 11.20 weighted average grant date per share value. Stock-based compensation expense recorded for PSUs for the three and nine months ended September 30, 2015 was $1.0 million and $2.9 million , respectively, and $0.8 million and $2.3 million for the three and nine months ended September 30, 2014 , respectively, and is included in general and administrative expenses on the Company’s Condensed Consolidated Statement of Operations. Each grant of PSUs is subject to a designated three -year initial performance period. 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 period. 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. If less than 200% of the initial PSUs granted are earned at the end of the initial three -year performance period, then the performance period will be extended an additional year to give the award recipients the opportunity to earn up to an aggregate of 200% of the initial PSUs granted. The Company accounted for these PSUs as equity awards pursuant to the FASB’s authoritative guidance for share-based payments. The aggregate grant date fair value of the market-based awards was determined using a Monte Carlo simulation model, which results in an expected percentage of PSUs earned. The fair value of these PSUs is recognized on a straight-line basis over the performance period. As it is probable that a portion of the awards will be earned during the extended performance period, the grant date fair value will be amortized over four years . However, if 200% of the initial PSUs granted are earned at the end of the initial performance period, then the remaining compensation expense will be accelerated in order to be fully recognized over three years . 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 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, risk-free interest rate, volatility and correlation coefficients. The risk-free interest rate is the U.S. Treasury bond rate on the date of grant that corresponds to the extended 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 is the standard deviation of the average percentage change in stock price 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 stock-based compensation expense of the PSUs granted during the nine months ended September 30, 2015 : Forecast period (years) 4.00 Risk-free interest rate 0.99 % Oasis stock price volatility 50.11 % For the PSUs granted during the nine months ended September 30, 2015 , the Monte Carlo simulation model resulted in 86% of PSUs expected to be earned over the extended performance period.

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Common Stock	Common Stock On March 9, 2015, the Company completed a public offering of 36,800,000 shares of its common stock (including 4,800,000 shares issued pursuant to the underwriters’ option to purchase additional common stock) at an offering price of $12.80 per share. Net proceeds from the offering were $463.1 million , after deducting underwriting discounts and commissions and estimated offering expenses, of which $0.4 million is included in common stock and $462.7 million is included in additional paid-in capital on the Company’s Condensed Consolidated Balance Sheet. The Company used the net proceeds to repay outstanding indebtedness under its Second Amended Credit Facility and for general corporate purposes. The offering was made pursuant to an effective shelf registration statement on Form S-3 filed with the SEC on July 15, 2014.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share Basic earnings (loss) per share is computed by dividing income available to common stockholders by the weighted average number of shares outstanding for the periods presented. The calculation of diluted earnings (loss) per share includes the impact of potentially dilutive non-vested restricted shares and PSUs outstanding during the periods presented, unless their effect is anti-dilutive. There are no adjustments made to income (loss) 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, 2015 and 2014 : Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In thousands) Basic weighted average common shares outstanding 137,014 99,715 127,827 99,647 Dilution effect of stock awards at end of period (1) — 591 — 709 Diluted weighted average common shares outstanding 137,014 100,306 127,827 100,356 Anti-dilutive stock-based compensation awards 2,787 1,067 2,939 927 ___________________ (1) No unvested stock awards were included in computing earnings (loss) per share for the three and nine months ended September 30, 2015 because the effect was anti-dilutive.

Business Segment Information

Business Segment Information	9 Months Ended
	Sep. 30, 2015
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 and includes the complementary marketing services provided by OPM. Revenues for the exploration and production segment are derived from the sale of oil and natural gas production. In the first quarter of 2012, the Company began its well services business segment (OWS) to perform 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 completion services, well completion product sales and tool rentals. In the first quarter of 2013, the Company formed its midstream services business segment (OMS) to perform salt water gathering and disposal and other midstream services for the Company’s oil and natural gas wells operated by OPNA. Revenues for the midstream segment are primarily derived from salt water transport, salt water disposal and fresh water sales. The revenues and expenses related to work performed by OWS and OMS 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 Statement of Operations. These segments represent the Company’s three current 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. The following table summarizes financial information for the Company’s business segments for the periods presented: Exploration and Production Well Services Midstream Services Eliminations Consolidated (In thousands) Three months ended September 30, 2015: Revenues from non-affiliates $ 175,270 $ 15,381 $ 6,584 $ — $ 197,235 Inter-segment revenues — 33,554 23,228 (56,782 ) — Total revenues 175,270 48,935 29,812 (56,782 ) 197,235 Operating income (loss) (38,289 ) 10,936 18,828 (11,401 ) (19,926 ) Other income (expense) 67,359 14 — — 67,373 Income before income taxes $ 29,070 $ 10,950 $ 18,828 $ (11,401 ) $ 47,447 Three months ended September 30, 2014: Revenues from non-affiliates $ 344,706 $ 20,925 $ 3,028 $ — $ 368,659 Inter-segment revenues — 66,298 10,596 (76,894 ) — Total revenues 344,706 87,223 13,624 (76,894 ) 368,659 Operating income 126,184 23,388 5,126 (20,595 ) 134,103 Other income (expense) 63,968 — — — 63,968 Income before income taxes $ 190,152 $ 23,388 $ 5,126 $ (20,595 ) $ 198,071 Nine months ended September 30, 2015: Revenues from non-affiliates $ 563,239 $ 27,308 $ 17,121 $ — $ 607,668 Inter-segment revenues — 131,220 58,994 (190,214 ) — Total revenues 563,239 158,528 76,115 (190,214 ) 607,668 Operating income (loss) (103,065 ) 29,554 44,083 (31,570 ) (60,998 ) Other income (expense) (1,037 ) 34 (44 ) — (1,047 ) Income (loss) before income taxes $ (104,102 ) $ 29,588 $ 44,039 $ (31,570 ) $ (62,045 ) Nine months ended September 30, 2014: Revenues from non-affiliates $ 1,030,735 $ 51,630 $ 8,191 $ — $ 1,090,556 Inter-segment revenues — 146,447 28,264 (174,711 ) — Total revenues 1,030,735 198,077 36,455 (174,711 ) 1,090,556 Operating income 602,797 53,137 15,854 (42,060 ) 629,728 Other income (expense) (98,140 ) 75 — — (98,065 ) Income before income taxes $ 504,657 $ 53,212 $ 15,854 $ (42,060 ) $ 531,663 As of September 30, 2015: Property, plant and equipment, net $ 5,130,061 $ 66,058 $ 261,989 $ (150,533 ) $ 5,307,575 Total assets 5,541,674 421,642 378,284 (616,492 ) 5,725,108 As of December 31, 2014: Property, plant and equipment, net $ 5,074,588 $ 58,767 $ 172,394 $ (118,963 ) $ 5,186,786 Total assets 5,802,295 281,844 212,685 (358,412 ) 5,938,412

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Included below is a discussion of various future commitments of the Company as of September 30, 2015 . The commitments under these arrangements are not recorded in the accompanying Condensed Consolidated Balance Sheet. The amounts disclosed represent undiscounted cash flows on a gross basis, and no inflation elements have been applied. Lease obligations. The Company’s total rental commitments under leases for office space and other property and equipment at September 30, 2015 were $28.7 million . Drilling contracts. As a result of its lowered 2015 capital expenditure program, the Company elected to early terminate certain drilling rig contracts and recorded a rig termination expense of $3.9 million in its Condensed Consolidated Statement of Operations for the nine months ended September 30, 2015 . The Company did not elect to early terminate any drilling rig contracts during the nine months ended September 30, 2014 . As of September 30, 2015 , the Company had certain drilling rig contracts with initial terms greater than one year. In the event of early termination under these contracts, the Company would be obligated to pay approximately $5.3 million as of September 30, 2015 for the days remaining through the end of the primary terms of the contracts. Volume commitment agreements. As of September 30, 2015 , the Company had certain agreements with an aggregate requirement to deliver a minimum quantity of approximately 29.2 MMBbl and 4.1 Bcf, prior to any applicable volume credits, within specified timeframes, all of which are less than ten years . Future commitments under these agreements were approximately $193.8 million as of September 30, 2015 . Purchase agreements . As of September 30, 2015 , the Company had certain agreements for the purchase of fresh water with an aggregate future commitment of approximately $38.6 million . Cost sharing agreements. As of September 30, 2015 , the Company had certain agreements to share the cost to construct and install electrical facilities. The Company’s estimated future commitment under these agreements was $2.3 million as of September 30, 2015 . Litigation. The Company is party to various legal and/or regulatory proceedings from time to time arising in the ordinary course of business. While the ultimate outcome and impact to the Company cannot be predicted with certainty, the Company believes that all such matters are without merit and involve amounts which, if resolved unfavorably, either individually or in the aggregate, will not have a material adverse effect on its financial condition, results of operations or cash flows. 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. On July 6, 2013, a freight train operated by Montreal, Maine and Atlantic Railway (“MMA”) carrying crude oil (the “Train”) derailed in Lac-Mégantic, Quebec. In March 2014, Oasis Petroleum Inc. and OP LLC were added to a group of over fifty named defendants, including other crude oil producers as well as the Canadian Pacific Railway, MMA and certain of its affiliates, owners and transloaders of the crude oil carried by the Train, several lessors of tank cars, and the Attorney General of Canada, in a motion filed in the Quebec Superior Court to authorize a class-action lawsuit seeking economic, compensatory and punitive damages, as well as costs for claims arising out of the derailment of the Train ( Yannick Gagne, etc., et al. v. Rail World, Inc., etc., et al. , Case No. 48006000001132) (the “Class-Action”). The motion generally alleges wrongful death and negligence in the failure to provide for the proper and safe transportation of crude oil. The Company believes that all claims against Oasis Petroleum Inc. and OP LLC in connection with the derailment of the Train in Lac-Mégantic, Quebec are without merit. On August 7, 2013, MMA filed for bankruptcy protection in the Quebec Superior Court and the United States Bankruptcy Court in Bangor, Maine (together, the “Bankruptcy Actions”). The trustees appointed in the Bankruptcy Actions have negotiated settlement agreements with the majority of the named defendants in the Class-Action, including Oasis Petroleum Inc. and OP LLC. The Quebec Superior Court and the United States Bankruptcy Court have issued orders approving the settlement agreements which were pending before them, but such orders have not yet become final and are subject to appeal. If the orders become final, pursuant to the settlement agreements, Oasis Petroleum Inc. and OP LLC have agreed to contribute to the compensation fund established for those suffering losses as a result of the Lac-Megantic derailment. The Company has determined that such contributions are fully covered by the Company’s insurance policies. Furthermore, the settlement agreements would bar future litigation against Oasis Petroleum Inc. and OP LLC in Canada and the United States arising out of the Lac-Megantic derailment.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information The Notes (see Note 7) 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 immaterial wholly-owned subsidiaries do not guarantee the Notes (“Non-Guarantor Subsidiaries”). The following financial information reflects consolidating financial information of the parent company, Oasis Petroleum Inc. (“Issuer”), and its Guarantors on a combined basis, prepared on the equity basis of accounting. The Non-Guarantor Subsidiaries are immaterial and, therefore, not presented separately. 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, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Cash and cash equivalents $ 757 $ 11,508 $ — $ 12,265 Accounts receivable 16 198,166 — 198,182 Accounts receivable – affiliates 1,258 221,784 (223,042 ) — Inventory — 12,929 — 12,929 Prepaid expenses 417 8,100 8,517 Other current assets — 131,757 — 131,757 Oil and gas properties (successful efforts method) — 6,337,945 — 6,337,945 Other property and equipment — 436,052 — 436,052 Accumulated depreciation, depletion, amortization and impairment — (1,466,422 ) — (1,466,422 ) Investments in and advances to subsidiaries 4,526,226 — (4,526,226 ) — Other long-term assets 227,143 27,849 (201,109 ) 53,883 Total assets $ 4,755,817 $ 5,919,668 $ (4,950,377 ) $ 5,725,108 LIABILITIES AND EQUITY Accounts payable – affiliates 221,784 1,258 (223,042 ) — Other current liabilities 24,551 391,382 — 415,933 Long-term debt 2,200,000 180,000 — 2,380,000 Other long-term liabilities — 820,802 (201,109 ) 619,693 Common stock 1,376 — — 1,376 Other stockholders’ equity 2,308,106 4,526,226 (4,526,226 ) 2,308,106 Total liabilities and stockholders’ equity $ 4,755,817 $ 5,919,668 $ (4,950,377 ) $ 5,725,108 Condensed Consolidating Balance Sheet December 31, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Cash and cash equivalents $ 776 $ 45,035 $ — $ 45,811 Accounts receivable — 306,471 — 306,471 Accounts receivable – affiliates 781 91,459 (92,240 ) — Prepaid expenses 297 13,976 — 14,273 Other current assets — 330,052 — 330,052 Oil and gas properties (successful efforts method) — 5,966,140 — 5,966,140 Other property and equipment — 313,439 — 313,439 Accumulated depreciation, depletion, amortization and impairment — (1,092,793 ) — (1,092,793 ) Investments in and advances to subsidiaries 4,032,494 — (4,032,494 ) — Other long-term assets 178,752 25,584 (149,317 ) 55,019 Total assets $ 4,213,100 $ 5,999,363 $ (4,274,051 ) $ 5,938,412 LIABILITIES AND EQUITY Accounts payable $ — $ 20,958 $ — $ 20,958 Accounts payable – affiliates 91,459 781 (92,240 ) — Other current liabilities 49,340 724,830 — 774,170 Long-term debt 2,200,000 500,000 — 2,700,000 Other long-term liabilities — 720,300 (149,317 ) 570,983 Total stockholders’ equity 1,872,301 4,032,494 (4,032,494 ) 1,872,301 Total liabilities and stockholders’ equity $ 4,213,100 $ 5,999,363 $ (4,274,051 ) $ 5,938,412 Condensed Consolidating Statement of Operations Three Months Ended September 30, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Total revenues $ — $ 197,235 $ — $ 197,235 Total operating expenses (5,903 ) (211,430 ) — (217,333 ) Gain on sale of properties — 172 — 172 Operating loss (5,903 ) (14,023 ) — (19,926 ) Equity in earnings of subsidiaries 49,899 — (49,899 ) — Interest expense, net of capitalized interest (34,020 ) (2,493 ) — (36,513 ) Other income (expense) 1 103,885 — 103,886 Income before income taxes 9,977 87,369 (49,899 ) 47,447 Income tax benefit (expense) 17,078 (37,470 ) — (20,392 ) Net income $ 27,055 $ 49,899 $ (49,899 ) $ 27,055 Condensed Consolidating Statement of Operations Three Months Ended September 30, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Total revenues $ — $ 368,659 $ — $ 368,659 General and administrative expenses (6,373 ) (17,542 ) — (23,915 ) Other operating expenses — (210,684 ) — (210,684 ) Gain on sale of properties — 43 — 43 Operating income (loss) (6,373 ) 140,476 — 134,103 Equity in earnings of subsidiaries 148,357 — (148,357 ) — Interest expense, net of capitalized interest (36,724 ) (2,696 ) — (39,420 ) Other income (expense) — 103,388 — 103,388 Income before income taxes 105,260 241,168 (148,357 ) 198,071 Income tax benefit (expense) 16,327 (92,811 ) — (76,484 ) Net income $ 121,587 $ 148,357 $ (148,357 ) $ 121,587 Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2015 Parent/ Combined Intercompany Consolidated (In thousands) Total revenues $ — $ 607,668 $ — $ 607,668 General and administrative expenses (20,847 ) (46,343 ) — (67,190 ) Other operating expenses — (601,648 ) — (601,648 ) Gain on sale of properties — 172 — 172 Operating loss (20,847 ) (40,151 ) — (60,998 ) Equity in earnings of subsidiaries 28,269 — (28,269 ) — Interest expense, net of capitalized interest (103,435 ) (9,267 ) — (112,702 ) Other income (expense) 5 111,650 — 111,655 Income (loss) before income taxes (96,008 ) 62,232 (28,269 ) (62,045 ) Income tax benefit (expense) 51,792 (33,963 ) — 17,829 Net income (loss) $ (44,216 ) $ 28,269 $ (28,269 ) $ (44,216 ) Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Total revenues $ — $ 1,090,556 $ — $ 1,090,556 General and administrative expenses (17,790 ) (50,396 ) — (68,186 ) Other operating expenses — (579,718 ) — (579,718 ) Gain on sale of properties — 187,076 — 187,076 Operating income (loss) (17,790 ) 647,518 — 629,728 Equity in earnings of subsidiaries 410,775 — (410,775 ) — Interest expense, net of capitalized interest (110,853 ) (7,715 ) — (118,568 ) Other income (expense) 3 20,500 — 20,503 Income before income taxes 282,135 660,303 (410,775 ) 531,663 Income tax benefit (expense) 48,238 (249,528 ) — (201,290 ) Net income $ 330,373 $ 410,775 $ (410,775 ) $ 330,373 Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Net cash provided by operating activities $ 3,323 $ 277,014 $ — $ 280,337 Cash flows from investing activities: Capital expenditures — (740,633 ) — (740,633 ) Derivative settlements — 291,436 — 291,436 Other investing activities — (1,161 ) — (1,161 ) Net cash used in investing activities — (450,358 ) — (450,358 ) Cash flows from financing activities: Proceeds from sale of common stock 462,833 — — 462,833 Proceeds from revolving credit facility — 618,000 — 618,000 Principal payments on revolving credit facility — (938,000 ) — (938,000 ) Other financing activities (466,175 ) 459,817 — (6,358 ) Net cash provided by (used in) financing activities (3,342 ) 139,817 — 136,475 Decrease in cash and cash equivalents (19 ) (33,527 ) — (33,546 ) Cash and cash equivalents at beginning of period 776 45,035 — 45,811 Cash and cash equivalents at end of period $ 757 $ 11,508 $ — $ 12,265 Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Net cash provided by (used in) operating activities $ (64,099 ) $ 737,591 $ — $ 673,492 Cash flows from investing activities: Capital expenditures — (998,889 ) — (998,889 ) Proceeds from sale of properties — 324,938 — 324,938 Other investing activities — (33,163 ) — (33,163 ) Net cash used in investing activities — (707,114 ) — (707,114 ) Cash flows from financing activities: Proceeds from revolving credit facility — 370,000 — 370,000 Principal payments on revolving credit facility — (355,570 ) — (355,570 ) Other financing activities 30,599 (36,114 ) — (5,515 ) Net cash provided by (used in) financing activities 30,599 (21,684 ) — 8,915 Increase (decrease) in cash and cash equivalents (33,500 ) 8,793 — (24,707 ) Cash and cash equivalents at beginning of period 34,277 57,624 — 91,901 Cash and cash equivalents at end of period $ 777 $ 66,417 $ — $ 67,194

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
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 noted below. Credit facility borrowing base . On October 6, 2015, the Lenders completed their regular semi-annual redetermination of the borrowing base of the Second Amended Credit Facility, resulting in a borrowing base decrease from $1,700.0 million to $1,525.0 million , which equals the Lenders’ current aggregate elected commitment. Consent solicitations. On October 26, 2015, the Company, the Company’s Guarantors, and U.S. Bank National Association, as trustee, entered into supplemental indentures respecting amendments (the “Amendments”) to the Indentures governing the Company’s outstanding 7.25% senior unsecured notes due 2019, 6.5% senior unsecured notes due 2021 and 6.875% senior unsecured notes due 2023 (collectively, the “Consent Notes”) following the Company’s receipt of requisite consents of the holders of the Consent Notes pursuant to consent solicitations that commenced on October 6, 2015. The Amendments amend the basket for secured credit facilities indebtedness in each of the Indentures by (i) adding a provision that allows the Company to incur secured credit facilities indebtedness up to the amount of the Company’s borrowing base at the time of the incurrence, but not to exceed the current borrowing base of $1,525.0 million and (ii) adding, deleting or revising several related definitions in the Indentures, which changes generally restrict the Company’s ability to incur second-lien indebtedness. Derivative instruments . In October 2015, the Company entered into new swap agreements with a weighted average price of $52.19 per barrel for total notional amounts of 120,000 barrels, 3,139,000 barrels, 1,615,000 barrels and 124,000 barrels, which settle in 2015, 2016, 2017 and 2018, respectively, based on the WTI crude oil index price. These derivative instruments do not qualify for and were not designated as hedging instruments for accounting purposes. Drilling contracts. In October 2015, the Company extended a drilling rig contract, increasing the amount the Company would be obligated to pay in the event of early termination under its drilling rig contracts with initial terms greater than one year to $7.1 million as of October 1, 2015 for the days remaining through the end of the contracts. Volume commitment agreements . In October and November 2015, the Company entered into new sales agreements with an aggregate requirement to deliver approximately 7.1 MMBbl within specified timeframes, all of which are less than two years. The future commitment under these agreements is based on WTI at the time of delivery, and therefore, cannot be estimated. Cost sharing agreements. In October 2015, the Company entered into an additional agreement to share the cost to construct and install electrical facilities. The Company’s estimated future commitment under this agreement was $4.9 million .

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of the Company include the accounts of Oasis and its wholly-owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. 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, 2014 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 presentation, 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, 2014 (“ 2014 Annual Report”).
Significant Accounting Policies	Recent Accounting Pronouncements Revenue recognition. In May 2014, the Financial Accounting Standards Board (“FASB”) issued 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 also contains some new disclosure requirements under GAAP. In August 2015, the FASB issued Accounting Standards Update No. 2015-14, Deferral of the Effective Date (“ASU 2015-14”). ASU 2015-14 defers the effective date of the new revenue standard by one year, making it effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations. Going concern. In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”). ASU 2014-15 codifies in GAAP management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. ASU 2014-15 is effective for the annual reporting period ending after December 15, 2016 and for annual periods and interim periods thereafter. The adoption of this guidance will not impact the Company’s financial position, cash flows or results of operations, but could result in additional disclosures. Extraordinary items. In January 2015, the FASB issued Accounting Standards Update No. 2015-01, Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items (“ASU 2015-01”). ASU 2015-01 removes the concept of extraordinary items from GAAP. Under existing guidance, an entity is required to separately disclose extraordinary items, net of tax, in the income statement after income from continuing operations if an event or transaction is of an unusual nature and occurs infrequently. This separate, net-of-tax presentation will no longer be allowed. ASU 2015-01 is effective for fiscal years beginning after December 15, 2015, including interim periods within those years. The Company does not expect the adoption of this guidance to have a material impact on its financial position, cash flows or results of operations. Debt issuance costs. In April 2015, the FASB issued Accounting Standards Update No. 2015-03, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). ASU 2015-03 requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability, consistent with the presentation of debt discount, but it does not affect the recognition or measurement of debt issuance costs. ASU 2015-03 is effective for fiscal years beginning after December 15, 2015, including interim periods within those years, and should be applied on a retrospective basis for all prior periods presented. The Company expects that the adoption of this guidance will only impact the presentation of its balance sheet. As of September 30, 2015 and December 31, 2014, the Company had capitalized, unamortized debt issuance costs associated with debt liabilities other than line-of-credit arrangements of $25.9 million and $29.3 million , respectively, included in deferred financing costs and other assets on its Condensed Consolidated Balance Sheet. In August 2015, the FASB issued Accounting Standards Update No. 2015-15, Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements (“ASU 2015-15”), which confirms that line-of-credit arrangements are not in the scope of ASU 2015-03. ASU 2015-15 states that, for debt issuance costs related to line-of-credit arrangements, the SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs ratably over the term of the line-of-credit arrangement, regardless of whether there are outstanding borrrowings under the line-of-credit arrangement. Inventory. In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Simplifying the Measurement of Inventory (“ASU 2015-11”). ASU 2015-11 changes the inventory measurement principle from lower of cost or market to lower of cost and net realizable value for entities using the first-in, first out (FIFO) or average cost methods. ASU 2015-11 is effective for fiscal years beginning after December 15, 2016, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations. Business combinations. In September 2015, the FASB issued Accounting Standards Update No. 2015-16, Simplifying the Accounting for Measurement-Period Adjustments (“ASU 2015-16”), which eliminates the requirement for an acquirer in a business combination to restate prior period financial statements for measurement period adjustments. ASU 2015-16 requires that the cumulative impact of measurement period adjustments on current and prior periods be recognized in the reporting period in which the adjustment amount is determined. ASU 2015-16 is effective for fiscal years beginning after December 15, 2015, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations.

Inventory (Tables)

Inventory (Tables)	9 Months Ended
	Sep. 30, 2015
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consists of the following: September 30, 2015 December 31, 2014 (In thousands) Equipment and materials $ 5,569 $ 14,225 Crude oil inventory 7,360 7,129 Total inventory $ 12,929 $ 21,354

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 December 31, 2014 (In thousands) Proved oil and gas properties (1) $ 5,669,125 $ 5,156,875 Less: Accumulated depreciation, depletion, amortization and impairment (1,393,283 ) (1,043,121 ) Proved oil and gas properties, net 4,275,842 4,113,754 Unproved oil and gas properties 668,820 809,265 Total oil and gas properties, net 4,944,662 4,923,019 Other property and equipment 436,052 313,439 Less: Accumulated depreciation (73,139 ) (49,672 ) Other property and equipment, net 362,913 263,767 Total property, plant and equipment, net $ 5,307,575 $ 5,186,786 __________________ (1) Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $38.4 million and $36.9 million at September 30, 2015 and December 31, 2014 , respectively.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2015
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: At fair value as of September 30, 2015 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 742 $ — $ — $ 742 Commodity derivative instruments (see Note 6) — 135,446 — 135,446 Total assets $ 742 $ 135,446 $ — $ 136,188 Liabilities: Commodity derivative instruments (see Note 6) $ — $ 90 $ — $ 90 Total liabilities $ — $ 90 $ — $ 90 At fair value as of December 31, 2014 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 742 $ — $ — $ 742 Commodity derivative instruments (see Note 6) — 315,507 — 315,507 Total assets $ 742 $ 315,507 $ — $ 316,249

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Commodity Derivative Instruments	As of September 30, 2015 , the Company had the following outstanding commodity derivative instruments, all of which settle monthly based on the average WTI: Settlement Period Derivative Instrument Total Notional Amount of Oil Weighted Average Prices Fair Value Swap Floor Ceiling (Barrels) ($/Barrel) (In thousands) 2015 Two-way collars 455,000 $ 86.00 $ 103.42 $ 18,790 2015 Swaps 2,093,000 $ 73.35 57,933 2016 Two-way collars 155,000 $ 86.00 $ 103.42 6,133 2016 Swaps 5,643,000 $ 57.75 51,499 2017 Swaps 372,000 $ 53.84 1,001 $ 135,356
Schedule of Location and Fair Value of Outstanding Commodity Derivative Instruments	The following table summarizes the location and fair value of all outstanding commodity derivative instruments recorded in the Company’s Condensed Consolidated Balance Sheet for the periods presented: Fair Value Asset (Liability) Commodity Balance Sheet Location September 30, 2015 December 31, 2014 (In thousands) Crude oil Derivative instruments — current assets $ 130,747 $ 302,159 Crude oil Derivative instruments — non-current assets 4,699 13,348 Crude oil Derivative instruments — non-current liabilities (90 ) — Total derivative instruments $ 135,356 $ 315,507
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 Statement of Operations for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, Statement of Operations Location 2015 2014 2015 2014 (In thousands) Net gain on derivative instruments $ 103,637 $ 103,426 $ 111,285 $ 20,253
Summary of Gross and Net Information about Commodity Derivative Assets	The following tables summarize gross and net information about the Company’s commodity derivative instruments for the periods presented: Offsetting of Derivative Assets Gross Amounts of Recognized Assets Gross Amounts Offset in the Balance Sheet Net Amounts of Assets Presented in the Balance Sheet (In thousands) As of September 30, 2015 $ 153,394 $ (17,948 ) $ 135,446 As of December 31, 2014 331,121 (15,614 ) 315,507
Summary of Gross and Net Information about Commodity Derivative Liabilities	Offsetting of Derivative Liabilities Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Balance Sheet Net Amounts of Liabilities Presented in the Balance Sheet (In thousands) As of September 30, 2015 $ 18,038 $ (17,948 ) $ 90 As of December 31, 2014 15,614 (15,614 ) —

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Interest Rate	As of September 30, 2015 , any outstanding LIBOR and ABR loans bore their respective interest rates plus the applicable margin indicated in the following table: Ratio of Total Outstanding Borrowings to Borrowing Base Applicable Margin for LIBOR Loans Applicable Margin for ABR Loans Less than .25 to 1 1.50 % 0.00 % Greater than or equal to .25 to 1 but less than .50 to 1 1.75 % 0.25 % Greater than or equal to .50 to 1 but less than .75 to 1 2.00 % 0.50 % Greater than or equal to .75 to 1 but less than .90 to 1 2.25 % 0.75 % Greater than or equal to .90 to 1 2.50 % 1.00 %

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 : (In thousands) Balance at December 31, 2014 $ 42,549 Liabilities incurred during period 1,233 Liabilities settled during period (112 ) Accretion expense during period (1) 1,654 Revisions to estimates 241 Balance at September 30, 2015 $ 45,565 ___________________ (1) Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statement of Operations.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
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 stock-based compensation expense of the PSUs granted during the nine months ended September 30, 2015 : Forecast period (years) 4.00 Risk-free interest rate 0.99 % Oasis stock price volatility 50.11 %

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2015
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, 2015 and 2014 : Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (In thousands) Basic weighted average common shares outstanding 137,014 99,715 127,827 99,647 Dilution effect of stock awards at end of period (1) — 591 — 709 Diluted weighted average common shares outstanding 137,014 100,306 127,827 100,356 Anti-dilutive stock-based compensation awards 2,787 1,067 2,939 927 ___________________ (1) No unvested stock awards were included in computing earnings (loss) per share for the three and nine months ended September 30, 2015 because the effect was anti-dilutive.

Business Segment Information (T

Business Segment Information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Summarized Financial Information of Segments	The following table summarizes financial information for the Company’s business segments for the periods presented: Exploration and Production Well Services Midstream Services Eliminations Consolidated (In thousands) Three months ended September 30, 2015: Revenues from non-affiliates $ 175,270 $ 15,381 $ 6,584 $ — $ 197,235 Inter-segment revenues — 33,554 23,228 (56,782 ) — Total revenues 175,270 48,935 29,812 (56,782 ) 197,235 Operating income (loss) (38,289 ) 10,936 18,828 (11,401 ) (19,926 ) Other income (expense) 67,359 14 — — 67,373 Income before income taxes $ 29,070 $ 10,950 $ 18,828 $ (11,401 ) $ 47,447 Three months ended September 30, 2014: Revenues from non-affiliates $ 344,706 $ 20,925 $ 3,028 $ — $ 368,659 Inter-segment revenues — 66,298 10,596 (76,894 ) — Total revenues 344,706 87,223 13,624 (76,894 ) 368,659 Operating income 126,184 23,388 5,126 (20,595 ) 134,103 Other income (expense) 63,968 — — — 63,968 Income before income taxes $ 190,152 $ 23,388 $ 5,126 $ (20,595 ) $ 198,071 Nine months ended September 30, 2015: Revenues from non-affiliates $ 563,239 $ 27,308 $ 17,121 $ — $ 607,668 Inter-segment revenues — 131,220 58,994 (190,214 ) — Total revenues 563,239 158,528 76,115 (190,214 ) 607,668 Operating income (loss) (103,065 ) 29,554 44,083 (31,570 ) (60,998 ) Other income (expense) (1,037 ) 34 (44 ) — (1,047 ) Income (loss) before income taxes $ (104,102 ) $ 29,588 $ 44,039 $ (31,570 ) $ (62,045 ) Nine months ended September 30, 2014: Revenues from non-affiliates $ 1,030,735 $ 51,630 $ 8,191 $ — $ 1,090,556 Inter-segment revenues — 146,447 28,264 (174,711 ) — Total revenues 1,030,735 198,077 36,455 (174,711 ) 1,090,556 Operating income 602,797 53,137 15,854 (42,060 ) 629,728 Other income (expense) (98,140 ) 75 — — (98,065 ) Income before income taxes $ 504,657 $ 53,212 $ 15,854 $ (42,060 ) $ 531,663 As of September 30, 2015: Property, plant and equipment, net $ 5,130,061 $ 66,058 $ 261,989 $ (150,533 ) $ 5,307,575 Total assets 5,541,674 421,642 378,284 (616,492 ) 5,725,108 As of December 31, 2014: Property, plant and equipment, net $ 5,074,588 $ 58,767 $ 172,394 $ (118,963 ) $ 5,186,786 Total assets 5,802,295 281,844 212,685 (358,412 ) 5,938,412

Condensed Consolidating Finan33

Condensed Consolidating Financial Information (Tables)	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet September 30, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Cash and cash equivalents $ 757 $ 11,508 $ — $ 12,265 Accounts receivable 16 198,166 — 198,182 Accounts receivable – affiliates 1,258 221,784 (223,042 ) — Inventory — 12,929 — 12,929 Prepaid expenses 417 8,100 8,517 Other current assets — 131,757 — 131,757 Oil and gas properties (successful efforts method) — 6,337,945 — 6,337,945 Other property and equipment — 436,052 — 436,052 Accumulated depreciation, depletion, amortization and impairment — (1,466,422 ) — (1,466,422 ) Investments in and advances to subsidiaries 4,526,226 — (4,526,226 ) — Other long-term assets 227,143 27,849 (201,109 ) 53,883 Total assets $ 4,755,817 $ 5,919,668 $ (4,950,377 ) $ 5,725,108 LIABILITIES AND EQUITY Accounts payable – affiliates 221,784 1,258 (223,042 ) — Other current liabilities 24,551 391,382 — 415,933 Long-term debt 2,200,000 180,000 — 2,380,000 Other long-term liabilities — 820,802 (201,109 ) 619,693 Common stock 1,376 — — 1,376 Other stockholders’ equity 2,308,106 4,526,226 (4,526,226 ) 2,308,106 Total liabilities and stockholders’ equity $ 4,755,817 $ 5,919,668 $ (4,950,377 ) $ 5,725,108 Condensed Consolidating Balance Sheet December 31, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Cash and cash equivalents $ 776 $ 45,035 $ — $ 45,811 Accounts receivable — 306,471 — 306,471 Accounts receivable – affiliates 781 91,459 (92,240 ) — Prepaid expenses 297 13,976 — 14,273 Other current assets — 330,052 — 330,052 Oil and gas properties (successful efforts method) — 5,966,140 — 5,966,140 Other property and equipment — 313,439 — 313,439 Accumulated depreciation, depletion, amortization and impairment — (1,092,793 ) — (1,092,793 ) Investments in and advances to subsidiaries 4,032,494 — (4,032,494 ) — Other long-term assets 178,752 25,584 (149,317 ) 55,019 Total assets $ 4,213,100 $ 5,999,363 $ (4,274,051 ) $ 5,938,412 LIABILITIES AND EQUITY Accounts payable $ — $ 20,958 $ — $ 20,958 Accounts payable – affiliates 91,459 781 (92,240 ) — Other current liabilities 49,340 724,830 — 774,170 Long-term debt 2,200,000 500,000 — 2,700,000 Other long-term liabilities — 720,300 (149,317 ) 570,983 Total stockholders’ equity 1,872,301 4,032,494 (4,032,494 ) 1,872,301 Total liabilities and stockholders’ equity $ 4,213,100 $ 5,999,363 $ (4,274,051 ) $ 5,938,412
Condensed Consolidating Statement of Operations	Condensed Consolidating Statement of Operations Three Months Ended September 30, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Total revenues $ — $ 197,235 $ — $ 197,235 Total operating expenses (5,903 ) (211,430 ) — (217,333 ) Gain on sale of properties — 172 — 172 Operating loss (5,903 ) (14,023 ) — (19,926 ) Equity in earnings of subsidiaries 49,899 — (49,899 ) — Interest expense, net of capitalized interest (34,020 ) (2,493 ) — (36,513 ) Other income (expense) 1 103,885 — 103,886 Income before income taxes 9,977 87,369 (49,899 ) 47,447 Income tax benefit (expense) 17,078 (37,470 ) — (20,392 ) Net income $ 27,055 $ 49,899 $ (49,899 ) $ 27,055 Condensed Consolidating Statement of Operations Three Months Ended September 30, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Total revenues $ — $ 368,659 $ — $ 368,659 General and administrative expenses (6,373 ) (17,542 ) — (23,915 ) Other operating expenses — (210,684 ) — (210,684 ) Gain on sale of properties — 43 — 43 Operating income (loss) (6,373 ) 140,476 — 134,103 Equity in earnings of subsidiaries 148,357 — (148,357 ) — Interest expense, net of capitalized interest (36,724 ) (2,696 ) — (39,420 ) Other income (expense) — 103,388 — 103,388 Income before income taxes 105,260 241,168 (148,357 ) 198,071 Income tax benefit (expense) 16,327 (92,811 ) — (76,484 ) Net income $ 121,587 $ 148,357 $ (148,357 ) $ 121,587 Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2015 Parent/ Combined Intercompany Consolidated (In thousands) Total revenues $ — $ 607,668 $ — $ 607,668 General and administrative expenses (20,847 ) (46,343 ) — (67,190 ) Other operating expenses — (601,648 ) — (601,648 ) Gain on sale of properties — 172 — 172 Operating loss (20,847 ) (40,151 ) — (60,998 ) Equity in earnings of subsidiaries 28,269 — (28,269 ) — Interest expense, net of capitalized interest (103,435 ) (9,267 ) — (112,702 ) Other income (expense) 5 111,650 — 111,655 Income (loss) before income taxes (96,008 ) 62,232 (28,269 ) (62,045 ) Income tax benefit (expense) 51,792 (33,963 ) — 17,829 Net income (loss) $ (44,216 ) $ 28,269 $ (28,269 ) $ (44,216 ) Condensed Consolidating Statement of Operations Nine Months Ended September 30, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Total revenues $ — $ 1,090,556 $ — $ 1,090,556 General and administrative expenses (17,790 ) (50,396 ) — (68,186 ) Other operating expenses — (579,718 ) — (579,718 ) Gain on sale of properties — 187,076 — 187,076 Operating income (loss) (17,790 ) 647,518 — 629,728 Equity in earnings of subsidiaries 410,775 — (410,775 ) — Interest expense, net of capitalized interest (110,853 ) (7,715 ) — (118,568 ) Other income (expense) 3 20,500 — 20,503 Income before income taxes 282,135 660,303 (410,775 ) 531,663 Income tax benefit (expense) 48,238 (249,528 ) — (201,290 ) Net income $ 330,373 $ 410,775 $ (410,775 ) $ 330,373
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Net cash provided by operating activities $ 3,323 $ 277,014 $ — $ 280,337 Cash flows from investing activities: Capital expenditures — (740,633 ) — (740,633 ) Derivative settlements — 291,436 — 291,436 Other investing activities — (1,161 ) — (1,161 ) Net cash used in investing activities — (450,358 ) — (450,358 ) Cash flows from financing activities: Proceeds from sale of common stock 462,833 — — 462,833 Proceeds from revolving credit facility — 618,000 — 618,000 Principal payments on revolving credit facility — (938,000 ) — (938,000 ) Other financing activities (466,175 ) 459,817 — (6,358 ) Net cash provided by (used in) financing activities (3,342 ) 139,817 — 136,475 Decrease in cash and cash equivalents (19 ) (33,527 ) — (33,546 ) Cash and cash equivalents at beginning of period 776 45,035 — 45,811 Cash and cash equivalents at end of period $ 757 $ 11,508 $ — $ 12,265 Condensed Consolidating Statement of Cash Flows Nine Months Ended September 30, 2014 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Net cash provided by (used in) operating activities $ (64,099 ) $ 737,591 $ — $ 673,492 Cash flows from investing activities: Capital expenditures — (998,889 ) — (998,889 ) Proceeds from sale of properties — 324,938 — 324,938 Other investing activities — (33,163 ) — (33,163 ) Net cash used in investing activities — (707,114 ) — (707,114 ) Cash flows from financing activities: Proceeds from revolving credit facility — 370,000 — 370,000 Principal payments on revolving credit facility — (355,570 ) — (355,570 ) Other financing activities 30,599 (36,114 ) — (5,515 ) Net cash provided by (used in) financing activities 30,599 (21,684 ) — 8,915 Increase (decrease) in cash and cash equivalents (33,500 ) 8,793 — (24,707 ) Cash and cash equivalents at beginning of period 34,277 57,624 — 91,901 Cash and cash equivalents at end of period $ 777 $ 66,417 $ — $ 67,194

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 33.6
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 25.9	$ 29.3

Inventory - Schedule of Invento

Inventory - Schedule of Inventory (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Equipment and materials	$ 5,569	$ 14,225
Crude oil inventory	7,360	7,129
Total inventory	$ 12,929	$ 21,354

Property, Plant and Equipment -

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Proved oil and gas properties	[1]	$ 5,669,125	$ 5,156,875
Less: Accumulated depreciation, depletion, amortization and impairment		(1,393,283)	(1,043,121)
Proved oil and gas properties, net		4,275,842	4,113,754
Unproved oil and gas properties		668,820	809,265
Total oil and gas properties, net		4,944,662	4,923,019
Other property and equipment		436,052	313,439
Less: Accumulated depreciation		(73,139)	(49,672)
Other property and equipment, net		362,913	263,767
Total property, plant and equipment, net		5,307,575	5,186,786
Asset retirement costs		$ 38,400	$ 36,900
[1]	Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $38.4 million and $36.9 million at September 30, 2015 and December 31, 2014, respectively.

Property, Plant and Equipment37

Property, Plant and Equipment - Additional Information (Detail) - USD ($)	Mar. 05, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties		$ 80,000	$ 1,439,000	$ 24,917,000	$ 2,243,000
Gain on sale of properties		172,000	43,000	172,000	187,076,000
Unproved property leases [Member]
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties		100,000	1,400,000	24,900,000	2,200,000
Impairment of oil and gas properties, periodic assessments				16,400,000
Proved Oil And Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties		$ 0	$ 0	$ 0	$ 0
Non-Operated Oil and Natural Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of properties	$ 324,900,000
Gain on sale of properties						$ 187,000,000

Fair Value Measurements - Hiera

Fair Value Measurements - Hierarchy of Fair Value, Assets and Liabilities Measured on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Assets:
Total assets	$ 136,188	$ 316,249
Total liabilities	90
Money market funds [Member]
Assets:
Total assets	742	742
Commodity derivative instruments [Member]
Assets:
Total assets	135,446	315,507
Total liabilities	90
Level 1 [Member]
Assets:
Total assets	742	742
Total liabilities	0
Level 1 [Member] | Money market funds [Member]
Assets:
Total assets	742	742
Level 1 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets	0	0
Total liabilities	0
Level 2 [Member]
Assets:
Total assets	135,446	315,507
Total liabilities	90
Level 2 [Member] | Money market funds [Member]
Assets:
Total assets	0	0
Level 2 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets	135,446	315,507
Total liabilities	90
Level 3 [Member]
Assets:
Total assets	0	0
Total liabilities	0
Level 3 [Member] | Money market funds [Member]
Assets:
Total assets	0	0
Level 3 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets	0	$ 0
Total liabilities	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Debt Instrument [Line Items]
Derivative credit risk valuation adjustment, derivative assets	$ 200,000		$ 200,000		$ 600,000
Long-term debt	2,380,000,000		2,380,000,000		2,700,000,000
Asset retirement obligation, carrying value	45,565,000		45,565,000		$ 42,549,000
Impairment of oil and gas properties	80,000	$ 1,439,000	24,917,000	$ 2,243,000
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt	2,200,000,000		2,200,000,000
Long-term debt, fair value	1,771,300,000		1,771,300,000
Second Amended Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding	180,000,000		180,000,000
Proved Oil And Gas Properties [Member]
Debt Instrument [Line Items]
Impairment of oil and gas properties	$ 0	$ 0	$ 0	$ 0

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Outstanding Commodity Derivative Instruments (Detail) $ in Thousands	Sep. 30, 2015USD ($)MBbls$ / bbl
Derivative [Line Items]
Fair value asset (liability) | $	$ 135,356
2015 Two-Way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (barrels) | MBbls	455
Average floor price (in dollars per barrel)	86
Average ceiling price (in dollars per barrel)	103.42
Fair value asset (liability) | $	$ 18,790
2015 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (barrels) | MBbls	2,093
Average swap price (in dollars per barrel)	73.35
Fair value asset (liability) | $	$ 57,933
2016 Two Way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (barrels) | MBbls	155
Average floor price (in dollars per barrel)	86
Average ceiling price (in dollars per barrel)	103.42
Fair value asset (liability) | $	$ 6,133
2016 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (barrels) | MBbls	5,643
Average swap price (in dollars per barrel)	57.75
Fair value asset (liability) | $	$ 51,499
2017 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (barrels) | MBbls	372
Average swap price (in dollars per barrel)	53.84
Fair value asset (liability) | $	$ 1,001

Derivative Instruments - Sche41

Derivative Instruments - Schedule of Location and Fair Value of Outstanding Commodity Derivative Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative instruments — current assets	$ 130,747	$ 302,159
Derivative instruments — non-current assets	4,699	13,348
Derivative instruments — non-current liabilities	(90)	0
Total derivative instruments	135,356
Crude oil [Member]
Derivatives, Fair Value [Line Items]
Derivative instruments — current assets	130,747	302,159
Derivative instruments — non-current assets	4,699	13,348
Derivative instruments — non-current liabilities	(90)	0
Total derivative instruments	$ 135,356	$ 315,507

Derivative Instruments - Realiz

Derivative Instruments - Realized and Unrealized Gains and Losses from Commodity Derivative Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net gain on derivative instruments	$ 103,637	$ 103,426	$ 111,285	$ 20,253

Derivative Instruments - Summar

Derivative Instruments - Summary of Gross and Net Information about Commodity Derivative Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Amounts of Recognized Assets	$ 153,394	$ 331,121
Derivative Assets, Gross Amounts Offset in the Balance Sheet	(17,948)	(15,614)
Net Amounts of Assets Presented in the Balance Sheet	135,446	315,507
Gross Amounts of Recognized Liabilities	18,038	15,614
Derivative Liabilities, Gross Amounts Offset in the Balance Sheet	(17,948)	(15,614)
Net Amounts of Liabilities Presented in the Balance Sheet	$ 90	$ 0

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details)	Apr. 13, 2015USD ($)	Sep. 30, 2015USD ($)financial_institution	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)financial_institution	Sep. 30, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Apr. 12, 2015USD ($)	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Ownership percentage, guarantors				100.00%
Number of financial institutions | financial_institution		18		18
Deferred financing costs		$ 33,600,000		$ 33,600,000
Amortization of deferred financing costs		1,600,000	$ 1,600,000	$ 5,500,000	$ 4,800,000
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Net proceeds from issuance of notes							$ 1,175,800,000
Redemption percentage (up to)				35.00%
Redemption term				180 days
Percentage of minimum outstanding principal amount (at least)				65.00%
Debt instrument, default in payment of interest, term				30 days
Event of default by payment default ($10.0 million or more)				$ 10,000,000
Event of default by final judgments (in excess of $10.0 million)				$ 10,000,000
Event of default by final judgments, payment term				60 days
Deferred financing costs		25,900,000		$ 25,900,000					$ 29,300,000
Second Amended Credit Facility [Member]
Debt Instrument [Line Items]
Extension of maturity date condition, retirement or refinancing of notes, term	90 days
Line of credit facility maximum increase to aggregate commitments	$ 1,700,000,000							$ 2,000,000,000
Line of credit facility, maximum borrowing capacity	$ 1,525,000,000							$ 1,500,000,000
Line of credit facility, capacity available for specific purpose other than for trade purchases		$ 2,500,000,000		$ 2,500,000,000
Commitment fee of borrowing base capacity not utilized		0.375%
Minimum current ratio (no less than)				1
Line of credit facility, amount outstanding		$ 180,000,000		$ 180,000,000
Outstanding letters of credit		5,200,000		5,200,000
Line of credit facility, remaining borrowing capacity		$ 1,339,800,000		$ 1,339,800,000
Weighted average interest rate		1.70%		1.70%					1.90%
Minimum [Member] | Second Amended Credit Facility [Member]
Debt Instrument [Line Items]
Percentage of the reserve value of assets as determined by reserve reports (at least 80%)				80.00%
Loan term				1 month
Ratio of EBITDAX to interest expense necessary to maintain covenants (no less than)				2.5
Maximum [Member] | Second Amended Credit Facility [Member]
Debt Instrument [Line Items]
Loan term				6 months
2022 Notes [Member] | Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Principal debt amount						$ 1,000,000,000
Stated interest rate						6.875%
Net proceeds from issuance of notes						$ 983,600,000
2019 Notes [Member] | Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Principal debt amount							$ 400,000,000
Stated interest rate							7.25%
2021 Notes [Member] | Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Principal debt amount							$ 400,000,000
Stated interest rate							6.50%
2023 Notes [Member] | Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Principal debt amount							$ 400,000,000
Stated interest rate							6.875%

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt Interest Rate (Detail)	9 Months Ended
	Sep. 30, 2015
Less than .25 to 1 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.25
Less than .25 to 1 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	1.50%
Less than .25 to 1 [Member] | ABR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	0.00%
Greater than or equal to .25 to 1 but less than .50 to 1 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.5
Greater than or equal to .25 to 1 but less than .50 to 1 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.25
Greater than or equal to .25 to 1 but less than .50 to 1 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	1.75%
Greater than or equal to .25 to 1 but less than .50 to 1 [Member] | ABR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	0.25%
Greater than or equal to .50 to 1 but less than .75 to 1 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.75
Greater than or equal to .50 to 1 but less than .75 to 1 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.5
Greater than or equal to .50 to 1 but less than .75 to 1 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	2.00%
Greater than or equal to .50 to 1 but less than .75 to 1 [Member] | ABR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	0.50%
Greater than or equal to .75 to 1 but less than .90 to 1 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.9
Greater than or equal to .75 to 1 but less than .90 to 1 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.75
Greater than or equal to .75 to 1 but less than .90 to 1 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	2.25%
Greater than or equal to .75 to 1 but less than .90 to 1 [Member] | ABR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	0.75%
Greater than .90 to 1 but less than or equal 1 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Outstanding Borrowings to Borrowing Base	0.9
Greater than .90 to 1 but less than or equal 1 [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	2.50%
Greater than .90 to 1 but less than or equal 1 [Member] | ABR [Member]
Debt Instrument [Line Items]
Debt instrument interest rate terms, in percentage	1.00%

Asset Retirement Obligations -

Asset Retirement Obligations - Schedule of Changes in Asset Retirement Obligations (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at December 31, 2014	$ 42,549
Liabilities incurred during period	1,233
Liabilities settled during period	(112)
Accretion expense during period	1,654	[1]
Revisions to estimates	241
Balance at September 30, 2015	$ 45,565
[1]	Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statement of Operations.

Asset Retirement Obligations 47

Asset Retirement Obligations - Additional Information (Detail) $ in Millions	Sep. 30, 2015USD ($)
Asset Retirement Obligation Disclosure [Abstract]
Total asset retirement obligations, current portion	$ 0.6

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Effective tax rate	43.00%	38.60%	28.70%	37.90%

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 19,629	$ 15,755
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
Restricted stock granted			1,234,320
Granted, weighted average grant date fair value per unit			$ 13.08
Stock-based compensation expense	$ 5,000	$ 5,200	$ 16,800	13,400
Restricted Stock [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate			0.00%
Restricted Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate			16.90%
Performance Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted			425,590
Granted, weighted average grant date fair value per unit			$ 11.20
Stock-based compensation expense	$ 1,000	$ 800	$ 2,900	$ 2,300
Right to received shares of common stock	1		1
Performance share units initial performance period, years			3 years
Grant date fair value amortization term			4 years
Number of trading days			30 days
Performance Share Units [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate			2.40%
PSU granted percentage of earnings			0.00%
Performance Share Units [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate			4.90%
PSU granted percentage of earnings			200.00%
PSU 2015 Grants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value amortization term			4 years
Expected percentage earned	86.00%		86.00%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Assumptions (Detail) - PSU 2015 Grants [Member]	9 Months Ended
	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forecast period (years)	4 years
Risk-free interest rate	0.99%
Oasis stock price volatility	50.11%

Common Stock (Details)

Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 09, 2015	Sep. 30, 2015	Sep. 30, 2014
Class of Stock [Line Items]
Shares issued, price per share	$ 12.80
Proceeds from sale of common stock	$ 463,100	$ 462,833	$ 0
Common Stock [Member]
Class of Stock [Line Items]
Issuance of common stock, shares	36,800,000
Additional Paid-in-Capital [Member]
Class of Stock [Line Items]
Proceeds from sale of common stock	$ 462,700
Common Stock [Member]
Class of Stock [Line Items]
Issuance of common stock, shares		36,800,000
Proceeds from sale of common stock	$ 400
Over-Allotment Option [Member] | Common Stock [Member]
Class of Stock [Line Items]
Issuance of common stock, shares	4,800,000

Earnings (Loss) Per Share - Sch

Earnings (Loss) Per Share - Schedule of Weighted-Average Number of Shares Outstanding (Detail) - shares		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic weighted average common shares outstanding		137,014,000	99,715,000	127,827,000	99,647,000
Dilution effect of stock awards at end of period	[1]	0	591,000	0	709,000
Diluted weighted average common shares outstanding		137,014,000	100,306,000	127,827,000	100,356,000
Anti-dilutive stock-based compensation awards		2,787,000	1,067,000	2,939,000	927,000
Equity Unit Purchase Agreements [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive stock-based compensation awards		0		0
[1]	No unvested stock awards were included in computing earnings (loss) per share for the three and nine months ended September 30, 2015 because the effect was anti-dilutive.

Business Segment Information -

Business Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2015Segment
Segment Reporting [Abstract]
Current operating units	3

Business Segment Information 54

Business Segment Information - Summarized Financial Information of Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total revenues	$ 197,235	$ 368,659	$ 607,668	$ 1,090,556
Operating income (loss)	(19,926)	134,103	(60,998)	629,728
Other income (expense)	67,373	63,968	(1,047)	(98,065)
Income (loss) before income taxes	47,447	198,071	(62,045)	531,663
Property, plant and equipment, net	5,307,575		5,307,575		$ 5,186,786
Total assets	5,725,108		5,725,108		5,938,412
Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total revenues	175,270	344,706	563,239	1,030,735
Well Services [Member]
Segment Reporting Information [Line Items]
Total revenues	48,935	87,223	158,528	198,077
Midstream Services [Member]
Segment Reporting Information [Line Items]
Total revenues	29,812	13,624	76,115	36,455
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	197,235	368,659	607,668	1,090,556
Operating income (loss)	(19,926)	134,103	(60,998)	629,728
Other income (expense)	67,373	63,968	(1,047)	(98,065)
Income (loss) before income taxes	47,447	198,071	(62,045)	531,663
Property, plant and equipment, net	5,307,575		5,307,575		5,186,786
Total assets	5,725,108		5,725,108		5,938,412
Operating Segments [Member] | Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total revenues	175,270	344,706	563,239	1,030,735
Operating income (loss)	(38,289)	126,184	(103,065)	602,797
Other income (expense)	67,359	63,968	(1,037)	(98,140)
Income (loss) before income taxes	29,070	190,152	(104,102)	504,657
Property, plant and equipment, net	5,130,061		5,130,061		5,074,588
Total assets	5,541,674		5,541,674		5,802,295
Operating Segments [Member] | Well Services [Member]
Segment Reporting Information [Line Items]
Total revenues	15,381	20,925	27,308	51,630
Operating income (loss)	10,936	23,388	29,554	53,137
Other income (expense)	14	0	34	75
Income (loss) before income taxes	10,950	23,388	29,588	53,212
Property, plant and equipment, net	66,058		66,058		58,767
Total assets	421,642		421,642		281,844
Operating Segments [Member] | Midstream Services [Member]
Segment Reporting Information [Line Items]
Total revenues	6,584	3,028	17,121	8,191
Operating income (loss)	18,828	5,126	44,083	15,854
Other income (expense)	0		(44)
Income (loss) before income taxes	18,828	5,126	44,039	15,854
Property, plant and equipment, net	261,989		261,989		172,394
Total assets	378,284		378,284		212,685
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	(56,782)	(76,894)	(190,214)	(174,711)
Operating income (loss)	(11,401)	(20,595)	(31,570)	(42,060)
Income (loss) before income taxes	(11,401)	(20,595)	(31,570)	(42,060)
Property, plant and equipment, net	(150,533)		(150,533)		(118,963)
Total assets	(616,492)		(616,492)		$ (358,412)
Segment Reconciling Items [Member] | Well Services [Member]
Segment Reporting Information [Line Items]
Total revenues	33,554	66,298	131,220	146,447
Segment Reconciling Items [Member] | Midstream Services [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 23,228	$ 10,596	$ 58,994	$ 28,264

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Thousands	Jul. 06, 2013defendant	Sep. 30, 2015USD ($)MBblsMMcf	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)MBblsMMcf	Sep. 30, 2014USD ($)	Oct. 01, 2015USD ($)
Commitments And Contingencies [Line Items]
Total rental commitments under leases		$ 28,700		$ 28,700
Rig termination		0	$ 0	3,895	$ 0
Future obligations under purchase agreements				38,600
Future obligations under cost sharing agreements				2,300
Number of named defendants (over) | defendant	50
Long Term Commitments [Member]
Commitments And Contingencies [Line Items]
Future obligations under supply agreements				193,800
Drilling contracts [Member]
Commitments And Contingencies [Line Items]
Payments upon early contract termination		$ 5,300		$ 5,300		$ 7,100
Williston Basin Project [Member] | Long Term Commitments [Member]
Commitments And Contingencies [Line Items]
Maximum commitment term (less than)				10 years
Williston Basin Project [Member] | Long Term Commitments [Member] | Crude oil [Member]
Commitments And Contingencies [Line Items]
Minimum quantity of delivery | MBbls		29,200		29,200
Williston Basin Project [Member] | Long Term Commitments [Member] | Natural Gas [Member]
Commitments And Contingencies [Line Items]
Minimum quantity of delivery | MMcf		4,100		4,100

Condensed Consolidating Finan56

Condensed Consolidating Financial Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Ownership percentage, guarantors	100.00%

Condensed Consolidating Finan57

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
ASSETS
Cash and cash equivalents	$ 12,265	$ 45,811	$ 67,194	$ 91,901
Accounts receivable	198,182	306,471
Inventory	12,929	21,354
Prepaid expenses	8,517	14,273
Other current assets	131,757	330,052
Oil and gas properties (successful efforts method)	6,337,945	5,966,140
Other property and equipment	436,052	313,439
Less: accumulated depreciation, depletion, amortization and impairment	(1,466,422)	(1,092,793)
Other long-term assets	53,883	55,019
Total assets	5,725,108	5,938,412
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable	19,505	20,958
Other current liabilities	415,933	774,170
Long-term debt	2,380,000	2,700,000
Other long-term liabilities	619,693	570,983
Common stock	1,376	1,001
Other stockholders’ equity	2,308,106
Total stockholders’ equity	2,309,482	1,872,301
Total liabilities and stockholders’ equity	5,725,108	5,938,412
Parent/Issuer [Member]
ASSETS
Cash and cash equivalents	757	776	777	34,277
Accounts receivable	16
Accounts receivable – affiliates	1,258	781
Prepaid expenses	417	297
Investments in and advances to subsidiaries	4,526,226	4,032,494
Other long-term assets	227,143	178,752
Total assets	4,755,817	4,213,100
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable – affiliates	221,784	91,459
Other current liabilities	24,551	49,340
Long-term debt	2,200,000	2,200,000
Common stock	1,376
Other stockholders’ equity	2,308,106
Total stockholders’ equity		1,872,301
Total liabilities and stockholders’ equity	4,755,817	4,213,100
Combined Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	11,508	45,035	$ 66,417	$ 57,624
Accounts receivable	198,166	306,471
Accounts receivable – affiliates	221,784	91,459
Inventory	12,929
Prepaid expenses	8,100	13,976
Other current assets	131,757	330,052
Oil and gas properties (successful efforts method)	6,337,945	5,966,140
Other property and equipment	436,052	313,439
Less: accumulated depreciation, depletion, amortization and impairment	(1,466,422)	(1,092,793)
Other long-term assets	27,849	25,584
Total assets	5,919,668	5,999,363
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable		20,958
Accounts payable – affiliates	1,258	781
Other current liabilities	391,382	724,830
Long-term debt	180,000	500,000
Other long-term liabilities	820,802	720,300
Other stockholders’ equity	4,526,226
Total stockholders’ equity		4,032,494
Total liabilities and stockholders’ equity	5,919,668	5,999,363
Intercompany Eliminations [Member]
ASSETS
Accounts receivable – affiliates	(223,042)	(92,240)
Investments in and advances to subsidiaries	(4,526,226)	(4,032,494)
Other long-term assets	(201,109)	(149,317)
Total assets	(4,950,377)	(4,274,051)
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable – affiliates	(223,042)	(92,240)
Other long-term liabilities	(201,109)	(149,317)
Other stockholders’ equity	(4,526,226)
Total stockholders’ equity		(4,032,494)
Total liabilities and stockholders’ equity	$ (4,950,377)	$ (4,274,051)

Condensed Consolidating Finan58

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues
Total revenues	$ 197,235	$ 368,659	$ 607,668	$ 1,090,556
Operating expenses
General and administrative expenses	(22,358)	(23,915)	(67,190)	(68,186)
Other operating expenses		(210,684)	(601,648)	(579,718)
Total operating expenses	(217,333)	(234,599)	(668,838)	(647,904)
Gain on sale of properties	172	43	172	187,076
Operating income (loss)	(19,926)	134,103	(60,998)	629,728
Other income (expense)
Interest expense, net of capitalized interest	(36,513)	(39,420)	(112,702)	(118,568)
Other income (expense)	103,886	103,388	111,655	20,503
Income (loss) before income taxes	47,447	198,071	(62,045)	531,663
Income tax benefit (expense)	(20,392)	(76,484)	17,829	(201,290)
Net income (loss)	27,055	121,587	(44,216)	330,373
Parent/Issuer [Member]
Operating expenses
General and administrative expenses		(6,373)	(20,847)	(17,790)
Total operating expenses	(5,903)
Operating income (loss)	(5,903)	(6,373)	(20,847)	(17,790)
Other income (expense)
Equity in earnings in subsidiaries	49,899	148,357	28,269	410,775
Interest expense, net of capitalized interest	(34,020)	(36,724)	(103,435)	(110,853)
Other income (expense)	1		5	3
Income (loss) before income taxes	9,977	105,260	(96,008)	282,135
Income tax benefit (expense)	17,078	16,327	51,792	48,238
Net income (loss)	27,055	121,587	(44,216)	330,373
Combined Guarantor Subsidiaries [Member]
Revenues
Total revenues	197,235	368,659	607,668	1,090,556
Operating expenses
General and administrative expenses		(17,542)	(46,343)	(50,396)
Other operating expenses		(210,684)	(601,648)	(579,718)
Total operating expenses	(211,430)
Gain on sale of properties	172	43	172	187,076
Operating income (loss)	(14,023)	140,476	(40,151)	647,518
Other income (expense)
Interest expense, net of capitalized interest	(2,493)	(2,696)	(9,267)	(7,715)
Other income (expense)	103,885	103,388	111,650	20,500
Income (loss) before income taxes	87,369	241,168	62,232	660,303
Income tax benefit (expense)	(37,470)	(92,811)	(33,963)	(249,528)
Net income (loss)	49,899	148,357	28,269	410,775
Intercompany Eliminations [Member]
Other income (expense)
Equity in earnings in subsidiaries	(49,899)	(148,357)	(28,269)	(410,775)
Income (loss) before income taxes	(49,899)	(148,357)	(28,269)	(410,775)
Net income (loss)	$ (49,899)	$ (148,357)	$ (28,269)	$ (410,775)

Condensed Consolidating Finan59

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Thousands	Mar. 09, 2015	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net cash provided by (used in) operating activities		$ 280,337	$ 673,492
Cash flows from investing activities:
Capital expenditures		(740,633)	(998,889)
Proceeds from sale of properties		78	324,938
Derivative settlements		291,436	(24,773)
Other investing activities		(1,161)	(33,163)
Net cash used in investing activities		(450,358)	(707,114)
Cash flows from financing activities:
Proceeds from sale of common stock	$ 463,100	462,833	0
Proceeds from revolving credit facility		618,000	370,000
Principal payments on revolving credit facility		(938,000)	(355,570)
Other financing activities		(6,358)	(5,515)
Net cash provided by financing activities		136,475	8,915
Decrease in cash and cash equivalents		(33,546)	(24,707)
Beginning of period		45,811	91,901
End of period		12,265	67,194
Parent/Issuer [Member]
Cash flows from operating activities:
Net cash provided by (used in) operating activities		3,323	(64,099)
Cash flows from financing activities:
Proceeds from sale of common stock		462,833
Other financing activities		(466,175)	30,599
Net cash provided by financing activities		(3,342)	30,599
Decrease in cash and cash equivalents		(19)	(33,500)
Beginning of period		776	34,277
End of period		757	777
Combined Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net cash provided by (used in) operating activities		277,014	737,591
Cash flows from investing activities:
Capital expenditures		(740,633)	(998,889)
Proceeds from sale of properties			324,938
Derivative settlements		291,436
Other investing activities		(1,161)	(33,163)
Net cash used in investing activities		(450,358)	(707,114)
Cash flows from financing activities:
Proceeds from revolving credit facility		618,000	370,000
Principal payments on revolving credit facility		(938,000)	(355,570)
Other financing activities		459,817	(36,114)
Net cash provided by financing activities		139,817	(21,684)
Decrease in cash and cash equivalents		(33,527)	8,793
Beginning of period		45,035	57,624
End of period		$ 11,508	$ 66,417

Subsequent Events (Details)

Subsequent Events (Details)	1 Months Ended	9 Months Ended
	Oct. 31, 2015USD ($)	Sep. 30, 2015USD ($)MBbls	Nov. 05, 2015MBbls	Oct. 30, 2015MBbls$ / bbl	Oct. 06, 2015USD ($)	Oct. 05, 2015USD ($)	Oct. 01, 2015USD ($)	Apr. 13, 2015USD ($)	Apr. 12, 2015USD ($)	Dec. 31, 2012
Subsequent Event [Line Items]
Future obligations under cost sharing agreements | $		$ 2,300,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Average swap price (in dollars per barrel) | $ / bbl				52.19
Future obligations under cost sharing agreements | $	$ 4,900,000
Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Line of credit facility maximum increase to aggregate commitments | $								$ 1,700,000,000	$ 2,000,000,000
Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of credit facility maximum increase to aggregate commitments | $					$ 1,525,000,000	$ 1,700,000,000
2015 Swaps [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Derivative, notional amount of oil (barrels)				120
2016 Swaps [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Derivative, notional amount of oil (barrels)				3,139
2017 Swaps [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Derivative, notional amount of oil (barrels)				1,615
2018 Swaps [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Derivative, notional amount of oil (barrels)				124
2019 Notes [Member] | Senior Unsecured Debt [Member]
Subsequent Event [Line Items]
Stated interest rate										7.25%
2021 Notes [Member] | Senior Unsecured Debt [Member]
Subsequent Event [Line Items]
Stated interest rate										6.50%
2023 Notes [Member] | Senior Unsecured Debt [Member]
Subsequent Event [Line Items]
Stated interest rate										6.875%
Drilling contracts [Member]
Subsequent Event [Line Items]
Payments upon early contract termination | $		$ 5,300,000					$ 7,100,000
Williston Basin Project [Member] | Long Term Commitments [Member] | Crude oil [Member]
Subsequent Event [Line Items]
Minimum quantity of delivery		29,200
Williston Basin Project [Member] | Long Term Commitments [Member] | Crude oil [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Minimum quantity of delivery			7,100