Kosmos Energy (KOS) 10-Q 3 Nov 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 28, 2014
Document and Entity Information	'	'
Entity Registrant Name	'Kosmos Energy Ltd.	'
Entity Central Index Key	'0001509991	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	386,872,550
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$600,626	$598,108
Restricted cash	34,621	21,475
Receivables:	'	'
Joint interest billings	54,027	19,930
Oil sales	41,764	281
Other	20,344	1,115
Inventories	57,571	47,424
Prepaid expenses and other	20,086	27,010
Current deferred tax assets	10,474	19,618
Derivatives	6,848	'
Total current assets	846,361	734,961
Property and equipment:	'	'
Oil and gas properties, net	1,641,393	1,508,062
Other property, net	12,208	14,900
Property and equipment, net	1,653,601	1,522,962
Other assets:	'	'
Restricted cash	16,125	31,500
Long-term receivables - joint interest billings	10,124	'
Deferred financing costs, net of accumulated amortization of $30,778 and $24,976 at September 30, 2014 and December 2013, respectively	51,337	40,111
Long-term deferred tax assets	21,767	16,292
Derivatives	3,892	'
Total assets	2,603,207	2,345,826
Current liabilities:	'	'
Accounts payable	89,838	94,172
Accrued liabilities	197,132	115,212
Derivatives	1,994	9,940
Total current liabilities	288,964	219,324
Long-term liabilities:	'	'
Long-term debt	794,106	900,000
Derivatives	429	3,811
Asset retirement obligations	42,861	39,596
Deferred tax liability	271,376	170,226
Other long-term liabilities	14,539	20,534
Total long-term liabilities	1,123,311	1,134,167
Shareholders' equity:	'	'
Preference shares, $0.01 par value; 200,000,000 authorized shares; zero issued at September 30, 2014 and December 31, 2013	'	'
Common shares, $0.01 par value; 2,000,000,000 authorized shares; 392,388,533 and 391,974,287 issued at September 30, 2014 and December 31, 2013, respectively	3,924	3,920
Additional paid-in capital	1,840,615	1,781,535
Accumulated deficit	-623,621	-774,220
Accumulated other comprehensive income	1,057	2,158
Treasury stock, at cost, 5,543,118 and 4,400,135 shares at September 30, 2014 and December 31, 2013, respectively	-31,043	-21,058
Total shareholders' equity	1,190,932	992,335
Total liabilities and shareholders' equity	$2,603,207	$2,345,826

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
CONSOLIDATED BALANCE SHEETS	'	'
Deferred financing costs, accumulated amortization (in dollars)	$30,778	$24,976
Preference shares, par value (in dollars per share)	$0.01	$0.01
Preference shares, authorized shares	200,000,000	200,000,000
Preference shares, issued shares	0	0
Common shares, par value (in dollars per share)	$0.01	$0.01
Common shares, authorized shares	2,000,000,000	2,000,000,000
Common shares, issued shares	392,388,533	391,974,287
Treasury stock, shares	5,543,118	4,400,135

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues and other income:	'	'	'	'
Oil and gas revenue	$137,485	$215,169	$678,635	$636,648
Gain on sale of assets	'	'	23,769	'
Interest income	69	77	323	191
Other income	882	133	2,190	708
Total revenues and other income	138,436	215,379	704,917	637,547
Costs and expenses:	'	'	'	'
Oil and gas production	15,097	32,576	54,366	79,651
Exploration expenses	21,334	75,607	57,652	194,384
General and administrative	35,148	38,077	95,041	118,787
Depletion and depreciation	36,959	58,367	152,883	175,578
Amortization-deferred financing costs	2,593	2,786	7,938	8,269
Interest expense	9,838	8,781	20,984	27,789
Derivatives, net	-40,407	7,585	-20,869	386
Restructuring charges	-46	'	11,758	'
Loss on extinguishment of debt	'	'	2,898	'
Other expenses, net	329	1,864	1,632	3,345
Total costs and expenses	80,845	225,643	384,283	608,189
Income before income taxes	57,591	-10,264	320,634	29,358
Income tax expense	38,468	34,224	170,035	124,568
Net income (loss)	$19,123	($44,488)	$150,599	($95,210)
Net income (loss) per share:	'	'	'	'
Basic (in dollars per share)	$0.05	($0.12)	$0.39	($0.25)
Diluted (in dollars per share)	$0.05	($0.12)	$0.39	($0.25)
Weighted average number of shares used to compute net income (loss) per share:	'	'	'	'
Basic (in shares)	379,969	377,654	378,881	376,509
Diluted (in shares)	382,190	377,654	382,287	376,509

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME	'	'	'	'
Net income (loss)	$19,123	($44,488)	$150,599	($95,210)
Other comprehensive income (loss):	'	'	'	'
Reclassification adjustments for derivative (gains) losses included in net income (loss)	-290	-405	-1,101	-1,122
Other comprehensive income	-290	-405	-1,101	-1,122
Comprehensive income (loss)	$18,833	($44,893)	$149,498	($96,332)

CONSOLIDATED_STATEMENTS_OF_SHA

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	Common Shares	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Treasury Stock	Total
In Thousands, unless otherwise specified
Balance at Dec. 31, 2013	$3,920	$1,781,535	($774,220)	$2,158	($21,058)	$992,335
Balance (in shares) at Dec. 31, 2013	391,974	'	'	'	'	'
Increase (Decrease) in Shareholders' Equity	'	'	'	'	'	'
Equity-based compensation	'	60,166	'	'	'	60,166
Derivatives, net	'	'	'	-1,101	'	-1,101
Restricted stock awards and units	4	-4	'	'	'	'
Restricted stock awards and units (in shares)	415	'	'	'	'	'
Restricted stock forfeitures	'	2	'	'	-2	'
Purchase of treasury stock	'	-1,084	'	'	-9,983	-11,067
Net income (loss)	'	'	150,599	'	'	150,599
Balance at Sep. 30, 2014	$3,924	$1,840,615	($623,621)	$1,057	($31,043)	$1,190,932
Balance (in shares) at Sep. 30, 2014	392,389	'	'	'	'	'

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Operating activities	'	'
Net income (loss)	$150,599	($95,210)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'
Depletion, depreciation and amortization	160,821	183,847
Deferred income taxes	103,372	62,757
Unsuccessful well costs	3,091	98,912
Change in fair value of derivatives	-13,508	4,752
Cash settlements on derivatives	-9,661	-18,658
Equity-based compensation	59,941	50,792
Gain on sale of assets	-23,769	'
Loss on extinguishment of debt	2,898	'
Other	-4,368	4,468
Changes in assets and liabilities:	'	'
Increase in receivables	-104,708	-56,725
Increase in inventories	-10,197	-2,419
Decrease (increase) in prepaid expenses and other	6,924	-1,126
Decrease in accounts payable	-4,334	-30,037
Increase in accrued liabilities	55,133	79,996
Net cash provided by operating activities	372,234	281,349
Investing activities	'	'
Oil and gas assets	-290,218	-244,452
Other property	-1,403	-3,712
Proceeds on sale of assets	58,315	'
Restricted cash	2,229	7,214
Net cash used in investing activities	-231,077	-240,950
Financing activities	'	'
Payments on long-term debt	-400,000	-100,000
Net proceeds from issuance of senior secured notes	294,000	'
Purchase of treasury stock	-11,067	-13,069
Deferred financing costs	-21,572	-2,227
Net cash used in financing activities	-138,639	-115,296
Net decrease in cash and cash equivalents	2,518	-74,897
Cash and cash equivalents at beginning of period	598,108	515,164
Cash and cash equivalents at end of period	600,626	440,267
Cash paid for:	'	'
Interest	20,192	27,046
Income taxes	$101,068	$49,716

Organization

Organization	9 Months Ended
	Sep. 30, 2014
Organization	'
Organization	'
	1. Organization
	Kosmos Energy Ltd. was incorporated pursuant to the laws of Bermuda in January 2011 to become a holding company for Kosmos Energy Holdings. Kosmos Energy Holdings is a privately held Cayman Islands company that was formed in March 2004. As a holding company, Kosmos Energy Ltd.’s management operations are conducted through a wholly owned subsidiary, Kosmos Energy, LLC. The terms “Kosmos,” the “Company,” “we,” “us,” “our,” “ours,” and similar terms refer to Kosmos Energy Ltd. and its wholly owned subsidiaries, unless the context indicates otherwise.
	We are a leading independent oil and gas exploration and production company focused on frontier and emerging areas along the Atlantic Margin. Our assets include existing production and other major development projects offshore Ghana, as well as exploration licenses with significant hydrocarbon potential offshore Ireland, Mauritania, Morocco (including Western Sahara), Senegal and Suriname. Kosmos is listed on the New York Stock Exchange and is traded under the ticker symbol KOS.
	We have one reportable segment, which is the exploration and production of oil and natural gas. Substantially all of our long-lived assets and product sales are currently related to production located offshore Ghana.

Accounting_Policies

Accounting Policies	9 Months Ended
	Sep. 30, 2014
Accounting Policies	'
Accounting Policies	'
	2. Accounting Policies
	General
	The interim-period financial information presented in the consolidated financial statements included in this report is unaudited and, in the opinion of management, includes all adjustments of a normal recurring nature necessary to present fairly the consolidated financial position as of September 30, 2014, the changes in the consolidated statements of shareholders’ equity for the nine months ended September 30, 2014, the consolidated results of operations for the three and nine months ended September 30, 2014 and 2013, and consolidated cash flows for the nine months ended September 30, 2014 and 2013. The results of the interim periods shown in this report are not necessarily indicative of the final results to be expected for the full year. The consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by Generally Accepted Accounting Principles in the United States of America (“GAAP”) have been condensed or omitted from these interim consolidated financial statements. These consolidated financial statements and the accompanying notes should be read in conjunction with our audited consolidated financial statements for the year ended December 31, 2013, included in our annual report on Form 10-K.
	Reclassifications
	Certain prior period amounts have been reclassified to conform with the current year presentation. Such reclassifications had no impact on our reported net income (loss), current assets, total assets, current liabilities, total liabilities or shareholders’ equity.
	Restricted Cash
	In accordance with our commercial debt facility (the “Facility”), we are required to maintain a restricted cash balance that is sufficient to meet the payment of interest and fees for the next six-month period on the 7.875% Senior Secured Notes due 2021 (“Senior Notes”) plus the Corporate Revolver or the Facility, whichever is greater. As of September 30, 2014 and December 31, 2013, we had $15.5 million and $18.6 million, respectively, in current restricted cash to meet this requirement. In addition, in accordance with certain of our petroleum contracts, we have posted letters of credit related to performance guarantees for our minimum work obligations. These letters of credit are cash collateralized in accounts held by us and as such are classified as restricted cash. Upon completion of the minimum work obligations and/or entering into the next phase of the petroleum contract, the requirement to post the existing letters of credit will be satisfied and the cash collateral will be released. However, additional letters of credit may be required should we choose to move into the next phase of certain of our petroleum contracts. As of September 30, 2014 and December 31, 2013, we had $19.1 million and $2.9 million, respectively, of current restricted cash and $16.1 million and $31.5 million, respectively, of long-term restricted cash used to cash collateralize performance guarantees related to our petroleum contracts.
	Inventories
	Inventories consisted of $55.0 million and $45.8 million of materials and supplies and $2.6 million and $1.6 million of hydrocarbons as of September 30, 2014 and December 31, 2013, respectively. The Company’s materials and supplies inventory primarily consists of casing and wellheads and is stated at the lower of cost, using the weighted average cost method, or market.
	Hydrocarbon inventory is carried at the lower of cost, using the weighted average cost method, or market. Hydrocarbon inventory costs include expenditures and other charges incurred in bringing the inventory to its existing condition. Selling expenses and general and administrative expenses are reported as period costs and excluded from inventory costs.
	Restructuring Charges
	The Company accounts for restructuring charges in accordance with ASC 420-Exit or Disposal Cost Obligations. Under these standards, the costs associated with restructuring charges are recorded during the period in which the liability is incurred. During the nine months ended September 30, 2014, we recognized $11.8 million in restructuring charges for employee severance and related benefit costs incurred as part of a corporate reorganization, which includes $5.0 million of accelerated non-cash expense related to awards previously granted under our Long-Term Incentive Plan (the “LTIP”).
	Recent Accounting Standards
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) Topic 605, “Revenue Recognition,” and most industry-specific guidance. ASU 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB ASC. The new guidance is effective for annual reporting periods beginning after December 15, 2016 for public companies. Early adoption is not permitted. Entities have the option of using either a full retrospective or modified approach to adopt ASU 2014-09. The Company is currently evaluating the new guidance and has not determined the impact this standard may have on its financial statements or decided upon the method of adoption.
	In April 2014, the FASB issued ASU 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity.” ASU 2014-08 prospectively changes the criteria for reporting discontinued operations while enhancing disclosures around disposals of assets whether or not the disposal meets the definition of a discontinued operation. ASU 2014-08 is effective for annual and interim periods beginning after December 31, 2014 with early adoption permitted but only for disposals that have not been reported in financial statements previously issued. The adoption of this new guidance is not expected to have a material impact on the Company’s consolidated financial statements.

Property_and_Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2014
Property and Equipment	'
Property and Equipment	'
	3. Property and Equipment
	Property and equipment is stated at cost and consisted of the following:
		September 30,			December 31,
		2014			2013
		(In thousands)
	Oil and gas properties:
	Proved properties	$	865,500		$	801,348
	Unproved properties	716,933			524,257
	Support equipment and facilities	732,567			710,289
	Total oil and gas properties	2,315,000			2,035,894
	Less: accumulated depletion	(673,607		)	(527,832		)
	Oil and gas properties, net	1,641,393			1,508,062
	Other property	32,745			31,658
	Less: accumulated depreciation	(20,537		)	(16,758		)
	Other property, net	12,208			14,900
	Property and equipment, net	$	1,653,601		$	1,522,962
	We recorded depletion expense of $34.6 million and $56.1 million for the three months ended September 30, 2014 and 2013, respectively and $145.8 million and $169.2 million for the nine months ended September 30, 2014 and 2013, respectively.
	In the first quarter of 2014, the Moroccan government issued a joint ministerial order approving a partial sale of our participating interests to BP Exploration (Morocco) Limited, a wholly owned subsidiary of BP plc (“BP”), covering our three blocks in the Agadir Basin, offshore Morocco. Upon receipt of this order, we closed the partial sale with BP. Under the terms of the agreements, BP acquired a non-operating interest in each of the Essaouira Offshore, Foum Assaka Offshore and Tarhazoute Offshore blocks. The sales price of the farm-outs was $56.9 million. All proceeds were received as of June 30, 2014. After giving effect to these farm-outs, our participating interests are 30.0%, 29.925% and 30.0% in the Essaouira Offshore, Foum Assaka Offshore and Tarhazoute Offshore blocks, respectively, and we remain the operator. The proceeds on the sale of the interests exceeded our book basis in the assets, resulting in a $23.8 million gain on the transaction.
	In the first quarter of 2014, the Moroccan government issued a joint ministerial order approving a partial sale of our participating interest to Capricorn Exploration and Development Company Limited, a wholly owned subsidiary of Cairn Energy PLC (“Cairn”), covering the Cap Boujdour Offshore block, offshore Western Sahara. Upon receipt of this order, we closed the partial sale with Cairn. During the second quarter of 2014, Cairn paid $1.5 million for their share of costs incurred from the effective date of the farm-out agreement through the closing date, which was recorded as a reduction in our basis. After giving effect to the farm-out, our participating interest in the Cap Boujdour Offshore block is 55.0% and we remain the operator.
	In August 2014, we entered into a farm-in agreement with Timis Corporation Limited, whereby we acquired a 60% participating interest and operatorship, covering the Cayar Offshore Profond and Saint Louis Offshore Profond blocks offshore Senegal. As part of the agreement, we will carry the full costs of a planned 3D seismic program. Additionally, we will carry the full costs of two contingent exploration wells, subject to a maximum gross cost per well of $120.0 million, should Kosmos elect to drill such wells. We also retain the option to increase our equity to 65% in exchange for carrying the full cost of a third contingent exploration or appraisal well, subject to a maximum gross cost of $120.0 million.

Suspended_Well_Costs

Suspended Well Costs	9 Months Ended
	Sep. 30, 2014
Suspended Well Costs	'
Suspended Well Costs	'
	4. Suspended Well Costs
	The following table reflects the Company’s capitalized exploratory well costs on completed wells as of and during the nine months ended September 30, 2014. The table excludes $3.1 million in costs that were capitalized and subsequently expensed during the same period.
		Nine Months
		Ended
		September 30,
		2014
		(In thousands)
	Beginning balance	$	376,166
	Additions to capitalized exploratory well costs pending the determination of proved reserves	53,367
	Reclassification due to determination of proved reserves	—
	Capitalized exploratory well costs charged to expense	—
	Ending balance	$	429,533
	The following table provides an aging of capitalized exploratory well costs based on the date drilling was completed and the number of projects for which exploratory well costs have been capitalized for more than one year since the completion of drilling:
		September 30, 2014		December 31, 2013
		(In thousands, except well counts)
	Exploratory well costs capitalized for a period of one year or less	$	52,502	$	11,426
	Exploratory well costs capitalized for a period of one to two years	137,367		229,140
	Exploratory well costs capitalized for a period of three to five years	239,664		135,600
	Ending balance	$	429,533	$	376,166
	Number of projects that have exploratory well costs that have been capitalized for a period greater than one year	8		8
	As of September 30, 2014, the projects with exploratory well costs capitalized for more than one year since the completion of drilling are related to the Mahogany, Teak-1, Teak-2 and Akasa discoveries in the West Cape Three Points (“WCTP”) Block and the Tweneboa, Enyenra, Ntomme and Wawa discoveries in the Deepwater Tano (“DT”) Block, which are all in Ghana.
	Effective January 14, 2014, Ghana’s Ministry of Energy and Ghana National Petroleum Corporation (“GNPC”) entered into a Memorandum of Understanding with Kosmos Energy, on behalf of the WCTP Petroleum Agreement (“PA”) Block partners, wherein all parties have settled all matters pertaining to the Notices of Dispute for the Mahogany East PoD, and the Ministry of Energy has approved the Appraisal Programs for the Mahogany, Teak, and Akasa discoveries.
	Mahogany— Three appraisal wells have been drilled. Additionally, we deepened a development well in the Jubilee Field to further appraise the Mahogany discovery. Following additional appraisal and evaluation, a decision regarding commerciality of the Mahogany discovery is expected to be made by the WCTP Block partners in early 2015. Within six months of such a declaration, a PoD would be prepared and submitted to Ghana’s Ministry of Energy, as required under the WCTP PA.
	Teak-1 Discovery—Two appraisal wells have been drilled. Following additional appraisal and evaluation, a decision regarding commerciality of the Teak-1 discovery is expected to be made by the WCTP Block partners in early 2015. Within six months of such a declaration, a PoD would be prepared and submitted to Ghana’s Ministry of Energy, as required under the WCTP PA.
	Teak-2 Discovery—We have performed a gauge installation on the well and are reprocessing seismic data. Following additional appraisal and evaluation, a decision regarding commerciality of the Teak-2 discovery is expected to be made by the WCTP Block partners in early 2015. Within six months of such a declaration, a PoD would be prepared and submitted to Ghana’s Ministry of Energy, as required under the WCTP PA.
	Akasa Discovery—We performed a drill stem test and gauge installation on the discovery well and drilled one appraisal well. Following additional appraisal and evaluation, a decision regarding commerciality of the Akasa discovery is expected to be made by the WCTP Block partners in early 2015. Within six months of such a declaration, a PoD would be prepared and submitted to Ghana’s Ministry of Energy, as required under the WCTP PA.
	Tweneboa, Enyenra and Ntomme (“TEN”) Discoveries—In May 2013, the government of Ghana approved the PoD over the TEN discoveries. Development of TEN has commenced and is expected to include the drilling and completion of up to 24 development wells, half of the wells are designed as producers, with the remaining wells designed for water or gas injection. The TEN project is expected to deliver first oil in the second half of 2016. The costs associated with the TEN development will remain as unproved property pending the determination of whether the discoveries are associated with proved reserves.
	Wawa Discovery—We are currently reprocessing seismic data and have acquired a high resolution seismic survey over the discovery area. Following additional evaluation and potential appraisal activities, a decision regarding commerciality of the Wawa discovery is expected to be made by the DT Block partners in 2016. Within six months of such declaration, a PoD would be prepared and submitted to Ghana’s Ministry of Energy, as required under the DT PA.

Accrued_Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2014
Accrued Liabilities	'
Accrued Liabilities	'
	5. Accrued Liabilities
	Accrued liabilities consisted of the following:
		September 30,		December 31,
		2014		2013
		(In thousands)
	Accrued liabilities:
	Accrued exploration, development and production	$	150,149	$	73,976
	Accrued general and administrative expenses	20,082		4,255
	Accrued taxes other than income	18,472		15,188
	Accrued interest	4,505		—
	Income taxes	2,282		20,379
	Accrued other	1,642		1,414
		$	197,132	$	115,212

Debt

Debt	9 Months Ended
	Sep. 30, 2014
Debt	'
Debt	'
	6. Debt
	Debt consists of the following:
			September 30,			December 31,
			2014			2013
			(In thousands)
	Outstanding debt principal balances:
	Facility		$	500,000		$	900,000
	Senior Notes		300,000			—
	Total		800,000			900,000
	Unamortized issuance discounts		(5,894		)	—
	Long-term debt		$	794,106		$	900,000
	Facility
	In March 2014, the Company amended and restated the Facility with a total commitment of $1.5 billion from a number of financial institutions. The Facility supports our oil and gas exploration, appraisal and development programs and corporate activities.
	As part of the debt refinancing in March 2014, the repayment of borrowings under the existing facility attributable to financial institutions that did not participate in the amended Facility was accounted for as an extinguishment of debt, and existing unamortized debt issuance costs attributable to those participants were expensed. As a result, we recorded a $2.9 million loss on the extinguishment of debt. As of September 30, 2014, we have $46.4 million of net deferred financing costs related to the Facility, which will be amortized over the remaining term of the Facility, including certain costs related to the amendment.
	As of September 30, 2014, borrowings under the Facility totaled $500.0 million and the undrawn availability under the Facility was $1.0 billion.
	Interest is the aggregate of the applicable margin (3.25% to 4.50%, depending on the length of time that has passed from the date the Facility was entered into); LIBOR; and mandatory cost (if any, as defined in the Facility). Interest is payable on the last day of each interest period (and, if the interest period is longer than six months, on the dates falling at six-month intervals after the first day of the interest period). We pay commitment fees on the undrawn and unavailable portion of the total commitments, if any. Commitment fees are equal to 40% per annum of the then-applicable respective margin when a commitment is available for utilization and, equal to 20% per annum of the then-applicable respective margin when a commitment is not available for utilization. We recognize interest expense in accordance with ASC 835—Interest, which requires interest expense to be recognized using the effective interest method. As part of the March 2014 amendment, the Facility’s estimated effective interest rate was changed and, accordingly, we adjusted our estimate of deferred interest previously recorded during prior years by $4.5 million, which was recorded as a reduction to interest expense.
	The Facility provides a revolving-credit and letter of credit facility. The availability period for the revolving-credit facility, as amended in March 2014 expires on March 31, 2018, however the Facility has a revolving-credit sublimit, which will be the lesser of $500.0 million and the total available facility at that time, that will be available for drawing until the date falling one month prior to the final maturity date. The letter of credit sublimit expires on the final maturity date. The available facility amount is subject to borrowing base constraints and, beginning on March 31, 2018, outstanding borrowings will be constrained by an amortization schedule. The Facility has a final maturity date of March 31, 2021. As of September 30, 2014, we had no letters of credit issued under the Facility.
	Kosmos has the right to cancel all the undrawn commitments under the Facility. The amount of funds available to be borrowed under the Facility, also known as the borrowing base amount, is determined each year on March 31 and September 30 as part of a forecast that is prepared by and agreed to by us and the Technical and Modeling Bank and the Facility Agent. The formula to calculate the borrowing base amount is based on the sum of the net present values of net cash flows and relevant capital expenditures reduced by certain percentages as well as value attributable to certain assets’ reserves and/or resources.
	If an event of default exists under the Facility, the lenders can accelerate the maturity and exercise other rights and remedies, including the enforcement of security granted pursuant to the Facility over certain assets held by our subsidiaries. The Facility contains customary cross default provisions.
	We were in compliance with the financial covenants contained in the Facility as of the September 30, 2014 forecast (the most recent assessment date).
	Corporate Revolver
	In November 2012, we secured a Corporate Revolver from a number of financial institutions. In April 2013, the availability under the Corporate Revolver was increased from $260.0 million to $300.0 million due to additional commitments received from existing and new financial institutions. As of September 30, 2014, there were no borrowings outstanding under the Corporate Revolver and the undrawn availability under the Corporate Revolver was $300.0 million. The Corporate Revolver contains customary cross default provisions.
	Revolving Letter of Credit Facility
	In July 2013, we entered into a revolving letter of credit facility agreement (“LC Facility”). The size of the LC Facility is $100.0 million, with additional commitments up to $50.0 million being available if the existing lender increases its commitment or if commitments from new financial institutions are added. As of September 30, 2014, we had $35.3 million of restricted cash collateralizing seven outstanding letters of credit under the LC Facility. The LC Facility contains customary cross default provisions.
	7.875% Senior Secured Notes due 2021
	During August 2014, the Company issued $300.0 million of Senior Notes and received net proceeds of approximately $292.5 million after deducting discounts, commissions and deferred financing costs. The Company used the net proceeds to repay a portion of the outstanding indebtedness under the Facility and for general corporate purposes.
	The Senior Notes mature on August 1, 2021. Interest is payable semi-annually in arrears each February 1 and August 1 commencing on February 1, 2015. The Senior Notes are secured (subject to certain exceptions and permitted liens) by a first ranking fixed equitable charge on all shares held by us in our direct subsidiary, Kosmos Energy Holdings. The Senior Notes are currently guaranteed on a subordinated, unsecured basis by our existing restricted subsidiaries that guarantee the Facility and the Corporate Revolver, and, in certain circumstances, the Senior Notes will become guaranteed by certain of our other existing or future restricted subsidiaries (the “Guarantees”).
	Redemption and Repurchase.  At any time prior to August 1, 2017 and subject to certain conditions, the Company may, on any one or more occasions, redeem up to 35% of the aggregate principal amount of Senior Notes issued under the indenture dated August 1, 2014 related to the Senior Notes (the “Indenture”) at a redemption price of 107.875%, plus accrued and unpaid interest, with the cash proceeds of certain eligible equity offerings. Additionally, at any time prior to August 1, 2017, the Company may, on any one or more occasions, redeem all or a part of the Senior Notes at a redemption price equal to 100%, plus any accrued and unpaid interest, and plus a make-whole premium. On or after August 1, 2017, the Company may redeem all or a part of the Senior Notes at the redemption prices (expressed as percentages of principal amount) set forth below plus accrued and unpaid interest:
	Year		Percentage
	On or after August 1, 2017, but before August 1, 2018		103.938	%
	On or after August 1, 2018, but before August 1, 2019		101.969	%
	On or after August 1, 2019 and thereafter		100.000	%
	We may also redeem the Senior Notes in whole, but not in part, at any time if changes in tax laws impose certain withholding taxes on amounts payable on the Senior Notes at a price equal to the principal amount of the Senior Notes plus accrued interest and additional amounts, if any, as may be necessary so that the net amount received by each holder after any withholding or deduction on payments of the Senior Notes will not be less than the amount such holder would have received if such taxes had not been withheld or deducted.
	Upon the occurrence of a change of control triggering event as defined under the Indenture, the Company will be required to make an offer to repurchase the Senior Notes at a repurchase price equal to 101% of the principal amount, plus accrued and unpaid interest to, but excluding, the date of repurchase.
	If we sell assets, under certain circumstances outlined in the Indenture, we will be required to use the net proceeds to make an offer to purchase the Senior Notes at an offer price in cash in an amount equal to 100% of the principal amount of the Senior Notes, plus accrued and unpaid interest to, but excluding, the repurchase date.
	Covenants.  The Indenture restricts our ability and the ability of our restricted subsidiaries to, among other things:  incur or guarantee additional indebtedness, create liens, pay dividends or make distributions in respect of capital stock, purchase or redeem capital stock,  make investments or certain other restricted payments, sell assets, enter into agreements that restrict the ability of our subsidiaries to make dividends or other payments to us, enter into transactions with affiliates, or effect certain consolidations, mergers or amalgamations. These covenants are subject to a number of important qualifications and exceptions. Certain of these covenants will be terminated if the Senior Notes are assigned an investment grade rating by both Standard & Poor’s Rating Services and Fitch Ratings Inc. and no default or event of default has occurred and is continuing.
	Collateral.  The Senior Notes are secured (subject to certain exceptions and permitted liens) by a first ranking fixed equitable charge on all currently outstanding shares, additional shares, dividends or other distributions paid in respect of such shares or any other property derived from such shares, in each case held by us in relation to the Company’s direct subsidiary, Kosmos Energy Holdings, pursuant to the terms of the Charge over Shares of Kosmos Energy Holdings dated November 23, 2012, as amended and restated on March 14, 2014, between the Company and BNP Paribas as Security and Intercreditor Agent. The Senior Notes share pari passu in the benefit of such equitable charge based on the respective amounts of the obligations under the Indenture and the amount of obligations under the Corporate Revolver. The Guarantees are not secured.
	At September 30, 2014, the estimated repayments of debt during the five fiscal year periods and thereafter are as follows:
			Payments Due by Year
			2014(2)			2015		2016		2017		2018		Thereafter
			(In thousands)
	Principal debt repayments(1)		$	—		$	—	$	—	$	—	$	—	$	800,000
		-1		Includes the scheduled principal maturities for the Senior Notes and the Facility. The scheduled maturities of debt related to the Facility are based on the level of borrowings and the estimated future available borrowing base as of September 30, 2014. Any increases or decreases in the level of borrowings or decreases in the available borrowing base would impact the scheduled maturities of debt during the next five years and thereafter.
		-2		Represents payments for the period October 1, 2014 through December 31, 2014.

Derivative_Financial_Instrumen

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2014
Derivative Financial Instruments	'
Derivative Financial Instruments	'
	7. Derivative Financial Instruments
	We use financial derivative contracts to manage exposures to commodity price and interest rate fluctuations. We do not hold or issue derivative financial instruments for trading purposes. We manage market and counterparty credit risk in accordance with our policies and guidelines. In accordance with these policies and guidelines, our management determines the appropriate timing and extent of derivative transactions.
	Oil Derivative Contracts
	The following table sets forth the volumes in barrels underlying the Company’s outstanding oil derivative contracts and the weighted average Dated Brent prices per Bbl for those contracts as of September 30, 2014.
							Weighted Average Dated Brent Price per Bbl
	Term		Type of Contract		MBbl		Net Deferred			Swap			Floor			Ceiling		Call
							Premium
							Payable
	2014:00:00
	October — December		Three-way collars		1,507		$	0.01		$	—		$	88.44		$	113.75	$	134.58
	2015:00:00
	January — December		Three-way collars		4,230		$	0.46		$	—		$	87.43		$	110.00	$	133.82
	January — December		Swaps with calls		2,000		—			99.00			—			—		115.00
	2016:00:00
	January — December		Purchased puts		2,000		$	3.41		$	—		$	85.00		$	—	$	—
	Provisional Oil Sales
	At September 30, 2014, we had sales volumes of 447.9 MBbls provisionally priced at an average of $92.95 per Bbl, after differentials, which are subject to final pricing during the next month.
	Interest Rate Swap Derivative Contracts
	The following table summarizes our open interest rate swaps as of September 30, 2014, whereby we pay a fixed rate of interest and the counterparty pays a variable LIBOR-based rate:
	Term		Weighted Average			Weighted Average		Floating Rate
			Notional Amount			Fixed Rate
			(In thousands)
	October 2014 — December 2014		$	110,555		1.93	%	6-month LIBOR
	January 2015 — December 2015		45,319			2.03	%	6-month LIBOR
	January 2016 — June 2016		12,500			2.27	%	6-month LIBOR
	The following tables disclose the Company’s derivative instruments as of September 30, 2014 and December 31, 2013 and gain/(loss) from derivatives during the three and nine months ended September 30, 2014 and 2013, respectively:
					Estimated Fair Value
					Asset (Liability)
					September 30,			December 31,
	Type of Contract		Balance Sheet Location		2014			2013
					(In thousands)
	Derivatives not designated as hedging instruments:
	Derivative assets:
	Commodity(1)		Derivatives assets—current		$	6,848		$	—
	Commodity(2)		Derivatives assets—long-term		3,892			—
	Derivative liabilities:
	Commodity(3)		Derivatives liabilities—current		$	(523	)	$	(7,873	)
	Interest rate		Derivatives liabilities—current		(1,471		)	(2,067		)
	Commodity(4)		Derivatives liabilities—long-term		(282		)	(3,144		)
	Interest rate		Derivatives liabilities—long-term		(147		)	(667		)
	Total derivatives not designated as hedging instruments				$	8,317		$	(13,751	)
		-1		Includes net deferred premiums payable of $0.4 million and zero related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
		-2		Includes net deferred premiums payable of $3.6 million and zero related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
		-3		Includes $0.1 million and zero as of September 30, 2014 and December 31 2013, respectively which represents our provisional oil sales contract. Also, includes net deferred premiums payable of $0.9 million and $0.1 million related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
		-4		Includes net deferred premiums payable of $3.8 million and $6.5 million related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
					Amount of Gain/(Loss)						Amount of Gain/(Loss)
					Three Months Ended						Nine Months Ended
					September 30,						September 30,
	Type of Contract		Location of Gain/(Loss)		2014			2013			2014			2013
					(In thousands)
	Derivatives in cash flow hedging relationships:
	Interest rate(1)		Interest expense		$	290		$	405		$	1,101		$	1,122
	Total derivatives in cash flow hedging relationships				$	290		$	405		$	1,101		$	1,122
	Derivatives not designated as hedging instruments:
	Commodity(2)		Oil and gas revenue		$	(4,886	)	$	(554	)	$	(8,253	)	$	(5,220	)
	Commodity		Derivatives, net		40,407			(7,585		)	20,869			(386		)
	Interest rate		Interest expense		(2		)	(318		)	(209		)	(268		)
	Total derivatives not designated as hedging instruments				$	35,519		$	(8,457	)	$	12,407		$	(5,874	)
		-1		Amounts were reclassified from accumulated other comprehensive income or loss (“AOCI”) into earnings upon settlement.
		-2		Amounts represent the mark-to-market portion of our provisional oil sales contracts.
	Offsetting of Derivative Assets and Derivative Liabilities
	Our derivative instruments which are subject to master netting arrangements with our counterparties only have the right of offset when there is an event of default. As of September 30, 2014 and December 31, 2013, there was not an event of default and, therefore, the associated gross asset or gross liability amounts related to these arrangements are presented on the consolidated balance sheets. Additionally, if an event of default occurred the offsetting amounts would be immaterial as of September 30, 2014 and December 31, 2013.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Measurements	'
Fair Value Measurements	'
	8. Fair Value Measurements
	In accordance with ASC 820—Fair Value Measurements and Disclosures, fair value measurements are based upon inputs that market participants use in pricing an asset or liability, which are classified into two categories: observable inputs and unobservable inputs. Observable inputs represent market data obtained from independent sources, whereas unobservable inputs reflect a company’s own market assumptions, which are used if observable inputs are not reasonably available without undue cost and effort. We prioritize the inputs used in measuring fair value into the following fair value hierarchy:
		·		Level 1—quoted prices for identical assets or liabilities in active markets.
		·		Level 2—quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability and inputs derived principally from or corroborated by observable market data by correlation or other means.
		·		Level 3—unobservable inputs for the asset or liability. The fair value input hierarchy level to which an asset or liability measurement in its entirety falls is determined based on the lowest level input that is significant to the measurement in its entirety.
	The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis as of September 30, 2014 and December 31, 2013, for each fair value hierarchy level:
			Fair Value Measurements Using:
			Quoted Prices in		Significant Other			Significant
			Active Markets for		Observable Inputs			Unobservable Inputs
			Identical Assets
			(Level 1)		(Level 2)			(Level 3)		Total
			(In thousands)
	September 30, 2014
	Assets:
	Commodity derivatives		$	—	$	10,740		$	—	$	10,740
	Liabilities:
	Commodity derivatives		—		(805		)	—		(805		)
	Interest rate derivatives		—		(1,618		)	—		(1,618		)
	Total		$	—	$	8,317		$	—	$	8,317
	December 31, 2013
	Liabilities:
	Commodity derivatives		$	—	$	(11,017	)	$	—	$	(11,017	)
	Interest rate derivatives		—		(2,734		)	—		(2,734		)
	Total		$	—	$	(13,751	)	$	—	$	(13,751	)
	The book values of cash and cash equivalents and restricted cash approximate fair value based on Level 1 inputs. Joint interest billings, oil sales and other receivables, and accounts payable and accrued liabilities approximate fair value due to the short-term nature of these instruments. Our long-term receivables, if any, after any allowances for doubtful accounts approximate fair value. The estimates of fair value of these items are based on Level 2 inputs.
	Commodity Derivatives
	Our commodity derivatives represent crude oil three-way collars, purchased puts and swaps with calls for notional barrels of oil at fixed Dated Brent oil prices. The values attributable to the our oil derivatives are based on (i) the contracted notional volumes, (ii) independent active futures price quotes for Dated Brent, (iii) a credit-adjusted yield curve applicable to each counterparty by reference to the credit default swap (“CDS”) market and (iv) an independently sourced estimate of volatility for Dated Brent. The volatility estimate was provided by certain independent brokers who are active in buying and selling oil options and was corroborated by market-quoted volatility factors. The deferred premium is included in the fair market value of the commodity derivatives. See Note 7—Derivative Financial Instruments for additional information regarding the Company’s derivative instruments.
	Provisional Oil Sales
	The value attributable to the provisional oil sales derivative is based on (i) the sales volumes subject to provisional pricing and (ii) an independently sourced forward curve over the term of the provisional pricing period.
	Interest Rate Derivatives
	We have interest rate swaps, whereby the Company pays a fixed rate of interest and the counterparty pays a variable LIBOR-based rate. The values attributable to the Company’s interest rate derivative contracts are based on (i) the contracted notional amounts, (ii) LIBOR yield curves provided by independent third parties and corroborated with forward active market-quoted LIBOR yield curves and (iii) a credit-adjusted yield curve as applicable to each counterparty by reference to the CDS market.
	Debt
	The following table presents the carrying values and fair values of financial instruments that are not carried at fair value in the consolidated balance sheets:
			September 30, 2014					December 31, 2013
			Carrying Value		Fair Value			Carrying Value		Fair Value
			(In thousands)
	Long-term debt		$	794,106	$	804,500		$	900,000	$	900,000
	The carrying value of the Facility approximates fair value since it is subject to short-term floating interest rates that approximate the rates available to us for those periods. The fair value of our Senior Notes is based on quoted market prices, which results in a Level 1 fair value measurement.

Equitybased_Compensation

Equity-based Compensation	9 Months Ended
	Sep. 30, 2014
Equity-based Compensation	'
Equity-based Compensation	'
	9. Equity-based Compensation
	Restricted Stock Awards and Restricted Stock Units
	We record compensation expense equal to the fair value of share-based payments over the vesting periods of the LTIP awards. We recorded compensation expense from awards granted under our LTIP of $19.0 million and $13.8 million during the three months ended September 30, 2014 and 2013, respectively, and $55.0 million and $50.8 million during the nine months ended September 30, 2014 and 2013. During the nine months ended September 30, 2014, an additional $5.0 million of equity-based compensation was recorded as restructuring charges. The total tax benefit for the three months ended September 30, 2014 and 2013 was $6.7 million and $4.8 million, respectively, and for the nine months ended September 30, 2014 and 2013 was $19.2 million and $17.4 million. Additionally, we expensed a tax shortfall related to equity-based compensation of $6.5 million and $6.9 million for the nine months ended September 30, 2014 and 2013 respectively. No tax shortfall was recorded for the three months ended September 30, 2014 and 2013. The Company granted both restricted stock awards and restricted stock units with service vesting criteria and granted both restricted stock awards and restricted stock units with a combination of market and service criteria under the LTIP. Restricted stock awards are issued and included in the number of outstanding shares upon the date of grant and, if such awards are forfeited, they become treasury stock. Upon vesting, restricted stock units become issued and outstanding stock.
	The following table reflects the outstanding restricted stock awards as of September 30, 2014:
				Weighted-		Market / Service		Weighted-
		Service Vesting		Average		Vesting		Average
		Restricted Stock		Grant-Date		Restricted Stock		Grant-Date
		Awards		Fair Value		Awards		Fair Value
		(In thousands)				(In thousands)
	Outstanding at December 31, 2013	6,384		$	16.48	3,438		$	12.95
	Granted	—		—		—		—
	Forfeited	(115	)	15.58		(74	)	10.87
	Vested	(2,799	)	17.04		—		—
	Outstanding at September 30, 2014	3,470		16.05		3,364		12.99
	The following table reflects the outstanding restricted stock units as of September 30, 2014:
				Weighted-		Market / Service		Weighted-
		Service Vesting		Average		Vesting		Average
		Restricted Stock		Grant-Date		Restricted Stock		Grant-Date
		Units		Fair Value		Units		Fair Value
		(In thousands)				(In thousands)
	Outstanding at December 31, 2013	2,238		$	10.74	1,858		$	15.59
	Granted	1,962		10.95		1,462		15.71
	Forfeited	(398	)	10.9		(179	)	15.48
	Vested	(517	)	10.72		—		—
	Outstanding at September 30, 2014	3,285		10.85		3,141		15.65
	As of September 30, 2014, total equity-based compensation to be recognized on unvested restricted stock awards and restricted stock units is $101.0 million over a weighted average period of 1.79 years. At September 30, 2014, the Company had approximately 2.4 million shares that remain available for issuance under the LTIP.
	For restricted stock awards with a combination of market and service vesting criteria, the number of common shares to be issued is determined by comparing the Company’s total shareholder return with the total shareholder return of a predetermined group of peer companies over the performance period and can vest in up to 100% of the awards granted. The grant date fair value of these awards ranged from $6.70 to $13.57 per award. The Monte Carlo simulation model utilizes multiple input variables that determine the probability of satisfying the market condition stipulated in the award grant and calculates the fair value of the award. The expected volatility utilized in the model was estimated using our historical volatility and the historical volatilities of our peer companies and ranged from 41.3% to 56.7%. The risk-free interest rate was based on the U.S. treasury rate for a term commensurate with the expected life of the grant and ranged from 0.5% to 1.1%.
	For restricted stock units with a combination of market and service vesting criteria, the number of common shares to be issued is determined by comparing the Company’s total shareholder return with the total shareholder return of a predetermined group of peer companies over the performance period and can vest in up to 200% of the awards granted. The grant date fair value of these awards ranged from $15.44 to $15.81 per award. The Monte Carlo simulation model utilizes multiple input variables that determine the probability of satisfying the market condition stipulated in the award grant and calculates the fair value of the award. The expected volatility utilized in the model was estimated using our historical volatility and the historical volatilities of our peer companies and ranged from 39.0% to 54.0%. The risk-free interest rate was based on the U.S. treasury rate for a term commensurate with the expected life of the grant and ranged from 0.5% to 1.2%.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Taxes	'
Income Taxes	'
	10. Income Taxes
	Income tax expense was $38.5 million and $34.2 million for the three months ended September 30, 2014 and 2013, respectively, and $170.0 million and $124.6 million for the nine months ended September 30, 2014 and 2013, respectively. The income tax provision consists of United States and Ghanaian income and Texas margin taxes.
	The components of income (loss) before income taxes were as follows:
		Three months ended September 30,						Nine months ended September 30,
		2014			2013			2014			2013
		(In thousands)
	Bermuda	$	(8,368	)	$	(5,880	)	$	(20,588	)	$	(19,320	)
	United States	3,049			2,740			10,542			8,014
	Foreign—other	62,910			(7,124		)	330,680			40,664
	Income (loss) before income taxes	$	57,591		$	(10,264	)	$	320,634		$	29,358
	Our effective tax rate for the three months ended September 30, 2014 and 2013 is 67% and (333)%, respectively. For the nine months ended September 30, 2014 and 2013, our effective tax rate is 53% and 424%, respectively. The effective tax rate for the United States is approximately 38% and 42% for the three months ended September 30, 2014 and 2013, respectively, and 102% and 125% for the nine months ended September 30, 2014 and 2013, respectively. The effective tax rate in the United States is impacted by the effect of tax shortfalls related to equity-based compensation. The effective tax rate for Ghana is approximately 33% and 36% for the three months ended September 30, 2014 and 2013, respectively, and approximately 35% and 36% for the nine months ended September 30, 2014 and 2013, respectively. Our other foreign jurisdictions have a 0% effective tax rate because they reside in countries with a 0% statutory rate, or we have experienced losses in those countries and have a full valuation allowance reserved against the corresponding net deferred tax assets.
	The Company has no material unrecognized income tax benefits.
	A subsidiary of the Company files a U.S. federal income tax return and a Texas margin tax return. In addition to the United States, the Company files income tax returns in the countries in which the Company operates. The Company is open to U.S. federal income tax examinations for tax years 2012 through 2013 and to Texas margin tax examinations for the tax years 2009 through 2013. In addition, the Company is open to income tax examinations for years 2004 through 2013 in its significant other foreign jurisdictions (Ghana, Cameroon, Mauritania, Suriname and Morocco).
	As of September 30, 2014, the Company had no material uncertain tax positions. The Company’s policy is to recognize potential interest and penalties related to income tax matters in income tax expense, but have not accrued any material amounts to date.

Net_Income_Loss_Per_Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2014
Net Income (Loss) Per Share	'
Net Income (Loss) Per Share	'
	11. Net Income (Loss) Per Share
	The following table is a reconciliation between net income and the amounts used to compute basic and diluted net income per share and the weighted average shares outstanding used to compute basic and diluted net income per share:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2014			2013			2014			2013
			(In thousands, except per share data)
	Numerator:
	Net income (loss)		$	19,123		$	(44,488	)	$	150,599		$	(95,210	)
	Less: Basic income allocable to participating securities(1)		(174		)	—			(1,919		)	—
	Basic net income (loss) allocable to common shareholders		18,949			(44,488		)	148,680			(95,210		)
	Diluted adjustments to income allocable to participating securities(1)		1			—			17			—
	Diluted net income (loss) allocable to common shareholders		$	18,950		$	(44,488	)	$	148,697		$	(95,210	)
	Denominator:
	Weighted average number of shares used to compute net income (loss) per share:
	Basic		379,969			377,654			378,881			376,509
	Restricted stock awards and units(1)(2)		2,221			—			3,406			—
	Diluted		382,190			377,654			382,287			376,509
	Net income (loss) per share:
	Basic		$	0.05		$	(0.12	)	$	0.39		$	(0.25	)
	Diluted		$	0.05		$	(0.12	)	$	0.39		$	(0.25	)
		-1		Our service vesting restricted stock awards represent participating securities because they participate in nonforfeitable dividends with common equity owners. Income allocable to participating securities represents the distributed and undistributed earnings attributable to the participating securities. Our restricted stock awards with market and service vesting criteria and all restricted stock units are not considered to be participating securities and, therefore, are excluded from the basic net income per common share calculation. Our service vesting restricted stock awards do not participate in undistributed net losses and, therefore, are excluded from the basic net income per common share calculation in periods we are in a net loss position.
		-2		We excluded outstanding restricted stock awards of 6.8 million and 13.9 million for the three months ended September 30, 2014 and 2013, respectively, and 4.7 million and 13.9 million for the nine months ended September 30, 2014 and 2013, respectively, from the computations of diluted net income per share because the effect would have been anti-dilutive.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies	'
Commitments and Contingencies	'
	12. Commitments and Contingencies
	We are involved in litigation, regulatory examinations and administrative proceedings primarily arising in the ordinary course of our business in jurisdictions in which we do business. Although the outcome of these matters cannot be predicted with certainty, management believes none of these matters, either individually or in the aggregate, would have a material effect upon the Company’s financial position; however, an unfavorable outcome could have a material adverse effect on our results from operations for a specific interim period or year.
	In September 2014, we took delivery of the new build 6th generation drillship “Atwood Achiever” from Atwood Oceanics, Inc.  The rig is expected to commence drilling operations in Northwest Africa in the fourth quarter of 2014. The rig agreement covers an initial period of three years at a day rate of approximately $0.6 million, with an option to extend the agreement for an additional three-year term. We have entered into a rig sharing agreement, whereby two rig slots (estimated to be 90 days during 2015 and 70 days during 2016) were assigned to a third-party.
	The estimated future minimum commitments as of September 30, 2014, are:
			Payments Due By Year(1)
			Total		2014(2)		2015		2016		2017		2018		Thereafter
			(In thousands)
	Operating leases		$	16,908	$	813	$	3,260	$	3,158	$	3,223	$	3,323	$	3,131
	Atwood Achiever drilling rig contract (3)		540,855		54,740		163,625		176,120		146,370		—		—
		-1		Does not include purchase commitments for jointly owned fields and facilities where we are not the operator and excludes commitments for exploration activities, including well commitments, in our petroleum contracts.
		-2		Represents payments for the period from October 1, 2014 through December 31, 2014.
		-3		Commitments calculated using a day rate of $595,000, excluding applicable taxes. The rig commitments reflect the execution of a rig sharing agreement, whereby two rig slots (estimated to be 90 days during 2015 and 70 days during 2016) were assigned to a third-party.

Accounting_Policies_Policies

Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies	'
General	'
	General
	The interim-period financial information presented in the consolidated financial statements included in this report is unaudited and, in the opinion of management, includes all adjustments of a normal recurring nature necessary to present fairly the consolidated financial position as of September 30, 2014, the changes in the consolidated statements of shareholders’ equity for the nine months ended September 30, 2014, the consolidated results of operations for the three and nine months ended September 30, 2014 and 2013, and consolidated cash flows for the nine months ended September 30, 2014 and 2013. The results of the interim periods shown in this report are not necessarily indicative of the final results to be expected for the full year. The consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by Generally Accepted Accounting Principles in the United States of America (“GAAP”) have been condensed or omitted from these interim consolidated financial statements. These consolidated financial statements and the accompanying notes should be read in conjunction with our audited consolidated financial statements for the year ended December 31, 2013, included in our annual report on Form 10-K.
Reclassifications	'
	Reclassifications
	Certain prior period amounts have been reclassified to conform with the current year presentation. Such reclassifications had no impact on our reported net income (loss), current assets, total assets, current liabilities, total liabilities or shareholders’ equity.
Restricted Cash	'
	Restricted Cash
	In accordance with our commercial debt facility (the “Facility”), we are required to maintain a restricted cash balance that is sufficient to meet the payment of interest and fees for the next six-month period on the 7.875% Senior Secured Notes due 2021 (“Senior Notes”) plus the Corporate Revolver or the Facility, whichever is greater. As of September 30, 2014 and December 31, 2013, we had $15.5 million and $18.6 million, respectively, in current restricted cash to meet this requirement. In addition, in accordance with certain of our petroleum contracts, we have posted letters of credit related to performance guarantees for our minimum work obligations. These letters of credit are cash collateralized in accounts held by us and as such are classified as restricted cash. Upon completion of the minimum work obligations and/or entering into the next phase of the petroleum contract, the requirement to post the existing letters of credit will be satisfied and the cash collateral will be released. However, additional letters of credit may be required should we choose to move into the next phase of certain of our petroleum contracts. As of September 30, 2014 and December 31, 2013, we had $19.1 million and $2.9 million, respectively, of current restricted cash and $16.1 million and $31.5 million, respectively, of long-term restricted cash used to cash collateralize performance guarantees related to our petroleum contracts.
Inventories	'
	Inventories
	Inventories consisted of $55.0 million and $45.8 million of materials and supplies and $2.6 million and $1.6 million of hydrocarbons as of September 30, 2014 and December 31, 2013, respectively. The Company’s materials and supplies inventory primarily consists of casing and wellheads and is stated at the lower of cost, using the weighted average cost method, or market.
	Hydrocarbon inventory is carried at the lower of cost, using the weighted average cost method, or market. Hydrocarbon inventory costs include expenditures and other charges incurred in bringing the inventory to its existing condition. Selling expenses and general and administrative expenses are reported as period costs and excluded from inventory costs.
Restructuring charges	'
	Restructuring Charges
	The Company accounts for restructuring charges in accordance with ASC 420-Exit or Disposal Cost Obligations. Under these standards, the costs associated with restructuring charges are recorded during the period in which the liability is incurred. During the nine months ended September 30, 2014, we recognized $11.8 million in restructuring charges for employee severance and related benefit costs incurred as part of a corporate reorganization, which includes $5.0 million of accelerated non-cash expense related to awards previously granted under our Long-Term Incentive Plan (the “LTIP”).
Recent Accounting Standards	'
	Recent Accounting Standards
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) Topic 605, “Revenue Recognition,” and most industry-specific guidance. ASU 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB ASC. The new guidance is effective for annual reporting periods beginning after December 15, 2016 for public companies. Early adoption is not permitted. Entities have the option of using either a full retrospective or modified approach to adopt ASU 2014-09. The Company is currently evaluating the new guidance and has not determined the impact this standard may have on its financial statements or decided upon the method of adoption.
	In April 2014, the FASB issued ASU 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity.” ASU 2014-08 prospectively changes the criteria for reporting discontinued operations while enhancing disclosures around disposals of assets whether or not the disposal meets the definition of a discontinued operation. ASU 2014-08 is effective for annual and interim periods beginning after December 31, 2014 with early adoption permitted but only for disposals that have not been reported in financial statements previously issued. The adoption of this new guidance is not expected to have a material impact on the Company’s consolidated financial statements.

Property_and_Equipment_Tables

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2014
Property and Equipment	'
Schedule of property and equipment	'
		September 30,			December 31,
		2014			2013
		(In thousands)
	Oil and gas properties:
	Proved properties	$	865,500		$	801,348
	Unproved properties	716,933			524,257
	Support equipment and facilities	732,567			710,289
	Total oil and gas properties	2,315,000			2,035,894
	Less: accumulated depletion	(673,607		)	(527,832		)
	Oil and gas properties, net	1,641,393			1,508,062
	Other property	32,745			31,658
	Less: accumulated depreciation	(20,537		)	(16,758		)
	Other property, net	12,208			14,900
	Property and equipment, net	$	1,653,601		$	1,522,962

Suspended_Well_Costs_Tables

Suspended Well Costs (Tables)	9 Months Ended
	Sep. 30, 2014
Suspended Well Costs	'
Schedule of capitalized exploratory well costs	'
		Nine Months
		Ended
		September 30,
		2014
		(In thousands)
	Beginning balance	$	376,166
	Additions to capitalized exploratory well costs pending the determination of proved reserves	53,367
	Reclassification due to determination of proved reserves	—
	Capitalized exploratory well costs charged to expense	—
	Ending balance	$	429,533
Schedule of aging of capitalized exploratory well costs and number of projects for which exploratory well costs were capitalized for more than one year	'
		September 30, 2014		December 31, 2013
		(In thousands, except well counts)
	Exploratory well costs capitalized for a period of one year or less	$	52,502	$	11,426
	Exploratory well costs capitalized for a period of one to two years	137,367		229,140
	Exploratory well costs capitalized for a period of three to five years	239,664		135,600
	Ending balance	$	429,533	$	376,166
	Number of projects that have exploratory well costs that have been capitalized for a period greater than one year	8		8

Accrued_Liabilities_Tables

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2014
Accrued Liabilities	'
Accrued Liabilities	'
		September 30,		December 31,
		2014		2013
		(In thousands)
	Accrued liabilities:
	Accrued exploration, development and production	$	150,149	$	73,976
	Accrued general and administrative expenses	20,082		4,255
	Accrued taxes other than income	18,472		15,188
	Accrued interest	4,505		—
	Income taxes	2,282		20,379
	Accrued other	1,642		1,414
		$	197,132	$	115,212

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 30, 2014
Debt	'
Schedule of debt	'
			September 30,			December 31,
			2014			2013
			(In thousands)
	Outstanding debt principal balances:
	Facility		$	500,000		$	900,000
	Senior Notes		300,000			—
	Total		800,000			900,000
	Unamortized issuance discounts		(5,894		)	—
	Long-term debt		$	794,106		$	900,000
Schedule of redemption prices (expressed as percentages of principal amount) of all or a part of the Senior Notes	'
	Year		Percentage
	On or after August 1, 2017, but before August 1, 2018		103.938	%
	On or after August 1, 2018, but before August 1, 2019		101.969	%
	On or after August 1, 2019 and thereafter		100.000	%
Schedule of estimated repayments of debt	'
	At September 30, 2014, the estimated repayments of debt during the five fiscal year periods and thereafter are as follows
			Payments Due by Year
			2014(2)			2015		2016		2017		2018		Thereafter
			(In thousands)
	Principal debt repayments(1)		$	—		$	—	$	—	$	—	$	—	$	800,000
		-1		Includes the scheduled principal maturities for the Senior Notes and the Facility. The scheduled maturities of debt related to the Facility are based on the level of borrowings and the estimated future available borrowing base as of September 30, 2014. Any increases or decreases in the level of borrowings or decreases in the available borrowing base would impact the scheduled maturities of debt during the next five years and thereafter.
		-2		Represents payments for the period October 1, 2014 through December 31, 2014.

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative Financial Instruments	'
Schedule of oil derivative contracts	'
	The following table sets forth the volumes in barrels underlying the Company’s outstanding oil derivative contracts and the weighted average Dated Brent prices per Bbl for those contracts as of September 30, 2014
							Weighted Average Dated Brent Price per Bbl
	Term		Type of Contract		MBbl		Net Deferred			Swap			Floor			Ceiling		Call
							Premium
							Payable
	2014:00:00
	October — December		Three-way collars		1,507		$	0.01		$	—		$	88.44		$	113.75	$	134.58
	2015:00:00
	January — December		Three-way collars		4,230		$	0.46		$	—		$	87.43		$	110.00	$	133.82
	January — December		Swaps with calls		2,000		—			99.00			—			—		115.00
	2016:00:00
	January — December		Purchased puts		2,000		$	3.41		$	—		$	85.00		$	—	$	—
Schedule of interest rate swaps derivative contracts	'
	The following table summarizes our open interest rate swaps as of September 30, 2014, whereby we pay a fixed rate of interest and the counterparty pays a variable LIBOR-based rate
	Term		Weighted Average			Weighted Average		Floating Rate
			Notional Amount			Fixed Rate
			(In thousands)
	October 2014 — December 2014		$	110,555		1.93	%	6-month LIBOR
	January 2015 — December 2015		45,319			2.03	%	6-month LIBOR
	January 2016 — June 2016		12,500			2.27	%	6-month LIBOR
Schedule of derivative instruments by balance sheet location	'
					Estimated Fair Value
					Asset (Liability)
					September 30,			December 31,
	Type of Contract		Balance Sheet Location		2014			2013
					(In thousands)
	Derivatives not designated as hedging instruments:
	Derivative assets:
	Commodity(1)		Derivatives assets—current		$	6,848		$	—
	Commodity(2)		Derivatives assets—long-term		3,892			—
	Derivative liabilities:
	Commodity(3)		Derivatives liabilities—current		$	(523	)	$	(7,873	)
	Interest rate		Derivatives liabilities—current		(1,471		)	(2,067		)
	Commodity(4)		Derivatives liabilities—long-term		(282		)	(3,144		)
	Interest rate		Derivatives liabilities—long-term		(147		)	(667		)
	Total derivatives not designated as hedging instruments				$	8,317		$	(13,751	)
		-1		Includes net deferred premiums payable of $0.4 million and zero related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
		-2		Includes net deferred premiums payable of $3.6 million and zero related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
		-3		Includes $0.1 million and zero as of September 30, 2014 and December 31 2013, respectively which represents our provisional oil sales contract. Also, includes net deferred premiums payable of $0.9 million and $0.1 million related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
		-4		Includes net deferred premiums payable of $3.8 million and $6.5 million related to commodity derivative contracts as of September 30, 2014 and December 31, 2013, respectively.
Schedule of derivative instruments by location of gain/(loss)	'
					Amount of Gain/(Loss)						Amount of Gain/(Loss)
					Three Months Ended						Nine Months Ended
					September 30,						September 30,
	Type of Contract		Location of Gain/(Loss)		2014			2013			2014			2013
					(In thousands)
	Derivatives in cash flow hedging relationships:
	Interest rate(1)		Interest expense		$	290		$	405		$	1,101		$	1,122
	Total derivatives in cash flow hedging relationships				$	290		$	405		$	1,101		$	1,122
	Derivatives not designated as hedging instruments:
	Commodity(2)		Oil and gas revenue		$	(4,886	)	$	(554	)	$	(8,253	)	$	(5,220	)
	Commodity		Derivatives, net		40,407			(7,585		)	20,869			(386		)
	Interest rate		Interest expense		(2		)	(318		)	(209		)	(268		)
	Total derivatives not designated as hedging instruments				$	35,519		$	(8,457	)	$	12,407		$	(5,874	)
		-1		Amounts were reclassified from accumulated other comprehensive income or loss (“AOCI”) into earnings upon settlement.
		-2		Amounts represent the mark-to-market portion of our provisional oil sales contracts.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Measurements	'
Schedule of Company's assets and liabilities that are measured at fair value on a recurring basis	'
		Fair Value Measurements Using:
		Quoted Prices in		Significant Other			Significant
		Active Markets for		Observable Inputs			Unobservable Inputs
		Identical Assets
		(Level 1)		(Level 2)			(Level 3)		Total
		(In thousands)
	September 30, 2014
	Assets:
	Commodity derivatives	$	—	$	10,740		$	—	$	10,740
	Liabilities:
	Commodity derivatives	—		(805		)	—		(805		)
	Interest rate derivatives	—		(1,618		)	—		(1,618		)
	Total	$	—	$	8,317		$	—	$	8,317
	December 31, 2013
	Liabilities:
	Commodity derivatives	$	—	$	(11,017	)	$	—	$	(11,017	)
	Interest rate derivatives	—		(2,734		)	—		(2,734		)
	Total	$	—	$	(13,751	)	$	—	$	(13,751	)
Schedule of carrying values and fair values of financial instruments that are not carried at fair value	'
		September 30, 2014					December 31, 2013
		Carrying Value		Fair Value			Carrying Value		Fair Value
		(In thousands)
	Long-term debt	$	794,106	$	804,500		$	900,000	$	900,000

Equitybased_Compensation_Table

Equity-based Compensation (Tables) (LTIP)	9 Months Ended
	Sep. 30, 2014
Restricted stock awards	'
Equity-based Compensation	'
Schedule of plan activity	'
				Weighted-		Market / Service		Weighted-
		Service Vesting		Average		Vesting		Average
		Restricted Stock		Grant-Date		Restricted Stock		Grant-Date
		Awards		Fair Value		Awards		Fair Value
		(In thousands)				(In thousands)
	Outstanding at December 31, 2013	6,384		$	16.48	3,438		$	12.95
	Granted	—		—		—		—
	Forfeited	(115	)	15.58		(74	)	10.87
	Vested	(2,799	)	17.04		—		—
	Outstanding at September 30, 2014	3,470		16.05		3,364		12.99
Restricted stock units	'
Equity-based Compensation	'
Schedule of plan activity	'
				Weighted-		Market / Service		Weighted-
		Service Vesting		Average		Vesting		Average
		Restricted Stock		Grant-Date		Restricted Stock		Grant-Date
		Units		Fair Value		Units		Fair Value
		(In thousands)				(In thousands)
	Outstanding at December 31, 2013	2,238		$	10.74	1,858		$	15.59
	Granted	1,962		10.95		1,462		15.71
	Forfeited	(398	)	10.9		(179	)	15.48
	Vested	(517	)	10.72		—		—
	Outstanding at September 30, 2014	3,285		10.85		3,141		15.65

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2014
Income Taxes	'
Schedule of components of the provision for income taxes attributable to the entity's income (loss) before income taxes	'
		Three months ended September 30,						Nine months ended September 30,
		2014			2013			2014			2013
		(In thousands)
	Bermuda	$	(8,368	)	$	(5,880	)	$	(20,588	)	$	(19,320	)
	United States	3,049			2,740			10,542			8,014
	Foreign—other	62,910			(7,124		)	330,680			40,664
	Income (loss) before income taxes	$	57,591		$	(10,264	)	$	320,634		$	29,358

Net_Income_Loss_Per_Share_Tabl

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2014
Net Income (Loss) Per Share	'
Schedule of reconciliation between net income and the amounts used to compute basic and diluted net income per share and the weighted average shares outstanding used to compute basic and diluted net income per share	'
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2014			2013			2014			2013
			(In thousands, except per share data)
	Numerator:
	Net income (loss)		$	19,123		$	(44,488	)	$	150,599		$	(95,210	)
	Less: Basic income allocable to participating securities(1)		(174		)	—			(1,919		)	—
	Basic net income (loss) allocable to common shareholders		18,949			(44,488		)	148,680			(95,210		)
	Diluted adjustments to income allocable to participating securities(1)		1			—			17			—
	Diluted net income (loss) allocable to common shareholders		$	18,950		$	(44,488	)	$	148,697		$	(95,210	)
	Denominator:
	Weighted average number of shares used to compute net income (loss) per share:
	Basic		379,969			377,654			378,881			376,509
	Restricted stock awards and units(1)(2)		2,221			—			3,406			—
	Diluted		382,190			377,654			382,287			376,509
	Net income (loss) per share:
	Basic SS		$	0.05		$	(0.12	)	$	0.39		$	(0.25	)
	Diluted		$	0.05		$	(0.12	)	$	0.39		$	(0.25	)
		-1		Our service vesting restricted stock awards represent participating securities because they participate in nonforfeitable dividends with common equity owners. Income allocable to participating securities represents the distributed and undistributed earnings attributable to the participating securities. Our restricted stock awards with market and service vesting criteria and all restricted stock units are not considered to be participating securities and, therefore, are excluded from the basic net income per common share calculation. Our service vesting restricted stock awards do not participate in undistributed net losses and, therefore, are excluded from the basic net income per common share calculation in periods we are in a net loss position.
		-2		We excluded outstanding restricted stock awards of 6.8 million and 13.9 million for the three months ended September 30, 2014 and 2013, respectively, and 4.7 million and 13.9 million for the nine months ended September 30, 2014 and 2013, respectively, from the computations of diluted net income per share because the effect would have been anti-dilutive.

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies	'
Schedule of estimated future minimum commitments	'
	The estimated future minimum commitments under this contract as of September 30, 2014, are:
			Payments Due By Year(1)
			Total		2014(2)		2015		2016		2017		2018		Thereafter
			(In thousands)
	Operating leases		$	16,908	$	813	$	3,260	$	3,158	$	3,223	$	3,323	$	3,131
	Atwood Achiever drilling rig contract (3)		540,855		54,740		163,625		176,120		146,370		—		—
		-1		Does not include purchase commitments for jointly owned fields and facilities where we are not the operator and excludes commitments for exploration activities, including well commitments, in our petroleum contracts.
		-2		Represents payments for the period from October 1, 2014 through December 31, 2014.
		-3		Commitments calculated using a day rate of $595,000, excluding applicable taxes. The rig commitments reflect the execution of a rig sharing agreement, whereby two rig slots (estimated to be 90 days during 2015 and 70 days during 2016) were assigned to a third-party.

Organization_Details

Organization (Details)	9 Months Ended
	Sep. 30, 2014
	segment
Organization	'
Number of reportable segments	1

Accounting_Policies_Details

Accounting Policies (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Restricted Cash	'	'
Current restricted cash	$34,621,000	$21,475,000
Long-term restricted cash	16,125,000	31,500,000
Inventories	'	'
Materials and supplies inventory	55,000,000	45,800,000
Hydrocarbons inventory	2,600,000	1,600,000
Restricted Cash | Facility interest or the Senior Notes plus the Corporate Revolver interest	'	'
Restricted Cash	'	'
Restricted cash period required as per commercial debt facility to meet interest and commitment fee payments	'6 months	'
Current restricted cash	15,500,000	18,600,000
Restricted Cash | Petroleum agreements - performance guarantees	'	'
Restricted Cash	'	'
Current restricted cash	19,100,000	2,900,000
Long-term restricted cash	$16,100,000	$31,500,000

Accounting_Policies_Details_3

Accounting Policies (Details 3) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Restructuring charges	($46,000)	$11,758,000
LTIP	'	'
Non-cash expense included in restructuring charges	'	$5,000,000

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)

3 Months Ended

9 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

1 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Mar. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Aug. 31, 2014

Farm-out agreements

Farm-out agreements

Farm-out agreements

Farm-out agreements

BP

BP

Cairn

Timis Corporation Limited

Essaouira Offshore Block

Foum Assaka Offshore Block

Tarhazoute Offshore Block

Cap Boujdour Offshore block

Farm-out agreements

Farm-out agreements

Farm-out agreements

Farm-in agreement

Essaouira Offshore, Foum Assaka Offshore and Tarhazoute Offshore blocks

Essaouira Offshore, Foum Assaka Offshore and Tarhazoute Offshore blocks

Cap Boujdour Offshore block

Cayar Offshore Profond and Saint Louis Offshore Profond blocks

item

item

Oil and gas properties:

'

'

'

'

'

'

'

'

'

'

'

'

'

Proved properties

$865,500,000

'

$865,500,000

'

$801,348,000

'

'

'

'

'

'

'

'

Unproved properties

716,933,000

'

716,933,000

'

524,257,000

'

'

'

'

'

'

'

'

Support equipment and facilities

732,567,000

'

732,567,000

'

710,289,000

'

'

'

'

'

'

'

'

Total oil and gas properties

2,315,000,000

'

2,315,000,000

'

2,035,894,000

'

'

'

'

'

'

'

'

Less: accumulated depletion

-673,607,000

'

-673,607,000

'

-527,832,000

'

'

'

'

'

'

'

'

Oil and gas properties, net

1,641,393,000

'

1,641,393,000

'

1,508,062,000

'

'

'

'

'

'

'

'

Other property

32,745,000

'

32,745,000

'

31,658,000

'

'

'

'

'

'

'

'

Less: accumulated depreciation

-20,537,000

'

-20,537,000

'

-16,758,000

'

'

'

'

'

'

'

'

Other property, net

12,208,000

'

12,208,000

'

14,900,000

'

'

'

'

'

'

'

'

Property and equipment, net

1,653,601,000

'

1,653,601,000

'

1,522,962,000

'

'

'

'

'

'

'

'

Depletion expense

34,600,000

56,100,000

145,800,000

169,200,000

'

'

'

'

'

'

'

'

'

Property and Equipment

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of blocks covered by farm-out agreements

'

'

'

'

'

'

'

'

'

3

'

'

'

Proceeds on sale of assets

'

'

58,315,000

'

'

'

'

'

'

'

56,900,000

'

'

Participating interests (as a percent)

'

'

'

'

'

30.00%

29.93%

30.00%

55.00%

'

'

'

60.00%

Gain on sale of assets

'

'

23,769,000

'

'

'

'

'

'

'

23,800,000

'

'

Reimbursement of shared costs previously incurred

'

'

'

'

'

'

'

'

'

'

'

$1,500,000

'

Number of contingent exploration wells

'

'

'

'

'

'

'

'

'

'

'

'

2

Maximum cost per contingent exploration well

'

'

'

'

'

'

'

'

'

'

'

'

120,000,000

Participating interest for carrying the full cost of third contingent exploration or appraisal well (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

65.00%

Suspended_Well_Costs_Details

Suspended Well Costs (Details) (USD $)	9 Months Ended		9 Months Ended							1 Months Ended	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	31-May-13	Sep. 30, 2014
	project	project	Mahogany Discovery	Mahogany Discovery	Teak-1 Discovery	Teak-1 Discovery	Teak-2 Discovery	Akasa Discovery	Akasa Discovery	TEN Discoveries	Wawa Discovery
			item	Maximum	item	Maximum	Maximum	item	Maximum	Maximum	Maximum
										Forecast
										item
Suspended Well Costs	'	'	'	'	'	'	'	'	'	'	'
Capitalized exploratory well costs subsequently expensed in the same period	$3,100,000	'	'	'	'	'	'	'	'	'	'
Reconciliation of capitalized exploratory well costs on completed wells	'	'	'	'	'	'	'	'	'	'	'
Beginning balance	376,166,000	'	'	'	'	'	'	'	'	'	'
Additions to capitalized exploratory well costs pending the determination of proved reserves	53,367,000	'	'	'	'	'	'	'	'	'	'
Balance at the end of the period	429,533,000	'	'	'	'	'	'	'	'	'	'
Aging of capitalized exploratory well costs and number of projects for which exploratory well costs were capitalized for more than one year	'	'	'	'	'	'	'	'	'	'	'
Exploratory well costs capitalized for a period of one year or less	52,502,000	11,426,000	'	'	'	'	'	'	'	'	'
Exploratory well costs capitalized for a period one to two years	137,367,000	229,140,000	'	'	'	'	'	'	'	'	'
Exploratory well costs capitalized for a period three to five years	239,664,000	135,600,000	'	'	'	'	'	'	'	'	'
Ending balance	$429,533,000	'	'	'	'	'	'	'	'	'	'
Number of projects that have exploratory well costs that have been capitalized for a period greater than one year	8	8	'	'	'	'	'	'	'	'	'
Projects with exploratory well costs capitalized for more than one year	'	'	'	'	'	'	'	'	'	'	'
Number of appraisal wells	'	'	3	'	2	'	'	1	'	'	'
Submission of PoD to Ghana's Ministry of Energy, period	'	'	'	'6 months	'	'6 months	'6 months	'	'6 months	'	'6 months
Number of development wells	'	'	'	'	'	'	'	'	'	24	'

Accrued_Liabilities_Details

Accrued Liabilities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accrued liabilities:	'	'
Accrued exploration, development and production	$150,149	$73,976
Accrued general and administrative expenses	20,082	4,255
Accrued taxes other than income	18,472	15,188
Accrued interest	4,505	'
Income taxes	2,282	20,379
Accrued other	1,642	1,414
Accrued liabilities	$197,132	$115,212

Debt_Details

Debt (Details) (USD $)

9 Months Ended

1 Months Ended

9 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

Sep. 30, 2014

Dec. 31, 2013

Mar. 31, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Apr. 30, 2013

Mar. 31, 2013

Sep. 30, 2014

Jul. 31, 2013

Aug. 31, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Facility

Facility

Facility

Facility

Facility

Corporate Revolver

Corporate Revolver

Corporate Revolver

Revolving Letter of Credit Facility

Revolving Letter of Credit Facility

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Minimum

Maximum

item

7.875% senior notes due 2021

7.875% senior notes due 2021

7.875% senior notes due 2021

7.875% senior notes due 2021

7.875% senior notes due 2021

7.875% senior notes due 2021

Prior to August 1, 2017

On or after August 1, 2017, but before August 1, 2018

On or after August 1, 2018, but before August 1, 2019

On or after August 1, 2019 and thereafter

Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding debt principal

$800,000,000

$900,000,000

'

$500,000,000

$900,000,000

'

'

'

'

'

'

'

'

$300,000,000

'

'

'

'

Unamortized issuance discounts

5,894,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

794,106,000

900,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total commitment

'

'

1,500,000,000

'

'

'

'

'

300,000,000

260,000,000

'

100,000,000

'

'

'

'

'

'

Loss on extinguishment of debt

2,898,000

'

2,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net deferred financing costs

51,337,000

40,111,000

'

46,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount outstanding

'

'

'

500,000,000

'

'

'

0

'

'

'

'

'

'

'

'

'

'

Undrawn availability

'

'

'

1,000,000,000

'

'

'

300,000,000

'

'

'

'

'

'

'

'

'

'

Applicable margin (as a percent)

'

'

'

'

'

3.25%

4.50%

'

'

'

'

'

'

'

'

'

'

'

Variable rate basis

'

'

'

'LIBOR

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interval period for payment of interest

'

'

'

'6 months

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitment fee percentage of the then-applicable margin when commitment is available for utilization

'

'

'

40.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitment fee percentage of the then-applicable margin when commitment is not available for utilization

'

'

'

20.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Adjustment in estimate of deferred interest

'

'

4,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving-credit sublimit amount after March 31, 2018

'

'

'

500,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Availability period of revolving-credit sublimit

'

'

'

'1 month

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount outstanding under letters of credit

'

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional commitments

'

'

'

'

'

'

'

'

'

'

'

50,000,000

'

'

'

'

'

'

Number of letters of credit

'

'

'

'

'

'

'

'

'

'

7

'

'

'

'

'

'

'

Restricted cash

'

'

'

'

'

'

'

'

'

'

35,300,000

'

'

'

'

'

'

'

Senior notes offering face amount

'

'

'

'

'

'

'

'

'

'

'

'

300,000,000

'

'

'

'

'

Proceeds, net of offering discounts and deferred financing costs

'

'

'

'

'

'

'

'

'

'

'

'

292,500,000

'

'

'

'

'

Redemption price, as a percent of the of principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

103.94%

101.97%

100.00%

Scheduled maturities of debt during the five year period and thereafter

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Thereafter

$800,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Senior notes redemption, start date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1-Aug-14

1-Aug-17

1-Aug-18

1-Aug-19

Senior notes redemption, end date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

31-Jul-17

31-Jul-18

31-Jul-19

1-Aug-21

Maximum percentage of principal amount available to be redeemed with proceeds from equity offerings

'

'

'

'

'

'

'

'

'

'

'

'

'

'

35.00%

'

'

'

Redemption price percentage using proceeds from equity offerings

'

'

'

'

'

'

'

'

'

'

'

'

'

'

107.88%

'

'

'

Redemption price percentage following change of control

'

'

'

'

'

'

'

'

'

'

'

'

'

101.00%

'

'

'

'

Redemption price percentage, excluding proceeds from equity offerings

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

Redemption price percentage following sell of certain assets

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Details)	9 Months Ended
	Sep. 30, 2014
	MBbls
Provisional Oil Sales	'
Derivative Financial Instruments	'
Volumes (in MBbl)	447.9
Average price, subject to final pricing	92.95
Three-way Collars | Term October 2014 to December 2014 | Price risk derivatives	'
Derivative Financial Instruments	'
Volumes (in MBbl)	1,507
Weighted average deferred premium payable per Bbl	0.01
Weighted average floor price per Bbl	88.44
Weighted average ceiling price per Bbl	113.75
Weighted average call price per Bbl	134.58
Three-way Collars | Term January 2015 to December 2015 | Price risk derivatives	'
Derivative Financial Instruments	'
Volumes (in MBbl)	4,230
Weighted average deferred premium payable per Bbl	0.46
Weighted average floor price per Bbl	87.43
Weighted average ceiling price per Bbl	110
Weighted average call price per Bbl	133.82
Purchased Puts [Member] | Term January 2016 to December 2016 | Price risk derivatives	'
Derivative Financial Instruments	'
Volumes (in MBbl)	2,000
Weighted average deferred premium payable per Bbl	3.41
Weighted average floor price per Bbl	85
Swaps with calls | Term January 2015 to December 2015 | Price risk derivatives	'
Derivative Financial Instruments	'
Volumes (in MBbl)	2,000
Weighted average swap price per Bbl	99
Weighted average call price per Bbl	115

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Details 2) (Interest Rate Swap, USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014
Term October 2014 to December 2014	'
Derivative Financial Instruments	'
Weighted Average Notional Amount	$110,555
Weighted Average Fixed Rate (as a percent)	1.93%
Floating Rate	'6-month LIBOR
Term January 2015 to December 2015	'
Derivative Financial Instruments	'
Weighted Average Notional Amount	45,319
Weighted Average Fixed Rate (as a percent)	2.03%
Floating Rate	'6-month LIBOR
Term January 2016 to June 2016	'
Derivative Financial Instruments	'
Weighted Average Notional Amount	$12,500
Weighted Average Fixed Rate (as a percent)	2.27%
Floating Rate	'6-month LIBOR

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Details 3) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Derivative instruments, Balance Sheet Location	'	'
Derivatives assets - current	$6,848,000	'
Derivatives assets-long-term	3,892,000	'
Derivatives liabilities - current	-1,994,000	-9,940,000
Derivatives liabilities - long-term	-429,000	-3,811,000
Not designated as hedging instruments	'	'
Derivative instruments, Balance Sheet Location	'	'
Total	8,317,000	-13,751,000
Commodity derivatives | Not designated as hedging instruments	'	'
Derivative instruments, Balance Sheet Location	'	'
Derivatives assets - current	6,848,000	'
Derivatives assets-long-term	3,892,000	'
Derivatives liabilities - current	-523,000	-7,873,000
Derivatives liabilities - long-term	-282,000	-3,144,000
Provisional oil sales contract	100,000	0
Deferred premiums related to commodity derivative contracts	400,000	0
Deferred premiums related to commodity derivative contracts	3,600,000	0
Deferred premiums related to commodity derivative contracts	900,000	100,000
Deferred premiums related to commodity derivative contracts	3,800,000	6,500,000
Interest rate contracts | Not designated as hedging instruments	'	'
Derivative instruments, Balance Sheet Location	'	'
Derivatives liabilities - current	-1,471,000	-2,067,000
Derivatives liabilities - long-term	($147,000)	($667,000)

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Details 4) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative instruments, Location of Gain/(Loss)	'	'	'	'
Amount of Gain/(Loss), derivatives not designated as hedging instruments	$35,519	($8,457)	$12,407	($5,874)
Commodity derivatives | Oil and gas revenue	'	'	'	'
Derivative instruments, Location of Gain/(Loss)	'	'	'	'
Amount of Gain/(Loss), derivatives not designated as hedging instruments	-4,886	-554	-8,253	-5,220
Commodity derivatives | Derivatives, net	'	'	'	'
Derivative instruments, Location of Gain/(Loss)	'	'	'	'
Amount of Gain/(Loss), derivatives not designated as hedging instruments	40,407	-7,585	20,869	-386
Interest rate contracts | Interest expense	'	'	'	'
Derivative instruments, Location of Gain/(Loss)	'	'	'	'
Amount of Gain/(Loss), derivatives not designated as hedging instruments	-2	-318	-209	-268
Derivatives in cash flow hedging relationships	'	'	'	'
Derivative instruments, Location of Gain/(Loss)	'	'	'	'
Total derivatives in cash flow hedging relationships	290	405	1,101	1,122
Derivatives in cash flow hedging relationships | Interest rate contracts | Interest expense	'	'	'	'
Derivative instruments, Location of Gain/(Loss)	'	'	'	'
Amount of Gain/(Loss) reclassified from AOCI into earnings	$290	$405	$1,101	$1,122

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Carrying Value	'	'
Liabilities:	'	'
Long-term debt	$794,106	$900,000
Total Fair Value	'	'
Liabilities:	'	'
Long-term debt	804,500	900,000
Recurring basis | Level 2	'	'
Liabilities:	'	'
Derivative liability, fair value	'	-13,751
Total fair value, net	8,317	'
Recurring basis | Level 2 | Commodity derivatives	'	'
Assets:	'	'
Derivative asset, fair value	10,740	'
Liabilities:	'	'
Derivative liability, fair value	-805	-11,017
Recurring basis | Level 2 | Interest rate contracts	'	'
Liabilities:	'	'
Derivative liability, fair value	-1,618	-2,734
Recurring basis | Total Fair Value	'	'
Liabilities:	'	'
Derivative liability, fair value	'	-13,751
Total fair value, net	8,317	'
Recurring basis | Total Fair Value | Commodity derivatives	'	'
Assets:	'	'
Derivative asset, fair value	10,740	'
Liabilities:	'	'
Derivative liability, fair value	-805	-11,017
Recurring basis | Total Fair Value | Interest rate contracts	'	'
Liabilities:	'	'
Derivative liability, fair value	($1,618)	($2,734)

Equitybased_Compensation_Detai

Equity-based Compensation (Details) (USD $)

3 Months Ended

9 Months Ended

40 Months Ended

9 Months Ended

40 Months Ended

9 Months Ended

In Millions, except Share data, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

LTIP

LTIP

LTIP

LTIP

Service Vesting Restricted Stock Awards

Market/Service Vesting Restricted Stock Awards

Market/Service Vesting Restricted Stock Awards

Market/Service Vesting Restricted Stock Awards

Service Vesting Restricted Stock Units

Market/Service Vesting Restricted Stock Units

Market/Service Vesting Restricted Stock Units

Market/Service Vesting Restricted Stock Units

Restricted Stock Awards and Restricted Stock Units

Restructuring Charges

LTIP

LTIP

Minimum

Maximum

LTIP

LTIP

Minimum

Maximum

LTIP

LTIP

LTIP

LTIP

LTIP

Compensation agreement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Compensation expense recognized

$19

$13.80

$55

$50.80

'

'

'

'

'

'

'

'

'

$5

Tax benefit

6.7

4.8

19.2

17.4

'

'

'

'

'

'

'

'

'

'

Tax shortfall related to equity-based compensation

0

0

6.5

6.9

'

'

'

'

'

'

'

'

'

'

Outstanding unvested awards activity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding at the beginning of the period (in shares)

'

'

'

'

6,384,000

3,438,000

'

'

2,238,000

1,858,000

'

'

'

'

Granted (in shares)

'

'

'

'

'

'

'

'

1,962,000

1,462,000

'

'

'

'

Forfeited (in shares)

'

'

'

'

-115,000

-74,000

'

'

-398,000

-179,000

'

'

'

'

Vested (in shares)

'

'

'

'

-2,799,000

'

'

'

-517,000

'

'

'

'

'

Outstanding at the end of the period (in shares)

'

'

'

'

3,470,000

3,364,000

'

'

3,285,000

3,141,000

'

'

'

'

Weighted-Average Grant-Date Fair Value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding at beginning of the period (in dollars per share)

'

'

'

'

$16.48

$12.95

'

'

$10.74

$15.59

'

'

'

'

Granted (in dollars per share)

'

'

'

'

'

'

$6.70

$13.57

$10.95

$15.71

$15.44

$15.81

'

'

Forfeited (in dollars per share)

'

'

'

'

$15.58

$10.87

'

'

$10.90

$15.48

'

'

'

'

Vested (in dollars per share)

'

'

'

'

$17.04

'

'

'

$10.72

'

'

'

'

'

Outstanding at the end of the period (in dollars per share)

'

'

'

'

$16.05

$12.99

'

'

$10.85

$15.65

'

'

'

'

Compensation expense not yet recognized

'

'

'

'

'

'

'

'

'

'

'

'

$101

'

Weighted average period over which compensation expense is to be recognized

'

'

'

'

'

'

'

'

'

'

'

'

'1 year 9 months 15 days

'

Other disclosures

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares remaining available for grant

2,400,000

'

2,400,000

'

'

'

'

'

'

'

'

'

'

'

Vesting percentage of the awards granted

'

'

'

'

'

'

'

100.00%

'

'

'

200.00%

'

'

Significant assumptions used to calculate fair values

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected volatility (as a percent)

'

'

'

'

'

'

41.30%

56.70%

'

'

39.00%

54.00%

'

'

Risk-free interest rate (as a percent)

'

'

'

'

'

'

0.50%

1.10%

'

'

0.50%

1.20%

'

'

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Taxes	'	'	'	'
Income tax expense	$38,468	$34,224	$170,035	$124,568
Income (loss) before income taxes	57,591	-10,264	320,634	29,358
Effective tax rate (as a percent)	67.00%	-333.00%	53.00%	424.00%
Bermuda	'	'	'	'
Income Taxes	'	'	'	'
Income (loss) before income taxes	-8,368	-5,880	-20,588	-19,320
United States	'	'	'	'
Income Taxes	'	'	'	'
Income (loss) before income taxes	3,049	2,740	10,542	8,014
Effective tax rate (as a percent)	38.00%	42.00%	102.00%	125.00%
Foreign-other	'	'	'	'
Income Taxes	'	'	'	'
Income (loss) before income taxes	$62,910	($7,124)	$330,680	$40,664
Effective tax rate (as a percent)	'	'	0.00%	'
Statutory tax rate (as a percent)	'	'	0.00%	'
Ghana	'	'	'	'
Income Taxes	'	'	'	'
Effective tax rate (as a percent)	33.00%	36.00%	35.00%	36.00%

Net_Income_Loss_Per_Share_Deta

Net Income (Loss) Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Numerator:	'	'	'	'
Net income (loss)	$19,123	($44,488)	$150,599	($95,210)
Less: Basic income allocable to participating securities	174	'	1,919	'
Basic net income (loss) allocable to common shareholders	18,949	-44,488	148,680	-95,210
Diluted adjustments to income allocable to participating securities	1	'	17	'
Diluted net income (loss) allocable to common shareholders	$18,950	($44,488)	$148,697	($95,210)
Weighted average number of shares used to compute net income per share:	'	'	'	'
Basic (in shares)	379,969,000	377,654,000	378,881,000	376,509,000
Restricted stock awards and units (in shares)	2,221,000	'	3,406,000	'
Diluted (in shares)	382,190,000	377,654,000	382,287,000	376,509,000
Net income (loss) per share:	'	'	'	'
Basic (in dollars per share)	$0.05	($0.12)	$0.39	($0.25)
Diluted (in dollars per share)	$0.05	($0.12)	$0.39	($0.25)
Outstanding restricted stock awards excluded from the computations of diluted net income per share (in shares)	6,800,000	13,900,000	4,700,000	13,900,000

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	1 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
	item
Operating leases	'	'
Future minimum rental commitments	'	'
Total	$16,908,000	$16,908,000
2014	813,000	813,000
2015	3,260,000	3,260,000
2016	3,158,000	3,158,000
2017	3,223,000	3,223,000
2018	3,323,000	3,323,000
Thereafter	3,131,000	3,131,000
Atwood Achiever drilling rig contract	'	'
Offshore drilling rig contract commitments	'	'
Drilling rig contract period	'3 years	'
Initial rig rate per day	600,000	'
Optional extension period	'3 years	'
Number of rig slots taken by third-party	2	'
Estimated number of days of rig slots assigned to third party in 2015	'90 days	'
Estimated number of days of rig slots assigned to third party in 2016	'70 days	'
Future minimum rental commitments	'	'
Total	540,855,000	540,855,000
2014	54,740,000	54,740,000
2015	163,625,000	163,625,000
2016	176,120,000	176,120,000
2017	146,370,000	146,370,000
Rig rate per day	'	$595,000