Chord Energy (CHRD) 10-Q 10 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	May. 04, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
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		180,449,655

Condensed Consolidated Balance

Condensed Consolidated Balance Sheet (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 19,397	$ 9,730
Accounts receivable — oil and gas revenues	92,684	96,495
Accounts receivable — joint interest and other	104,512	100,914
Inventory	10,723	11,072
Prepaid expenses	7,411	7,328
Derivative instruments	91,590	139,697
Other current assets	46	50
Total current assets	326,363	365,286
Property, plant and equipment
Oil and gas properties (successful efforts method)	6,327,027	6,284,401
Other property and equipment	477,343	443,265
Less: accumulated depreciation, depletion, amortization and impairment	(1,627,201)	(1,509,424)
Total property, plant and equipment, net	5,177,169	5,218,242
Assets held for sale	25,845	26,728
Derivative instruments	7,521	15,776
Other assets	23,370	23,343
Total assets	5,560,268	5,649,375
Current liabilities
Accounts payable	10,101	9,983
Revenues and production taxes payable	115,412	132,356
Accrued liabilities	126,765	167,669
Accrued interest payable	24,277	49,413
Derivative instruments	1,018	0
Advances from joint interest partners	4,390	4,647
Other current liabilities	500	6,500
Total current liabilities	282,463	370,568
Long-term debt	2,201,938	2,302,584
Deferred income taxes	580,526	608,155
Asset retirement obligations	36,088	35,338
Liabilities held for sale	10,155	10,228
Derivative instruments	1,558	0
Other liabilities	3,091	3,160
Total liabilities	$ 3,115,819	$ 3,330,033
Commitments and contingencies
Stockholders’ equity
Common stock, $0.01 par value: 300,000,000 shares authorized; 181,298,001 shares issued and 180,582,855 shares outstanding at March 31, 2016 and 139,583,990 shares issued and 139,076,064 shares outstanding at December 31, 2015	$ 1,774	$ 1,376
Treasury stock, at cost: 715,146 and 507,926 shares at March 31, 2016 and December 31, 2015, respectively	(14,652)	(13,620)
Additional paid-in capital	1,687,261	1,497,065
Retained earnings	770,066	834,521
Total stockholders’ equity	2,444,449	2,319,342
Total liabilities and stockholders’ equity	$ 5,560,268	$ 5,649,375

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheet (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	181,298,001	139,583,990
Common stock, shares outstanding (in shares)	180,582,855	139,076,064
Treasury stock, shares (in shares)	715,146	507,926

Condensed Consolidated Statemen

Condensed Consolidated Statement of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Oil and gas revenues	$ 117,315	$ 173,859
Well services and midstream revenues	12,968	6,528
Total revenues	130,283	180,387
Operating expenses
Lease operating expenses	31,064	39,125
Well services and midstream operating expenses	4,389	1,952
Marketing, transportation and gathering expenses	8,552	7,278
Production taxes	10,753	16,621
Depreciation, depletion and amortization	122,449	118,478
Exploration expenses	363	843
Rig termination	0	1,080
Impairment	3,562	5,321
General and administrative expenses	24,366	23,324
Total operating expenses	205,498	214,022
Operating loss	(75,215)	(33,635)
Other income (expense)
Net gain on derivative instruments	14,375	47,072
Interest expense, net of capitalized interest	(38,739)	(38,784)
Gain on extinguishment of debt	7,016	0
Other income (expense)	479	(70)
Total other income (expense)	(16,869)	8,218
Loss before income taxes	(92,084)	(25,417)
Income tax benefit	27,629	7,376
Net loss	$ (64,455)	$ (18,041)
Loss per share:
Basic (in dollars per share)	$ (0.40)	$ (0.17)
Diluted (in dollars per share)	$ (0.40)	$ (0.17)
Weighted average shares outstanding:
Basic (in shares)	162,922	109,303
Diluted (in shares)	162,922	109,303

Condensed Consolidated Stateme5

Condensed Consolidated Statement of Changes in Stockholders' Equity (Unaudited) - 3 months ended Mar. 31, 2016 - 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, 2015		139,076	508
Balance at Dec. 31, 2015	$ 2,319,342	$ 1,376	$ (13,620)	$ 1,497,065	$ 834,521
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, shares		39,100
Issuance of common stock	183,164	$ 391		182,773
Stock-based compensation, shares		2,614
Stock-based compensation	7,430			7,430
Vesting of restricted shares	0	$ 7		(7)
Treasury stock - tax withholdings, shares		(207)	207
Treasury stock – tax withholdings	(1,032)		$ (1,032)
Net loss	(64,455)				(64,455)
Balance, shares at Mar. 31, 2016		180,583	715
Balance at Mar. 31, 2016	$ 2,444,449	$ 1,774	$ (14,652)	$ 1,687,261	$ 770,066

Condensed Consolidated Stateme6

Condensed Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net loss	$ (64,455)	$ (18,041)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	122,449	118,478
Gain on extinguishment of debt	(7,016)	0
Impairment	3,562	5,321
Deferred income taxes	(27,629)	(7,376)
Derivative instruments	(14,375)	(47,072)
Stock-based compensation expenses	6,730	7,606
Deferred financing costs amortization and other	5,066	1,655
Working capital and other changes:
Change in accounts receivable	(995)	63,313
Change in inventory	349	(602)
Change in prepaid expenses	241	1,892
Change in other current assets	4	5,539
Change in other assets	77	0
Change in accounts payable, interest payable and accrued liabilities	(64,056)	(42,341)
Change in other current liabilities	(6,000)	0
Change in other liabilities	(3)	(11)
Net cash provided by (used in) operating activities	(46,051)	88,361
Cash flows from investing activities:
Capital expenditures	(103,411)	(359,113)
Derivative settlements	73,313	109,259
Advances from joint interest partners	(257)	(828)
Net cash used in investing activities	(30,355)	(250,682)
Cash flows from financing activities:
Repurchase of senior unsecured notes	(22,308)	0
Proceeds from revolving credit facility	214,000	145,000
Principal payments on revolving credit facility	(287,000)	(480,000)
Deferred financing costs	(751)	0
Proceeds from sale of common stock	183,164	463,218
Purchases of treasury stock	(1,032)	(1,520)
Net cash provided by financing activities	86,073	126,698
Increase (decrease) in cash and cash equivalents	9,667	(35,623)
Cash and cash equivalents:
Beginning of period	9,730	45,811
End of period	19,397	10,188
Supplemental non-cash transactions:
Change in accrued capital expenditures	(19,230)	(90,189)
Change in asset retirement obligations	$ 1,212	$ 1,413

Organization and Operations of

Organization and Operations of the Company	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Organization and Operations of the Company	Organization and Operations of the Company Oasis Petroleum Inc. (together with its consolidated subsidiaries, “Oasis” or the “Company”) was originally formed in 2007 and was incorporated pursuant to the laws of the State of Delaware in 2010. The Company is an independent exploration and production company focused on the acquisition and development of unconventional oil and natural gas resources in the North Dakota and Montana regions of the Williston Basin. Oasis Petroleum North America LLC (“OPNA”) conducts the Company’s exploration and production activities and owns its proved and unproved oil and natural gas properties. The Company also operates a well services business through Oasis Well Services LLC (“OWS”) and a midstream services business through Oasis Midstream Services LLC (“OMS”), both of which are separate reportable business segments that are complementary to its primary development and production activities.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2016
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, 2015 is derived from audited financial statements. 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, 2015 (“ 2015 Annual Report”). Risks and Uncertainties As an oil and natural gas producer, the Company’s revenue, profitability and future growth are substantially dependent upon the prevailing and future prices for oil and natural gas, which are dependent upon numerous factors beyond its control such as economic, political and regulatory developments and competition from other energy sources. The energy markets have historically been very volatile, and there can be no assurance that oil and natural gas prices will not be subject to wide fluctuations in the future. Oil and natural gas prices have declined significantly since mid-2014. As a result of sustained lower commodity prices, the Company decreased its 2016 capital expenditures as compared to 2015 and continues to concentrate its drilling activities in certain areas that are the most economic in the Williston Basin. An extended period of low prices for oil and, to a lesser extent, natural gas could have a material adverse effect on the Company’s financial position, results of operations, cash flows and quantities of oil and natural gas reserves that may be economically produced. Significant Accounting Policies There have been no material changes to the Company’s critical accounting policies and estimates from those disclosed in the 2015 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. In March 2016, the FASB issued Accounting Standards Update No. 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which clarifies the implementation guidance on principal versus agent considerations on such matters. 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. 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. Financial instruments. In January 2016, the FASB issued Accounting Standards Update No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”), which requires that most equity instruments be measured at fair value with subsequent changes in fair value recognized in net income. ASU 2016-01 also impacts financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. ASU 2016-01 does not apply to equity method investments or investments in consolidated subsidiaries. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, 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. Leases. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (“ASU 2016-02”), which requires a lessee to recognize lease payment obligations and a corresponding right-of-use asset to be measured at fair value on the balance sheet. ASU 2016-02 also requires certain qualitative and quantitative disclosures about the amount, timing and uncertainty of cash flows arising from leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, 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. Embedded derivatives. In March 2016, the FASB issued Accounting Standards Update No. 2016-06, Contingent Put and Call Options in Debt Instruments (“ASU 2016-06”), which clarifies what steps are required when assessing whether the economic characteristics and risks of call (put) options are clearly and closely related to the economic characteristics and risks of their debt hosts, which is one of the criteria for bifurcating an embedded derivative. ASU 2016-06 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. Stock-based compensation. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”), which updates several aspects of the accounting for share-based payment transactions, including recognition of excess tax benefits and deficiencies, the classification of those excess tax benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. ASU 2016-09 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.

Inventory

Inventory	3 Months Ended
	Mar. 31, 2016
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, well fracturing equipment, and equipment to be used in the natural gas processing plant that is under construction. 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: March 31, 2016 December 31, 2015 (In thousands) Equipment and materials $ 4,729 $ 4,920 Crude oil inventory 5,994 6,152 Total inventory $ 10,723 $ 11,072

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2016
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 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 March 31, 2016 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 54 $ — $ — $ 54 Commodity derivative instruments (see Note 5) — 99,111 — 99,111 Total assets $ 54 $ 99,111 $ — $ 99,165 Liabilities: Commodity derivative instruments (see Note 5) $ — $ 2,576 $ — $ 2,576 Total liabilities $ — $ 2,576 $ — $ 2,576 At fair value as of December 31, 2015 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 742 $ — $ — $ 742 Commodity derivative instruments (see Note 5) — 155,473 — 155,473 Total assets $ 742 $ 155,473 $ — $ 156,215 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 March 31, 2016 and December 31, 2015 . 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 $0.1 million and $0.3 million at March 31, 2016 and December 31, 2015 , respectively. There were no transfers between fair value levels during the three months ended March 31, 2016 and 2015 . 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 March 31, 2016 , 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 March 31, 2016 was $2,201.9 million , which included $2,170.2 million of senior unsecured notes, $65.0 million of borrowings under the revolving credit facility and a $33.3 million reduction for deferred financing costs on the senior unsecured notes (see Note 8 – 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 $1,632.7 million at March 31, 2016 . Non-Financial Assets and Liabilities Asset retirement obligations. The carrying amount of ARO in the Company’s Condensed Consolidated Balance Sheet at March 31, 2016 was $37.0 million (see Note 9 – 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 and 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 proved oil and natural gas properties to the 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. As of March 31, 2016 , the Company had certain proved oil and natural gas properties and other midstream properties held for sale (see Note 7 — Assets Held for Sale). For the three months ended March 31, 2016, the Company recorded an impairment loss of $3.6 million , of which $2.4 million was included in earnings in its midstream services segment and $1.1 million was included in earnings in its exploration and production segment, to adjust the current carrying value of these assets, net of the associated ARO liabilities, to their estimated fair value of $15.7 million . For the year ended December 31, 2015, the Company recorded an impairment loss of $9.4 million to adjust its net assets held for sale to their estimated fair value. The fair value was determined based on the expected sales price, less costs to sell. No other impairment charges on proved oil and natural gas properties were recorded for the three months ended March 31, 2016 . No impairment charges on proved oil and natural gas properties were recorded for the three months ended March 31, 2015 . In addition, 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 $5.3 million for the three months ended March 31, 2015 . For the three months ended March 31, 2016 , the Company did not record similar impairment charges as current expiring leases were already expensed as a result of the Company’s periodic assessments of unproved properties in prior periods.

Derivative Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2016
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 March 31, 2016 , 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 4 – 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 March 31, 2016 , the Company had the following outstanding commodity derivative instruments, all of which settle monthly based on the average NYMEX West Texas Intermediate crude oil index price (“WTI”): Settlement Period Derivative Instrument Total Notional Amount of Oil Weighted Average Prices Fair Value Swap Floor Ceiling (Barrels) ($/Barrel) (In thousands) 2016 Swaps 8,707,000 $ 50.60 $ 82,960 2017 Swaps 3,967,000 $ 48.01 13,906 2017 Two-way collars 668,000 $ 40.00 $ 47.58 (638 ) 2018 Swaps 279,000 $ 47.61 433 2018 Two-way collars 62,000 $ 40.00 $ 47.58 (126 ) $ 96,535 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 March 31, 2016 December 31, 2015 (In thousands) Crude oil Derivative instruments — current assets $ 91,590 $ 139,697 Crude oil Derivative instruments — non-current assets 7,521 15,776 Crude oil Derivative instruments — current liabilities (1,018 ) — Crude oil Derivative instruments — non-current liabilities (1,558 ) — Total derivative instruments $ 96,535 $ 155,473 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 March 31, Statement of Operations Location 2016 2015 (In thousands) Net gain on derivative instruments $ 14,375 $ 47,072 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 March 31, 2016 $ 108,205 $ (9,094 ) $ 99,111 As of December 31, 2015 155,473 — 155,473 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 March 31, 2016 $ 11,670 $ (9,094 ) $ 2,576 As of December 31, 2015 — — —

Property, Plant and Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2016
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: March 31, 2016 December 31, 2015 (In thousands) Proved oil and gas properties (1) $ 5,698,259 $ 5,655,759 Less: accumulated depreciation, depletion, amortization and impairment (1,539,515 ) (1,428,427 ) Proved oil and gas properties, net 4,158,744 4,227,332 Unproved oil and gas properties 628,768 628,642 Other property and equipment 477,343 443,265 Less: accumulated depreciation (87,686 ) (80,997 ) Other property and equipment, net 389,657 362,268 Total property, plant and equipment, net $ 5,177,169 $ 5,218,242 __________________ (1) Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $31.1 million and $30.7 million at March 31, 2016 and December 31, 2015 , respectively.

Assets Held for Sale

Assets Held for Sale	3 Months Ended
	Mar. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Assets Held for Sale	Assets Held for Sale Net assets held for sale represent the assets that were expected to be sold, net of liabilities, which were expected to be assumed by the purchaser. As of March 31, 2016 and December 31, 2015, certain legacy wells that have been producing from conventional reservoirs such as the Madison, Red River and other formations in the Williston Basin other than the Bakken or Three Forks formations were held for sale. These assets primarily consist of oil and gas properties in the Company’s exploration and production segment and include certain other property and equipment in the Company’s midstream segment. For the three months ended March 31, 2016 and the year ended December 31, 2015, the Company recorded losses of $3.6 million and $9.4 million , respectively, which were included in impairment on the Company’s Condensed Consolidated Statement of Operations, to adjust the carrying value of these assets to their estimated fair value, determined based on the expected sales price, less costs to sell. The Company sold these assets on April 1, 2016 (see Note 17 – Subsequent Events). The following table presents balance sheet data related to the assets held for sale: March 31, 2016 (In thousands) Assets: Oil and gas properties $ 121,137 Other property and equipment 34 Less: accumulated depreciation, depletion, amortization and impairment (95,326 ) Total assets $ 25,845 Liabilities: Asset retirement obligation $ (10,155 ) Total liabilities $ (10,155 ) Net assets $ 15,690

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt As of March 31, 2016 and December 31, 2015 , the Company’s long-term debt consisted of the following: March 31, 2016 December 31, 2015 (In thousands) Senior unsecured notes 7.25% senior unsecured notes due February 1, 2019 $ 400,000 $ 400,000 6.5% senior unsecured notes due November 1, 2021 399,000 400,000 6.875% senior unsecured notes due March 15, 2022 985,000 1,000,000 6.875% senior unsecured notes due January 15, 2023 386,200 400,000 Less: deferred financing costs related to senior unsecured notes (33,262 ) (35,416 ) Senior secured revolving line of credit 65,000 138,000 Total long-term debt $ 2,201,938 $ 2,302,584 Senior unsecured notes. At March 31, 2016 , the Company had $2,170.2 million principal amount of senior unsecured notes outstanding with maturities ranging from February 2019 to January 2023 and coupons ranging from 6.5% to 7.25% (the “Notes”). Interest on the Notes is payable semi-annually in arrears. The Notes are guaranteed on a senior unsecured basis by the Company, along with its material subsidiaries (the “Guarantors”), which are 100% owned by the Company. These guarantees are full and unconditional and joint and several among the Guarantors, subject to certain customary release provisions. The indentures governing the Notes contain customary events of default as well as covenants that place restrictions on the Company and certain of its subsidiaries. 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 March 31, 2016 and December 31, 2015 . In March 2016, the Company repurchased an aggregate principal amount of $29.8 million of its outstanding Notes, consisting of $1.0 million principal amount of its 6.5% senior unsecured notes due November 2021, $15.0 million principal amount of its 6.875% senior unsecured notes due March 2022 and $13.8 million principal amount of its 6.875% senior unsecured notes due January 2023, for an aggregate cost of $22.3 million , including accrued interest and fees. The Company recognized a pre-tax gain of $7.0 million related to these repurchases, which was net of the $0.5 million write-off of unamortized deferred financing costs, and is reflected in gain on extinguishment of debt in the Company’s Condensed Consolidated Statement of Operations for the three months ended March 31, 2016 . Senior secured revolving line of credit. The Company has a senior secured revolving line of credit of $2,500.0 million as of March 31, 2016 (the “Credit Facility”), which has a maturity date of April 13, 2020. The Credit Facility is restricted to a borrowing base, which is reserve-based and subject to semi-annual redeterminations on April 1 and October 1 of each year. On February 23, 2016, the lenders under the Credit Facility completed their regular semi-annual redetermination of the borrowing base scheduled for April 1, 2016, resulting in a decrease in the borrowing base and aggregate elected commitment from $1,525.0 million to $1,150.0 million . As of March 31, 2016 , the Company had $45.0 million of LIBOR loans, $20.0 million of ABR loans and $14.2 million of outstanding letters of credit issued under the Credit Facility, resulting in an unused borrowing base committed capacity of $1,070.8 million . The weighted average interest rate on borrowings outstanding under the Credit Facility was 1.9% as of both March 31, 2016 and December 31, 2015 . On a quarterly basis, the Company also pays a 0.375% (as of March 31, 2016 ) 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. The Company was in compliance with the financial covenants of the Credit Facility as of March 31, 2016 . Deferred financing costs. As of March 31, 2016 , the Company had $39.3 million of deferred financing costs related to the Notes and the Credit Facility. Deferred financing costs of $33.3 million related to the Notes are included in long-term debt on the Company’s Condensed Consolidated Balance Sheet as of March 31, 2016 , and are being amortized over the respective terms of the Notes. Deferred financing costs of $6.0 million related to the Credit Facility are included in other assets on the Company’s Condensed Consolidated Balance Sheet as of March 31, 2016 , and are being amortized over the term of the Credit Facility. Amortization of deferred financing costs recorded for the three months ended March 31, 2016 and 2015 was $2.1 million and $1.6 million , respectively, and are included in interest expense on the Company’s Condensed Consolidated Statement of Operations. For the three months ended March 31, 2016 , the Company’s interest expense also included a $1.8 million charge for unamortized deferred financing costs related to the Credit Facility, which were written off in proportion to the decrease in the borrowing base. No deferred financing costs were written off during the three months ended March 31, 2015 .

Asset Retirement Obligations

Asset Retirement Obligations	3 Months Ended
	Mar. 31, 2016
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The following table reflects the changes in the Company’s ARO during the three months ended March 31, 2016 : (In thousands) Balance at December 31, 2015 $ 35,812 Liabilities incurred during period 64 Liabilities settled during period (5 ) Accretion expense during period (1) 465 Revisions to estimates 571 Liabilities held for sale (2) 73 Balance at March 31, 2016 $ 36,980 ___________________ (1) Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statement of Operations. (2) Represents the change in ARO related to the properties held for sale during the three months ended March 31, 2016 . The total ARO related to the properties held for sale as of March 31, 2016 was $10.2 million (see Note 7 – Assets Held for Sale). At March 31, 2016 , the current portion of the total ARO balance was approximately $0.9 million and is included in accrued liabilities on the Company’s Condensed Consolidated Balance Sheet.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate for the three months ended March 31, 2016 and 2015 was 30.0% and 29.0% , respectively. The effective tax rates for both periods were lower than the combined federal statutory rate and the statutory rates for the states in which the Company conducts business due to the impact of permanent differences on the pre-tax loss for each period. The permanent differences were primarily between amounts expensed for book purposes versus the amounts deductible for income tax purposes related to stock-based compensation vesting during the three months ended March 31, 2016 and 2015 at stock prices lower than the grant date values. The Company had deferred tax assets for its federal and state tax net operating losses and other tax carryforwards at March 31, 2016 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. During the three months ended March 31, 2016 , the Company recorded a valuation allowance of $0.9 million and $0.6 million for Montana net operating losses and federal charitable contribution carryovers, respectively, based on management’s assessment that it is more likely than not that these net deferred tax assets will not be realized prior to their expiration due to current economic conditions and expectations for the future. Management determined that a valuation allowance was not required for its U.S. federal tax net operating loss carryforwards as they are expected to be fully utilized before their expiration. As of March 31, 2016 , the Company did not have any uncertain tax positions requiring adjustments to its tax liability.

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Common Stock	Common Stock On February 2, 2016, the Company completed a public offering of 39,100,000 shares of its common stock (including 5,100,000 shares issued pursuant to the underwriters’ option to purchase additional common stock) at an offering price of $4.685 per share. Net proceeds from the offering were $183.2 million , after deducting underwriting discounts and commissions and offering expenses, of which $0.4 million is included in common stock and $182.8 million is included in additional paid-in capital on the Company’s Condensed Consolidated Balance Sheet as of March 31, 2016 . The Company used the net proceeds 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.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2016
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 three months ended March 31, 2016 , the Company assumed annual forfeiture rates by employee group ranging from 0% to 20.0% based on the Company’s forfeiture history for this type of award. During the three months ended March 31, 2016 , employees and non-employee directors of the Company were granted restricted stock awards equal to 2,563,700 shares of common stock with a $ 4.32 weighted average grant date per share value. Stock-based compensation expense recorded for restricted stock awards for the three months ended March 31, 2016 and 2015 was $5.8 million and $6.8 million , respectively, and 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 three months ended March 31, 2016 , the Company assumed annual forfeiture rates by employee group ranging from 3.3% to 4.6% based on the Company’s forfeiture history for the officer employee groups receiving PSUs. During the three months ended March 31, 2016 , officers of the Company were granted 910,000 PSUs with a $ 3.00 weighted average grant date per share value. Stock-based compensation expense recorded for PSUs for the three months ended March 31, 2016 and 2015 was $0.9 million and $0.8 million , respectively, and is included in general and administrative expenses on the Company’s Condensed Consolidated Statement of Operations. The Company accounted for these PSUs as equity awards pursuant to the FASB’s authoritative guidance for share-based payments. The number of PSUs to be earned is subject to a market condition, which is based on a comparison of the total shareholder return (“TSR”) achieved with respect to shares of the Company’s common stock against the TSR achieved by a defined peer group at the end of the performance periods. Depending on the Company’s TSR performance relative to the defined peer group, award recipients will earn between 0% and 200% of the initial PSUs granted. The grant date fair value for each grant of PSUs is recognized on a straight-line basis over a four-year total performance period. All compensation expense related to the PSUs will be recognized if the requisite performance period is fulfilled, even if the market condition is not achieved. The aggregate grant date fair value of the market-based awards was determined using a Monte Carlo simulation model, which results in an expected percentage of PSUs earned. 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 total 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 three months ended March 31, 2016 : Forecast period (years) 4.00 Risk-free interest rate 1.25 % Oasis stock price volatility 59.38 % For the PSUs granted during the three months ended March 31, 2016 , the Monte Carlo simulation model resulted in approximately 69% of PSUs expected to be earned.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per Share Basic earnings (loss) per share is computed by dividing the earnings (loss) attributable to 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 the earnings (loss) attributable 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 months ended March 31, 2016 and 2015 : Three Months Ended March 31, 2016 2015 (In thousands) Basic weighted average common shares outstanding 162,922 109,303 Dilution effect of stock awards at end of period (1) — — Diluted weighted average common shares outstanding 162,922 109,303 Anti-dilutive stock-based compensation awards 4,668 3,046 ___________________ (1) No unvested stock awards were included in computing loss per share for the three months ended March 31, 2016 and 2015 because the effect was anti-dilutive.

Business Segment Information

Business Segment Information	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Business Segment Information	Business Segment Information The Company’s exploration and production segment is engaged in the acquisition and development of oil and natural gas properties. Revenues for the exploration and production segment are derived from the sale of oil and natural gas production. The Company’s well services business segment (OWS) performs completion services for the Company’s oil and natural gas wells operated by OPNA. Revenues for the well services segment are derived from providing well completion services and tool rentals. The Company’s midstream services business segment (OMS) performs 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 pipeline 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 March 31, 2016: Revenues from non-affiliates $ 117,315 $ 5,985 $ 6,983 $ — $ 130,283 Inter-segment revenues — 24,903 22,835 (47,738 ) — Total revenues 117,315 30,888 29,818 (47,738 ) 130,283 Operating income (loss) (88,877 ) 4,006 15,144 (5,488 ) (75,215 ) Other income (expense) (16,887 ) 5 13 — (16,869 ) Income (loss) before income taxes $ (105,764 ) $ 4,011 $ 15,157 $ (5,488 ) $ (92,084 ) Three months ended March 31, 2015: Revenues from non-affiliates $ 173,859 $ 2,708 $ 3,820 $ — $ 180,387 Inter-segment revenues — 48,197 13,822 (62,019 ) — Total revenues 173,859 50,905 17,642 (62,019 ) 180,387 Operating income (loss) (42,247 ) 9,610 9,308 (10,306 ) (33,635 ) Other income (expense) 8,239 (2 ) (19 ) — 8,218 Income (loss) before income taxes $ (34,008 ) $ 9,608 $ 9,289 $ (10,306 ) $ (25,417 ) As of March 31, 2016: Property, plant and equipment, net $ 4,994,366 $ 57,821 $ 295,913 $ (170,931 ) $ 5,177,169 Total assets (1) 5,367,881 62,076 301,242 (170,931 ) 5,560,268 As of December 31, 2015: Property, plant and equipment, net $ 5,057,311 $ 61,402 $ 264,956 $ (165,427 ) $ 5,218,242 Total assets (1) 5,478,439 66,952 269,411 (165,427 ) 5,649,375 ___________________ (1) As of March 31, 2016, total assets included assets held for sale of $25.8 million in the exploration and production segment and $34,000 in the midstream services segment. As of December 31, 2015, total assets included assets held for sale of $26.7 million in the exploration and production segment (see Note 7 – Assets Held for Sale). For the periods presented, the intercompany receivables (payables) for all segments were reclassified to capital contributions from (distributions to) parent and not included in total assets.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2016
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 March 31, 2016 . 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 as of March 31, 2016 were $24.6 million . Drilling contracts. As of March 31, 2016 , the Company had certain drilling rig contracts with initial terms of one year or greater. In the event of early termination under these contracts, the Company would be obligated to pay approximately $1.8 million as of March 31, 2016 through the end of the primary terms of the contracts. Volume commitment agreements. As of March 31, 2016 , the Company had certain agreements with an aggregate requirement to deliver or transport a minimum quantity of approximately 32.5 MMBbl of crude oil, 23.0 MMBbl of natural gas liquids and 221.8 Bcf of natural gas, prior to any applicable volume credits, within specified timeframes, all of which are ten years or less. The estimable future commitments under these agreements were approximately $446.2 million as of March 31, 2016 . The future commitments under certain agreements cannot be estimated as they are based on fixed differentials relative to WTI under the agreements as compared to the differential relative to WTI for the Williston Basin for the production month. Purchase agreements . As of March 31, 2016 , the Company had certain agreements for the purchase of fresh water with an aggregate future commitment of approximately $42.4 million . 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.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information The Notes (see Note 8 – Long-Term Debt) are guaranteed on a senior unsecured basis by the Guarantors, which are 100% owned by the Company. These guarantees are full and unconditional and joint and several among the Guarantors. Certain of the Company’s 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 March 31, 2016 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Current assets Cash and cash equivalents $ 90 $ 19,307 $ — $ 19,397 Accounts receivable – oil and gas revenues — 92,684 — 92,684 Accounts receivable – joint interest and other — 104,512 — 104,512 Accounts receivable – affiliates 1,348 150,125 (151,473 ) — Inventory — 10,723 — 10,723 Prepaid expenses 139 7,272 — 7,411 Derivative instruments — 91,590 — 91,590 Other current assets — 46 — 46 Total current assets 1,577 476,259 (151,473 ) 326,363 Property, plant and equipment Oil and gas properties (successful efforts method) — 6,327,027 — 6,327,027 Other property and equipment — 477,343 — 477,343 Less: accumulated depreciation, depletion, amortization and impairment — (1,627,201 ) — (1,627,201 ) Total property, plant and equipment, net — 5,177,169 — 5,177,169 Assets held for sale — 25,845 — 25,845 Investments in and advances to subsidiaries 4,541,136 — (4,541,136 ) — Derivative instruments — 7,521 — 7,521 Deferred income taxes 213,270 — (213,270 ) — Other assets — 23,370 — 23,370 Total assets $ 4,755,983 $ 5,710,164 $ (4,905,879 ) $ 5,560,268 LIABILITIES AND EQUITY Current liabilities Accounts payable $ — $ 10,101 $ — $ 10,101 Accounts payable – affiliates 150,125 1,348 (151,473 ) — Revenues and production taxes payable — 115,412 — 115,412 Accrued liabilities 216 126,549 — 126,765 Accrued interest payable 24,255 22 — 24,277 Derivative instruments — 1,018 — 1,018 Advances from joint partners — 4,390 — 4,390 Other current liabilities — 500 — 500 Total current liabilities 174,596 259,340 (151,473 ) 282,463 Long-term debt 2,136,938 65,000 — 2,201,938 Deferred income taxes — 793,796 (213,270 ) 580,526 Asset retirement obligations — 36,088 — 36,088 Liabilities held for sale — 10,155 — 10,155 Derivative instruments — 1,558 — 1,558 Other liabilities — 3,091 — 3,091 Total liabilities 2,311,534 1,169,028 (364,743 ) 3,115,819 Stockholders’ equity Capital contributions from affiliates — 3,375,186 (3,375,186 ) — Common stock, $0.01 par value: 300,000,000 shares authorized; 181,298,001 shares issued and 180,582,855 shares outstanding 1,774 — — 1,774 Treasury stock, at cost: 715,146 shares (14,652 ) — — (14,652 ) Additional paid-in-capital 1,687,261 8,743 (8,743 ) 1,687,261 Retained earnings 770,066 1,157,207 (1,157,207 ) 770,066 Total stockholders’ equity 2,444,449 4,541,136 (4,541,136 ) 2,444,449 Total liabilities and stockholders’ equity $ 4,755,983 $ 5,710,164 $ (4,905,879 ) $ 5,560,268 Condensed Consolidating Balance Sheet December 31, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Current assets Cash and cash equivalents $ 777 $ 8,953 $ — $ 9,730 Accounts receivable – oil and gas revenues — 96,495 — 96,495 Accounts receivable – joint interest and other 15 100,899 — 100,914 Accounts receivable – affiliates 1,248 247,488 (248,736 ) — Inventory — 11,072 — 11,072 Prepaid expenses 278 7,050 — 7,328 Derivative instruments — 139,697 — 139,697 Other current assets — 50 — 50 Total current assets 2,318 611,704 (248,736 ) 365,286 Property, plant and equipment Oil and gas properties (successful efforts method) — 6,284,401 — 6,284,401 Other property and equipment — 443,265 — 443,265 Less: accumulated depreciation, depletion, amortization and impairment — (1,509,424 ) — (1,509,424 ) Total property, plant and equipment, net — 5,218,242 — 5,218,242 Assets held for sale — 26,728 — 26,728 Investments in and advances to subsidiaries 4,573,172 — (4,573,172 ) — Derivative instruments — 15,776 — 15,776 Deferred income taxes 205,174 — (205,174 ) — Other assets 100 23,243 — 23,343 Total assets $ 4,780,764 $ 5,895,693 $ (5,027,082 ) $ 5,649,375 LIABILITIES AND EQUITY Current liabilities Accounts payable $ — $ 9,983 $ — $ 9,983 Accounts payable – affiliates 247,488 1,248 (248,736 ) — Revenue and production taxes payable — 132,356 — 132,356 Accrued liabilities 10 167,659 — 167,669 Accrued interest payable 49,340 73 — 49,413 Advances from joint interest partners — 4,647 — 4,647 Other current liabilities — 6,500 — 6,500 Total current liabilities 296,838 322,466 (248,736 ) 370,568 Long-term debt 2,164,584 138,000 — 2,302,584 Deferred income taxes — 813,329 (205,174 ) 608,155 Asset retirement obligations — 35,338 — 35,338 Liabilities held for sale — 10,228 — 10,228 Other liabilities — 3,160 — 3,160 Total liabilities 2,461,422 1,322,521 (453,910 ) 3,330,033 Stockholders’ equity Capital contributions from affiliates — 3,369,895 (3,369,895 ) — Common stock, $0.01 par value: 300,000,000 shares authorized; 139,583,990 shares issued and 139,076,064 shares outstanding 1,376 — — 1,376 Treasury stock, at cost: 507,926 shares (13,620 ) — — (13,620 ) Additional paid-in-capital 1,497,065 8,743 (8,743 ) 1,497,065 Retained earnings 834,521 1,194,534 (1,194,534 ) 834,521 Total stockholders’ equity 2,319,342 4,573,172 (4,573,172 ) 2,319,342 Total liabilities and stockholders’ equity $ 4,780,764 $ 5,895,693 $ (5,027,082 ) $ 5,649,375 Condensed Consolidating Statement of Operations Three Months Ended March 31, 2016 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 117,315 $ — $ 117,315 Well services and midstream revenues — 12,968 — 12,968 Total revenues — 130,283 — 130,283 Operating expenses Lease operating expenses — 31,064 — 31,064 Well services and midstream operating expenses — 4,389 — 4,389 Marketing, transportation and gathering expenses — 8,552 — 8,552 Production taxes — 10,753 — 10,753 Depreciation, depletion and amortization — 122,449 — 122,449 Exploration expenses — 363 — 363 Impairment — 3,562 — 3,562 General and administrative expenses 7,451 16,915 — 24,366 Total operating expenses 7,451 198,047 — 205,498 Operating loss (7,451 ) (67,764 ) — (75,215 ) Other income (expense) Equity in loss of subsidiaries (37,327 ) — 37,327 — Net gain on derivative instruments — 14,375 — 14,375 Interest expense, net of capitalized interest (34,832 ) (3,907 ) — (38,739 ) Gain on extinguishment of debt 7,016 — — 7,016 Other income 43 436 — 479 Total other income (expense) (65,100 ) 10,904 37,327 (16,869 ) Loss before income taxes (72,551 ) (56,860 ) 37,327 (92,084 ) Income tax benefit 8,096 19,533 — 27,629 Net loss $ (64,455 ) $ (37,327 ) $ 37,327 $ (64,455 ) Condensed Consolidating Statement of Operations Three Months Ended March 31, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 173,859 $ — $ 173,859 Well services and midstream revenues — 6,528 — 6,528 Total revenues — 180,387 — 180,387 Operating expenses Lease operating expenses — 39,125 — 39,125 Well services and midstream operating expenses — 1,952 — 1,952 Marketing, transportation and gathering expenses — 7,278 — 7,278 Production taxes — 16,621 — 16,621 Depreciation, depletion and amortization — 118,478 — 118,478 Exploration expenses — 843 — 843 Rig termination — 1,080 — 1,080 Impairment — 5,321 — 5,321 General and administrative expenses 8,619 14,705 — 23,324 Total operating expenses 8,619 205,403 — 214,022 Operating loss (8,619 ) (25,016 ) — (33,635 ) Other income (expense) Equity in earnings of subsidiaries 12,619 — (12,619 ) — Net gain on derivative instruments — 47,072 — 47,072 Interest expense, net of capitalized interest (35,221 ) (3,563 ) — (38,784 ) Other expense (1 ) (69 ) — (70 ) Total other income (expense) (22,603 ) 43,440 (12,619 ) 8,218 Income (loss) before income taxes (31,222 ) 18,424 (12,619 ) (25,417 ) Income tax benefit (expense) 13,181 (5,805 ) — 7,376 Net income (loss) $ (18,041 ) $ 12,619 $ (12,619 ) $ (18,041 ) Condensed Consolidating Statement of Cash Flows Three Months Ended March 31, 2016 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Cash flows from operating activities: Net loss $ (64,455 ) $ (37,327 ) $ 37,327 $ (64,455 ) Adjustments to reconcile net loss to cash provided by (used in) operating activities: Equity in loss of subsidiaries 37,327 — (37,327 ) — Depreciation, depletion and amortization — 122,449 — 122,449 Gain on extinguishment of debt (7,016 ) — — (7,016 ) Impairment — 3,562 — 3,562 Deferred income taxes (8,096 ) (19,533 ) — (27,629 ) Derivative instruments — (14,375 ) — (14,375 ) Stock-based compensation expenses 6,547 183 — 6,730 Deferred financing costs amortization and other 1,701 3,365 — 5,066 Working capital and other changes: Change in accounts receivable (85 ) 96,353 (97,263 ) (995 ) Change in inventory — 349 — 349 Change in prepaid expenses 139 102 — 241 Change in other current assets — 4 — 4 Change in other assets 77 — — 77 Change in accounts payable, interest payable and accrued liabilities (122,242 ) (39,077 ) 97,263 (64,056 ) Change in other current liabilities — (6,000 ) — (6,000 ) Change in other liabilities — (3 ) — (3 ) Net cash provided by (used in) operating activities (156,103 ) 110,052 — (46,051 ) Cash flows from investing activities: Capital expenditures — (103,411 ) — (103,411 ) Derivative settlements — 73,313 — 73,313 Advances from joint interest partners — (257 ) — (257 ) Net cash used in investing activities — (30,355 ) — (30,355 ) Cash flows from financing activities: Repurchase of senior unsecured notes (22,308 ) — — (22,308 ) Proceeds from revolving credit facility — 214,000 — 214,000 Principal payments on revolving credit facility — (287,000 ) — (287,000 ) Deferred financing costs — (751 ) — (751 ) Proceeds from sale of common stock 183,164 — — 183,164 Purchases of treasury stock (1,032 ) — — (1,032 ) Investment in / capital contributions from subsidiaries (4,408 ) 4,408 — — Net cash provided by (used in) financing activities 155,416 (69,343 ) — 86,073 Increase (decrease) in cash and cash equivalents (687 ) 10,354 — 9,667 Cash and cash equivalents at beginning of period 777 8,953 — 9,730 Cash and cash equivalents at end of period $ 90 $ 19,307 $ — $ 19,397 Condensed Consolidating Statement of Cash Flows Three Months Ended March 31, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Cash flows from operating activities: Net income (loss) $ (18,041 ) $ 12,619 $ (12,619 ) $ (18,041 ) Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities: Equity in earnings of subsidiaries (12,619 ) — 12,619 — Depreciation, depletion and amortization — 118,478 — 118,478 Impairment — 5,321 — 5,321 Deferred income taxes (13,180 ) 5,804 — (7,376 ) Derivative instruments — (47,072 ) — (47,072 ) Stock-based compensation expenses 7,542 64 — 7,606 Deferred financing costs amortization and other 1,119 536 — 1,655 Working capital and other changes: Change in accounts receivable (251 ) 11,255 52,309 63,313 Change in inventory — (602 ) — (602 ) Change in prepaid expenses 149 1,743 — 1,892 Change in other current assets — 5,539 — 5,539 Change in accounts payable, interest payable and accrued liabilities 27,293 (17,325 ) (52,309 ) (42,341 ) Change in other liabilities — (11 ) — (11 ) Net cash provided by (used in) operating activities (7,988 ) 96,349 — 88,361 Cash flows from investing activities: Capital expenditures — (359,113 ) — (359,113 ) Derivative settlements — 109,259 — 109,259 Advances from joint interest partners — (828 ) — (828 ) Net cash used in investing activities — (250,682 ) — (250,682 ) Cash flows from financing activities: Proceeds from revolving credit facility — 145,000 — 145,000 Principal payments on revolving credit facility — (480,000 ) — (480,000 ) Proceeds from sale of common stock 463,218 — — 463,218 Purchases of treasury stock (1,520 ) — — (1,520 ) Investment in / capital contributions from subsidiaries (453,712 ) 453,712 — — Net cash provided by financing activities 7,986 118,712 — 126,698 Decrease in cash and cash equivalents (2 ) (35,621 ) — (35,623 ) Cash and cash equivalents at beginning of period 776 45,035 — 45,811 Cash and cash equivalents at end of period $ 774 $ 9,414 $ — $ 10,188

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2016
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. Divestiture. On April 1, 2016, the Company completed the sale of certain legacy wells that have been producing from conventional reservoirs and other formations in the Williston Basin other than the Bakken or Three Forks formations for cash proceeds of approximately $12.2 million , which includes, and is subject to further, customary post close adjustments, and a $4.0 million 10% secured promissory note due within one year. Extinguishment of debt. In April 2016, the Company repurchased an additional aggregate principal amount of $46.8 million of its outstanding Notes, consisting of $1.0 million principal amount of its 7.25% senior unsecured notes due February 2019, $1.3 million principal amount of its 6.5% senior unsecured notes due November 2021 and $44.5 million principal amount of its 6.875% senior unsecured notes due March 2022, for an aggregate cost of $34.6 million , including accrued interest and fees. Derivative instruments . In April and May 2016, the Company entered into new swap and three-way costless collar agreements with a weighted average floor price of $46.23 per barrel for total notional amounts of 153,000 barrels, 1,061,000 barrels and 62,000 barrels, which settle in 2016, 2017 and 2018, respectively, based on WTI. These derivative instruments do not qualify for and were not designated as hedging instruments for accounting purposes.

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2016
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, 2015 is derived from audited financial statements. 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, 2015 (“ 2015 Annual Report”).
Risks and Uncertainties	Risks and Uncertainties As an oil and natural gas producer, the Company’s revenue, profitability and future growth are substantially dependent upon the prevailing and future prices for oil and natural gas, which are dependent upon numerous factors beyond its control such as economic, political and regulatory developments and competition from other energy sources. The energy markets have historically been very volatile, and there can be no assurance that oil and natural gas prices will not be subject to wide fluctuations in the future. Oil and natural gas prices have declined significantly since mid-2014. As a result of sustained lower commodity prices, the Company decreased its 2016 capital expenditures as compared to 2015 and continues to concentrate its drilling activities in certain areas that are the most economic in the Williston Basin. An extended period of low prices for oil and, to a lesser extent, natural gas could have a material adverse effect on the Company’s financial position, results of operations, cash flows and quantities of oil and natural gas reserves that may be economically produced.
Recent Accounting Pronouncements	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. In March 2016, the FASB issued Accounting Standards Update No. 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which clarifies the implementation guidance on principal versus agent considerations on such matters. 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. 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. Financial instruments. In January 2016, the FASB issued Accounting Standards Update No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”), which requires that most equity instruments be measured at fair value with subsequent changes in fair value recognized in net income. ASU 2016-01 also impacts financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. ASU 2016-01 does not apply to equity method investments or investments in consolidated subsidiaries. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, 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. Leases. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (“ASU 2016-02”), which requires a lessee to recognize lease payment obligations and a corresponding right-of-use asset to be measured at fair value on the balance sheet. ASU 2016-02 also requires certain qualitative and quantitative disclosures about the amount, timing and uncertainty of cash flows arising from leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, 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. Embedded derivatives. In March 2016, the FASB issued Accounting Standards Update No. 2016-06, Contingent Put and Call Options in Debt Instruments (“ASU 2016-06”), which clarifies what steps are required when assessing whether the economic characteristics and risks of call (put) options are clearly and closely related to the economic characteristics and risks of their debt hosts, which is one of the criteria for bifurcating an embedded derivative. ASU 2016-06 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. Stock-based compensation. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”), which updates several aspects of the accounting for share-based payment transactions, including recognition of excess tax benefits and deficiencies, the classification of those excess tax benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. ASU 2016-09 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.

Inventory (Tables)

Inventory (Tables)	3 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consists of the following: March 31, 2016 December 31, 2015 (In thousands) Equipment and materials $ 4,729 $ 4,920 Crude oil inventory 5,994 6,152 Total inventory $ 10,723 $ 11,072

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2016
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 March 31, 2016 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 54 $ — $ — $ 54 Commodity derivative instruments (see Note 5) — 99,111 — 99,111 Total assets $ 54 $ 99,111 $ — $ 99,165 Liabilities: Commodity derivative instruments (see Note 5) $ — $ 2,576 $ — $ 2,576 Total liabilities $ — $ 2,576 $ — $ 2,576 At fair value as of December 31, 2015 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money market funds $ 742 $ — $ — $ 742 Commodity derivative instruments (see Note 5) — 155,473 — 155,473 Total assets $ 742 $ 155,473 $ — $ 156,215

Derivative Instruments (Tables)

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Commodity Derivative Instruments	As of March 31, 2016 , the Company had the following outstanding commodity derivative instruments, all of which settle monthly based on the average NYMEX West Texas Intermediate crude oil index price (“WTI”): Settlement Period Derivative Instrument Total Notional Amount of Oil Weighted Average Prices Fair Value Swap Floor Ceiling (Barrels) ($/Barrel) (In thousands) 2016 Swaps 8,707,000 $ 50.60 $ 82,960 2017 Swaps 3,967,000 $ 48.01 13,906 2017 Two-way collars 668,000 $ 40.00 $ 47.58 (638 ) 2018 Swaps 279,000 $ 47.61 433 2018 Two-way collars 62,000 $ 40.00 $ 47.58 (126 ) $ 96,535
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 March 31, 2016 December 31, 2015 (In thousands) Crude oil Derivative instruments — current assets $ 91,590 $ 139,697 Crude oil Derivative instruments — non-current assets 7,521 15,776 Crude oil Derivative instruments — current liabilities (1,018 ) — Crude oil Derivative instruments — non-current liabilities (1,558 ) — Total derivative instruments $ 96,535 $ 155,473
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 March 31, Statement of Operations Location 2016 2015 (In thousands) Net gain on derivative instruments $ 14,375 $ 47,072
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 March 31, 2016 $ 108,205 $ (9,094 ) $ 99,111 As of December 31, 2015 155,473 — 155,473
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 March 31, 2016 $ 11,670 $ (9,094 ) $ 2,576 As of December 31, 2015 — — —

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	The following table sets forth the Company’s property, plant and equipment: March 31, 2016 December 31, 2015 (In thousands) Proved oil and gas properties (1) $ 5,698,259 $ 5,655,759 Less: accumulated depreciation, depletion, amortization and impairment (1,539,515 ) (1,428,427 ) Proved oil and gas properties, net 4,158,744 4,227,332 Unproved oil and gas properties 628,768 628,642 Other property and equipment 477,343 443,265 Less: accumulated depreciation (87,686 ) (80,997 ) Other property and equipment, net 389,657 362,268 Total property, plant and equipment, net $ 5,177,169 $ 5,218,242 __________________ (1) Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $31.1 million and $30.7 million at March 31, 2016 and December 31, 2015 , respectively.

Assets Held for Sale (Tables)

Assets Held for Sale (Tables)	3 Months Ended
	Mar. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Assets Held for Sale	The following table presents balance sheet data related to the assets held for sale: March 31, 2016 (In thousands) Assets: Oil and gas properties $ 121,137 Other property and equipment 34 Less: accumulated depreciation, depletion, amortization and impairment (95,326 ) Total assets $ 25,845 Liabilities: Asset retirement obligation $ (10,155 ) Total liabilities $ (10,155 ) Net assets $ 15,690

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	As of March 31, 2016 and December 31, 2015 , the Company’s long-term debt consisted of the following: March 31, 2016 December 31, 2015 (In thousands) Senior unsecured notes 7.25% senior unsecured notes due February 1, 2019 $ 400,000 $ 400,000 6.5% senior unsecured notes due November 1, 2021 399,000 400,000 6.875% senior unsecured notes due March 15, 2022 985,000 1,000,000 6.875% senior unsecured notes due January 15, 2023 386,200 400,000 Less: deferred financing costs related to senior unsecured notes (33,262 ) (35,416 ) Senior secured revolving line of credit 65,000 138,000 Total long-term debt $ 2,201,938 $ 2,302,584

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	3 Months Ended
	Mar. 31, 2016
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 three months ended March 31, 2016 : (In thousands) Balance at December 31, 2015 $ 35,812 Liabilities incurred during period 64 Liabilities settled during period (5 ) Accretion expense during period (1) 465 Revisions to estimates 571 Liabilities held for sale (2) 73 Balance at March 31, 2016 $ 36,980 ___________________ (1) Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statement of Operations. (2) Represents the change in ARO related to the properties held for sale during the three months ended March 31, 2016 . The total ARO related to the properties held for sale as of March 31, 2016 was $10.2 million (see Note 7 – Assets Held for Sale).

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2016
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 three months ended March 31, 2016 : Forecast period (years) 4.00 Risk-free interest rate 1.25 % Oasis stock price volatility 59.38 %

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	3 Months Ended
	Mar. 31, 2016
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 months ended March 31, 2016 and 2015 : Three Months Ended March 31, 2016 2015 (In thousands) Basic weighted average common shares outstanding 162,922 109,303 Dilution effect of stock awards at end of period (1) — — Diluted weighted average common shares outstanding 162,922 109,303 Anti-dilutive stock-based compensation awards 4,668 3,046 ___________________ (1) No unvested stock awards were included in computing loss per share for the three months ended March 31, 2016 and 2015 because the effect was anti-dilutive.

Business Segment Information (T

Business Segment Information (Tables)	3 Months Ended
	Mar. 31, 2016
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 March 31, 2016: Revenues from non-affiliates $ 117,315 $ 5,985 $ 6,983 $ — $ 130,283 Inter-segment revenues — 24,903 22,835 (47,738 ) — Total revenues 117,315 30,888 29,818 (47,738 ) 130,283 Operating income (loss) (88,877 ) 4,006 15,144 (5,488 ) (75,215 ) Other income (expense) (16,887 ) 5 13 — (16,869 ) Income (loss) before income taxes $ (105,764 ) $ 4,011 $ 15,157 $ (5,488 ) $ (92,084 ) Three months ended March 31, 2015: Revenues from non-affiliates $ 173,859 $ 2,708 $ 3,820 $ — $ 180,387 Inter-segment revenues — 48,197 13,822 (62,019 ) — Total revenues 173,859 50,905 17,642 (62,019 ) 180,387 Operating income (loss) (42,247 ) 9,610 9,308 (10,306 ) (33,635 ) Other income (expense) 8,239 (2 ) (19 ) — 8,218 Income (loss) before income taxes $ (34,008 ) $ 9,608 $ 9,289 $ (10,306 ) $ (25,417 ) As of March 31, 2016: Property, plant and equipment, net $ 4,994,366 $ 57,821 $ 295,913 $ (170,931 ) $ 5,177,169 Total assets (1) 5,367,881 62,076 301,242 (170,931 ) 5,560,268 As of December 31, 2015: Property, plant and equipment, net $ 5,057,311 $ 61,402 $ 264,956 $ (165,427 ) $ 5,218,242 Total assets (1) 5,478,439 66,952 269,411 (165,427 ) 5,649,375 ___________________ (1) As of March 31, 2016, total assets included assets held for sale of $25.8 million in the exploration and production segment and $34,000 in the midstream services segment. As of December 31, 2015, total assets included assets held for sale of $26.7 million in the exploration and production segment (see Note 7 – Assets Held for Sale). For the periods presented, the intercompany receivables (payables) for all segments were reclassified to capital contributions from (distributions to) parent and not included in total assets.

Condensed Consolidating Finan35

Condensed Consolidating Financial Information (Tables)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet March 31, 2016 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Current assets Cash and cash equivalents $ 90 $ 19,307 $ — $ 19,397 Accounts receivable – oil and gas revenues — 92,684 — 92,684 Accounts receivable – joint interest and other — 104,512 — 104,512 Accounts receivable – affiliates 1,348 150,125 (151,473 ) — Inventory — 10,723 — 10,723 Prepaid expenses 139 7,272 — 7,411 Derivative instruments — 91,590 — 91,590 Other current assets — 46 — 46 Total current assets 1,577 476,259 (151,473 ) 326,363 Property, plant and equipment Oil and gas properties (successful efforts method) — 6,327,027 — 6,327,027 Other property and equipment — 477,343 — 477,343 Less: accumulated depreciation, depletion, amortization and impairment — (1,627,201 ) — (1,627,201 ) Total property, plant and equipment, net — 5,177,169 — 5,177,169 Assets held for sale — 25,845 — 25,845 Investments in and advances to subsidiaries 4,541,136 — (4,541,136 ) — Derivative instruments — 7,521 — 7,521 Deferred income taxes 213,270 — (213,270 ) — Other assets — 23,370 — 23,370 Total assets $ 4,755,983 $ 5,710,164 $ (4,905,879 ) $ 5,560,268 LIABILITIES AND EQUITY Current liabilities Accounts payable $ — $ 10,101 $ — $ 10,101 Accounts payable – affiliates 150,125 1,348 (151,473 ) — Revenues and production taxes payable — 115,412 — 115,412 Accrued liabilities 216 126,549 — 126,765 Accrued interest payable 24,255 22 — 24,277 Derivative instruments — 1,018 — 1,018 Advances from joint partners — 4,390 — 4,390 Other current liabilities — 500 — 500 Total current liabilities 174,596 259,340 (151,473 ) 282,463 Long-term debt 2,136,938 65,000 — 2,201,938 Deferred income taxes — 793,796 (213,270 ) 580,526 Asset retirement obligations — 36,088 — 36,088 Liabilities held for sale — 10,155 — 10,155 Derivative instruments — 1,558 — 1,558 Other liabilities — 3,091 — 3,091 Total liabilities 2,311,534 1,169,028 (364,743 ) 3,115,819 Stockholders’ equity Capital contributions from affiliates — 3,375,186 (3,375,186 ) — Common stock, $0.01 par value: 300,000,000 shares authorized; 181,298,001 shares issued and 180,582,855 shares outstanding 1,774 — — 1,774 Treasury stock, at cost: 715,146 shares (14,652 ) — — (14,652 ) Additional paid-in-capital 1,687,261 8,743 (8,743 ) 1,687,261 Retained earnings 770,066 1,157,207 (1,157,207 ) 770,066 Total stockholders’ equity 2,444,449 4,541,136 (4,541,136 ) 2,444,449 Total liabilities and stockholders’ equity $ 4,755,983 $ 5,710,164 $ (4,905,879 ) $ 5,560,268 Condensed Consolidating Balance Sheet December 31, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) ASSETS Current assets Cash and cash equivalents $ 777 $ 8,953 $ — $ 9,730 Accounts receivable – oil and gas revenues — 96,495 — 96,495 Accounts receivable – joint interest and other 15 100,899 — 100,914 Accounts receivable – affiliates 1,248 247,488 (248,736 ) — Inventory — 11,072 — 11,072 Prepaid expenses 278 7,050 — 7,328 Derivative instruments — 139,697 — 139,697 Other current assets — 50 — 50 Total current assets 2,318 611,704 (248,736 ) 365,286 Property, plant and equipment Oil and gas properties (successful efforts method) — 6,284,401 — 6,284,401 Other property and equipment — 443,265 — 443,265 Less: accumulated depreciation, depletion, amortization and impairment — (1,509,424 ) — (1,509,424 ) Total property, plant and equipment, net — 5,218,242 — 5,218,242 Assets held for sale — 26,728 — 26,728 Investments in and advances to subsidiaries 4,573,172 — (4,573,172 ) — Derivative instruments — 15,776 — 15,776 Deferred income taxes 205,174 — (205,174 ) — Other assets 100 23,243 — 23,343 Total assets $ 4,780,764 $ 5,895,693 $ (5,027,082 ) $ 5,649,375 LIABILITIES AND EQUITY Current liabilities Accounts payable $ — $ 9,983 $ — $ 9,983 Accounts payable – affiliates 247,488 1,248 (248,736 ) — Revenue and production taxes payable — 132,356 — 132,356 Accrued liabilities 10 167,659 — 167,669 Accrued interest payable 49,340 73 — 49,413 Advances from joint interest partners — 4,647 — 4,647 Other current liabilities — 6,500 — 6,500 Total current liabilities 296,838 322,466 (248,736 ) 370,568 Long-term debt 2,164,584 138,000 — 2,302,584 Deferred income taxes — 813,329 (205,174 ) 608,155 Asset retirement obligations — 35,338 — 35,338 Liabilities held for sale — 10,228 — 10,228 Other liabilities — 3,160 — 3,160 Total liabilities 2,461,422 1,322,521 (453,910 ) 3,330,033 Stockholders’ equity Capital contributions from affiliates — 3,369,895 (3,369,895 ) — Common stock, $0.01 par value: 300,000,000 shares authorized; 139,583,990 shares issued and 139,076,064 shares outstanding 1,376 — — 1,376 Treasury stock, at cost: 507,926 shares (13,620 ) — — (13,620 ) Additional paid-in-capital 1,497,065 8,743 (8,743 ) 1,497,065 Retained earnings 834,521 1,194,534 (1,194,534 ) 834,521 Total stockholders’ equity 2,319,342 4,573,172 (4,573,172 ) 2,319,342 Total liabilities and stockholders’ equity $ 4,780,764 $ 5,895,693 $ (5,027,082 ) $ 5,649,375
Condensed Consolidating Statement of Operations	Condensed Consolidating Statement of Operations Three Months Ended March 31, 2016 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 117,315 $ — $ 117,315 Well services and midstream revenues — 12,968 — 12,968 Total revenues — 130,283 — 130,283 Operating expenses Lease operating expenses — 31,064 — 31,064 Well services and midstream operating expenses — 4,389 — 4,389 Marketing, transportation and gathering expenses — 8,552 — 8,552 Production taxes — 10,753 — 10,753 Depreciation, depletion and amortization — 122,449 — 122,449 Exploration expenses — 363 — 363 Impairment — 3,562 — 3,562 General and administrative expenses 7,451 16,915 — 24,366 Total operating expenses 7,451 198,047 — 205,498 Operating loss (7,451 ) (67,764 ) — (75,215 ) Other income (expense) Equity in loss of subsidiaries (37,327 ) — 37,327 — Net gain on derivative instruments — 14,375 — 14,375 Interest expense, net of capitalized interest (34,832 ) (3,907 ) — (38,739 ) Gain on extinguishment of debt 7,016 — — 7,016 Other income 43 436 — 479 Total other income (expense) (65,100 ) 10,904 37,327 (16,869 ) Loss before income taxes (72,551 ) (56,860 ) 37,327 (92,084 ) Income tax benefit 8,096 19,533 — 27,629 Net loss $ (64,455 ) $ (37,327 ) $ 37,327 $ (64,455 ) Condensed Consolidating Statement of Operations Three Months Ended March 31, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Revenues Oil and gas revenues $ — $ 173,859 $ — $ 173,859 Well services and midstream revenues — 6,528 — 6,528 Total revenues — 180,387 — 180,387 Operating expenses Lease operating expenses — 39,125 — 39,125 Well services and midstream operating expenses — 1,952 — 1,952 Marketing, transportation and gathering expenses — 7,278 — 7,278 Production taxes — 16,621 — 16,621 Depreciation, depletion and amortization — 118,478 — 118,478 Exploration expenses — 843 — 843 Rig termination — 1,080 — 1,080 Impairment — 5,321 — 5,321 General and administrative expenses 8,619 14,705 — 23,324 Total operating expenses 8,619 205,403 — 214,022 Operating loss (8,619 ) (25,016 ) — (33,635 ) Other income (expense) Equity in earnings of subsidiaries 12,619 — (12,619 ) — Net gain on derivative instruments — 47,072 — 47,072 Interest expense, net of capitalized interest (35,221 ) (3,563 ) — (38,784 ) Other expense (1 ) (69 ) — (70 ) Total other income (expense) (22,603 ) 43,440 (12,619 ) 8,218 Income (loss) before income taxes (31,222 ) 18,424 (12,619 ) (25,417 ) Income tax benefit (expense) 13,181 (5,805 ) — 7,376 Net income (loss) $ (18,041 ) $ 12,619 $ (12,619 ) $ (18,041 )
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows Three Months Ended March 31, 2016 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Cash flows from operating activities: Net loss $ (64,455 ) $ (37,327 ) $ 37,327 $ (64,455 ) Adjustments to reconcile net loss to cash provided by (used in) operating activities: Equity in loss of subsidiaries 37,327 — (37,327 ) — Depreciation, depletion and amortization — 122,449 — 122,449 Gain on extinguishment of debt (7,016 ) — — (7,016 ) Impairment — 3,562 — 3,562 Deferred income taxes (8,096 ) (19,533 ) — (27,629 ) Derivative instruments — (14,375 ) — (14,375 ) Stock-based compensation expenses 6,547 183 — 6,730 Deferred financing costs amortization and other 1,701 3,365 — 5,066 Working capital and other changes: Change in accounts receivable (85 ) 96,353 (97,263 ) (995 ) Change in inventory — 349 — 349 Change in prepaid expenses 139 102 — 241 Change in other current assets — 4 — 4 Change in other assets 77 — — 77 Change in accounts payable, interest payable and accrued liabilities (122,242 ) (39,077 ) 97,263 (64,056 ) Change in other current liabilities — (6,000 ) — (6,000 ) Change in other liabilities — (3 ) — (3 ) Net cash provided by (used in) operating activities (156,103 ) 110,052 — (46,051 ) Cash flows from investing activities: Capital expenditures — (103,411 ) — (103,411 ) Derivative settlements — 73,313 — 73,313 Advances from joint interest partners — (257 ) — (257 ) Net cash used in investing activities — (30,355 ) — (30,355 ) Cash flows from financing activities: Repurchase of senior unsecured notes (22,308 ) — — (22,308 ) Proceeds from revolving credit facility — 214,000 — 214,000 Principal payments on revolving credit facility — (287,000 ) — (287,000 ) Deferred financing costs — (751 ) — (751 ) Proceeds from sale of common stock 183,164 — — 183,164 Purchases of treasury stock (1,032 ) — — (1,032 ) Investment in / capital contributions from subsidiaries (4,408 ) 4,408 — — Net cash provided by (used in) financing activities 155,416 (69,343 ) — 86,073 Increase (decrease) in cash and cash equivalents (687 ) 10,354 — 9,667 Cash and cash equivalents at beginning of period 777 8,953 — 9,730 Cash and cash equivalents at end of period $ 90 $ 19,307 $ — $ 19,397 Condensed Consolidating Statement of Cash Flows Three Months Ended March 31, 2015 Parent/ Issuer Combined Guarantor Subsidiaries Intercompany Eliminations Consolidated (In thousands) Cash flows from operating activities: Net income (loss) $ (18,041 ) $ 12,619 $ (12,619 ) $ (18,041 ) Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities: Equity in earnings of subsidiaries (12,619 ) — 12,619 — Depreciation, depletion and amortization — 118,478 — 118,478 Impairment — 5,321 — 5,321 Deferred income taxes (13,180 ) 5,804 — (7,376 ) Derivative instruments — (47,072 ) — (47,072 ) Stock-based compensation expenses 7,542 64 — 7,606 Deferred financing costs amortization and other 1,119 536 — 1,655 Working capital and other changes: Change in accounts receivable (251 ) 11,255 52,309 63,313 Change in inventory — (602 ) — (602 ) Change in prepaid expenses 149 1,743 — 1,892 Change in other current assets — 5,539 — 5,539 Change in accounts payable, interest payable and accrued liabilities 27,293 (17,325 ) (52,309 ) (42,341 ) Change in other liabilities — (11 ) — (11 ) Net cash provided by (used in) operating activities (7,988 ) 96,349 — 88,361 Cash flows from investing activities: Capital expenditures — (359,113 ) — (359,113 ) Derivative settlements — 109,259 — 109,259 Advances from joint interest partners — (828 ) — (828 ) Net cash used in investing activities — (250,682 ) — (250,682 ) Cash flows from financing activities: Proceeds from revolving credit facility — 145,000 — 145,000 Principal payments on revolving credit facility — (480,000 ) — (480,000 ) Proceeds from sale of common stock 463,218 — — 463,218 Purchases of treasury stock (1,520 ) — — (1,520 ) Investment in / capital contributions from subsidiaries (453,712 ) 453,712 — — Net cash provided by financing activities 7,986 118,712 — 126,698 Decrease in cash and cash equivalents (2 ) (35,621 ) — (35,623 ) Cash and cash equivalents at beginning of period 776 45,035 — 45,811 Cash and cash equivalents at end of period $ 774 $ 9,414 $ — $ 10,188

Inventory - Schedule of Invento

Inventory - Schedule of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Equipment and materials	$ 4,729	$ 4,920
Crude oil inventory	5,994	6,152
Total inventory	$ 10,723	$ 11,072

Fair Value Measurements - Hiera

Fair Value Measurements - Hierarchy of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets:
Total assets	$ 99,165	$ 156,215
Total liabilities	2,576
Money market funds [Member]
Assets:
Total assets	54	742
Commodity derivative instruments [Member]
Assets:
Total assets	99,111	155,473
Total liabilities	2,576
Level 1 [Member]
Assets:
Total assets	54	742
Total liabilities	0
Level 1 [Member] | Money market funds [Member]
Assets:
Total assets	54	742
Level 1 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets	0	0
Total liabilities	0
Level 2 [Member]
Assets:
Total assets	99,111	155,473
Total liabilities	2,576
Level 2 [Member] | Money market funds [Member]
Assets:
Total assets	0	0
Level 2 [Member] | Commodity derivative instruments [Member]
Assets:
Total assets	99,111	155,473
Total liabilities	2,576
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 (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Debt Instrument [Line Items]
Derivative credit risk valuation adjustment, derivative assets	$ 100,000		$ 300,000
Long-term debt	2,201,938,000		2,302,584,000
Deferred financing costs	39,300,000
Asset retirement obligation, carrying value	36,980,000		35,812,000
Impairment	3,562,000	$ 5,321,000
Estimated fair value of net assets	15,690,000
Proved Oil And Gas Properties [Member]
Debt Instrument [Line Items]
Impairment	0	0
Proved Oil And Gas Properties [Member] | Assets held for sale [Member]
Debt Instrument [Line Items]
Impairment	3,600,000		$ 9,400,000
Proved Oil And Gas Properties [Member] | Assets held for sale [Member] | Operating Segments [Member] | Midstream Services [Member]
Debt Instrument [Line Items]
Impairment	2,400,000
Proved Oil And Gas Properties [Member] | Assets held for sale [Member] | Operating Segments [Member] | Exploration and Production [Member]
Debt Instrument [Line Items]
Impairment	1,100,000
Unproved Oil And Gas Properties [Member]
Debt Instrument [Line Items]
Impairment		$ 5,300,000
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, fair value	1,632,700,000
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding	65,000,000
Long-term Debt [Member] | Notes [Member] | Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt	2,170,200,000
Deferred financing costs	$ 33,300,000

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Outstanding Commodity Derivative Instruments (Details) $ in Thousands	Mar. 31, 2016USD ($)MBbls$ / bbl
Derivative [Line Items]
Fair value asset (liability) | $	$ 96,535
2016 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in MBbls) | MBbls	8,707
Average swap price (in dollars per barrel)	50.60
Fair value asset (liability) | $	$ 82,960
2017 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in MBbls) | MBbls	3,967
Average swap price (in dollars per barrel)	48.01
Fair value asset (liability) | $	$ 13,906
2017 Two Way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (in MBbls) | MBbls	668
Average floor price (in dollars per barrel)	40
Average ceiling price (in dollars per barrel)	47.58
Fair value asset (liability) | $	$ (638)
2018 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil (in MBbls) | MBbls	279
Average swap price (in dollars per barrel)	47.61
Fair value asset (liability) | $	$ 433
2018 Two Way Collars [Member]
Derivative [Line Items]
Total notional amount of oil (in MBbls) | MBbls	62
Average floor price (in dollars per barrel)	40
Average ceiling price (in dollars per barrel)	47.58
Fair value asset (liability) | $	$ (126)

Derivative Instruments - Sche40

Derivative Instruments - Schedule of Location and Fair Value of Outstanding Commodity Derivative Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative instruments — current assets	$ 91,590	$ 139,697
Derivative instruments — non-current assets	7,521	15,776
Derivative instruments — current liabilities	(1,018)	0
Derivative instruments — non-current liabilities	(1,558)	0
Total derivative instruments	96,535
Crude oil [Member]
Derivatives, Fair Value [Line Items]
Derivative instruments — current assets	91,590	139,697
Derivative instruments — non-current assets	7,521	15,776
Derivative instruments — current liabilities	(1,018)	0
Derivative instruments — non-current liabilities	(1,558)	0
Total derivative instruments	$ 96,535	$ 155,473

Derivative Instruments - Realiz

Derivative Instruments - Realized and Unrealized Gains and Losses from Commodity Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net gain on derivative instruments	$ 14,375	$ 47,072

Derivative Instruments - Summar

Derivative Instruments - Summary of Gross and Net Information about Commodity Derivative Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Amounts of Recognized Assets	$ 108,205	$ 155,473
Derivative Assets, Gross Amounts Offset in the Balance Sheet	(9,094)	0
Net Amounts of Assets Presented in the Balance Sheet	99,111	155,473
Gross Amounts of Recognized Liabilities	11,670	0
Derivative Liabilities, Gross Amounts Offset in the Balance Sheet	(9,094)	0
Net Amounts of Liabilities Presented in the Balance Sheet	$ 2,576	$ 0

Property, Plant and Equipment -

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Proved oil and gas properties	[1]	$ 5,698,259	$ 5,655,759
Less: accumulated depreciation, depletion, amortization and impairment		(1,539,515)	(1,428,427)
Proved oil and gas properties, net		4,158,744	4,227,332
Unproved oil and gas properties		628,768	628,642
Other property and equipment		477,343	443,265
Less: accumulated depreciation		(87,686)	(80,997)
Other property and equipment, net		389,657	362,268
Total property, plant and equipment, net		5,177,169	5,218,242
Asset retirement costs		$ 31,100	$ 30,700
[1]	Included in the Company’s proved oil and gas properties are estimates of future asset retirement costs of $31.1 million and $30.7 million at March 31, 2016 and December 31, 2015, respectively.

Assets Held for Sale (Details)

Assets Held for Sale (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment	$ 3,562,000	$ 5,321,000
Oil and gas properties	121,137,000
Other property and equipment	34,000
Less: accumulated depreciation, depletion, amortization and impairment	(95,326,000)
Total assets	25,845,000		$ 26,728,000
Asset retirement obligation	(10,155,000)
Total liabilities	(10,155,000)
Net assets	15,690,000
Proved Oil And Gas Properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment	0	$ 0
Proved Oil And Gas Properties [Member] | Assets held for sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment	$ 3,600,000		$ 9,400,000

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total long-term debt	$ 2,201,938	$ 2,302,584
Less: deferred financing costs related to senior unsecured notes	(33,262)	(35,416)
Senior Unsecured Debt [Member] | 7.25% senior unsecured notes due February 1, 2019 [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 400,000	400,000
Stated interest rate (as percent)	7.25%
Senior Unsecured Debt [Member] | 6.5% senior unsecured notes due November 1, 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 399,000	400,000
Stated interest rate (as percent)	6.50%
Senior Unsecured Debt [Member] | 6.875% senior unsecured notes due March 15, 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 985,000	1,000,000
Stated interest rate (as percent)	6.875%
Senior Unsecured Debt [Member] | 6.875% senior unsecured notes due January 15, 2023 [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 386,200	400,000
Stated interest rate (as percent)	6.875%
Line of Credit [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 65,000	$ 138,000

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2016	Mar. 31, 2015	Feb. 23, 2016	Feb. 22, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Ownership percentage, guarantors (as percent)		100.00%
Repurchase of senior unsecured debt		$ 22,308,000	$ 0
Gain on extinguishment of debt		7,016,000	0
Deferred financing costs	$ 39,300,000	39,300,000
Interest Expense [Member]
Debt Instrument [Line Items]
Amortization of deferred financing costs		$ 2,100,000	1,600,000
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Redemption percentage (up to) (as percent)		35.00%
Redemption term		180 days
Percentage of minimum outstanding principal amount (at least)		65.00%
Senior Unsecured Debt [Member] | Minimum [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.50%	6.50%
Senior Unsecured Debt [Member] | Maximum [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	7.25%	7.25%
Senior Unsecured Debt [Member] | Notes [Member]
Debt Instrument [Line Items]
Unsecured debt	$ 2,170,200,000	$ 2,170,200,000
Senior Unsecured Debt [Member] | Notes [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Deferred financing costs	$ 33,300,000	$ 33,300,000
Senior Unsecured Debt [Member] | 6.5% senior unsecured notes due November 1, 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.50%	6.50%
Amount of debt extinguished	$ 1,000,000
Senior Unsecured Debt [Member] | 6.875% senior unsecured notes due March 15, 2022 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.875%	6.875%
Amount of debt extinguished	$ 15,000,000
Senior Unsecured Debt [Member] | 6.875% senior unsecured notes due January 15, 2023 [Member]
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.875%	6.875%
Amount of debt extinguished	$ 13,800,000
Senior Unsecured Debt [Member] | Purchased Notes [Member]
Debt Instrument [Line Items]
Amount of debt extinguished	29,800,000
Repurchase of senior unsecured debt	22,300,000
Gain on extinguishment of debt		$ 7,000,000
Senior Unsecured Debt [Member] | Purchased Notes [Member] | Gain of Extinguishment of Debt [Member]
Debt Instrument [Line Items]
Unamortized deferred financing costs	500,000	500,000
Line of Credit [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility amount	2,500,000,000	$ 2,500,000,000
Line of credit facility, current borrowing capacity				$ 1,150,000,000	$ 1,525,000,000
Commitment fee percentage		0.375%
Line of credit facility, amount outstanding	65,000,000	$ 65,000,000
Outstanding letters of credit	14,200,000	14,200,000
Line of credit facility, remaining borrowing capacity	$ 1,070,800,000	$ 1,070,800,000
Weighted average interest rate (as percent)	1.90%	1.90%				1.90%
Unamortized deferred financing costs	$ 1,800,000	$ 1,800,000
Write-off of deferred financing costs			$ 0
Line of Credit [Member] | Revolving Credit Facility [Member] | Other Assets [Member]
Debt Instrument [Line Items]
Deferred financing costs	6,000,000	6,000,000
Line of Credit [Member] | Revolving Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding	45,000,000	45,000,000
Line of Credit [Member] | Revolving Credit Facility [Member] | Alternate Based Rate (ABR) [Member]
Debt Instrument [Line Items]
Line of credit facility, amount outstanding	$ 20,000,000	$ 20,000,000

Asset Retirement Obligations -

Asset Retirement Obligations - Schedule of Changes in Asset Retirement Obligations (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at December 31, 2015	$ 35,812
Liabilities incurred during period	64
Liabilities settled during period	(5)
Accretion expense during period	465	[1]
Revisions to estimates	571
Liabilities held for sale	73	[2]
Balance at March 31, 2016	$ 36,980
[1]	Included in depreciation, depletion and amortization on the Company’s Condensed Consolidated Statement of Operations.
[2]	Represents the change in ARO related to the properties held for sale during the three months ended March 31, 2016. The total ARO related to the properties held for sale as of March 31, 2016 was $10.2 million (see Note 7 – Assets Held for Sale).

Asset Retirement Obligations 48

Asset Retirement Obligations - Additional Information (Details) $ in Thousands	Mar. 31, 2016USD ($)
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation	$ 10,155
Total asset retirement obligations, current portion	$ 900

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Effective tax rate (as percent)	30.00%	29.00%
Montana Net Operating Losses [Member]
Valuation Allowance [Line Items]
Valuation allowance increase, deferred tax asset	$ 0.9
Federal Charitable Contribution Carryovers [Member]
Valuation Allowance [Line Items]
Valuation allowance increase, deferred tax asset	$ 0.6

Common Stock (Details)

Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 02, 2016	Mar. 31, 2016	Mar. 31, 2015
Class of Stock [Line Items]
Shares issued, price per share (in usd per share)	$ 4.685
Net proceeds from offering		$ 183,164	$ 463,218
Common Stock [Member]
Class of Stock [Line Items]
Issuance of common stock (in shares)		39,100,000
Net proceeds from offering		$ 400
Additional Paid-in-Capital [Member]
Class of Stock [Line Items]
Net proceeds from offering		$ 182,800
Common Stock [Member]
Class of Stock [Line Items]
Issuance of common stock (in shares)	39,100,000
Common Stock [Member] | Over-Allotment Option [Member]
Class of Stock [Line Items]
Issuance of common stock (in shares)	5,100,000

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expenses	$ 6,730	$ 7,606
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock granted (in shares)	2,563,700
Granted, weighted average grant date fair value per unit (in usd per share)	$ 4.32
Stock-based compensation expenses	$ 5,800	6,800
Restricted Stock [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate (as a percent)	0.00%
Restricted Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate (as a percent)	20.00%
Performance Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock granted (in shares)	910,000
Granted, weighted average grant date fair value per unit (in usd per share)	$ 3
Stock-based compensation expenses	$ 900	$ 800
Right to received shares of common stock (in shares)	1
Number of trading days	30 days
Expected percentage earned (as a percent)	69.00%
Performance Share Units [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate (as a percent)	3.30%
PSU granted percentage of earnings (as a percent)	0.00%
Performance Share Units [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual forfeiture rate (as a percent)	4.60%
PSU granted percentage of earnings (as a percent)	200.00%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Assumptions (Details) - Performance Share Units [Member]	3 Months Ended
	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forecast period (years)	4 years
Risk-free interest rate (as percent)	1.25%
Oasis stock price volatility (as percent)	59.38%

Earnings (Loss) Per Share - Sch

Earnings (Loss) Per Share - Schedule of Weighted-Average Number of Shares Outstanding (Details) - shares shares in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding (in shares)		162,922	109,303
Dilution effect of stock awards at end of period (in shares)	[1]	0	0
Diluted weighted average common shares outstanding (in shares)		162,922	109,303
Anti-dilutive stock-based compensation awards (in shares)		4,668	3,046
[1]	No unvested stock awards were included in computing loss per share for the three months ended March 31, 2016 and 2015 because the effect was anti-dilutive.

Business Segment Information -

Business Segment Information - Additional Information (Details)	3 Months Ended
	Mar. 31, 2016Segment
Segment Reporting [Abstract]
Number of current operating units	3

Business Segment Information 55

Business Segment Information - Summarized Financial Information of Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total revenues		$ 130,283	$ 180,387
Operating income (loss)		(75,215)	(33,635)
Other income (expense)		(16,869)	8,218
Loss before income taxes		(92,084)	(25,417)
Property, plant and equipment, net		5,177,169		$ 5,218,242
Total assets		5,560,268		5,649,375
Assets held for sale		25,845		26,728
Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total revenues		117,315	173,859
Well Services [Member]
Segment Reporting Information [Line Items]
Total revenues		30,888	50,905
Midstream Services [Member]
Segment Reporting Information [Line Items]
Total revenues		29,818	17,642
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		130,283	180,387
Operating income (loss)		(75,215)	(33,635)
Other income (expense)		(16,869)	8,218
Loss before income taxes		(92,084)	(25,417)
Property, plant and equipment, net		5,177,169		5,218,242
Total assets	[1]	5,560,268		5,649,375
Operating Segments [Member] | Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total revenues		117,315	173,859
Operating income (loss)		(88,877)	(42,247)
Other income (expense)		(16,887)	8,239
Loss before income taxes		(105,764)	(34,008)
Property, plant and equipment, net		4,994,366		5,057,311
Total assets	[1]	5,367,881		5,478,439
Assets held for sale		25,800		26,700
Operating Segments [Member] | Well Services [Member]
Segment Reporting Information [Line Items]
Total revenues		5,985	2,708
Operating income (loss)		4,006	9,610
Other income (expense)		5	(2)
Loss before income taxes		4,011	9,608
Property, plant and equipment, net		57,821		61,402
Total assets	[1]	62,076		66,952
Operating Segments [Member] | Midstream Services [Member]
Segment Reporting Information [Line Items]
Total revenues		6,983	3,820
Operating income (loss)		15,144	9,308
Other income (expense)		13	(19)
Loss before income taxes		15,157	9,289
Property, plant and equipment, net		295,913		264,956
Total assets	[1]	301,242		269,411
Assets held for sale		34
Segment Reconciling Items [Member] | Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total revenues		0	0
Segment Reconciling Items [Member] | Well Services [Member]
Segment Reporting Information [Line Items]
Total revenues		24,903	48,197
Segment Reconciling Items [Member] | Midstream Services [Member]
Segment Reporting Information [Line Items]
Total revenues		22,835	13,822
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues		(47,738)	(62,019)
Operating income (loss)		(5,488)	(10,306)
Other income (expense)		0	0
Loss before income taxes		(5,488)	$ (10,306)
Property, plant and equipment, net		(170,931)		(165,427)
Total assets	[1]	$ (170,931)		$ (165,427)
[1]	As of March 31, 2016, total assets included assets held for sale of $25.8 million in the exploration and production segment and $34,000 in the midstream services segment. As of December 31, 2015, total assets included assets held for sale of $26.7 million in the exploration and production segment (see Note 7 – Assets Held for Sale). For the periods presented, the intercompany receivables (payables) for all segments were reclassified to capital contributions from (distributions to) parent and not included in total assets.

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - 3 months ended Mar. 31, 2016 $ in Millions	USD ($)	MBbls	MMcf
Commitments And Contingencies [Line Items]
Total rental commitments under leases	$ 24.6
Future obligations under purchase agreements	42.4
Long Term Commitments [Member]
Commitments And Contingencies [Line Items]
Future obligations under supply agreements	$ 446.2
Williston Basin Project [Member] | Long Term Commitments [Member]
Commitments And Contingencies [Line Items]
Maximum commitment term (less than)	10 years
Williston Basin Project [Member] | Crude oil [Member] | Long Term Commitments [Member]
Commitments And Contingencies [Line Items]
Minimum quantity of delivery (in MBbl of crude oil, MBbl of natural gas liquids, and MMcf of natural gas) | MBbls		32,500
Williston Basin Project [Member] | Natural Gas [Member] | Long Term Commitments [Member]
Commitments And Contingencies [Line Items]
Minimum quantity of delivery (in MBbl of crude oil, MBbl of natural gas liquids, and MMcf of natural gas)		23,000	221,800
Drilling contracts [Member]
Commitments And Contingencies [Line Items]
Payments upon early contract termination	$ 1.8

Condensed Consolidating Finan57

Condensed Consolidating Financial Information - Additional Information (Details)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Ownership percentage, guarantors (as percent)	100.00%

Condensed Consolidating Finan58

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 19,397	$ 9,730	$ 10,188	$ 45,811
Accounts receivable – oil and gas revenues	92,684	96,495
Accounts receivable – joint interest and other	104,512	100,914
Accounts receivable – affiliates	0	0
Inventory	10,723	11,072
Prepaid expenses	7,411	7,328
Derivative instruments	91,590	139,697
Other current assets	46	50
Total current assets	326,363	365,286
Property, plant and equipment
Oil and gas properties (successful efforts method)	6,327,027	6,284,401
Other property and equipment	477,343	443,265
Less: accumulated depreciation, depletion, amortization and impairment	(1,627,201)	(1,509,424)
Total property, plant and equipment, net	5,177,169	5,218,242
Assets held for sale	25,845	26,728
Investments in and advances to subsidiaries	0	0
Derivative instruments	7,521	15,776
Deferred income taxes	0	0
Other assets	23,370	23,343
Total assets	5,560,268	5,649,375
Current liabilities
Accounts payable	10,101	9,983
Accounts payable – affiliates	0	0
Revenues and production taxes payable	115,412	132,356
Accrued liabilities	126,765	167,669
Accrued interest payable	24,277	49,413
Derivative instruments	1,018	0
Advances from joint interest partners	4,390	4,647
Other current liabilities	500	6,500
Total current liabilities	282,463	370,568
Long-term debt	2,201,938	2,302,584
Deferred income taxes	580,526	608,155
Asset retirement obligations	36,088	35,338
Liabilities held for sale	10,155	10,228
Derivative instruments	1,558	0
Other liabilities	3,091	3,160
Total liabilities	3,115,819	3,330,033
Stockholders’ equity
Capital contributions from affiliates	0	0
Common stock, $0.01 par value: 300,000,000 shares authorized; 181,298,001 shares issued and 180,582,855 shares outstanding at March 31, 2016 and 139,583,990 shares issued and 139,076,064 shares outstanding at December 31, 2015	1,774	1,376
Treasury stock, at cost: 715,146 and 507,926 shares at March 21, 2016 and December 31, 2015, respectively	(14,652)	(13,620)
Additional paid-in capital	1,687,261	1,497,065
Retained earnings	770,066	834,521
Total stockholders’ equity	2,444,449	2,319,342
Total liabilities and stockholders’ equity	5,560,268	5,649,375
Parent/Issuer [Member]
Current assets
Cash and cash equivalents	90	777	774	776
Accounts receivable – oil and gas revenues	0	0
Accounts receivable – joint interest and other	0	15
Accounts receivable – affiliates	1,348	1,248
Inventory	0	0
Prepaid expenses	139	278
Derivative instruments	0	0
Other current assets	0	0
Total current assets	1,577	2,318
Property, plant and equipment
Oil and gas properties (successful efforts method)	0	0
Other property and equipment	0	0
Less: accumulated depreciation, depletion, amortization and impairment	0	0
Total property, plant and equipment, net	0	0
Assets held for sale	0	0
Investments in and advances to subsidiaries	4,541,136	4,573,172
Derivative instruments	0	0
Deferred income taxes	213,270	205,174
Other assets	0	100
Total assets	4,755,983	4,780,764
Current liabilities
Accounts payable	0	0
Accounts payable – affiliates	150,125	247,488
Revenues and production taxes payable	0	0
Accrued liabilities	216	10
Accrued interest payable	24,255	49,340
Derivative instruments	0
Advances from joint interest partners	0	0
Other current liabilities	0	0
Total current liabilities	174,596	296,838
Long-term debt	2,136,938	2,164,584
Deferred income taxes	0	0
Asset retirement obligations	0	0
Liabilities held for sale	0	0
Derivative instruments	0
Other liabilities	0	0
Total liabilities	2,311,534	2,461,422
Stockholders’ equity
Capital contributions from affiliates	0	0
Common stock, $0.01 par value: 300,000,000 shares authorized; 181,298,001 shares issued and 180,582,855 shares outstanding at March 31, 2016 and 139,583,990 shares issued and 139,076,064 shares outstanding at December 31, 2015	1,774	1,376
Treasury stock, at cost: 715,146 and 507,926 shares at March 21, 2016 and December 31, 2015, respectively	(14,652)	(13,620)
Additional paid-in capital	1,687,261	1,497,065
Retained earnings	770,066	834,521
Total stockholders’ equity	2,444,449	2,319,342
Total liabilities and stockholders’ equity	4,755,983	4,780,764
Combined Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents	19,307	8,953	9,414	45,035
Accounts receivable – oil and gas revenues	92,684	96,495
Accounts receivable – joint interest and other	104,512	100,899
Accounts receivable – affiliates	150,125	247,488
Inventory	10,723	11,072
Prepaid expenses	7,272	7,050
Derivative instruments	91,590	139,697
Other current assets	46	50
Total current assets	476,259	611,704
Property, plant and equipment
Oil and gas properties (successful efforts method)	6,327,027	6,284,401
Other property and equipment	477,343	443,265
Less: accumulated depreciation, depletion, amortization and impairment	(1,627,201)	(1,509,424)
Total property, plant and equipment, net	5,177,169	5,218,242
Assets held for sale	25,845	26,728
Investments in and advances to subsidiaries	0	0
Derivative instruments	7,521	15,776
Deferred income taxes	0	0
Other assets	23,370	23,243
Total assets	5,710,164	5,895,693
Current liabilities
Accounts payable	10,101	9,983
Accounts payable – affiliates	1,348	1,248
Revenues and production taxes payable	115,412	132,356
Accrued liabilities	126,549	167,659
Accrued interest payable	22	73
Derivative instruments	1,018
Advances from joint interest partners	4,390	4,647
Other current liabilities	500	6,500
Total current liabilities	259,340	322,466
Long-term debt	65,000	138,000
Deferred income taxes	793,796	813,329
Asset retirement obligations	36,088	35,338
Liabilities held for sale	10,155	10,228
Derivative instruments	1,558
Other liabilities	3,091	3,160
Total liabilities	1,169,028	1,322,521
Stockholders’ equity
Capital contributions from affiliates	3,375,186	3,369,895
Common stock, $0.01 par value: 300,000,000 shares authorized; 181,298,001 shares issued and 180,582,855 shares outstanding at March 31, 2016 and 139,583,990 shares issued and 139,076,064 shares outstanding at December 31, 2015	0	0
Treasury stock, at cost: 715,146 and 507,926 shares at March 21, 2016 and December 31, 2015, respectively	0	0
Additional paid-in capital	8,743	8,743
Retained earnings	1,157,207	1,194,534
Total stockholders’ equity	4,541,136	4,573,172
Total liabilities and stockholders’ equity	5,710,164	5,895,693
Intercompany Eliminations [Member]
Current assets
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable – oil and gas revenues	0	0
Accounts receivable – joint interest and other	0	0
Accounts receivable – affiliates	(151,473)	(248,736)
Inventory	0	0
Prepaid expenses	0	0
Derivative instruments	0	0
Other current assets	0	0
Total current assets	(151,473)	(248,736)
Property, plant and equipment
Oil and gas properties (successful efforts method)	0	0
Other property and equipment	0	0
Less: accumulated depreciation, depletion, amortization and impairment	0	0
Total property, plant and equipment, net	0	0
Assets held for sale	0	0
Investments in and advances to subsidiaries	(4,541,136)	(4,573,172)
Derivative instruments	0	0
Deferred income taxes	(213,270)	(205,174)
Other assets	0	0
Total assets	(4,905,879)	(5,027,082)
Current liabilities
Accounts payable	0	0
Accounts payable – affiliates	(151,473)	(248,736)
Revenues and production taxes payable	0	0
Accrued liabilities	0	0
Accrued interest payable	0	0
Derivative instruments	0
Advances from joint interest partners	0	0
Other current liabilities	0	0
Total current liabilities	(151,473)	(248,736)
Long-term debt	0	0
Deferred income taxes	(213,270)	(205,174)
Asset retirement obligations	0	0
Liabilities held for sale	0	0
Derivative instruments	0
Other liabilities	0	0
Total liabilities	(364,743)	(453,910)
Stockholders’ equity
Capital contributions from affiliates	(3,375,186)	(3,369,895)
Common stock, $0.01 par value: 300,000,000 shares authorized; 181,298,001 shares issued and 180,582,855 shares outstanding at March 31, 2016 and 139,583,990 shares issued and 139,076,064 shares outstanding at December 31, 2015	0	0
Treasury stock, at cost: 715,146 and 507,926 shares at March 21, 2016 and December 31, 2015, respectively	0	0
Additional paid-in capital	(8,743)	(8,743)
Retained earnings	(1,157,207)	(1,194,534)
Total stockholders’ equity	(4,541,136)	(4,573,172)
Total liabilities and stockholders’ equity	$ (4,905,879)	$ (5,027,082)

Condensed Consolidating Finan59

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Oil and gas revenues	$ 117,315	$ 173,859
Well services and midstream revenues	12,968	6,528
Total revenues	130,283	180,387
Operating expenses
Lease operating expenses	31,064	39,125
Well services and midstream operating expenses	4,389	1,952
Marketing, transportation and gathering expenses	8,552	7,278
Production taxes	10,753	16,621
Depreciation, depletion and amortization	122,449	118,478
Exploration expenses	363	843
Rig termination	0	1,080
Impairment	3,562	5,321
General and administrative expenses	24,366	23,324
Total operating expenses	205,498	214,022
Operating loss	(75,215)	(33,635)
Other income (expense)
Equity in earnings (loss) of subsidiaries	0	0
Net gain on derivative instruments	14,375	47,072
Interest expense, net of capitalized interest	(38,739)	(38,784)
Gain on extinguishment of debt	7,016	0
Other income (expense)	479	(70)
Total other income (expense)	(16,869)	8,218
Loss before income taxes	(92,084)	(25,417)
Income tax benefit (expense)	27,629	7,376
Net loss	(64,455)	(18,041)
Parent/Issuer [Member]
Revenues
Oil and gas revenues	0	0
Well services and midstream revenues	0	0
Total revenues	0	0
Operating expenses
Lease operating expenses	0	0
Well services and midstream operating expenses	0	0
Marketing, transportation and gathering expenses	0	0
Production taxes	0	0
Depreciation, depletion and amortization	0	0
Exploration expenses	0	0
Rig termination		0
Impairment	0	0
General and administrative expenses	7,451	8,619
Total operating expenses	7,451	8,619
Operating loss	(7,451)	(8,619)
Other income (expense)
Equity in earnings (loss) of subsidiaries	(37,327)	12,619
Net gain on derivative instruments	0	0
Interest expense, net of capitalized interest	(34,832)	(35,221)
Gain on extinguishment of debt	7,016
Other income (expense)	43	(1)
Total other income (expense)	(65,100)	(22,603)
Loss before income taxes	(72,551)	(31,222)
Income tax benefit (expense)	8,096	13,181
Net loss	(64,455)	(18,041)
Combined Guarantor Subsidiaries [Member]
Revenues
Oil and gas revenues	117,315	173,859
Well services and midstream revenues	12,968	6,528
Total revenues	130,283	180,387
Operating expenses
Lease operating expenses	31,064	39,125
Well services and midstream operating expenses	4,389	1,952
Marketing, transportation and gathering expenses	8,552	7,278
Production taxes	10,753	16,621
Depreciation, depletion and amortization	122,449	118,478
Exploration expenses	363	843
Rig termination		1,080
Impairment	3,562	5,321
General and administrative expenses	16,915	14,705
Total operating expenses	198,047	205,403
Operating loss	(67,764)	(25,016)
Other income (expense)
Equity in earnings (loss) of subsidiaries	0	0
Net gain on derivative instruments	14,375	47,072
Interest expense, net of capitalized interest	(3,907)	(3,563)
Gain on extinguishment of debt	0
Other income (expense)	436	(69)
Total other income (expense)	10,904	43,440
Loss before income taxes	(56,860)	18,424
Income tax benefit (expense)	19,533	(5,805)
Net loss	(37,327)	12,619
Intercompany Eliminations [Member]
Revenues
Oil and gas revenues	0	0
Well services and midstream revenues	0	0
Total revenues	0	0
Operating expenses
Lease operating expenses	0	0
Well services and midstream operating expenses	0	0
Marketing, transportation and gathering expenses	0	0
Production taxes	0	0
Depreciation, depletion and amortization	0	0
Exploration expenses	0	0
Rig termination		0
Impairment	0	0
General and administrative expenses	0	0
Total operating expenses	0	0
Operating loss	0	0
Other income (expense)
Equity in earnings (loss) of subsidiaries	37,327	(12,619)
Net gain on derivative instruments	0	0
Interest expense, net of capitalized interest	0	0
Gain on extinguishment of debt	0
Other income (expense)	0	0
Total other income (expense)	37,327	(12,619)
Loss before income taxes	37,327	(12,619)
Income tax benefit (expense)	0	0
Net loss	$ 37,327	$ (12,619)

Condensed Consolidating Finan60

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ (64,455)	$ (18,041)
Equity in earnings (loss) of subsidiaries	0	0
Depreciation, depletion and amortization	122,449	118,478
Gain on extinguishment of debt	(7,016)	0
Impairment	3,562	5,321
Deferred income taxes	(27,629)	(7,376)
Derivative instruments	(14,375)	(47,072)
Stock-based compensation expenses	6,730	7,606
Deferred financing costs amortization and other	5,066	1,655
Change in accounts receivable	(995)	63,313
Change in inventory	349	(602)
Change in prepaid expenses	241	1,892
Change in other current assets	4	5,539
Change in other assets	77	0
Change in accounts payable, interest payable and accrued liabilities	(64,056)	(42,341)
Change in other current liabilities	(6,000)	0
Change in other liabilities	(3)	(11)
Net cash provided by (used in) operating activities	(46,051)	88,361
Cash flows from investing activities:
Capital expenditures	(103,411)	(359,113)
Derivative settlements	73,313	109,259
Advances from joint interest partners	(257)	(828)
Net cash used in investing activities	(30,355)	(250,682)
Cash flows from financing activities:
Repurchase of senior unsecured notes	(22,308)	0
Proceeds from revolving credit facility	214,000	145,000
Principal payments on revolving credit facility	(287,000)	(480,000)
Deferred financing costs	(751)	0
Proceeds from sale of common stock	183,164	463,218
Purchases of treasury stock	(1,032)	(1,520)
Investment in / capital contributions from subsidiaries	0	0
Net cash provided by financing activities	86,073	126,698
Increase (decrease) in cash and cash equivalents	9,667	(35,623)
Beginning of period	9,730	45,811	$ 45,811
End of period	19,397	10,188	9,730
Parent/Issuer [Member]
Cash flows from operating activities:
Net income (loss)	(64,455)	(18,041)
Equity in earnings (loss) of subsidiaries	37,327	(12,619)
Depreciation, depletion and amortization	0	0
Gain on extinguishment of debt	(7,016)
Impairment	0	0
Deferred income taxes	(8,096)	(13,180)
Derivative instruments	0	0
Stock-based compensation expenses	6,547	7,542
Deferred financing costs amortization and other	1,701	1,119
Change in accounts receivable	(85)	(251)
Change in inventory	0	0
Change in prepaid expenses	139	149
Change in other current assets	0	0
Change in other assets	77
Change in accounts payable, interest payable and accrued liabilities	(122,242)	27,293
Change in other current liabilities	0
Change in other liabilities	0	0
Net cash provided by (used in) operating activities	(156,103)	(7,988)
Cash flows from investing activities:
Capital expenditures	0	0
Derivative settlements	0	0
Advances from joint interest partners	0	0
Net cash used in investing activities	0	0
Cash flows from financing activities:
Repurchase of senior unsecured notes	(22,308)
Proceeds from revolving credit facility	0	0
Principal payments on revolving credit facility	0	0
Deferred financing costs	0
Proceeds from sale of common stock	183,164	463,218
Purchases of treasury stock	(1,032)	(1,520)
Investment in / capital contributions from subsidiaries	(4,408)	(453,712)
Net cash provided by financing activities	155,416	7,986
Increase (decrease) in cash and cash equivalents	(687)	(2)
Beginning of period	777	776	776
End of period	90	774	777
Combined Guarantor Subsidiaries [Member]
Cash flows from operating activities:
Net income (loss)	(37,327)	12,619
Equity in earnings (loss) of subsidiaries	0	0
Depreciation, depletion and amortization	122,449	118,478
Gain on extinguishment of debt	0
Impairment	3,562	5,321
Deferred income taxes	(19,533)	5,804
Derivative instruments	(14,375)	(47,072)
Stock-based compensation expenses	183	64
Deferred financing costs amortization and other	3,365	536
Change in accounts receivable	96,353	11,255
Change in inventory	349	(602)
Change in prepaid expenses	102	1,743
Change in other current assets	4	5,539
Change in other assets	0
Change in accounts payable, interest payable and accrued liabilities	(39,077)	(17,325)
Change in other current liabilities	(6,000)
Change in other liabilities	(3)	(11)
Net cash provided by (used in) operating activities	110,052	96,349
Cash flows from investing activities:
Capital expenditures	(103,411)	(359,113)
Derivative settlements	73,313	109,259
Advances from joint interest partners	(257)	(828)
Net cash used in investing activities	(30,355)	(250,682)
Cash flows from financing activities:
Repurchase of senior unsecured notes	0
Proceeds from revolving credit facility	214,000	145,000
Principal payments on revolving credit facility	(287,000)	(480,000)
Deferred financing costs	(751)
Proceeds from sale of common stock	0	0
Purchases of treasury stock	0	0
Investment in / capital contributions from subsidiaries	4,408	453,712
Net cash provided by financing activities	(69,343)	118,712
Increase (decrease) in cash and cash equivalents	10,354	(35,621)
Beginning of period	8,953	45,035	45,035
End of period	19,307	9,414	8,953
Intercompany Eliminations [Member]
Cash flows from operating activities:
Net income (loss)	37,327	(12,619)
Equity in earnings (loss) of subsidiaries	(37,327)	12,619
Depreciation, depletion and amortization	0	0
Gain on extinguishment of debt	0
Impairment	0	0
Deferred income taxes	0	0
Derivative instruments	0	0
Stock-based compensation expenses	0	0
Deferred financing costs amortization and other	0	0
Change in accounts receivable	(97,263)	52,309
Change in inventory	0	0
Change in prepaid expenses	0	0
Change in other current assets	0	0
Change in other assets	0
Change in accounts payable, interest payable and accrued liabilities	97,263	(52,309)
Change in other current liabilities	0
Change in other liabilities	0	0
Net cash provided by (used in) operating activities	0	0
Cash flows from investing activities:
Capital expenditures	0	0
Derivative settlements	0	0
Advances from joint interest partners	0	0
Net cash used in investing activities	0	0
Cash flows from financing activities:
Repurchase of senior unsecured notes	0
Proceeds from revolving credit facility	0	0
Principal payments on revolving credit facility	0	0
Deferred financing costs	0
Proceeds from sale of common stock	0	0
Purchases of treasury stock	0	0
Investment in / capital contributions from subsidiaries	0	0
Net cash provided by financing activities	0	0
Increase (decrease) in cash and cash equivalents	0	0
Beginning of period	0	0	0
End of period	$ 0	$ 0	$ 0

Condensed Consolidating Finan61

Condensed Consolidating Financial Information Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet - Additional Information (Details) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	181,298,001	139,583,990
Common stock, shares outstanding (in shares)	180,582,855	139,076,064
Treasury stock, shares (in shares)	715,146	507,926

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands	Apr. 01, 2016USD ($)	Apr. 30, 2016USD ($)$ / bbl	Mar. 31, 2016USD ($)	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	May. 10, 2016MBbls
Subsequent Event [Line Items]
Repurchase of senior unsecured debt				$ 22,308	$ 0
Senior Unsecured Debt [Member] | Purchased Notes [Member]
Subsequent Event [Line Items]
Amount of debt extinguished			$ 29,800
Repurchase of senior unsecured debt			$ 22,300
Senior Unsecured Debt [Member] | 7.25% senior unsecured notes due February 1, 2019 [Member]
Subsequent Event [Line Items]
Stated interest rate (as percent)			7.25%	7.25%
Senior Unsecured Debt [Member] | 6.5% senior unsecured notes due November 1, 2021 [Member]
Subsequent Event [Line Items]
Amount of debt extinguished			$ 1,000
Stated interest rate (as percent)			6.50%	6.50%
Senior Unsecured Debt [Member] | 6.875% senior unsecured notes due March 15, 2022 [Member]
Subsequent Event [Line Items]
Amount of debt extinguished			$ 15,000
Stated interest rate (as percent)			6.875%	6.875%
Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from sale of legacy wells	$ 12,200
Loans receivable	$ 4,000
Interest rate of receivable (as percent)	10.00%
Term of loan receivable	1 year
Average swap price (in dollars per barrel) | $ / bbl		46.23
Subsequent Event [Member] | 2016 Swaps and Three-way costless collars [Member]
Subsequent Event [Line Items]
Total notional amount of oil (in MBbls) | MBbls						153
Subsequent Event [Member] | 2017 Swaps and Three-way costless collars [Member]
Subsequent Event [Line Items]
Total notional amount of oil (in MBbls) | MBbls						1,061
Subsequent Event [Member] | 2018 Swaps and Three-way costless collars [Member]
Subsequent Event [Line Items]
Total notional amount of oil (in MBbls) | MBbls						62
Subsequent Event [Member] | Senior Unsecured Debt [Member] | Purchased Notes [Member]
Subsequent Event [Line Items]
Amount of debt extinguished		$ 46,800
Repurchase of senior unsecured debt		34,600
Subsequent Event [Member] | Senior Unsecured Debt [Member] | 7.25% senior unsecured notes due February 1, 2019 [Member]
Subsequent Event [Line Items]
Amount of debt extinguished		$ 1,000
Stated interest rate (as percent)		7.25%
Subsequent Event [Member] | Senior Unsecured Debt [Member] | 6.5% senior unsecured notes due November 1, 2021 [Member]
Subsequent Event [Line Items]
Amount of debt extinguished		$ 1,300
Stated interest rate (as percent)		6.50%
Subsequent Event [Member] | Senior Unsecured Debt [Member] | 6.875% senior unsecured notes due March 15, 2022 [Member]
Subsequent Event [Line Items]
Amount of debt extinguished		$ 44,500
Stated interest rate (as percent)		6.875%