Cobalt International Energy 10-Q 8 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	3 Months Ended
	Mar. 31, 2017shares
Document And Entity Information [Abstract]
Entity Registrant Name	Cobalt International Energy, Inc.
Entity Central Index Key	1,471,261
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Trading Symbol	CIE
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding	448,309,776
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 118,493	$ 613,534
Restricted cash	11,274	2,517
Joint interest and other receivables	176,402	167,573
Other current assets	29,109	23,149
Investments	640,642	340,418
Total current assets	975,920	1,147,191
Oil and natural gas properties, net of accumulated depletion of $28,721 and $20,204 as of March 31, 2017 and December 31, 2016, respectively	952,150	1,078,885
Other property, net of accumulated depreciation and amortization of $8,788 and $8,426, as of March 31, 2017 and December, 31, 2016, respectively	3,540	3,902
Other assets	500	500
Total assets	1,932,110	2,230,478
Current liabilities:
Trade and other accounts payable	34,868	36,954
Accrued liabilities	235,265	227,418
Accrued contract amendment costs		19,582
Angolan preliminary consideration	250,000	250,000
Total current liabilities	520,133	533,954
Long-term debt	2,492,093	2,479,349
Long-term derivative liabilities	54,117	50,123
Asset retirement obligations	7,893	6,523
Other long-term liabilities	1,799	1,863
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value per share; 2,000,000,000 shares authorized, 442,738,080 and 441,210,817 issued and outstanding as of March 31, 2017 and December 31, 2016, respectively	4,427	4,412
Additional paid-in capital	4,223,635	4,219,611
Accumulated deficit	(5,371,987)	(5,065,357)
Total stockholders’ equity	(1,143,925)	(841,334)
Total liabilities and stockholders’ equity	$ 1,932,110	$ 2,230,478

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Oil and natural gas properties, accumulated depletion (in dollars)	$ 28,721	$ 20,204
Other property, accumulated depreciation and amortization (in dollars)	$ 8,788	$ 8,426
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares issued	442,738,080	441,210,817
Common stock, shares outstanding	442,738,080	441,210,817

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Oil, natural gas and natural gas liquids revenues	$ 9,867	$ 1,636
Operating costs and expenses:
Seismic and exploration costs	7,019	6,063
Dry hole costs and impairments	237,105	(425)
Lease operating expenses	2,698	956
General and administrative expenses	18,926	28,456
Accretion expense	290	102
Depreciation, depletion and amortization	8,879	3,170
Total operating costs and expenses	274,917	38,322
Operating loss	(265,050)	(36,686)
Other (expense) income, net:
Other income	1,845	4,375
Interest income	1,434	1,338
Interest expense	(44,484)	(15,642)
Total other expense, net	(41,205)	(9,929)
Net loss	$ (306,255)	$ (46,615)
Basic and diluted loss per share	$ (0.69)	$ (0.11)
Weighted average common shares outstanding (basic and diluted)	441,792	409,260

Condensed Consolidated Stateme5

Condensed Consolidated Statement of Changes in Stockholders' Equity - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2016	$ (841,334)	$ 4,412	$ 4,219,611	$ (5,065,357)
Balance (Accounting Standards Update 2016-09) at Dec. 31, 2016			375	(375)
Equity based compensation	3,664		3,664
Common stock issued for restricted stock		15	(15)
Net loss	(306,255)			(306,255)
Balance at Mar. 31, 2017	$ (1,143,925)	$ 4,427	$ 4,223,635	$ (5,371,987)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net loss	$ (306,255)	$ (46,615)
Adjustments to reconcile net loss to net cash flows used in operating activities:
Dry hole costs and impairments	237,105	(425)
Equity based compensation	3,593	7,763
Accretion expense	290	102
Depreciation, depletion and amortization	8,879	3,170
Gain on embedded derivatives	(1,906)
Amortization of premium (accretion of discount) on investments	217	733
Amortization of debt discount and debt issuance costs	4,416	24,901
Changes in operating assets and liabilities:
Joint interest and other receivables	(7,384)	(1,791)
Other current assets	(6,179)	22,132
Trade and other accounts payable	(3,008)	11,954
Accrued liabilities	24,352	(3,399)
Accrued contract amendment costs	(19,582)
Other	14	3,392
Net cash flows (used in) provided by operating activities	(65,448)	21,917
Cash flows from investing activities:
Additions to oil and natural gas properties	(118,950)	(211,533)
Capital expenditures for other property		(2,946)
Proceeds from maturity of investment securities	88,995	910,041
Purchase of investment securities	(390,881)	(673,633)
Net cash flows (used in) provided by investing activities	(420,836)	21,929
(Decrease) increase in cash, cash equivalents and restricted cash	(486,284)	43,846
Cash, cash equivalents and restricted cash — beginning of year	616,051	138,886
Cash, cash equivalents and restricted cash — end of period	$ 129,767	$ 182,732

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES General Cobalt International Energy, Inc., together with its wholly–owned subsidiaries (“we,” “our” or “us”) is an independent exploration and production company with operations in the deepwater U.S. Gulf of Mexico and offshore Angola and Gabon in West Africa. We operate in one reportable segment as our chief operating decision maker, the Chief Executive Officer, assesses performance and allocates resources based on the consolidated results of our business. Liquidity and Going Concern The accompanying unaudited condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The unaudited condensed consolidated financial statements do not include any adjustments that might be necessary should we be unable to continue as a going concern. Although we commenced initial production from our Heidelberg project in January 2016, our ongoing capital and operating expenditures will vastly exceed the revenue we expect to receive from our oil and natural gas operations for the foreseeable future. In order to grow production, we need to develop our discoveries into producing oil and natural gas properties, which will require that we raise substantial additional funding. If we are unable to raise substantial additional funding on a timely basis or on acceptable terms, we may be required to significantly curtail our exploration, appraisal and development activities. In assessing whether there is substantial doubt about our ability to continue as a going concern, we prepared a detailed cash forecast that included all projected cash inflows and outflows as well as consideration of any cash related covenants associated with our financing structure. The indentures governing our 10.75% first lien notes due 2021 (the “First Lien Notes”) and our 7.75% second lien notes due 2023 (the “Second Lien Notes”) (collectively, the “Secured Notes”) contain certain covenants including the maintenance of a minimum consolidated cash balance of at least $200.0 million. As this detailed cash forecast shows that our projected cash balance would be out of compliance with the minimum consolidated cash balance covenant within one year after the date these unaudited condensed consolidated financial statements are issued, we have concluded that there is substantial doubt about our ability to continue as a going concern. Our ability to continue as a going concern is subject to, among other factors, (i) our ability to monetize assets, obtain financing or refinance existing indebtedness and continue our cost cutting efforts for long–term rig and support services; (ii) the production rates achieved from Heidelberg; (iii) oil and natural gas prices; (iv) the number of commercially viable hydrocarbon discoveries made and the quantities of hydrocarbons discovered; (v) the speed and cost with which we can bring such discoveries to production; (vi) whether and to what extent we invest in additional oil leases and concessional licenses; and (vii) the actual cost of exploration, appraisal and development of our prospects. There can be no assurance that we will be able to obtain additional funding on satisfactory terms or at all. In addition, no assurance can be given that any such financing, if obtained, will be adequate to meet our capital needs and support our growth. If additional funding cannot be obtained on a timely basis and on satisfactory terms, then our operations would be materially negatively impacted. If we become unable to continue as a going concern, we may find it necessary to file a voluntary petition for reorganization under the Bankruptcy Code in order to provide us additional time to identify an appropriate solution to our financial situation and implement a plan of reorganization aimed at improving our capital structure. Basis of Presentation Our unaudited condensed consolidated financial statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Accordingly, certain information and disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted. We believe that the presentations and disclosures herein are adequate to make the information not misleading. The unaudited condensed consolidated financial statements reflect all adjustments (consisting of normal recurring adjustments) for a fair presentation of the interim periods. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in Item 8 of our Annual Report on Form 10–K for the year ended December 31, 2016. All intercompany accounts and transactions have been eliminated in consolidation. In the Notes to Unaudited Condensed Consolidated Financial Statements, all dollar and share amounts in tabulations are in thousands of dollars and shares, respectively, unless otherwise indicated. Recently Issued Accounting Standards In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, Compensation – Stock Compensation (Subtopic 718) In November 2016, the FASB issued ASU 2016–18, Statement of Cash Flows Prior to Adoption (1) After Adoption Three months ended March 31, 2016: (Accretion of discount) amortization of premium on investments $ 928 $ 733 Joint interest and other receivables (1,901 ) (1,791 ) Net cash flows provided by operating activities 22,002 21,917 Change in restricted funds 14,339 — Proceeds from maturity of investment securities 570,582 910,041 Purchase of investment securities (387,209 ) (673,633 ) Net cash flows (used in) provided by investing activities (16,767 ) 21,929 Increase in cash, cash equivalents and restricted cash 5,235 43,846 (1) Amounts are after reclassification of Angolan operations to no longer reflect these operations as discontinued. No other new accounting pronouncements issued or effective during the three months ended March 31, 2017 have had or are expected to have a material impact on our unaudited condensed consolidated financial statements.

Investments

Investments	3 Months Ended
	Mar. 31, 2017
Investments Debt And Equity Securities [Abstract]
Investments	NOTE 2. INVESTMENTS Our investments in held–to–maturity securities consist of the following: March 31, 2017 December 31, 2016 Corporate securities $ 396,153 $ 227,854 Commercial paper 273,046 292,466 U.S. Treasury securities — 161,778 Total $ 669,199 $ 682,098 These investments are recorded in our unaudited condensed consolidated balance sheets as follows: March 31, 2017 December 31, 2016 Cash and cash equivalents $ 28,557 $ 341,680 Short-term investments (1) 640,642 340,418 $ 669,199 $ 682,098 (1) As of December 31, 2016, $9.1 million of these investments served as collateral for certain of our obligations. At March 31, 2017 and December 31, 2016, the contractual maturities of our investments were within one year. Actual maturities may differ from contractual maturities as some borrowers have the right to call or prepay obligations with or without call or prepayment penalties.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 3. FAIR VALUE MEASUREMENTS The fair value hierarchy has three levels based on the reliability of the inputs used to determine fair value. Level 1 refers to fair values determined based on quoted prices in active markets for identical assets or liabilities. Level 2 refers to fair values determined based on quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration. Level 3 refers to fair values determined based on unobservable inputs used in the measurement of assets and liabilities at fair value. Recurring Basis The following tables presents the fair value hierarchy for our assets that are required to be measured at fair value on a recurring basis: Fair Value Measurements at the End of the Reporting Period Fair Value Level 1 Level 2 Level 3 As of March 31, 2017: Embedded derivative liabilities: 10.75% first lien notes due 2021 $ 21,572 $ — $ — $ 21,572 7.75% second lien notes due 2023 32,545 — — 32,545 Total $ 54,117 $ — $ — $ 54,117 As of December 31, 2016: Embedded derivative liabilities: 10.75% first lien notes due 2021 $ 27,012 $ — $ — $ 27,012 7.75% second lien notes due 2023 23,111 — — 23,111 Total $ 50,123 $ — $ — $ 50,123 The fair values of these embedded derivatives were estimated using the “with” and “without” method. Using this methodology, the First Lien Notes and the Second Lien Notes were first valued with the embedded derivatives (the “with” scenario) and subsequently valued without the embedded derivative (the “without” scenario). The fair values of the embedded derivatives were estimated as the difference between the fair values of the First Lien Notes and Second Lien Notes in the “with” and “without” scenarios. The fair values of the First Lien Notes and Second Lien Notes in the “with” and “without” scenarios were estimated using a risk–neutral probability of default model. Significant Level 3 assumptions used in the valuation of the embedded derivatives were the fair values of our long–term debt, the expected recovery rates, the risk–neutral probability of default and the risk–free rates. The reconciliation of changes in the fair value of our embedded derivatives is as follows for the three months ended March 31: 2017 Beginning of period $ 50,123 Issuance of additional Second Lien Notes 5,900 Change in fair value (1,906 ) End of period $ 54,117 Financial Instruments The estimated fair values of our financial instruments have been determined at discrete points in time based on relevant market information. Our financial instruments consist of cash and cash equivalents, joint interest and other receivables, held–to–maturity investments, accounts payable and accrued liabilities. The carrying amounts of our financial instruments, other than held–to–maturity–investments and long–term debt, approximate fair value because of the short–term nature of the items. There were no significant unrecognized holding gains or losses related to our held–to–maturity investments as of March 31, 2017 and December 31, 2016. Accordingly, the carrying value of our held–to–maturity investments approximates their fair value. Our held–to–maturity investments are not traded on a public exchange and the fair value of these investments is based on inputs using valuations obtained from independent brokers. As these valuations use readily observable market parameters that are actively quoted and can be validated through external sources, we have categorized these investments as Level 2. The estimated fair values of our long–term debt are as follows: March 31, 2017 December 31, 2016 10.75% first lien notes due 2021 $ 473,440 $ 482,250 7.75% second lien notes due 2023 361,985 327,449 2.625% convertible senior notes due 2019 203,321 305,378 3.125% convertible senior notes due 2024 268,872 332,344 $ 1,307,618 $ 1,447,421 The fair values of our long–term debt were estimated using quoted market prices. As these valuations use quoted prices in active markets for identical assets or liabilities, we have categorized the long–term debt as Level 1.

Oil and Natural Gas Properties

Oil and Natural Gas Properties	3 Months Ended
	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Oil and Natural Gas Properties	NOTE 4. OIL AND NATURAL GAS PROPERTIES Oil and natural gas properties consist of the following: March 31, 2017 December 31, 2016 Proved oil and natural gas properties: Well and development costs $ 128,575 $ 118,245 Accumulated depletion (28,721 ) (20,204 ) Total proved oil and natural gas properties 99,854 98,041 Unproved oil and natural gas properties: Oil and natural gas leaseholds 629,770 651,295 Accumulated valuation allowance (490,189 ) (507,198 ) 139,581 144,097 Exploratory wells in process 712,715 836,747 Total unproved oil and natural gas properties 852,296 980,844 Total oil and natural gas properties, net $ 952,150 $ 1,078,885 Capitalized Exploratory Well Costs Costs for exploratory wells that find reserves that cannot yet be classified as proved are capitalized if the well has found a sufficient quantity of reserves to justify its completion as a producing well and we are making sufficient progress assessing the reserves and the economic and operating viability of the project. Often, the ability to move into the development phase and record proved reserves is dependent on obtaining permits and government or partner approvals, the timing of which is ultimately beyond our control. Exploratory well costs remain suspended as long as we are actively pursuing such approvals and permits, and believe they will be obtained. For complex exploratory projects, it is not unusual to have exploratory wells remain suspended on the balance sheet for several years while additional appraisal drilling and seismic work is performed on the field or while we seek government or partner approval of development plans. Our assessment of suspended exploratory well costs is continuous until a determination is made to either sanction the project or to expense the well costs as dry hole costs as sufficient progress has not been made in assessing the reserves and the economic and operating viability of the project. In the three months ended March 31, 2017, we expensed suspended exploratory well costs of $232.8 million related to our Shenandoah discovery following the suspension of appraisal activity by the operator. Of this amount, $159.7 million had been capitalized for a period greater than one year after completion of drilling. The net changes in and the cumulative costs of capitalized exploratory wells (excluding any related leasehold costs) are as follows: March 31, 2017 December 31, 2016 Beginning of period $ 836,747 $ 1,727,181 Additions to capitalized exploration Exploratory well costs 94,189 499,985 Capitalized interest 14,228 99,541 Amounts charged to expense (1) (232,449 ) (1,489,960 ) End of period $ 712,715 $ 836,747 (1) Amounts represent dry hole costs related to exploratory wells which did not encounter commercial hydrocarbons or where it was determined that sufficient progress was not being made. March 31, 2017 December 31, 2016 Cumulative costs: Exploratory well costs $ 443,855 $ 582,115 Capitalized interest 268,860 254,632 $ 712,715 $ 836,747 Well costs capitalized for a period greater than one year after completion of drilling (included in table above) $ 458,924 $ 609,893 As of March 31, 2017 and December 31, 2016, capitalized exploratory well costs that have been suspended longer than one year are associated with our North Platte, Anchor, and Diaman discoveries. These well costs are suspended pending ongoing evaluation including, but not limited to, results of additional appraisal drilling, well–test analysis, additional geological and geophysical data and approval of a development plan. We believe these discoveries exhibit sufficient indications of hydrocarbons to justify potential development and are actively pursuing efforts to fully assess them. If additional information becomes available that raises substantial doubt as to the economic or operational viability of these discoveries, the associated costs will be expensed at that time.

Long-term Debt, Net

Long-term Debt, Net	3 Months Ended
	Mar. 31, 2017
Long Term Debt [Abstract]
Long-term Debt, Net	NOTE 5. LONG–TERM DEBT, NET Long–term debt, net consisted of the following: March 31, 2017 December 31, 2016 10.75% first lien notes due 2021: Principal outstanding $ 500,000 $ 500,000 Unamortized discount (1) (33,131 ) (34,416 ) Carrying amount 466,869 465,584 7.75% second lien notes due 2023: Principal outstanding 723,970 584,732 Unamortized discount (2) (38,757 ) (54,856 ) Carrying amount 685,213 529,876 2.625% convertible senior notes due 2019: Principal outstanding 625,603 763,446 Unamortized discount and debt issuance costs (3) (82,990 ) (109,689 ) Carrying amount 542,613 653,757 3.125% convertible senior notes due 2024: Principal outstanding 1,144,136 1,204,145 Unamortized discount and debt issuance costs (4) (346,738 ) (374,013 ) Carrying amount 797,398 830,132 Total $ 2,492,093 $ 2,479,349 (1) (2) (3) Effective interest rate of 8.2% (4) Effective interest rate of 8.9% On January 31, 2017, we consummated a follow–on debt exchange transaction (the “Transaction”) with certain holders (the “Holders”) of our outstanding 2.625% convertible senior notes due 2019 (the “2019 Notes”) and 3.125% convertible senior notes due 2024 (the “2024 Notes”) whereby we issued an aggregate principal amount of $139.2 million in additional Second Lien Notes in exchange for $137.8 million aggregate principal amount of the 2019 Notes and $60.0 million aggregate principal amount of the 2024 Notes held by the Holders. Our Secured Notes have requirements to pay an applicable premium upon a change in control or an event of default and also have a requirement to repay amounts outstanding using the proceeds from an asset sale. These requirements were determined to be an embedded derivative that requires us to bifurcate and fair value the derivative as of January 31, 2017 and to fair value the derivative as of each subsequent reporting date (see Note 3). At January 31, 2017, we recognized an additional derivative liability of $5.9 million for our Second Lien Notes, which decreased the carrying value of these notes. We accounted for the Transaction as a troubled debt restructuring. We did not recognize any gain or loss on the Transaction and have prospectively adjusted the effective interest rates on the 2019 Notes and 2024 Notes. Costs related to the Transaction totaled $1.0 million and are included in “General and administrative expenses” in our unaudited condensed consolidated statements of operations.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 6. COMMITMENTS AND CONTINGENCIES We are currently, and from time to time we may become, involved in various legal and regulatory proceedings arising in the normal course of business. In November 2014, two purported stockholders, St. Lucie County Fire District Firefighters’ Pension Trust Fund and Fire and Police Retiree Health Care Fund, San Antonio, filed a class action lawsuit in the U.S. District Court for the Southern District of Texas on behalf of a putative class of all purchasers of our securities from February 21, 2012 through November 4, 2014 (the “St. Lucie lawsuit”). The St. Lucie lawsuit, filed against us and certain officers, former and current members of the Board of Directors, underwriters, and investment firms and funds, asserted violations of federal securities laws based on alleged misrepresentations and omissions in SEC filings and other public disclosures, primarily regarding compliance with the U.S. Foreign Corrupt Practices Act (“FCPA”) in our Angolan operations and the performance of certain wells offshore Angola. In December 2014, Steven Neuman, a purported stockholder, filed a substantially similar lawsuit against us and certain of our officers in the U.S. District Court for the Southern District of Texas on behalf of a putative class of all purchasers of our securities from February 21, 2012 through August 4, 2014 (the “Neuman lawsuit”). Like the St. Lucie lawsuit, the Neuman lawsuit asserted violations of federal securities laws based on alleged misrepresentations and omissions in SEC filings and other public disclosures regarding our compliance with the FCPA in our Angolan operations. In March 2015, the Court entered an order consolidating the Neuman lawsuit with the St. Lucie lawsuit (the “Consolidated Action”) and also entered an order in the Consolidated Action appointing Lead Plaintiffs and Lead Counsel. Lead Plaintiffs filed their consolidated amended complaint in May 2015. Among other remedies, the Consolidated Action seeks damages in an unspecified amount, along with an award of attorney fees and other costs and expenses to the plaintiffs. We filed a motion to dismiss the consolidated amended complaint in June 2015, and the other defendants also filed motions to dismiss. The Court denied our motion to dismiss in January 2016, and, in March 2016, the Court also denied our motion requesting that the Court certify its order on the motions to dismiss so that we may seek interlocutory appellate review of the order. Lead Plaintiffs also have filed a motion for class certification, seeking to certify a class of all persons and entities who purchased or otherwise acquired our securities between March 1, 2011 and November 3, 2014. The matter remains ongoing. In May 2016, Gaines, a purported stockholder, filed a derivative action in the 295th District Court in Harris County, Texas against us, as a nominal defendant, certain of our current and former officers and directors, and certain investment firms and funds. The lawsuit alleges that current and former officers and directors breached their fiduciary duties by making, and permitting us to make, alleged misrepresentations about two of our exploration wells offshore Angola; that certain officers received performance-based compensation in excess of what they were entitled; and that the investment firms and funds owed a fiduciary duty to us as controlling stockholders and breached that duty by engaging in insider trading. The lawsuit further alleges that demand was wrongfully refused. The plaintiff asserts claims for breach of fiduciary duty and unjust enrichment and seeks damages in an unspecified amount, disgorgement of profits, appropriate equitable relief, and an award of attorney fees and other costs and expenses. In July 2016, we filed our answer and special exceptions challenging the plaintiff’s standing to bring such claims against us. The Court heard arguments on our special exceptions in December 2016. The matter remains ongoing. In November 2016, McDonaugh, a purported stockholder, filed a derivative action in the 80th District Court in Harris County, Texas against us, as a nominal defendant, and certain of our current and former officers and directors. The lawsuit alleges that defendants breached their fiduciary duties by failing to maintain adequate internal controls and by permitting or failing to prevent alleged misrepresentations and omissions in our SEC filings and other public disclosures, including in relation to compliance with the FCPA in our Angolan operations and regarding the performance of certain wells offshore Angola. The lawsuit also alleges that defendants received compensation or other benefits in excess of what they were entitled and that certain officers and directors engaged in unlawful trading and misappropriation of information. The lawsuit further alleges that demand was wrongfully refused. The plaintiff asserts claims for breach of fiduciary duty and unjust enrichment and seeks damages in an unspecified amount, reform of our governance and internal controls, restitution and disgorgement of profits, and an award of attorney fees and other costs and expenses. We filed our answer and special exceptions challenging the plaintiff’s standing to bring such claims against us in January 2017. The matter remains ongoing. In April 2017, Hafkey, a purported stockholder, filed a derivative action in the 295th District Court in Harris County, Texas against us, as a nominal defendant, and certain of our current and former officers and directors. The lawsuit alleges that current and former officers and directors breached their fiduciary duties by making, and permitting us to make, alleged misrepresentations about two of our exploratory wells offshore Angola; that certain directors caused us to waste corporate assets; and that certain officers received performance–based compensation in excess of what they were entitled. The lawsuit further alleges that demand was wrongfully refused. The plaintiff asserts claims for breach of fiduciary duty, corporate waste, and unjust enrichment and seeks damages in an unspecified amount, disgorgement of profits, appropriate equitable relief, and an award of attorney fees and other costs and expenses. Our deadline to answer or otherwise respond to the plaintiff’s petition is June 5, 2017. In May 2016, we filed suit against XL Specialty Insurance Company (“XL”) in Harris County District Court in Houston, Texas. We assert XL improperly denied coverage for insurance claims made in July 2012 and other claims subsequently submitted to them in connection with our defending against the St. Lucie lawsuit, the Ogden derivative action, and other investigations and actions. In December 2016, we amended our petition to add Axis Insurance Company (“Axis”). Axis provides coverage in excess of the XL policy’s limit of liability. We allege breach of contract, violation of the Texas Prompt Payment of Claims Act, and seek a declaratory judgment that XL and Axis are obligated to pay any additional loss suffered by us due to the circumstances, investigation, and claims described in the suit. In December 2016, we also amended our petition to add claims against Illinois National Insurance Company, an AIG subsidiary (“AIG”), which served as our insurer after XL. Against AIG, we allege breach of contract, violation of the Texas Prompt Payment of Claims Act, violation of the Texas Deceptive Trade Practices-Consumer Protection Act, and seek a declaratory judgment that AIG is obligated to pay any additional loss suffered by us due to the circumstances, investigations, and actions related to the Lontra and/or Loengo wells. In April 2017, we and certain of our current and former officers and directors settled claims against XL pursuant to which XL agreed to pay $11.5 million. We continue to pursue our claims against both Axis and AIG. We are vigorously defending against the current lawsuits and do not believe they will have a material adverse effect on our business. However, we cannot predict the occurrence or outcome of these proceedings with certainty, and if we are unsuccessful in these litigations and any loss exceeds our available insurance, this could have a material adverse effect on our results of operations. As previously disclosed, on March 8, 2017, we submitted a Notice of Dispute to Sonangol pursuant to the purchase and sale agreement (the “Agreement”) for the sale by us to Sonangol of the entire issued and outstanding share capital of our indirect wholly–owned subsidiaries, CIE Angola Block 20 Ltd. and CIE Angola Block 21 Ltd., which respectively hold our 40% working interest in each of Block 20 and Block 21 offshore Angola. Subsequently, we filed a Request for Arbitration (“RFA”) with the International Chamber of Commerce (“ICC”) against Sonangol for breach of the Agreement. Through this arbitration proceeding, we are requesting an award against Sonangol in excess of $2 billion dollars, plus applicable interest and costs. We also filed a separate RFA with the ICC against Sonangol Pesquisa e Produção, S.A. (“Sonangol P&P”)

Equity-Based Compensation

Equity-Based Compensation	3 Months Ended
	Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-Based Compensation	NOTE 7. EQUITY–BASED COMPENSATION We grant various forms of equity–based compensation to our employees and non–employee directors. These equity–based awards consist of restricted stock awards, non–qualified stock options, performance stock units (“PSUs”), restricted stock units (“RSUs”) and stock appreciation rights. Grants in 2017 Performance Stock Units In February 2017, we issued 6.6 million PSUs to our employees. These PSUs vest in March 2020 subject to our common stock attaining a specified return by the vesting date. These PSUs may be settled by, at our discretion, either the issuance of our common stock, cash or a combination thereof. As these PSUs had both service and market conditions, we estimated the fair value of these PSUs using the Monte Carlo simulation model. The fair value of these PSUs on the date of grant was $4.3 million. Restricted Stock Units In February 2017, we issued 9.9 million RSUs to our employees. These RSU’s vest in three equal annual installments by, at our discretion, either the issuance of our common stock, cash, or a combination thereof. The fair value of these RSUs on the date of grant was $7.5 million. Non–Employee Director Grants In the three months ended March 31, 2017, we granted a total of 0.1 million shares of our common stock to our non–employee directors as retainer awards. The directors have elected to defer the issuance of this stock. Accordingly, we have recorded a liability for the future issuance of these shares. The fair value of these retainer awards on the date of grant was $0.1 million. In addition, we granted 0.03 million RSUs to one of our non–employee directors. These RSUs will be settled by, at our discretion, either the issuance of our common stock, cash or a combination thereof. The fair value of these RSUs on the date of grant was $0.04 million. Compensation Costs Equity–based compensation cost is measured at the date of grant based on the calculated fair value of the award and is generally recognized on a straight–line basis over the requisite service period, including those with graded vesting. We account for forfeitures as they occur rather than by applying an estimated forfeiture rate at the time of grant. The following table presents the compensation costs recognized in our unaudited condensed consolidated statements of operations: Three Months Ended March 31, 2017 2016 Equity awards $ 3,664 $ 7,763 Liability awards (71 ) — Total $ 3,593 $ 7,763 These costs are included in “General and administrative expenses” in our unaudited condensed consolidated statements of operations. As of March 31, 2017, there was $27.8 million of unrecognized compensation costs which are expected to be recognized over a weighted average period of 2.1 years.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Earnings Per Share	NOTE 8. EARNINGS PER SHARE A reconciliation of the number of shares used for the basic and diluted loss per share computations is as follows: Three Months Ended March 31, 2017 2016 Weighted average common shares outstanding (basic and diluted) 441,792 409,260 Anti-dilutive shares excluded from diluted loss per share (1) 92,713 105,252 (1) Excludes restricted stock awards, non–qualified stock options, PSUs, RSUs, stock appreciation rights, the 2019 Notes and the 2024 Notes that are potentially issuable as their effect, if included, would have been anti–dilutive.

Other Supplement Information

Other Supplement Information	3 Months Ended
	Mar. 31, 2017
Supplemental Financial Information [Abstract]
Other Supplemental Information	NOTE 9. OTHER SUPPLEMENTAL INFORMATION Cash, cash equivalents and restricted cash are recorded in our unaudited condensed consolidated balance sheet as follows: As of March 31, 2017 2016 Cash and cash equivalents $ 118,493 $ 85,406 Restricted cash 11,274 97,326 Cash, cash equivalents and restricted cash $ 129,767 $ 182,732 Restricted cash serves as collateral for certain of our obligations and is invested in interest–bearing accounts. Supplemental noncash transactions are as follows: As of March 31, 2017 2016 Non-cash disclosure - changes in accrued capital expenditures $ (15,512 ) $ 11,232 Accrued liabilities consist of the following: March 31, December 31, 2017 2016 Costs for additions to oil and natural gas properties $ 59,026 $ 73,808 Social obligation payments 86,273 86,473 Funds from release of letter of credit on Block 9 18,375 18,375 Interest 54,511 13,793 Angolan consumption tax and withholding on services 9,796 9,796 Bonuses 2,692 8,900 Seismic and other operating costs 575 5,625 General expenses 2,209 5,849 Other 1,808 4,799 Total accrued liabilities $ 235,265 $ 227,418

Other Matters

Other Matters	3 Months Ended
	Mar. 31, 2017
Other Matters Disclosure [Abstract]
Other Matters	NOTE 10. OTHER MATTERS In February 2017, we received a letter from the Department of Justice (“DOJ”) advising us that the DOJ has closed its investigation into our operations in Angola. This formally concluded the DOJ investigation and no regulatory action has been taken against us as a result of this investigation. In March 2017, the SEC informed us by telephone that they have initiated an informal inquiry regarding the Sonangol Research and Technology Center (the “Technology Center”). As background, in December 2011, we executed the Block 20 Production Sharing Contract under which we and BP Exploration Angola (Kwanza Benguela) Limited are required to make certain social contributions to Sonangol, including for the Technology Center. In March 2017, we also received a voluntary request for information regarding such inquiry. We believe our activities in Angola have complied with all applicable laws, including the Foreign Corrupt Practices Act, and we are cooperating with the SEC’s inquiry. In September 2016, we announced that we entered into an amendment to our drilling contract with Rowan (UK) Reliance Limited (“Rowan”) and recorded a charge of $95.9 million, of which $76.3 million was paid in 2016. This amendment provided for the early termination of our long–term drilling contract for one of their drillships. The drilling contract was originally scheduled to terminate in February 2018, but the amendment provides for a contact termination date in March 2017. As of December 31, 2016, we had accrued costs of $19.6 million, which was paid in March 2017.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	NOTE 11. SUBSEQUENT EVENTS In April 2017, we completed an additional follow–on debt exchange transaction with certain holders of our outstanding convertible notes whereby we issued an aggregate principal amount of $178.6 million in additional Second Lien Notes in exchange for $6.4 million aggregate principal amount of the 2019 Notes and $296.3 million aggregate principal amount of the 2024 Notes held by these holders. We evaluated subsequent events for appropriate accounting and disclosure through the date these unaudited condensed consolidated financial statements were issued and determined that there were no other material items that required recognition or disclosure in our unaudited condensed consolidated financial statements.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Our unaudited condensed consolidated financial statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Accordingly, certain information and disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted. We believe that the presentations and disclosures herein are adequate to make the information not misleading. The unaudited condensed consolidated financial statements reflect all adjustments (consisting of normal recurring adjustments) for a fair presentation of the interim periods. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in Item 8 of our Annual Report on Form 10–K for the year ended December 31, 2016. All intercompany accounts and transactions have been eliminated in consolidation. In the Notes to Unaudited Condensed Consolidated Financial Statements, all dollar and share amounts in tabulations are in thousands of dollars and shares, respectively, unless otherwise indicated.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, Compensation – Stock Compensation (Subtopic 718) In November 2016, the FASB issued ASU 2016–18, Statement of Cash Flows Prior to Adoption (1) After Adoption Three months ended March 31, 2016: (Accretion of discount) amortization of premium on investments $ 928 $ 733 Joint interest and other receivables (1,901 ) (1,791 ) Net cash flows provided by operating activities 22,002 21,917 Change in restricted funds 14,339 — Proceeds from maturity of investment securities 570,582 910,041 Purchase of investment securities (387,209 ) (673,633 ) Net cash flows (used in) provided by investing activities (16,767 ) 21,929 Increase in cash, cash equivalents and restricted cash 5,235 43,846 (1) Amounts are after reclassification of Angolan operations to no longer reflect these operations as discontinued. No other new accounting pronouncements issued or effective during the three months ended March 31, 2017 have had or are expected to have a material impact on our unaudited condensed consolidated financial statements.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Effect of Applying Guidance on Unaudited Condensed Consolidated Statements of Cash Flows	. The following table shows the effects of applying the guidance: Prior to Adoption (1) After Adoption Three months ended March 31, 2016: (Accretion of discount) amortization of premium on investments $ 928 $ 733 Joint interest and other receivables (1,901 ) (1,791 ) Net cash flows provided by operating activities 22,002 21,917 Change in restricted funds 14,339 — Proceeds from maturity of investment securities 570,582 910,041 Purchase of investment securities (387,209 ) (673,633 ) Net cash flows (used in) provided by investing activities (16,767 ) 21,929 Increase in cash, cash equivalents and restricted cash 5,235 43,846 (1) Amounts are after reclassification of Angolan operations to no longer reflect these operations as discontinued.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2017
Investments Debt And Equity Securities [Abstract]
Schedule of Fair Value of Held-to-maturity Securities Recorded at Amortized Cost	Our investments in held–to–maturity securities consist of the following: March 31, 2017 December 31, 2016 Corporate securities $ 396,153 $ 227,854 Commercial paper 273,046 292,466 U.S. Treasury securities — 161,778 Total $ 669,199 $ 682,098
Schedule of Investments Recorded in Unaudited Condensed Consolidated Balance Sheets	These investments are recorded in our unaudited condensed consolidated balance sheets as follows: March 31, 2017 December 31, 2016 Cash and cash equivalents $ 28,557 $ 341,680 Short-term investments (1) 640,642 340,418 $ 669,199 $ 682,098 (1) As of December 31, 2016, $9.1 million of these investments served as collateral for certain of our obligations.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Hierarchy of Assets Required to be Measured at Fair value on a Recurring basis	The following tables presents the fair value hierarchy for our assets that are required to be measured at fair value on a recurring basis: Fair Value Measurements at the End of the Reporting Period Fair Value Level 1 Level 2 Level 3 As of March 31, 2017: Embedded derivative liabilities: 10.75% first lien notes due 2021 $ 21,572 $ — $ — $ 21,572 7.75% second lien notes due 2023 32,545 — — 32,545 Total $ 54,117 $ — $ — $ 54,117 As of December 31, 2016: Embedded derivative liabilities: 10.75% first lien notes due 2021 $ 27,012 $ — $ — $ 27,012 7.75% second lien notes due 2023 23,111 — — 23,111 Total $ 50,123 $ — $ — $ 50,123
Reconciliation of Changes in the Fair Value of Embedded Derivatives	The reconciliation of changes in the fair value of our embedded derivatives is as follows for the three months ended March 31: 2017 Beginning of period $ 50,123 Issuance of additional Second Lien Notes 5,900 Change in fair value (1,906 ) End of period $ 54,117
Summary of Estimated Fair Values of Long-term Debt	March 31, 2017 December 31, 2016 10.75% first lien notes due 2021: Principal outstanding $ 500,000 $ 500,000 Unamortized discount (1) (33,131 ) (34,416 ) Carrying amount 466,869 465,584 7.75% second lien notes due 2023: Principal outstanding 723,970 584,732 Unamortized discount (2) (38,757 ) (54,856 ) Carrying amount 685,213 529,876 2.625% convertible senior notes due 2019: Principal outstanding 625,603 763,446 Unamortized discount and debt issuance costs (3) (82,990 ) (109,689 ) Carrying amount 542,613 653,757 3.125% convertible senior notes due 2024: Principal outstanding 1,144,136 1,204,145 Unamortized discount and debt issuance costs (4) (346,738 ) (374,013 ) Carrying amount 797,398 830,132 Total $ 2,492,093 $ 2,479,349 (1) (2) (3) Effective interest rate of 8.2% (4) Effective interest rate of 8.9%
Estimated fair values of long-term debt
Summary of Estimated Fair Values of Long-term Debt	The estimated fair values of our long–term debt are as follows: March 31, 2017 December 31, 2016 10.75% first lien notes due 2021 $ 473,440 $ 482,250 7.75% second lien notes due 2023 361,985 327,449 2.625% convertible senior notes due 2019 203,321 305,378 3.125% convertible senior notes due 2024 268,872 332,344 $ 1,307,618 $ 1,447,421

Oil and Natural Gas Properties

Oil and Natural Gas Properties (Tables)	3 Months Ended
	Mar. 31, 2017
Property Plant And Equipment [Abstract]
Schedule of Oil and Natural Gas Properties	Oil and natural gas properties consist of the following: March 31, 2017 December 31, 2016 Proved oil and natural gas properties: Well and development costs $ 128,575 $ 118,245 Accumulated depletion (28,721 ) (20,204 ) Total proved oil and natural gas properties 99,854 98,041 Unproved oil and natural gas properties: Oil and natural gas leaseholds 629,770 651,295 Accumulated valuation allowance (490,189 ) (507,198 ) 139,581 144,097 Exploratory wells in process 712,715 836,747 Total unproved oil and natural gas properties 852,296 980,844 Total oil and natural gas properties, net $ 952,150 $ 1,078,885
Schedule of Net Changes in Capitalized Exploratory Wells	The net changes in and the cumulative costs of capitalized exploratory wells (excluding any related leasehold costs) are as follows: March 31, 2017 December 31, 2016 Beginning of period $ 836,747 $ 1,727,181 Additions to capitalized exploration Exploratory well costs 94,189 499,985 Capitalized interest 14,228 99,541 Amounts charged to expense (1) (232,449 ) (1,489,960 ) End of period $ 712,715 $ 836,747 (1) Amounts represent dry hole costs related to exploratory wells which did not encounter commercial hydrocarbons or where it was determined that sufficient progress was not being made.
Schedule of Cumulative Costs of Capitalized Exploratory Wells	March 31, 2017 December 31, 2016 Cumulative costs: Exploratory well costs $ 443,855 $ 582,115 Capitalized interest 268,860 254,632 $ 712,715 $ 836,747 Well costs capitalized for a period greater than one year after completion of drilling (included in table above) $ 458,924 $ 609,893

Long-term Debt, Net (Tables)

Long-term Debt, Net (Tables)	3 Months Ended
	Mar. 31, 2017
Long Term Debt [Abstract]
Summary of Estimated Fair Values of Long-term Debt	March 31, 2017 December 31, 2016 10.75% first lien notes due 2021: Principal outstanding $ 500,000 $ 500,000 Unamortized discount (1) (33,131 ) (34,416 ) Carrying amount 466,869 465,584 7.75% second lien notes due 2023: Principal outstanding 723,970 584,732 Unamortized discount (2) (38,757 ) (54,856 ) Carrying amount 685,213 529,876 2.625% convertible senior notes due 2019: Principal outstanding 625,603 763,446 Unamortized discount and debt issuance costs (3) (82,990 ) (109,689 ) Carrying amount 542,613 653,757 3.125% convertible senior notes due 2024: Principal outstanding 1,144,136 1,204,145 Unamortized discount and debt issuance costs (4) (346,738 ) (374,013 ) Carrying amount 797,398 830,132 Total $ 2,492,093 $ 2,479,349 (1) (2) (3) Effective interest rate of 8.2% (4) Effective interest rate of 8.9%

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Compensation Costs Recognized in Unaudited Condensed Consolidated Statements of Operations	The following table presents the compensation costs recognized in our unaudited condensed consolidated statements of operations: Three Months Ended March 31, 2017 2016 Equity awards $ 3,664 $ 7,763 Liability awards (71 ) — Total $ 3,593 $ 7,763

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted Loss Per Share Computations	A reconciliation of the number of shares used for the basic and diluted loss per share computations is as follows: Three Months Ended March 31, 2017 2016 Weighted average common shares outstanding (basic and diluted) 441,792 409,260 Anti-dilutive shares excluded from diluted loss per share (1) 92,713 105,252 (1) Excludes restricted stock awards, non–qualified stock options, PSUs, RSUs, stock appreciation rights, the 2019 Notes and the 2024 Notes that are potentially issuable as their effect, if included, would have been anti–dilutive.

Other Supplement Information (T

Other Supplement Information (Tables)	3 Months Ended
	Mar. 31, 2017
Supplemental Financial Information [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash Recorded in Unaudited Condensed Consolidated Balance Sheet	Cash, cash equivalents and restricted cash are recorded in our unaudited condensed consolidated balance sheet as follows: As of March 31, 2017 2016 Cash and cash equivalents $ 118,493 $ 85,406 Restricted cash 11,274 97,326 Cash, cash equivalents and restricted cash $ 129,767 $ 182,732
Schedule of Supplemental Noncash Transactions	Supplemental noncash transactions are as follows: As of March 31, 2017 2016 Non-cash disclosure - changes in accrued capital expenditures $ (15,512 ) $ 11,232
Schedule of Accrued Liabilities	Accrued liabilities consist of the following: March 31, December 31, 2017 2016 Costs for additions to oil and natural gas properties $ 59,026 $ 73,808 Social obligation payments 86,273 86,473 Funds from release of letter of credit on Block 9 18,375 18,375 Interest 54,511 13,793 Angolan consumption tax and withholding on services 9,796 9,796 Bonuses 2,692 8,900 Seismic and other operating costs 575 5,625 General expenses 2,209 5,849 Other 1,808 4,799 Total accrued liabilities $ 235,265 $ 227,418

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2017USD ($)segment	Jan. 01, 2017USD ($)	Dec. 31, 2016USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reportable segment | segment	1
Cumulative effect of change in accounting for equity based compensation	$ (1,143,925,000)		$ (841,334,000)
Accounting Standards Update 2016-09
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect adjustment for previously unrecognized excess tax benefits	0
Additional Paid-in Capital
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting for equity based compensation	4,223,635,000		4,219,611,000
Additional Paid-in Capital | Accounting Standards Update 2016-09
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting for equity based compensation		$ 375,000	375,000
Accumulated Deficit
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting for equity based compensation	$ (5,371,987,000)		(5,065,357,000)
Accumulated Deficit | Accounting Standards Update 2016-09
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of change in accounting for equity based compensation		$ (375,000)	$ (375,000)
10.75% First Lien Notes due 2021
Summary Of Significant Accounting Policies [Line Items]
Interest rate (as a percent)	10.75%		10.75%
Debt instrument maturity year	2,021
Debt covenant, minimum consolidated cash balance	$ 200,000,000
7.75% Second Lien Notes due 2023
Summary Of Significant Accounting Policies [Line Items]
Interest rate (as a percent)	7.75%		7.75%
Debt instrument maturity year	2,023
Debt covenant, minimum consolidated cash balance	$ 200,000,000

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Summary of Effect of Applying Guidance on Unaudited Condensed Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
(Accretion of discount) amortization of premium on investments	$ 217	$ 733
Joint interest and other receivables	(7,384)	(1,791)
Net cash flows provided by operating activities	(65,448)	21,917
Proceeds from maturity of investment securities	88,995	910,041
Purchase of investment securities	(390,881)	(673,633)
Net cash flows (used in) provided by investing activities	(420,836)	21,929
Increase in cash, cash equivalents and restricted cash	$ (486,284)	43,846
New Accounting Pronouncement Early Adoption Effect
Summary Of Significant Accounting Policies [Line Items]
(Accretion of discount) amortization of premium on investments		733
Joint interest and other receivables		(1,791)
Net cash flows provided by operating activities		21,917
Proceeds from maturity of investment securities		910,041
Purchase of investment securities		(673,633)
Net cash flows (used in) provided by investing activities		21,929
Increase in cash, cash equivalents and restricted cash		43,846
New Accounting Pronouncement Early Adoption Effect | Prior to Adoption
Summary Of Significant Accounting Policies [Line Items]
(Accretion of discount) amortization of premium on investments		928
Joint interest and other receivables		(1,901)
Net cash flows provided by operating activities		22,002
Change in restricted funds		14,339
Proceeds from maturity of investment securities		570,582
Purchase of investment securities		(387,209)
Net cash flows (used in) provided by investing activities		(16,767)
Increase in cash, cash equivalents and restricted cash		$ 5,235

Investments - Schedule of Fair

Investments - Schedule of Fair Value of Held-to-maturity Securities Recorded at Amortized Cost (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 669,199	$ 682,098
Corporate securities
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	396,153	227,854
U.S. Treasury securities
Schedule Of Held To Maturity Securities [Line Items]
Fair market value		161,778
Commercial paper
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 273,046	$ 292,466

Investments - Schedule of Inves

Investments - Schedule of Investments Recorded in Unaudited Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 669,199	$ 682,098
Cash and cash equivalents
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	28,557	341,680
Short-term investments
Schedule Of Held To Maturity Securities [Line Items]
Fair market value	$ 640,642	$ 340,418

Investments - Schedule of Inv31

Investments - Schedule of Investments Recorded in Unaudited Condensed Consolidated Balance Sheets (Parenthetical) (Details) $ in Millions	Dec. 31, 2016USD ($)
Short-term investments
Schedule Of Held To Maturity Securities [Line Items]
Investments served as collateral for certain obligations	$ 9.1

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Hierarchy of Assets Required to be Measured at Fair value on a Recurring basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded derivative liabilities, Fair Value	$ 54,117	$ 50,123
Recurring basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded derivative liabilities, Fair Value	54,117	50,123
Recurring basis | 10.75% first lien notes due 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded derivative liabilities, Fair Value	21,572	27,012
Recurring basis | 7.75% second lien notes due 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded derivative liabilities, Fair Value	32,545	23,111
Level 3 | Recurring basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded derivative liabilities, Fair Value	54,117	50,123
Level 3 | Recurring basis | 10.75% first lien notes due 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded derivative liabilities, Fair Value	21,572	27,012
Level 3 | Recurring basis | 7.75% second lien notes due 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Embedded derivative liabilities, Fair Value	$ 32,545	$ 23,111

Fair Value Measurements - Fai33

Fair Value Measurements - Fair Value Hierarchy of Assets Required to be Measured at Fair value on a Recurring basis (Parenthetical) (Details)	Mar. 31, 2017	Dec. 31, 2016
10.75% First Lien Notes due 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate (as a percent)	10.75%	10.75%
7.75% Second Lien Notes due 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate (as a percent)	7.75%	7.75%
Recurring basis | 10.75% First Lien Notes due 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate (as a percent)	10.75%	10.75%
Recurring basis | 7.75% Second Lien Notes due 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate (as a percent)	7.75%	7.75%

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Changes in the Fair Value of Embedded Derivatives (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)
Embedded Derivative [Abstract]
Beginning of period	$ 50,123
Issuance of additional Second Lien Notes	5,900
Change in fair value	(1,906)
End of period	$ 54,117

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Held-to-maturity securities unrecognized holding gains	$ 0	$ 0
Held-to-maturity securities unrecognized holding losses	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Estimated Fair Values of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 1,307,618	$ 1,447,421
10.75% first lien notes due 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, fair value	473,440	482,250
7.75% second lien notes due 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, fair value	361,985	327,449
2.625% convertible senior notes due 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, fair value	203,321	305,378
3.125% convertible senior notes due 2024
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 268,872	$ 332,344

Fair Value Measurements - Sum37

Fair Value Measurements - Summary of Estimated Fair Values of Long-term Debt (Parenthetical) (Details)	Mar. 31, 2017	Jan. 31, 2017	Dec. 31, 2016
10.75% first lien notes due 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate (as a percent)	10.75%		10.75%
7.75% second lien notes due 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate (as a percent)	7.75%		7.75%
2.625% convertible senior notes due 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate (as a percent)	2.625%	2.625%	2.625%
3.125% convertible senior notes due 2024
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate (as a percent)	3.125%	3.125%	3.125%

Oil and Natural Gas Propertie38

Oil and Natural Gas Properties - Schedule of Oil and Natural Gas Properties (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Abstract]
Well and development costs	$ 128,575	$ 118,245
Accumulated depletion	(28,721)	(20,204)
Total proved oil and natural gas properties	99,854	98,041
Oil and natural gas leaseholds	629,770	651,295
Accumulated valuation allowance	(490,189)	(507,198)
Total oil and gas leasehold	139,581	144,097
Exploratory wells in process	712,715	836,747	$ 1,727,181
Total unproved oil and natural gas properties	852,296	980,844
Total oil and natural gas properties, net	$ 952,150	$ 1,078,885

Oil and Natural Gas Properties-

Oil and Natural Gas Properties- Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Exploratory Wells Drilled [Line Items]
Exploratory well costs	$ 712,715	$ 836,747	$ 1,727,181
Well costs capitalized for a period greater than one year after completion of drilling	458,924	$ 609,893
Suspended Exploratory Well Costs | Shenandoah Discovery
Exploratory Wells Drilled [Line Items]
Exploratory well costs	232,800
Well costs capitalized for a period greater than one year after completion of drilling	$ 159,700

Oil and Natural Gas Propertie40

Oil and Natural Gas Properties - Schedule of Net Changes in Capitalized Exploratory Wells (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Beginning of period		$ 836,747	$ 1,727,181
Amounts charged to expense	[1]	(232,449)	(1,489,960)
End of period		712,715	836,747
Exploration well costs
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Beginning of period		582,115
Additions to capitalized exploration		94,189	499,985
End of period		443,855	582,115
Capitalized interest
Net changes in capitalized exploratory well costs (excluding any related leasehold costs)
Beginning of period		254,632
Additions to capitalized exploration		14,228	99,541
End of period		$ 268,860	$ 254,632
[1]	Amounts represent dry hole costs related to exploratory wells which did not encounter commercial hydrocarbons or where it was determined that sufficient progress was not being made.

Oil and Natural Gas Propertie41

Oil and Natural Gas Properties - Schedule of Cumulative Costs of Capitalized Exploratory Wells (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cumulative costs of capitalized exploratory well costs (excluding any related leasehold costs)
Cumulative costs	$ 712,715	$ 836,747	$ 1,727,181
Well costs capitalized for a period greater than one year after completion of drilling	458,924	609,893
Exploration well costs
Cumulative costs of capitalized exploratory well costs (excluding any related leasehold costs)
Cumulative costs	443,855	582,115
Capitalized interest
Cumulative costs of capitalized exploratory well costs (excluding any related leasehold costs)
Cumulative costs	$ 268,860	$ 254,632

Long-term Debt, Net - Schedule

Long-term Debt, Net - Schedule of Long-term Debt, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt instrument
Long-term debt, net	$ 2,492,093	$ 2,479,349
10.75% first lien notes due 2021
Debt instrument
Principal outstanding	500,000	500,000
Unamortized discount	(33,131)	(34,416)
Carrying amount	466,869	465,584
7.75% second lien notes due 2023
Debt instrument
Principal outstanding	723,970	584,732
Unamortized discount	(38,757)	(54,856)
Carrying amount	685,213	529,876
2.625% convertible senior notes due 2019
Debt instrument
Principal outstanding	625,603	763,446
Unamortized discount and debt issuance costs	(82,990)	(109,689)
Carrying amount	542,613	653,757
3.125% convertible senior notes due 2024
Debt instrument
Principal outstanding	1,144,136	1,204,145
Unamortized discount and debt issuance costs	(346,738)	(374,013)
Carrying amount	$ 797,398	$ 830,132

Long-term Debt, Net - Schedul43

Long-term Debt, Net - Schedule of Long-term Debt, Net (Parenthetical) (Details)	Mar. 31, 2017
10.75% first lien notes due 2021
Debt instrument
Effective interest rate	12.60%
7.75% first lien notes due 2023
Debt instrument
Effective interest rate	8.80%
2.625% convertible senior notes due 2019
Debt instrument
Effective interest rate	8.20%
3.125% convertible senior notes due 2024
Debt instrument
Effective interest rate	8.90%

Long-term Debt, Net - Additiona

Long-term Debt, Net - Additional Information (Details) - USD ($)	Jan. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
General and administrative expenses
Debt instrument
Transaction related costs	$ 1,000,000
2.625% convertible senior notes due 2019
Debt instrument
Interest rate (as a percent)	2.625%	2.625%	2.625%
Aggregate principal amount of notes issued	$ 137,800,000
3.125% convertible senior notes due 2024
Debt instrument
Interest rate (as a percent)	3.125%	3.125%	3.125%
Aggregate principal amount of notes issued	$ 60,000,000
7.75% second lien notes due 2023
Debt instrument
Interest rate (as a percent)		7.75%	7.75%
Aggregate principal amount of notes issued	139,200,000
Derivative liability	$ 5,900,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	Mar. 08, 2017USD ($)	May 31, 2016USD ($)Well	Nov. 30, 2014Stockholder	Apr. 30, 2017Well
Commitments And Contingencies [Line Items]
Number of purported stockholders | Stockholder			2
Number of exploration wells | Well		2
Block 20, offshore Angola | CIE Angola Block 20 Ltd
Commitments And Contingencies [Line Items]
Percentage of working interest acquired	40.00%
Block 21, offshore Angola | CIE Angola Block 21 Ltd
Commitments And Contingencies [Line Items]
Percentage of working interest acquired	40.00%
Claims against XL Specialty Insurance Company
Commitments And Contingencies [Line Items]
Claims settlement amount		$ 11.5
Sonangol
Commitments And Contingencies [Line Items]
Claims settlement amount	$ 2,000
Sonangol P P | Block 21, offshore Angola
Commitments And Contingencies [Line Items]
Claims settlement amount	$ 174
Subsequent event
Commitments And Contingencies [Line Items]
Number of exploration wells | Well				2

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Details) shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 28, 2017USD ($)Installmentshares	Mar. 31, 2017USD ($)shares
Equity Based Compensation
Unrecognized compensation		$ 27,800
Period for recognition of unrecognized compensation cost		2 years 1 month 6 days
Performance stock units
Equity Based Compensation
Granted (in shares) | shares	6,600
Vesting date	2020-03
Grant date fair value	$ 4,300
Restricted stock units
Equity Based Compensation
Granted (in shares) | shares	9,900
Grant date fair value	$ 7,500
Number of equal vesting installments | Installment	3
Restricted stock units | Non-employee director grants
Equity Based Compensation
Granted (in shares) | shares		30
Grant date fair value		$ 40
Retainer awards | Non-employee director grants | Common Stock
Equity Based Compensation
Granted (in shares) | shares		100
Grant date fair value		$ 100

Equity-Based Compensation - Sch

Equity-Based Compensation - Schedule of Compensation Costs Recognized (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Equity Based Compensation
Compensation costs	$ 3,593	$ 7,763
Liability awards	(71)
Equity awards
Equity Based Compensation
Compensation costs	$ 3,664	$ 7,763

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted Loss Per Share Computations (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Weighted average common shares outstanding (basic and diluted)	441,792	409,260
Anti-dilutive shares excluded from diluted loss per share	92,713	105,252

Earnings Per Share - Schedule49

Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted Loss Per Share Computations (Parenthetical) (Details)	3 Months Ended
	Mar. 31, 2017
2.625% convertible senior notes due 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Debt instrument maturity year	2,019
3.125% convertible senior notes due 2024
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Debt instrument maturity year	2,024

Other Supplemental Information

Other Supplemental Information - Schedule of Cash, Cash Equivalents and Restricted Cash Recorded in Unaudited Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 118,493	$ 613,534	$ 85,406
Restricted cash	11,274	2,517	97,326
Cash, cash equivalents and restricted cash	$ 129,767	$ 616,051	$ 182,732	$ 138,886

Other Supplemental Informatio51

Other Supplemental Information - Schedule of Supplemental Noncash Transactions (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Non-cash disclosure - changes in accrued capital expenditures	$ (15,512)	$ 11,232

Other Supplement Information -

Other Supplement Information - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Accrued Liabilities [Line Items]
Costs for additions to oil and natural gas properties	$ 59,026	$ 73,808
Social obligation payments	86,273	86,473
Interest	54,511	13,793
Bonuses	2,692	8,900
Seismic and other operating costs	575	5,625
General expenses	2,209	5,849
Other	1,808	4,799
Total accrued liabilities	235,265	227,418
Angolan
Schedule Of Accrued Liabilities [Line Items]
Angolan consumption tax and withholding on services	9,796	9,796
Block 9
Schedule Of Accrued Liabilities [Line Items]
Funds from release of letter of credit on Block 9	$ 18,375	$ 18,375

Other Matters - Additional Info

Other Matters - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2016	Mar. 31, 2017	Dec. 31, 2016
Other Commitments [Line Items]
Accrued contract amendment costs		$ (19,582)
Contract Termination
Other Commitments [Line Items]
Loss on amendment of contract	$ 95,900
Payment of loss on contract termination			$ 76,300
Contract termination date		Mar. 31, 2017
Accrued contract amendment costs			$ 19,600

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Apr. 30, 2017	Mar. 31, 2017	Jan. 31, 2017
7.75% second lien notes due 2023
Subsequent Event [Line Items]
Aggregate principal amount of notes issued			$ 139,200,000
Debt instrument maturity year		2,023
2.625% convertible senior notes due 2019
Subsequent Event [Line Items]
Aggregate principal amount of notes issued			137,800,000
Debt instrument maturity year		2,019
3.125% convertible senior notes due 2024
Subsequent Event [Line Items]
Aggregate principal amount of notes issued			$ 60,000,000
Debt instrument maturity year		2,024
Subsequent event | 7.75% second lien notes due 2023
Subsequent Event [Line Items]
Aggregate principal amount of notes issued	$ 178,600,000
Subsequent event | 2.625% convertible senior notes due 2019
Subsequent Event [Line Items]
Aggregate principal amount of notes issued	$ 6,400,000
Debt instrument maturity year	2,019
Subsequent event | 3.125% convertible senior notes due 2024
Subsequent Event [Line Items]
Aggregate principal amount of notes issued	$ 296,300,000
Debt instrument maturity year	2,024