Kosmos Energy (KOS) 10-K 23 Feb 21 2020 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 15, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35167
Entity Registrant Name	Kosmos Energy Ltd.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-0686001
Entity Address, Address Line One	8176 Park Lane
Entity Address, City or Town	Dallas,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75231
City Area Code	214
Local Phone Number	445 9600
Title of 12(b) Security	Common Stock $0.01 par value
Trading Symbol	KOS
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float	$ 659,507,173
Entity Common Stock, Shares Outstanding		407,843,523
Documents Incorporated by Reference	Part III, Items 10‑14, is incorporated by reference from the Proxy Statement for the Annual Meeting of Shareholders which will be filed with the Securities and Exchange Commission not later than 120 days subsequent to December 31, 2020. Certain exhibits previously filed with the Securities and Exchange Commission are incorporated by reference into Part IV of this report.
Entity Central Index Key	0001509991
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 149,027	$ 224,502
Restricted cash	195	4,302
Receivables:
Joint interest billings, net	26,002	81,424
Oil sales	44,491	64,142
Other	8,320	28,727
Inventories	128,972	114,412
Prepaid expenses and other	27,870	36,192
Derivatives	15,414	12,856
Total current assets	400,291	566,557
Property and equipment:
Oil and gas properties, net	3,310,276	3,624,751
Other property, net	10,637	17,581
Property and equipment, net	3,320,913	3,642,332
Other assets:
Restricted cash	542	542
Long-term receivables	117,497	43,430
Deferred financing costs, net of accumulated amortization of $17,296 and $14,681 at December 31, 2020 and December 31, 2019, respectively	3,706	6,321
Deferred tax assets	0	32,779
Derivatives	964	2,302
Other	23,680	22,969
Total assets	3,867,593	4,317,232
Current liabilities:
Accounts payable	221,430	149,483
Accrued liabilities	203,260	380,704
Current maturities of long-term debt	7,500	0
Derivatives	28,009	8,914
Total current liabilities	460,199	539,101
Long-term liabilities:
Long-term debt, net	2,103,931	2,008,063
Derivatives	8,069	11,478
Asset retirement obligations	244,166	230,526
Deferred tax liabilities	573,619	653,221
Other long-term liabilities	37,455	33,141
Total long-term liabilities	2,967,240	2,936,429
Stockholders’ equity:
Preference shares, $0.01 par value; 200,000,000 authorized shares; zero issued at December 31, 2020 and December 31, 2019	0	0
Common stock, $0.01 par value; 2,000,000,000 authorized shares; 449,718,317 and 445,779,367 issued at December 31, 2020 and December 31, 2019, respectively	4,497	4,458
Additional paid-in capital	2,307,220	2,297,221
Accumulated deficit	(1,634,556)	(1,222,970)
Treasury stock, at cost, 44,263,269 shares at December 31, 2020 and December 31, 2019, respectively	(237,007)	(237,007)
Total stockholders’ equity	440,154	841,702
Total liabilities and stockholders’ equity	$ 3,867,593	$ 4,317,232

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Deferred financing costs, accumulated amortization	$ 17,296	$ 14,681
Preference shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preference shares, authorized shares (in shares)	200,000,000	200,000,000
Preference shares, issued shares (in shares)	0	0
Common shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, authorized shares (in shares)	2,000,000,000	2,000,000,000
Common shares, issued shares (in shares)	449,718,317	445,779,367
Treasury stock shares (in shares)	44,263,269	44,263,269

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Mar. 26, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues and other income:
Oil and gas revenue										$ 804,033	$ 1,499,416	$ 886,666
Gain on sale of assets										92,163	10,528	7,666
Other income, net										2	(35)	8,037
Total revenues and other income		$ 366,316	$ 224,787	$ 127,314	$ 177,781	$ 460,215	$ 356,970	$ 395,934	$ 296,790	896,198	1,509,909	902,369
Costs and expenses:
Oil and gas production										338,477	402,613	224,727
Facilities insurance modifications, net										13,161	(24,254)	6,955
Exploration expenses										84,616	180,955	301,492
General and administrative										72,142	110,010	99,856
Depletion, depreciation and amortization										485,862	563,861	329,835
Impairment of long-lived assets		3,200	0	0	150,800					153,959	0	0
Interest and other financing costs, net										109,794	155,074	101,176
Derivatives, net										17,180	71,885	(31,430)
Gain on equity method investments, net										0	0	(72,881)
Other expenses, net										37,802	24,648	(6,501)
Total costs and expenses		382,579	261,279	374,130	295,005	462,492	317,435	346,495	358,370	1,312,993	1,484,792	953,229
Income (loss) before income taxes										(416,795)	25,117	(50,860)
Income tax expense (benefit)										(5,209)	80,894	43,131
Net income (loss)		$ 7,956	$ (37,384)	$ (199,391)	$ (182,767)	$ (35,773)	$ 16,065	$ 16,837	$ (52,906)	$ (411,586)	$ (55,777)	$ (93,991)
Net loss per share:
Basic (in dollars per share)		$ 0.02	$ (0.09)	$ (0.49)	$ (0.45)	$ (0.09)	$ 0.04	$ 0.04	$ (0.13)	$ (1.02)	$ (0.14)	$ (0.23)
Diluted (in dollars per share)		$ 0.02	$ (0.09)	$ (0.49)	$ (0.45)	$ (0.09)	$ 0.04	$ 0.04	$ (0.13)	$ (1.02)	$ (0.14)	$ (0.23)
Weighted average number of shares used to compute net loss per share:
Basic (in shares)										405,212	401,368	404,585
Diluted (in shares)										405,212	401,368	404,585
Dividends declared per common share (in dollars per share)	$ 0.0452									$ 0.0452	$ 0.1808

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Treasury Stock
Balance (in shares) at Dec. 31, 2017		398,599
Balance at Dec. 31, 2017	$ 897,112	$ 3,986	$ 2,014,525	$ (1,073,202)	$ (48,197)
Increase (Decrease) in Shareholders' Equity
Acquisition of oil and gas properties (in shares)		34,994
Acquisition of oil and gas properties	307,944	$ 350	307,594
Equity-based compensation	36,464		36,464
Restricted stock awards and units (in shares)		9,322
Restricted stock awards and units	0	$ 93	(93)
Purchase of treasury stock / tax withholdings	(206,051)		(17,241)		(188,810)
Net loss	(93,991)			(93,991)
Balance (in shares) at Dec. 31, 2018		442,915
Balance at Dec. 31, 2018	941,478	$ 4,429	2,341,249	(1,167,193)	(237,007)
Increase (Decrease) in Shareholders' Equity
Dividends	(74,813)		(74,813)
Equity-based compensation	32,797		32,797
Restricted stock awards and units (in shares)		2,864
Restricted stock awards and units	0	$ 29	(29)
Purchase of treasury stock / tax withholdings	(1,983)		(1,983)		0
Net loss	(55,777)			(55,777)
Balance (in shares) at Dec. 31, 2019		445,779
Balance at Dec. 31, 2019	$ 841,702	$ 4,458	2,297,221	(1,222,970)	(237,007)
Increase (Decrease) in Shareholders' Equity
Dividends declared per common stock (in dollars per share)	$ 0.1808
Dividends	$ (18,576)		(18,576)
Equity-based compensation	33,561		33,561
Restricted stock awards and units (in shares)		3,939
Restricted stock awards and units	0	$ 39	(39)
Purchase of treasury stock / tax withholdings	(4,947)		(4,947)
Net loss	(411,586)			(411,586)
Balance (in shares) at Dec. 31, 2020		449,718
Balance at Dec. 31, 2020	$ 440,154	$ 4,497	$ 2,307,220	$ (1,634,556)	$ (237,007)
Increase (Decrease) in Shareholders' Equity
Dividends declared per common stock (in dollars per share)	$ 0.0452

CONSOLIDATED STATEMENTS OF SH_2

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	1 Months Ended	12 Months Ended
	Mar. 26, 2020	Dec. 31, 2020	Dec. 31, 2019
Statement of Stockholders' Equity [Abstract]
Dividends declared per common stock (in dollars per share)	$ 0.0452	$ 0.0452	$ 0.1808

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (411,586)	$ (55,777)	$ (93,991)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depletion, depreciation and amortization (including deferred financing costs)	495,209	573,118	339,214
Deferred income taxes	(42,587)	(90,370)	9,145
Unsuccessful well costs and leasehold impairments	23,157	87,813	123,199
Impairment of long-lived assets	153,959	0	0
Change in fair value of derivatives	22,800	67,436	(29,960)
Change in fair value of derivatives	(22,800)	(67,436)	29,960
Cash settlements on derivatives, net (including $(2.7) million and $(36.3) million and $(137.1) million on commodity hedges during 2020, 2019, and 2018)	(10,944)	(31,458)	(137,942)
Equity-based compensation	32,706	32,370	35,230
Gain on sale of assets	(92,163)	(10,528)	(7,666)
Loss on extinguishment of debt	2,902	24,794	4,324
Other	15,922	9,069	2,820
Changes in assets and liabilities:
(Increase) decrease in receivables	92,093	(29,735)	175,954
(Increase) decrease in inventories	(23,167)	(28,970)	8,848
(Increase) decrease in prepaid expenses and other	7,882	34,586	(18,731)
Increase (decrease) in accounts payable	71,947	(83,921)	7,440
Increase (decrease) in accrued liabilities	(141,985)	129,723	(157,393)
Net cash provided by (used in) operating activities	196,145	628,150	260,491
Investing activities
Oil and gas assets	(377,491)	(340,217)	(213,806)
Other property	(2,102)	(11,796)	(7,935)
Acquisition of oil and gas properties, net of cash acquired	0	0	(961,764)
Return of investment from KTIPI	0	0	184,664
Proceeds on sale of assets	99,118	15,000	13,703
Notes receivable from partners	(65,112)	(26,918)	0
Net cash provided by (used in) investing activities	(345,587)	(363,931)	(985,138)
Financing activities
Borrowings under long-term debt	300,000	175,000	1,175,000
Payments on long-term debt	(250,000)	(425,000)	(325,000)
Advances under production prepayment agreement	50,000	0	0
Net proceeds from issuance of senior notes	0	641,875	0
Redemption of senior secured notes	0	(535,338)	0
Purchase of treasury stock / tax withholdings	(4,947)	(1,983)	(206,051)
Dividends	(19,271)	(72,599)	0
Deferred financing costs	(5,922)	(2,444)	(38,672)
Net cash provided by (used in) financing activities	69,860	(220,489)	605,277
Net increase (decrease) in cash, cash equivalents and restricted cash	(79,582)	43,730	(119,370)
Cash, cash equivalents and restricted cash at beginning of period	149,764	229,346	185,616
Cash, cash equivalents and restricted cash at end of period	229,346	185,616	304,986
Cash paid for:
Interest, net of capitalized interest	103,674	99,928	83,831
Income taxes, net of refund received	104,061	43,909	45,984
Non-cash activity:
Production Prepayment Agreement converted to GoM Term Loan	50,000	0	0
Common stock issued for acquisition of oil and gas properties	$ 0	$ 0	$ 307,944

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Cash Flows [Abstract]
Cash settlements on commodity hedges derivatives	$ (2.7)	$ (36.3)	$ (137.1)

Organization

Organization	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Kosmos Energy Ltd. was originally incorporated pursuant to the laws of Bermuda in January 2011 to become a holding company for Kosmos Energy Holdings. Kosmos Energy Ltd. changed its jurisdiction of incorporation from Bermuda to the State of Delaware in December 2018 and transferred all of our equity interests in Kosmos Energy Holdings to a new, wholly-owned subsidiary, Kosmos Energy Delaware Holdings, LLC, a Delaware limited liability company. 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. Kosmos is a full-cycle deepwater independent oil and gas exploration and production company focused along the Atlantic Margins. Our key assets include production offshore Ghana, Equatorial Guinea and the U.S. Gulf of Mexico, as well as a world-class gas development offshore Mauritania and Senegal. We also maintain a sustainable proven basin exploration program in Equatorial Guinea, Ghana and the U.S. Gulf of Mexico. Kosmos is listed on the NYSE and LSE and is traded under the ticker symbol KOS. Kosmos is engaged in a single line of business, which is the exploration, development, and production of oil and natural gas. Substantially all of our long-lived assets and all of our product sales are related to operations in four geographic areas: Ghana, Equatorial Guinea, Mauritania/Senegal and the U.S. Gulf of Mexico.

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Accounting Policies	Accounting Policies Principles of Consolidation The accompanying consolidated financial statements include the accounts of Kosmos Energy Ltd. and its wholly-owned subsidiaries. They also include the Company’s share of the undivided interest in certain assets, liabilities, revenues and expenses. Investments in corporate joint ventures, which we exercise significant influence over, are accounted for using the equity method of accounting. All intercompany transactions have been eliminated. Investments in companies that are partially owned by the Company are integral to the Company’s operations. The other parties, who also have an equity interest in these companies, are independent third parties that share in the business results according to their ownership. Kosmos does not invest in these companies in order to remove liabilities from its balance sheet. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosures of contingent assets and liabilities. These estimates could change materially if different information or assumptions were used. We base our assumptions and estimates on historical experience and other sources that we believe to be reasonable at the time. Actual results could differ from these estimates. Reclassifications Certain prior period amounts have been reclassified to conform with the current year presentation. Such reclassifications had no significant impact on our reported net loss, current assets, total assets, current liabilities, total liabilities, shareholders’ equity or cash flows, except as disclosed related to the adoption of recent accounting pronouncements. Cash, Cash Equivalents and Restricted Cash December 31, 2020 2019 2018 (In thousands) Cash and cash equivalents $ 149,027 $ 224,502 $ 173,515 Restricted cash - current 195 4,302 4,527 Restricted cash - long-term 542 542 7,574 Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows $ 149,764 $ 229,346 $ 185,616 Cash and cash equivalents includes demand deposits and funds invested in highly liquid instruments with original maturities of three months or less at the date of purchase. When our net leverage ratio exceeds 2.50x, we are required under the Facility 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 7.125% Senior Notes plus the Corporate Revolver or the Facility, whichever is greater. As of December 31, 2020, we exceeded this ratio and restricted approximately $28.5 million in cash to meet our requirements in January 2021. In accordance with certain of our petroleum contracts, we have posted letters of credit related to performance guarantees for our minimum work obligations. Certain of 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 December 31, 2020 and 2019, we had $0.2 million and $4.3 million, respectively, of current restricted cash and $0.3 million and $0.3 million, respectively, of long‑term restricted cash used to cash collateralize performance guarantees related to our petroleum contracts. As of December 31, 2020 and 2019, we also had $0.2 million in other long-term restricted cash. Receivables Our receivables consist of joint interest billings, oil and gas sales, related party and other receivables. For our oil sales receivable in Ghana, we require a letter of credit to be posted to secure the outstanding receivable. Receivables from joint interest owners are stated at amounts due, net of any allowances for doubtful accounts. As required by ASU 2016-13, "Measurement of Credit Losses on Financial Instruments", we determine our allowance based on historical experience, current conditions and reasonable and supportable forecasts by considering the length of time past due, future net revenues of the debtor’s ownership interest in oil and natural gas properties we operate, and the owner’s ability to pay its obligation, among other things. We had an allowance for doubtful accounts of $5.7 million and $2.7 million in current joint interest billings receivables as of December 31, 2020 and 2019, respectively. Inventories Inventories consisted of $127.5 million and $112.3 million of materials and supplies and $1.5 million and $2.1 million of hydrocarbons as of December 31, 2020 and 2019, 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 net realizable value. We recorded write downs of $8.6 million, $4.6 million and $0.3 million during the years ended December 31, 2020, 2019 and 2018 for materials and supplies inventories as Other expenses, net in the consolidated statements of operations and other in the consolidated statements of cash flows. Hydrocarbon inventory is carried at the lower of cost, using the weighted average cost method, or net realizable value. 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. Leases In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” ASU 2016-02 was issued to increase transparency and comparability across organizations by recognizing substantially all leases on the balance sheet through the concept of right-of-use lease assets and liabilities. Under prior accounting guidance, lessees did not recognize lease assets or liabilities for leases classified as operating leases. The ASU was effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years with early adoption permitted. In July 2018, the FASB issued ASU 2018-11, which added a transition option permitting entities to apply the provisions of the new standard at its adoption date instead of the earliest comparative period presented in the consolidated financial statements. Under this transition option, comparative reporting would not be required, and the provisions of the standard would be applied prospectively to leases in effect at the date of adoption. The Company adopted the guidance prospectively during the first quarter of 2019. As part of our adoption, we elected not to reassess historical lease classification, recognize short-term leases on our balance sheet, nor separate lease and non-lease components for our real estate leases. The adoption and implementation of this ASU resulted in a $21.7 million increase in assets and liabilities related to our leasing activities, which primarily consists of office leases. Our adoption of ASU 2016-02 did not impact retained earnings or other components of equity as of December 31, 2018. We account for leases in accordance with ASC Topic 842, Leases, (“ASC 842”). We determine if an arrangement is a lease at contract inception. A lease exists when a contract conveys to the customer the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. The definition of a lease embodies two conditions: (1) there is an identified asset in the contract that is land or a depreciable asset (i.e., property, plant, and equipment), and (2) the customer has the right to control the use of the identified asset. In the normal course of business, the Company enters into various lease agreements for real estate and equipment related to its exploration, development and production activities that are currently accounted for as operating leases. Operating leases are included in Other assets, Accrued liabilities, and Other long-term liabilities on our consolidated balance sheets. The lease liabilities are initially and subsequently measured at the present value of the unpaid lease payments at the lease commencement date. Key estimates and judgments include how we determined: (1) the discount rate we use to discount the unpaid lease payments to present value; (2) lease term; and (3) lease payments. 1. ASC 842 requires a lessee to discount its unpaid lease payments using the interest rate implicit in the lease or, if that rate cannot be readily determined, its incremental borrowing rate. As most of our leases where we are the lessee do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. Our incremental borrowing rate for a lease is the rate of interest we would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. 2. The lease term for all of our leases includes the non-cancellable period of the lease plus any additional periods covered by either an option to extend (or not to terminate) the lease that we are reasonably certain to exercise, or an option to extend (or not to terminate) the lease controlled by the lessor. 3. Lease payments included in the measurement of the lease asset or liability comprise the following: fixed payments (including in-substance fixed payments), variable payments that depend on index or rate, and the exercise price of a lessee option to purchase the underlying asset if we are reasonably certain to exercise. Amounts expected to be payable under residual value guarantee are also lease payments included in the measurement of the lease liability. The Right-of-use ("ROU") asset is initially measured at cost, which comprises the initial amount of the lease liability adjusted for lease payments made at or before the lease commencement date, plus any initial direct costs incurred less any lease incentives received. For operating leases, the ROU asset is subsequently measured throughout the lease term at the carrying amount of the lease liability, plus initial direct costs, plus (minus) any prepaid (accrued) lease payments, less the unamortized balance of lease incentives received. Lease expense for lease payments is recognized on a straight-line basis over the lease term. We monitor for events or changes in circumstances that require a reassessment of a lease. When a reassessment results in the re-measurement of a lease liability, a corresponding adjustment is made to the carrying amount of the corresponding ROU asset unless doing so would reduce the carrying amount of the ROU asset to an amount less than zero. In that case, the amount of the adjustment that would result in a negative ROU asset balance is recorded in profit or loss. We have lease agreements which include lease and non-lease components. We have elected to combine lease and non-lease components for all lease contracts. We have elected not to recognize ROU assets and lease liabilities for all short-term leases that have a lease term of 12 months or less. We recognize the lease payments associated with our short-term leases as an expense on a straight-line basis over the lease term. We adopted ASU 2016-02 using a modified retrospective transition approach as of the effective date as permitted by the amendments in ASU 2018-11, which provides an alternative modified retrospective transition method. As a result, we were not required to adjust our comparative period financial information for effects of the standard or make the new required lease disclosures for periods before the date of adoption (i.e. January 1, 2019). We have elected to adopt the package of transition practical expedients and, therefore, have not reassessed (1) whether existing or expired contracts contain a lease, (2) lease classification for existing or expired leases or (3) the accounting for initial direct costs that were previously capitalized. We did not elect the practical expedient to use hindsight for leases existing at the adoption date. Exploration and Development Costs The Company follows the successful efforts method of accounting for its oil and gas properties. Acquisition costs for proved and unproved properties are capitalized when incurred. Costs of unproved properties are transferred to proved properties when a determination that proved reserves have been found. Exploration costs, including geological and geophysical costs and costs of carrying unproved properties, are expensed as incurred. Exploratory drilling costs are capitalized when incurred. If exploratory wells are determined to be commercially unsuccessful or dry holes, the applicable costs are expensed and recorded in exploration expense on the consolidated statement of operations. Costs incurred to drill and equip development wells, including unsuccessful development wells, are capitalized. Costs incurred to operate and maintain wells and equipment and to lift oil and natural gas to the surface are expensed as oil and gas production expense. The Company evaluates unproved property periodically for impairment. The impairment assessment considers results of exploration activities, commodity price outlooks, planned future sales or expiration of all or a portion of such projects. If it is determined that future appraisal drilling or development activities are unlikely to occur, the associated capitalized costs are recorded as exploration expense in the consolidated statement of operations. Depletion, Depreciation and Amortization Proved properties and support equipment and facilities are depleted using the unit‑of‑production method based on estimated proved oil and natural gas reserves. Capitalized exploratory drilling costs that result in a discovery of proved reserves and development costs are depleted using the unit‑of‑production method based on estimated proved developed oil and natural gas reserves for the related field. Depreciation and amortization of other property is computed using the straight-line method over the assets’ estimated useful lives (not to exceed the lease term for leasehold improvements), ranging from one Years Leasehold improvements 1 to 8 Office furniture, fixtures and computer equipment 3 to 7 Vehicles 5 Amortization of deferred financing costs is computed using the straight‑line method over the life of the related debt. Capitalized Interest Interest costs from external borrowings are capitalized on major projects with an expected construction period of one year or longer. Capitalized interest is added to the cost of the underlying asset and is depleted on the unit‑of‑production method in the same manner as the underlying assets. Asset Retirement Obligations The Company accounts for asset retirement obligations as required by ASC 410—Asset Retirement and Environmental Obligations. Under these standards, the fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. If a reasonable estimate of fair value cannot be made in the period the asset retirement obligation is incurred, the liability is recognized when a reasonable estimate of fair value can be made. If a tangible long‑lived asset with an existing asset retirement obligation is acquired, a liability for that obligation is recognized at the asset’s acquisition or in service date. In addition, a liability for the fair value of a conditional asset retirement obligation is recorded if the fair value of the liability can be reasonably estimated. We capitalize the asset retirement costs by increasing the carrying amount of the related long‑lived asset by the same amount as the liability. We record increases in the discounted abandonment liability resulting from the passage of time in depletion, depreciation and amortization in the consolidated statement of operations. Estimating the future restoration and removal costs requires management to make estimates and judgments because most of the removal obligations are many years in the future and contracts and regulations often have vague descriptions of what constitutes removal. Additionally, asset removal technologies and costs are constantly changing, as are regulatory, political, environmental, safety and public relations considerations. Inherent in the present value calculation are numerous assumptions and judgments including the ultimate settlement amounts, inflation factors, credit adjusted discount rates, timing of settlement and changes in the legal, regulatory, environmental and political environments. To the extent future revisions to these assumptions impact the present value of the existing asset retirement obligations, a corresponding adjustment is made to the oil and gas property balance. Impairment of Long‑lived Assets We review our long‑lived assets for impairment when changes in circumstances indicate that the carrying amount of an asset may not be recoverable. ASC 360 — Property, Plant and Equipment requires an impairment loss to be recognized if the carrying amount of a long‑lived asset is not recoverable and exceeds its fair value. The carrying amount of a long‑lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. That assessment shall be based on the carrying amount of the asset at the date it is tested for recoverability, whether in use or under development. Assets to be disposed of and assets not expected to provide any future service potential to us are recorded at the lower of carrying amount or fair value. Oil and gas properties are grouped in accordance with ASC 932 — Extractive Activities-Oil and Gas. The basis for grouping is a reasonable aggregation of properties typically by field or by logical grouping of assets with significant shared infrastructure. For long-lived assets whereby the carrying value exceeds the estimated future undiscounted cash flows, the carrying amount is reduced to fair value. Fair value is generally estimated using the income approach described in the ASC 820 — Fair Value Measurement. If applicable, we utilize prices and other relevant information generated by market transactions involving assets and liabilities that are identical or comparable to the item being measured as the basis for determining fair value. The expected future cash flows used for impairment reviews and related fair value measurements are typically based on judgmental assessments of future production, pricing estimates, capital and operating costs, market-based weighted average cost of capital, and risk adjustment factors applied to reserves. These assumptions are applied to develop future cash flow projections that are then discounted to estimated fair value, using a market-based weighted-average cost of capital. Although we base the fair value estimate of each asset group on assumptions we believe to be reasonable, those assumptions are inherently unpredictable and uncertain, and actual results could differ from the estimate. Negative revisions of estimated reserve quantities, increases in future cost estimates, divestiture of a significant component of the asset group, or sustained decreases in crude oil prices could lead to a reduction in expected future cash flows and possibly an additional impairment of long-lived assets in future periods. We believe the assumptions used in our analysis to test for impairment are appropriate and result in a reasonable estimate of future cash flows and fair value. Kosmos has consistently used an average of third-party industry forecasts to determine our pricing assumptions. Where unproved reserves exist, an appropriately risk-adjusted amount of these reserves may be included in the evaluation. Derivative Instruments and Hedging Activities We utilize oil derivative contracts to mitigate our exposure to commodity price risk associated with our anticipated future oil production. These derivative contracts consist of collars, put options, call options and swaps. We also have used interest rate derivative contracts to mitigate our exposure to interest rate fluctuations related to our long‑term debt. Our derivative financial instruments are recorded on the balance sheet as either assets or liabilities and are measured at fair value. We do not apply hedge accounting to our derivative contracts. See Note 9—Derivative Financial Instruments. Estimates of Proved Oil and Natural Gas Reserves Reserve quantities and the related estimates of future net cash flows affect our periodic calculations of depletion and assessment of impairment of our oil and natural gas properties. Proved oil and natural gas reserves are the estimated quantities of crude oil, natural gas and natural gas liquids that geological and engineering data demonstrate with reasonable certainty to be recoverable in future periods from known reservoirs under existing economic and operating conditions. As additional proved reserves are discovered, reserve quantities and future cash flows will be estimated by independent petroleum consultants and prepared in accordance with guidelines established by the SEC and the FASB. The accuracy of these reserve estimates is a function of: • the engineering and geological interpretation of available data; • estimates of the amount and timing of future operating cost, production taxes, development cost and workover cost; • the accuracy of various mandated economic assumptions; and • the judgments of the persons preparing the estimates. Revenue Recognition We recognize revenues on the volumes of hydrocarbons sold to a purchaser. The volumes sold may be more or less than the volumes to which we are entitled based on our ownership interest in the property. These differences result in a condition known in the industry as a production imbalance. A receivable or liability is recognized only to the extent that we have an imbalance on a specific property greater than the expected remaining proved reserves on such property. As of December 31, 2020 and 2019, we had no oil and gas imbalances recorded in our consolidated financial statements. Our oil and gas revenues are recognized when hydrocarbons have been sold to a purchaser at a fixed or determinable price, title has transferred and collection is probable. Certain revenues are based on provisional price contracts which contain an embedded derivative that is required to be separated from the host contract for accounting purposes. The host contract is the receivable from oil sales at the spot price on the date of sale. The embedded derivative, which is not designated as a hedge, is marked to market through oil and gas revenue each period until the final settlement occurs, which generally is limited to the month after the sale. Oil and gas revenue is composed of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Revenues from contract with customer - Equatorial Guinea $ 149,033 $ 297,831 $ — Revenues from contract with customer - Ghana 375,603 740,464 741,033 Revenues from contract with customers - U.S. Gulf of Mexico 285,017 459,960 147,596 Provisional oil sales contracts (5,620) 1,161 (1,963) Oil and gas revenue $ 804,033 $ 1,499,416 $ 886,666 Equity‑based Compensation For equity‑based compensation awards, compensation expense is recognized in the Company’s financial statements over the awards’ vesting periods based on their grant date fair value. The Company utilizes (i) the closing stock price on the date of grant to determine the fair value of service vesting restricted stock awards and restricted stock units and (ii) a Monte Carlo simulation to determine the fair value of restricted stock awards and restricted stock units with a combination of market and service vesting criteria. Forfeitures are recognized in the period in which they occur. Restructuring Charges The Company accounts for restructuring charges and related termination benefits in accordance with ASC 712-Compensation-Nonretirement Postemployment Benefits. Under this standard, the costs associated with termination benefits are recorded during the period in which the liability is incurred. During the years ended December 31, 2020 and 2019, we recognized $16.5 million and $11.5 million, respectively, in restructuring charges for employee severance and related benefit costs incurred as part of a corporate reorganization in Other expenses, net in the consolidated statement of operations. Treasury Stock We record treasury stock purchases at cost. Our treasury purchases are from our employees that surrendered shares to the Company to satisfy their statutory tax withholding requirements and are not part of a formal stock repurchase plan. Our treasury stock consists of a share repurchase in 2018 and forfeited restricted stock awards granted under our long‑term incentive plan. Income Taxes The Company accounts for income taxes as required by ASC 740—Income Taxes. Under this method, deferred income taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. On a quarterly basis, management evaluates the need for and adequacy of valuation allowances based on the expected realizability of the deferred tax assets and adjusts the amount of such allowances, if necessary. We recognize tax benefits from uncertain tax positions only if it is more likely than not that the tax position will be sustained upon examination by the tax authorities, based on the technical merits of the position. Accordingly, we measure tax benefits from such positions based on the most likely outcome to be realized. Foreign Currency Translation The U.S. dollar is the functional currency for all of the Company’s material foreign operations. Foreign currency transaction gains and losses and adjustments resulting from translating monetary assets and liabilities denominated in foreign currencies are included in other expenses. Cash balances held in foreign currencies are not significant, and as such, the effect of exchange rate changes is not material to any reporting period. Concentration of Credit Risk Our revenue can be materially affected by current economic conditions and the price of oil. However, based on the current demand for crude oil and the fact that alternative purchasers are readily available, we believe that the loss of our marketing agent and/or any of the purchasers identified by our marketing agent would not have a long‑term material adverse effect on our financial position or results of international operations. For our U.S. Gulf of Mexico operations, crude oil and natural gas are transported to customers using third-party pipelines. For the years ended December 31, 2020, 2019 and 2018 revenue from Phillips 66 Company made up approximately 23%, 20% and 11%, respectively, of our total consolidated revenue and was included in our U.S. Gulf of Mexico segment. Recent Accounting Standards Recently Adopted In June 2016, ASU 2016-13, "Measurement of Credit Losses on Financial Instruments," was issued requiring measurement of all expected credit losses for certain types of financial instruments, including trade receivables, held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. This standard was effective January 1, 2020. We assessed all receivable positions for expected credit losses through the implementation of ASU 2016-13, current expected credit loss standard (CECL). Our receivables are collectible in the original term of the underlying agreements and current expected credit losses under the CECL standard are not significant. Not Yet Adopted

Acquisitions and Divestitures

Acquisitions and Divestitures	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisitions and Divestitures	Acquisitions and Divestitures 2020 Transactions During the third quarter of 2020, Kosmos entered into an agreement with Shell to farm down interests in a portfolio of frontier exploration assets for cash consideration of $96.0 million and future contingent consideration of up to $100.0 million. Under the terms of the agreement, Shell acquired Kosmos' participating interest in blocks offshore Sao Tome and Principe (excluding Block 5 offshore Sao Tome and Principe), Suriname, and Namibia, and will acquire our participating interest in South Africa. Kosmos received proceeds totaling $95.0 million during the fourth quarter of 2020 resulting in gain on sale of assets of $92.1 million, with the remaining proceeds of $1.0 million related to Kosmos' participating interest in South Africa expected to be received in 2021 upon customary approval by the government of The Republic of South Africa. The future contingent consideration is based on the outcome of the first four wells drilled in the purchased assets, excluding South Africa, and is payable upon submission of an appraisal plan to the relevant governmental authority under the relevant host government contract. Shell will pay $50.0 million for each appraisal plan submitted, capped in the aggregate at a maximum of $100.0 million. In October 2020, Kosmos withdrew from Block C6 offshore Mauritania. In May 2020, a withdrawal notice for our blocks offshore Cote d'Ivoire was issued to partners and the Government of Cote d'Ivoire. In July 2020, we provided notice that we declined to enter the final exploration phase of the Suriname Block 45 petroleum agreement. 2019 Transactions During the first quarter of 2019, we agreed to a petroleum contract covering offshore Marine XXI block with the national oil company of the Republic of the Congo, Société Nationale des Pétroles du Congo. The petroleum contract was subject to a required governmental approval process before the petroleum contract could be made effective. The petroleum contract had not been approved by the government of the Republic of Congo nor entered into force when, in February 2020, we terminated our interests in the Marine XXI block petroleum contract. In March 2019, we completed an agreement to acquire Ophir's remaining interest in Block EG-24, offshore Equatorial Guinea, which increased our participating interest to 80% and named Kosmos as operator. The Equatorial Guinean national oil company, GEPetrol, has a 20% carried interest during the exploration period. Should a commercial discovery be made, GEPetrol's 20% carried interest will convert to a 20% participating interest. In September 2019, we completed a farm-in agreement with OK Energy to acquire a 45% non-operated interest in the Northern Cape Ultra Deep block offshore the Republic of South Africa. The petroleum contract covers approximately 6,930 square kilometers at water depths ranging from 2,500 to 3,100 meters and has an initial exploration phase of two years. In November 2019, we completed a farm-out agreement with Shell Sao Tome and Principe B.V. to farm-out a 20% participating interest in Block 6 and a 30% participating interest in Block 11, offshore Sao Tome and Principe, resulting in our participating interests in Blocks 6 and 11 being 25% and 35%, respectively. During the year ended December 31, 2019, we recognized a $10.5 million gain related to the farm-out of Blocks 6 and 11 offshore Sao Tome and Principe. 2018 Transactions In March 2018, as part of our alliance with BP, we entered into petroleum contracts covering Blocks 10 and 13 with the Democratic Republic of Sao Tome and Principe. We presently have a 35% participating interest in the blocks and the operator, BP, holds a 50% participating interest. The national petroleum agency, Agencia Nacional Do Petroleo De Sao Tome E Principe ("ANP-STP") has a 15% carried interest in the blocks through exploration. The petroleum contracts cover approximately 13,600 square kilometers, with a first exploration period of four years from the effective date (March 2018). The exploration periods can be extended an additional four years at our election subject to fulfilling specific work obligations. The first exploration period work programs include a 13,500 square kilometer 3D seismic acquisition requirement across the two blocks. In June 2018, we completed a farm-in agreement with a subsidiary of Ophir for Block EG-24, offshore Equatorial Guinea, whereby we acquired our initial non-operated participating interest of 40%. As part of the agreement, we reimbursed a portion of Ophir's previously incurred exploration costs and agreed to carry Ophir's share of the costs. The petroleum contract covers approximately 3,500 square kilometers, with a first exploration period of three years from the effective date (March 2018) which can be extended up to four In September 2018, we completed the acquisition of DGE, a deepwater company operating in the U.S. Gulf of Mexico, from First Reserve Corporation and other shareholders for a total consideration of $1.275 billion, comprised of $952.6 million in cash, $307.9 million in Kosmos common stock and $14.9 million of transaction related costs. We funded the cash portion of the purchase price using cash on hand and drawings under our existing credit facilities. We also received $200.0 million of additional firm commitments under the Facility, which provided further liquidity to the Company. The DGE acquisition was accounted for under the asset acquisition method and the purchase price allocation is shown below. The purchase price allocation was based on the estimated relative fair value of identifiable assets acquired and liabilities assumed. The estimated fair value measurements of oil and gas assets acquired and asset retirement obligations liabilities assumed are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair value of oil and gas properties and asset retirement obligations were measured using the discounted cash flow technique of valuation. Significant inputs to the valuation of oil and gas properties include estimates of: (i) reserves, (ii) future operating and development costs, (iii) future commodity prices, (iv) future plugging and abandonment costs, (v) estimated future cash flows, and (vi) a market-based weighted average cost of capital rate. Purchase Price Allocation (in thousands) Fair value of assets acquired: Proved oil and gas properties $ 1,037,511 Unproved oil and gas properties 298,159 Accounts receivable and other 180,989 Total assets acquired $ 1,516,659 Fair value of liabilities assumed: Accrued liabilities and other $ 126,530 Asset retirement obligations 74,482 Derivative liabilities 40,265 Total liabilities assumed $ 241,277 Purchase price: Cash consideration paid $ 952,586 Fair value of common stock(1) 307,944 Transaction related costs 14,852 Total purchase price $ 1,275,382 ______________________________________ (1) Based on 34,993,585 shares of common stock issued at a price of $8.80 per share, which was the opening Kosmos common stock price on September 14, 2018, the closing date of the acquisition. As a result of the DGE acquisition, we included $147.6 million of revenues and $30.5 million of direct operating expenses in our consolidated statements of operations for the period from September 14, 2018 to December 31, 2018. In October 2018, Kosmos entered into a strategic exploration alliance with Shell Exploration Company B.V. (“Shell”) to jointly explore in Southern West Africa. Initially, the alliance focused on Namibia where Kosmos completed a farm-in to Shell's acreage in PEL 39, and Sao Tome and Principe where we entered into exclusive negotiations for Shell to take an interest in Kosmos’ acreage in Blocks 5, 6, 11, and 12. As part of the alliance, our two companies jointly evaluated opportunities in adjacent geographies. This alliance was consistent with Kosmos’ strategy of partnering with supermajors to leverage

Joint Interest Billings and Not

Joint Interest Billings and Notes Receivables	12 Months Ended
	Dec. 31, 2020
Joint Interest Billings
Joint Interest Billings and Notes Receivables	Joint Interest Billings and Notes Receivables Joint Interest Billings The Company’s joint interest billings consist of receivables from partners with interests in common oil and gas properties operated by the Company for shared costs. Joint interest billings are classified on the face of the consolidated balance sheets as current and long-term receivables based on when collection is expected to occur. In Ghana, the contractor group funded GNPC’s 5% share of TEN development costs. The block partners are being reimbursed for such costs plus interest out of a portion of GNPC’s TEN production revenues. As of December 31, 2020 and 2019, the current portion of the joint interest billing receivables due from GNPC for the TEN fields' development costs were $5.8 million and $14.0 million, respectively, and the long-term portion were $21.2 million and $16.0 million. Notes Receivables In February 2019, Kosmos and BP signed Carry Advance Agreements with the national oil companies of Mauritania and Senegal which obligate us separately to finance the respective national oil company’s share of certain development costs incurred through first gas production for Greater Tortue Ahmeyim Phase 1, currently projected in 2023. Kosmos’ share for the two agreements combined is up to $239.7 million, which is to be repaid with interest through the national oil companies’ share of future revenues. As of December 31, 2020 and 2019, the balance due from the national oil companies was $96.3 million, and $27.4 million, respectively, which is classified as Long-term receivables in our consolidated balance sheets.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment is stated at cost and consisted of the following: December 31, 2020 2019 (In thousands) Oil and gas properties: Proved properties $ 5,369,737 $ 4,904,648 Unproved properties 495,390 814,065 Total oil and gas properties 5,865,127 5,718,713 Accumulated depletion (2,554,851) (2,093,962) Oil and gas properties, net 3,310,276 3,624,751 Other property 59,949 61,598 Accumulated depreciation (49,312) (44,017) Other property, net 10,637 17,581 Property and equipment, net $ 3,320,913 $ 3,642,332 We recorded depletion expense of $460.9 million, $542.9 million and $316.3 million and depreciation expense of $5.5 million, $6.9 million and $4.6 million for the years ended December 31, 2020, 2019 and 2018, respectively. During the years ended December 31, 2020, 2019 and 2018, we recorded asset impairments totaling $154.0 million, zero and zero, respectively, in our consolidated statement of operations in connection with fair value assessments for oil and gas proved properties in the U.S. Gulf of Mexico.

Suspended Well Costs

Suspended Well Costs	12 Months Ended
	Dec. 31, 2020
Oil and Gas Exploration and Production Industries Disclosures [Abstract]
Suspended Well Costs	Suspended Well CostsThe Company capitalizes exploratory well costs as unproved properties within oil and gas properties until a determination is made that the well has either found proved reserves or is impaired. If proved reserves are found, the capitalized exploratory well costs are reclassified to proved properties. Well costs are charged to exploration expense if the exploratory well is determined to be impaired. The following table reflects the Company’s capitalized exploratory well costs on drilled wells as of and during the years ended December 31, 2020, 2019 and 2018. Years Ended December 31, 2020 2019 2018 (In thousands) Beginning balance $ 445,790 $ 367,665 $ 410,113 Additions to capitalized exploratory well costs pending the determination of proved reserves 4,001 78,125 10,518 Additions associated with the acquisition of DGE — — 26,224 Reclassification due to determination of proved reserves(1) (263,502) — (26,224) Capitalized exploratory well costs charged to expense(2) — — (52,966) Ending balance $ 186,289 $ 445,790 $ 367,665 ______________________________________ (1) Represents the reclassification of exploratory well costs associated with the Greater Tortue Ahmeyim Unit as a result of the execution of the Tortue Phase 1 SPA in February 2020 and Nearly Headless Nick well costs associated with the DGE acquisition in 2018. As of December 31, 2020, due to pricing revisions related to the decrease in commodity prices during the year the Greater Tortue Ahmeyim Unit did not have proved reserves recognition. (2) Primarily related to Akasa and Wawa wells as we wrote off $38.1 million and $13.6 million, respectively, of previously capitalized exploratory well costs to exploration expense during the third quarter of 2018. These impairments are included in our Ghana segment. The following table provides 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: Years Ended December 31, 2020 2019 2018 (In thousands, except well counts) Exploratory well costs capitalized for a period of one year or less $ — $ 29,121 $ — Exploratory well costs capitalized for a period of one to two years 28,692 78,245 299,253 Exploratory well costs capitalized for a period of three years or longer 157,597 338,424 68,412 Ending balance $ 186,289 $ 445,790 $ 367,665 Number of projects that have exploratory well costs that have been capitalized for a period greater than one year 3 3 3 As of December 31, 2020, the projects with exploratory well costs capitalized for more than one year since the completion of drilling are related to the BirAllah discovery (formerly known as the Marsouin discovery) in Block C8 offshore Mauritania, and the Yakaar and Teranga discoveries in the Cayar Offshore Profond block offshore Senegal. BirAllah Discovery — In November 2015, we completed the Marsouin-1 exploration well in the northern part of Block C8 offshore Mauritania, which encountered hydrocarbon pay. Following additional evaluation, a decision regarding commerciality is expected be made. During the fourth quarter of 2019, we completed the nearby Orca-1 exploration well which encountered hydrocarbon pay. Following additional evaluation, a decision regarding commerciality is expected to be made. The Bir Allah and Orca discoveries are being analyzed as a potential joint development. Yakaar and Teranga Discoveries — In May 2016, we completed the Teranga-1 exploration well in the Cayar Offshore Profond Block offshore Senegal, which encountered hydrocarbon pay. In June 2017, we completed the Yakaar-1 exploration well in the Cayar Offshore Profond Block offshore Senegal, which encountered hydrocarbon pay. In November 2017, an integrated Yakaar-Teranga appraisal plan was submitted to the government of Senegal. In September 2019, we completed the Yakaar-2 appraisal well which encountered hydrocarbon pay. The Yakaar-2 well was drilled approximately nine kilometers from the Yakaar-1 exploration well. Following additional evaluation, a decision regarding commerciality is expected to be made. The Yakaar and Teranga discoveries are being analyzed as a joint development. Asam Discovery - In October 2019, we completed the S-5 exploration offshore Equatorial Guinea, which encountered hydrocarbon pay. In July 2020, an appraisal plan was approved by the government of Equatorial Guinea. The well is located within tieback range of the Ceiba FPSO and work is currently ongoing to integrate all available data into models to establish the scale of the discovered resource. Additionally, engineering is progressing concepts around required subsea infrastructure necessary for a subsea tieback. Once the appraisal plan involving this work is complete, a decision regarding commerciality will be made.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases We have commitments under operating leases primarily related to office leases. Our leases have initial lease terms ranging from one year to ten years. Certain lease agreements contain provisions for future rent increases. The components of lease cost for the years ended December 31, 2020 and 2019 is as follows: December 31, 2020 2019 (In thousands) Operating lease cost $ 5,869 $ 5,480 Short-term lease cost(1) 13,705 15,874 Total lease cost $ 19,574 $ 21,354 __________________________________ (1) Includes $12.6 million and $13.9 million during the years ended December 31, 2020 and 2019, respectively, of costs associated with short-term drilling contracts. Other information related to operating leases at December 31, 2020 and 2019, is as follows: December 31 2020 2019 (In thousands, except lease term and discount rate) Balance sheet classifications Other assets (right-of-use assets) $ 19,799 $ 20,008 Accrued liabilities (current maturities of leases) 1,405 1,139 Other long-term liabilities (non-current maturities of leases) 22,771 22,240 Weighted average remaining lease term 8.4 years 8.8 years Weighted average discount rate 9.8 % 9.8 % The table below presents supplemental cash flow information related to leases during the years ended December 31, 2020 and 2019: December 31, 2020 2019 (In thousands) Operating cash flows for operating leases $ 5,225 $ 5,082 Investing cash flows for operating leases(1) 12,586 13,855 __________________________________ (1) Represents costs associated with short-term drilling contracts. Future minimum rental commitments under our leases at December 31, 2020, are as follows: Operating Leases(1) (In thousands) 2021 $ 3,307 2022 4,216 2023 4,287 2024 4,358 2025 4,429 Thereafter 15,470 Total undiscounted lease payments $ 36,067 Less: Imputed interest (11,891) Total lease liabilities $ 24,176 __________________________________ (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.

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt December 31, 2020 2019 (In thousands) Outstanding debt principal balances: Facility $ 1,200,000 $ 1,400,000 Corporate Revolver 100,000 — Senior Notes 650,000 650,000 GoM Term Loan 200,000 — Total 2,150,000 2,050,000 Unamortized deferred financing costs and discounts(1) (38,569) (41,937) Total debt, net 2,111,431 2,008,063 Less: Current maturities of long-term debt (7,500) — Long-term debt, net $ 2,103,931 $ 2,008,063 ________________________________________ (1) Includes $25.6 million and $32.8 million of unamortized deferred financing costs related to the Facility; $8.4 million and $9.1 million of unamortized deferred financing costs and discounts related to the Senior Notes; and $4.6 million and zero of unamortized deferred financing costs related to the GoM Term Loan as of December 31, 2020 and December 31, 2019, respectively. Facility The Facility supports our oil and gas exploration, appraisal and development programs and corporate activities with a borrowing base calculation that includes value related to the Jubilee, TEN, Ceiba and Okume fields. In February 2018, the Company amended and restated the Facility with a total commitment of $1.5 billion from a number of financial institutions with additional commitments up to $0.5 billion being available if the existing financial institutions increase their commitments or if commitments from new financial institutions are added. In November 2018, the Company exercised its option with existing financial institutions to provide the Company with an additional commitment of $100 million in the aggregate under the Facility taking total commitments to $1.6 billion. In December 2018, the Company entered into letter agreements with existing financial institutions, which provided the Company with an additional commitment of $100 million in the aggregate under the Facility effective January 31, 2019. This took the total commitments to $1.7 billion as of January 31, 2019. The commitments were reduced by $100.0 million to $1.6 billion following the Senior Notes issuance in April 2019. In April 2020, following the lenders' annual redetermination, the available borrowing base and Facility size were both reduced from $1.6 billion to approximately $1.5 billion. In addition, as part of the April 2020 redetermination process, the Company agreed to conduct an additional redetermination in September 2020. As a result, in October 2020, the available borrowing base was reduced to approximately $1.32 billion. The Company made repayments totaling $250 million during the fourth quarter of 2020. Additionally, the Company agreed to conduct semi-annual redeterminations every March and September, beginning with March 2021. When our net leverage ratio exceeds 2.50x, we are required under the Facility 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 7.125% Senior Notes plus the Corporate Revolver or the Facility, whichever is greater. As of December 31, 2020, we exceeded this ratio and restricted approximately $28.5 million in cash to meet our requirements in January 2021. As of December 31, 2020, borrowings under the Facility totaled $1.2 billion and the undrawn availability under the Facility was $120.0 million, which includes the additional commitments as referenced above. 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) and LIBOR. 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 30% 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. We determined the effective interest rate based on the estimated level of borrowings under the Facility. The Facility provides a revolving credit and letter of credit facility. The availability period for the revolving credit facility expires one month prior to the final maturity date. The letter of credit facility expires on the final maturity date. The available facility amount is subject to borrowing base constraints and, beginning on March 31, 2022, outstanding borrowings will be constrained by an amortization schedule. The Facility has a final maturity date of March 31, 2025. As of December 31, 2020, we had no letters of credit issued under the Facility. We have the right to cancel all the undrawn commitments under the amended and restated 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. In October 2020, the Company agreed to conduct semi-annual redeterminations every March and September, beginning with March 2021. 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 in Ghana and Equatorial Guinea. 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 below contained in the Facility as of September 30, 2020 (the most recent assessment date), which requires the maintenance of: • the field life cover ratio (as defined in the glossary), not less than 1.30x; and • the loan life cover ratio (as defined in the glossary), not less than 1.10x; and • the interest cover ratio (as defined in the glossary), not less than 2.25x. • the debt cover ratio (as defined in the glossary), amended as described below: As result of the impact of COVID-19 on the demand for oil and the related significant decrease in oil prices, our ability to comply with one of our financial covenants, the debt cover ratio, may be impacted in future periods. Therefore, in July 2020, we proactively worked with our lender group, prior to any inability to comply with the financial covenants thereunder, to amend the debt cover ratio calculation through December 31, 2021. The amendment makes this covenant less restrictive during the stated period up to a maximum of 4.75x and thereafter gradually returns to the originally agreed upon ratio of 3.5x. We were in compliance with the financial covenants as of the most recent assessment date. The Facility contains customary cross default provisions. Corporate Revolver In August 2018, we amended and restated the Corporate Revolver maintaining the borrowing capacity at $400.0 million, extending the maturity date from November 2018 to May 2022 and lowering the margin 100 basis points to 5%. This results in lower commitment fees on the undrawn portion of the total commitments, which is 30% per annum of the respective margin. The Corporate Revolver is available for general corporate purposes and for oil and gas exploration, appraisal and development programs. As of December 31, 2020, we have $3.7 million of net deferred financing costs related to the Corporate Revolver, which will be amortized over the remaining term. These deferred financing costs are included in the Other assets section of our consolidated balance sheets. As of December 31, 2020, there were $100.0 million in outstanding borrowings under the Corporate Revolver and the undrawn availability under the Corporate Revolver was $300.0 million. Interest is the aggregate of the applicable margin (5.0%); LIBOR; and mandatory cost (if any, as defined in the Corporate Revolver). 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 portion of the total commitments. Commitment fees for the lenders are equal to 30% per annum of the respective margin when a commitment is available for utilization. The Corporate Revolver expires on May 31, 2022. The available amount is not subject to borrowing base constraints. we have the right to cancel all the undrawn commitments under the Corporate Revolver. We are required to repay certain amounts due under the Corporate Revolver with sales of certain subsidiaries or sales of certain assets. If an event of default exists under the Corporate Revolver, the lenders can accelerate the maturity and exercise other rights and remedies, including the enforcement of security granted pursuant to the Corporate Revolver over certain assets held by us. We were in compliance with the financial covenants below contained in the Corporate Revolver as of September 30, 2020 (the most recent assessment date), which requires the maintenance of: • the interest cover ratio (as defined in the glossary), not less than 2.25x. • the debt cover ratio (as defined in the glossary), amended as described below: As result of the impact of COVID-19 on the demand for oil and the related significant decrease in oil prices, our ability to comply with one of our financial covenants, the debt cover ratio, may be impacted in future periods. Therefore, in July 2020, we proactively worked with our lender group, prior to any inability to comply with the financial covenants thereunder, to amend the debt cover ratio calculation through December 31, 2021. The amendment makes this covenant less restrictive during the stated period up to a maximum of 4.75x and thereafter gradually returns to the originally agreed upon ratio of 3.5x. We were in compliance with the financial covenants as of the most recent assessment date. The Corporate Revolver contains customary cross default provisions. Letters of Credit In July 2016, we amended and restated the revolving letter of credit facility agreement ("LC Facility'), extending the maturity date to July 2019. Other amendments included increasing the margin from 0.5% to 0.8% per annum on amounts outstanding, adding a commitment fee payable quarterly in arrears at an annual rate equal to 0.65% on the available commitment amount and providing for issuance fees to be payable to the lender per new issuance of a letter of credit. In February 2018, the LC Facility was increased to $73 million to facilitate the issuance of additional letters of credit. In July 2018 and December 2018, the LC Facility size was voluntarily reduced to $40.0 million and $20.0 million, respectively, based on the expiration of several large outstanding letters of credit. The LC Facility expired in July 2019, however, there were five outstanding letters of credit totaling $3.1 million which were released in May 2020, and the LC Facility was subsequently terminated in June 2020. In 2019, we issued two letters of credit totaling $20.4 million under a new letter of credit arrangement, which did not require cash collateral. In December 2020, as a result of the Shell farm down transaction discussed in Note 3 — Acquisitions and Divestitures, the letters of credit were released. 7.875% Senior Secured Notes due 2021 In April 2019, all of the Senior Secured Notes were redeemed for $543.8 million, including accrued interest and the early redemption premium. The redemption resulted in a $22.9 million loss on extinguishment of debt, which is included in Interest and other financing costs, net on the consolidated statement of operations. 7.125% Senior Notes due 2026 In April 2019, the Company issued $650.0 million of 7.125% Senior Notes and received net proceeds of approximately $640.0 million after deducting commissions and other expenses. We used the net proceeds to redeem all of the Senior Secured Notes, repay a portion of the outstanding indebtedness under the Corporate Revolver and pay fees and expenses related to the redemption, repayment and the issuance of the Senior Notes. The Senior Notes mature on April 4, 2026. We will pay interest in arrears on the Senior Notes each April 4 and October 4, commencing on October 4, 2019. The Senior Notes are senior, unsecured obligations of Kosmos Energy Ltd. and rank equal in right of payment with all of its existing and future senior indebtedness (including all borrowings under the Corporate Revolver) and rank effectively junior in right of payment to all of its existing and future secured indebtedness (including all borrowings under the Facility). The Senior Notes are guaranteed on a senior, unsecured basis by certain subsidiaries owning the Company's U.S. Gulf of Mexico assets, and on a subordinated, unsecured basis by certain subsidiaries that guarantee the Facility. At any time prior to April 4, 2022, and subject to certain conditions, the Company may, on one or more occasions, redeem up to 40% of the original principal amount of the Senior Notes with an amount not to exceed the net cash proceeds of certain equity offerings at a redemption price of 107.1% of the outstanding principal amount of the Senior Notes, together with accrued and unpaid interest and premium, if any, to, but excluding, the date of redemption. Additionally, at any time prior to April 4, 2022 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 April 4, 2022, 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 April 4, 2022, but before April 4, 2023 103.6 % On or after April 4, 2023, but before April 4, 2024 101.8 % On or after April 4, 2024 and thereafter 100.0 % 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 Senior Notes 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 Senior Notes 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. The Senior Notes 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. Production Prepayment Agreement, net In June 2020, the Company received $50 million from Trafigura under a Production Prepayment Agreement of crude oil sales related to a portion of our U.S. Gulf of Mexico production primarily in 2022 and 2023. The Company has terminated the Production Prepayment Agreement and the initial prepayment of $50 million advanced under the Production Prepayment Agreement by Trafigura in the second quarter of 2020 has been extinguished and converted into the GoM Term Loan as of September 30, 2020. GoM Term Loan In September 2020, the Company entered into a five-year $200 million senior secured term-loan credit agreement secured against the Company's U.S. Gulf of Mexico assets with net proceeds received of $197.7 million after deducting fees and other expenses. The GoM Term Loan also includes an accordion feature providing for incremental commitments of up to $100 million subject to certain conditions. The net proceeds will be used to pay down a portion of the Facility and to fund U.S. Gulf of Mexico working capital and general operating expenses. The $50 million advanced under the Production Prepayment Agreement with Trafigura in the second quarter of 2020 has been extinguished and converted as part of the GoM Term Loan with the remaining $150 million provided by an affiliate of Beal Bank. The GoM Term Loan bears interest at an effective rate of approximately 6% per annum and matures in 2025, with principal repayments beginning in the fourth quarter of 2021. The GoM Term Loan contains customary affirmative and negative covenants, including covenants that affect our ability to incur additional indebtedness, create liens, merge, dispose of assets, and make distributions, dividends, investments or capital expenditures, among other things. The GoM Term Loan is guaranteed on a senior, secured basis by certain subsidiaries owning the Company's U.S. Gulf of Mexico assets. The GoM Term Loan includes certain representations and warranties, indemnities and events of default that, subject to certain materiality thresholds and grace periods, arise as a result of a payment default, failure to comply with covenants, material inaccuracy of representation or warranty, and certain bankruptcy or insolvency proceedings. If there is an event of default, all or any portion of the outstanding indebtedness may be immediately due and payable and other rights may be exercised including against the collateral. At December 31, 2020, the estimated repayments of debt during the five years and thereafter are as follows: Payments Due by Year Total 2021 2022 2023 2024 2025 Thereafter (In thousands) Principal debt repayments(1) $ 2,150,000 $ 7,500 $ 258,571 $ 458,571 $ 458,572 $ 316,786 $ 650,000 _______________________________________ (1) Includes the scheduled maturities for the $650.0 million aggregate principal amount of Senior Notes and borrowings under the Facility, Corporate Revolver and GoM Term Loan. The scheduled maturities of debt related to the Facility as of December 31, 2020 are based on our level of borrowings and our estimated future available borrowing base commitment levels in future periods. Any increases or decreases in the level of borrowings or increases or decreases in the available borrowing base would impact the scheduled maturities of debt during the next five years and thereafter. Interest and other financing costs, net Interest and other financing costs, net incurred during the period comprised of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Interest expense $ 119,857 $ 145,507 $ 114,134 Amortization—deferred financing costs 9,347 9,257 9,379 Loss on extinguishment of debt 2,902 24,794 4,324 Capitalized interest (25,013) (28,077) (28,331) Deferred interest 2,402 1,919 (1,138) Interest income (4,773) (3,692) (3,455) Other, net 5,072 5,366 6,263 Interest and other financing costs, net $ 109,794 $ 155,074 $ 101,176

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	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. We have included an estimate of non-performance risk in the fair value measurement of our derivative contracts as required by ASC 820—Fair Value Measurements and Disclosures. Oil Derivative Contracts The following table sets forth the volumes in barrels underlying the Company’s outstanding oil derivative contracts and the weighted average prices per Bbl for those contracts as of December 31, 2020. Volumes and weighted average prices are net of any offsetting derivative contracts entered into. Weighted Average Price per Bbl Term Type of Contract Index MBbl Net Deferred Premium Payable/(Receivable) Swap Sold Put Floor Ceiling 2021: January — December Swaps with sold puts Dated Brent 6,000 $ — $ 53.96 $ 42.92 $ — $ — January — June Swaps with sold puts NYMEX WTI 1,000 — 47.75 37.50 — — January — December Three-way collars Dated Brent 4,000 0.34 — 33.13 40.63 52.60 January — December Three-way collars NYMEX WTI 1,000 1.00 — 37.50 45.00 55.00 January — December Sold calls(1) Dated Brent 7,000 — — — — 70.09 2022: January — December Sold calls(1) Dated Brent 1,581 — — — — 60.00 ______________________________________ (1) Represents call option contracts sold to counterparties to enhance other derivative positions. In February 2021, we entered into Dated Brent three-way collar contracts for 1.5 MMBbl from January 2022 through December 2022 with a sold put price of $40.00 per barrel, a floor price of $50.00 per barrel and a ceiling price of $70.00 per barrel. See Note 10—Fair Value Measurements for additional information regarding the Company’s derivative instruments. The following tables disclose the Company’s derivative instruments as of December 31, 2020 and 2019 and gain/(loss) from derivatives during the years ended December 31, 2020, 2019 and 2018. Estimated Fair Value Asset (Liability) December 31, Type of Contract Balance Sheet Location 2020 2019 (In thousands) Derivatives not designated as hedging instruments: Derivative assets: Commodity Derivatives assets—current $ 15,414 $ 12,856 Provisional oil sales Receivables: Oil sales (677) (3,287) Commodity Derivatives assets—long-term 964 2,302 Derivative liabilities: Commodity Derivatives liabilities—current (28,009) (8,914) Commodity Derivatives liabilities—long-term (8,069) (11,478) Total derivatives not designated as hedging instruments $ (20,377) $ (8,521) Amount of Gain/(Loss) Years Ended December 31, Type of Contract Location of Gain/(Loss) 2020 2019 2018 (In thousands) Derivatives not designated as hedging instruments: Commodity(1) Oil and gas revenue $ (5,620) $ 1,161 $ (1,963) Commodity Derivatives, net (17,180) (71,885) 31,430 Interest rate Interest expense — — 493 Total derivatives not designated as hedging instruments $ (22,800) $ (70,724) $ 29,960 ______________________________________ (1) Amounts represent the change in fair value 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 December 31, 2020 and 2019, 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.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements In accordance with ASC 820—Fair Value Measurements, 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 December 31, 2020 and 2019, for each fair value hierarchy level: Fair Value Measurements Using: Quoted Prices in Active Markets for Identical Assets Significant Other Significant Unobservable Inputs (Level 1) (Level 2) (Level 3) Total (In thousands) December 31, 2020 Assets: Commodity derivatives $ — $ 16,378 $ — $ 16,378 Provisional oil sales — (677) — (677) Liabilities: Commodity derivatives — (36,078) — (36,078) Total $ — $ (20,377) $ — $ (20,377) December 31, 2019 Assets: Commodity derivatives $ — $ 15,158 $ — $ 15,158 Provisional oil sales — (3,287) — (3,287) Liabilities: Commodity derivatives — (20,392) — (20,392) Total $ — $ (8,521) $ — $ (8,521) 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, after any allowances for doubtful accounts, and other long-term assets 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 collars, put options, call options and swaps for notional barrels of oil at fixed Dated Brent, NYMEX WTI or Argus LLS oil prices. The values attributable to our oil derivatives are based on (i) the contracted notional volumes, (ii) independent active futures price quotes for the respective index, (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 the respective index. 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 9—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 and (ii) the difference in the independent active futures price quotes for the respective index over the term of the pricing period designated in the sales contract and the spot price on the lifting date. Debt The following table presents the carrying values and fair values at December 31, 2020 and 2019: December 31, 2020 December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value (In thousands) Senior Notes $ 643,524 $ 613,412 $ 642,550 $ 664,957 GoM Term Loan 200,000 200,000 — — Corporate Revolver 100,000 100,000 — — Facility 1,200,000 1,200,000 1,400,000 1,400,000 Total $ 2,143,524 $ 2,113,412 $ 2,042,550 $ 2,064,957 The carrying value of our Senior Notes represents the principal amounts outstanding less unamortized discounts. The fair value of our Senior Notes is based on quoted market prices, which results in a Level 1 fair value measurement. The carrying values of the GoM Term Loan, Corporate Revolver and Facility approximate fair value since they are subject to short-term floating interest rates that approximate the rates available to us for those periods. Nonrecurring Fair Value Measurements - Long-lived assets Certain long-lived assets are reported at fair value on a non-recurring basis on the Company's consolidated balance sheet. These long-lived assets are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances. Our long-lived assets are reviewed for impairment when changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company calculates the estimated fair values of its long-lived assets using the income approach described in the ASC 820 — Fair Value Measurements. Significant inputs associated with the calculation of estimated discounted future net cash flows include anticipated future production, pricing estimates, capital and operating costs, market-based weighted average cost of capital, and risk adjustment factors applied to reserves. These are classified as Level 3 fair value assumptions. The Company utilizes an average of third-party industry forecasts of Dated Brent, adjusted for location and quality differentials, to determine our pricing assumptions. In order to evaluate the sensitivity of the assumptions, we analyze sensitivities to prices, production, and risk adjustment factors. As a result of the impact of COVID-19 on the demand for oil and the related significant decrease in oil prices, we reviewed our long-lived assets for impairment at March 31, 2020, which resulted in impairment charges of $150.8 million, reducing the carrying value of the properties to their estimated fair values of $243.7 million. As part of our impairment analysis, the average per barrel Dated Brent price of third-party industry forecasts used for purposes of determining discounted future cash flows ranged from the mid-$30s in 2020 increasing to the mid-$50s over several years. The expected future cash flows were discounted using a rate of approximately 10 percent, which the Company believes is a market-based weighted average cost of capital for industry peers determined appropriate at the time of the valuation. These impairment charges are included in Impairments of long-lived assets on the consolidated statement of operations.

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations The following table summarizes the changes in the Company’s asset retirement obligations: December 31, 2020 2019 (In thousands) Asset retirement obligations: Beginning asset retirement obligations $ 235,053 $ 151,953 Additions associated with Equatorial Guinea - Ceiba Field and Okume Complex — 114,395 Liabilities incurred during period 3,436 11,218 Liabilities settled during period (2,782) (7,156) Revisions in estimated retirement obligations (3,736) (49,471) Accretion expense 19,450 14,114 Ending asset retirement obligations $ 251,421 $ 235,053 The asset retirement obligations reflect the estimated present value of the amount of dismantlement, removal, site reclamation, and similar activities associated with our oil and gas properties. The Company utilizes current cost experience to estimate the expected cash outflows for retirement obligations. The Company estimates the ultimate productive life of the properties, a risk-adjusted discount rate, and an inflation factor in order to determine the current present value of this obligation. To the extent future revisions to these assumptions impact the present value of the existing asset retirement obligation, a corresponding adjustment is made to the oil and gas property balance. The revisions in estimated retirement obligations during 2020 and 2019 are related to changes in the estimated abandonment date in certain of our fields.

Equity-based Compensation

Equity-based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Equity-based Compensation	Equity‑based Compensation Restricted Stock Awards and Restricted Stock Units Our Long-Term Incentive Plan ("LTIP") provides for the granting of incentive awards in the form of stock options, stock appreciation rights, restricted stock awards, restricted stock units, among other award types. In January 2018 and January 2015, the board of directors approved amendments to the plan which added 11.0 million and 15.0 million shares, respectively, to the plan which were approved at the corresponding Annual General Meeting. The LTIP as amended provides for the issuance of 50.5 million shares pursuant to awards under the plan. As of December 31, 2020, the Company had approximately 6.5 million shares that remain available for issuance under the LTIP. We record equity-based 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 $32.7 million, $32.4 million and $35.2 million during the years ended December 31, 2020, 2019 and 2018, respectively. The total tax benefit for the years ended December 31, 2020, 2019 and 2018 was $4.7 million, $4.9 million and $6.6 million, respectively. Additionally, we expensed a net tax shortfall (windfall) related to equity‑based compensation of $1.3 million, $1.2 million and $(0.4) million for the years ended December 31, 2020, 2019 and 2018, respectively. The fair value of awards vested during 2020, 2019 and 2018 was approximately $26.0 million, $20.3 million, and $85.1 million, respectively. 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 vesting criteria under the LTIP. Substantially, all of these awards vest over a three year period. 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 December 31, 2020: Service Vesting Restricted Stock Awards Weighted- Average Grant-Date Fair Value Market / Service Vesting Restricted Stock Awards Weighted- Average Grant-Date Fair Value (In thousands) (In thousands) Outstanding at December 31, 2017: 220 $ 8.64 — $ — Granted — — — — Forfeited — — — — Vested (220) 8.64 — — Outstanding at December 31, 2018: — — — — There has been no additional restricted stock activity subsequent to December 31, 2018. The following table reflects the outstanding restricted stock units as of December 31, 2020: Service Vesting Weighted- Average Grant-Date Fair Value Market / Service Vesting Restricted Stock Units Weighted-Average Grant-Date Fair Value (In thousands) (In thousands) Outstanding at December 31, 2017: 4,183 $ 6.39 8,452 $ 11.26 Granted 2,402 7.07 8,111 12.38 Forfeited (229) 6.40 (302) 8.95 Vested (2,241) 6.95 (9,545) 13.75 Outstanding at December 31, 2018: 4,115 6.42 6,716 9.02 Granted 3,228 5.01 3,195 6.02 Forfeited (591) 5.90 (813) 7.93 Vested (2,021) 5.95 (1,300) 6.32 Outstanding at December 31, 2019: 4,731 5.71 7,798 8.42 Granted 3,481 5.48 3,394 8.37 Forfeited (1,187) 6.12 (726) 8.03 Vested (2,185) 5.91 (2,607) 9.47 Outstanding at December 31, 2020: 4,840 5.34 7,859 8.11 As of December 31, 2020, total equity‑based compensation to be recognized on unvested restricted stock units is $22.9 million over a weighted average period of 1.7 years. For restricted stock units with a combination of market and service vesting criteria, the number of shares of common stock 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 up to 200% of the awards granted. The grant date fair value ranged from $1.06 to $12.96 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 44.0% to 52.0%. The risk‑free interest rate was based on the U.S. treasury rate for a term commensurate with the expected life of the grant ranged from 0.8% to 2.5% for restricted stock units. The expected quarterly dividends ranged from $0.045 to $0.050 commensurate with our current dividend experience. In January 2021, we granted 2.5 million service vesting restricted stock units and 6.7 million market and service vesting restricted stock units to our employees under our long-term incentive plan. We expect to recognize approximately $32.2 million of non-cash compensation expense related to these grants over the next three years.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We provide for income taxes based on the laws and rates in effect in the countries in which our operations are conducted. The relationship between our pre‑tax income or loss from continuing operations and our income tax expense or benefit varies from period to period as a result of various factors which include changes in total pre‑tax income or loss, the jurisdictions in which our income (loss) is earned and the tax laws in those jurisdictions. In March 2020, the Coronavirus Aid, Relief, and Economic Security ACT ("CARES Act") became law. Among other things, the CARES Act permits taxpayers to carry back U.S. taxable losses generated during tax years 2018 through 2020 to the five tax years preceding the loss year to obtain tax refunds. Certain of our U.S. legal entities qualify for such relief and we recorded a current tax benefit of $4.9 million during the first quarter of 2020, with a total $12.2 million income tax refund claim. Other provisions of the CARES Act are not expected to have a material impact to our tax expense. Effective January 1, 2019, our outstanding shares in KTIPI were transferred to Trident in exchange for a 40.375% undivided interest in the Ceiba Field and Okume Complex and Trident became the operator. As a result, our interest in the Ceiba Field and Okume Complex will be accounted for under the proportionate consolidation method of accounting going forward. The following discussion reflects the proportionate consolidation of our Equatorial Guinean operations related to the Ceiba Field and Okume Complex for the years ended December 31, 2020 and 2019. For years ended prior to 2019 KTIPI was accounted for as an Equity Method Investment. The components of loss before income taxes were as follows: Years Ended December 31, 2020 2019 2018 (In thousands) United States $ (338,746) $ (149,919) $ 41,026 Bermuda — — (73,979) Foreign—other (78,049) 175,036 (17,907) Income (loss) before income taxes $ (416,795) $ 25,117 $ (50,860) The components of the provision for income taxes attributable to our income (loss) before income taxes consist of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Current: United States $ (12,208) $ 185 $ 122 Bermuda — — — Foreign—other 49,586 171,079 33,864 Total current 37,378 171,264 33,986 Deferred: United States 34,831 (18,776) 8,514 Bermuda — — — Foreign—other (77,418) (71,594) 631 Total deferred (42,587) (90,370) 9,145 Income tax expense (benefit) $ (5,209) $ 80,894 $ 43,131 Our reconciliation of income tax expense (benefit) computed by applying our statutory rate and the reported effective tax rate on income or (loss) from continuing operations is as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Tax at statutory rate(1) $ (87,527) $ 5,275 $ (10,681) Foreign income (loss) taxed at different rates (1,771) 32,690 5,013 Net non-taxable expense / insurance recoveries — (13,352) 3,256 West Leo arbitration settlement — — (2,834) Non-deductible insurance premiums — 2,625 — Non-deductible compensation 890 3,545 2,643 Deferred tax liability - undistributed earnings — — (2,565) Non-deductible and other items 387 3,998 656 Equity earnings - net of tax — — (15,305) Tax shortfall (windfall) on equity-based compensation, net 1,175 1,224 (387) Change in valuation allowance 86,539 44,889 63,335 U.S. tax loss carryback rate differential (4,902) — — Total tax expense $ (5,209) $ 80,894 $ 43,131 Effective tax rate(2) 1 % 322 % 85 % ______________________________________ (1) On December 28, 2018, we changed our jurisdiction of incorporation from Bermuda to the State of Delaware. Kosmos Energy Ltd. discontinued as a Bermuda exempted company pursuant to Section 132G of the Companies Act 1981 of Bermuda and, pursuant to Section 265 of the General Corporation Law of the State of Delaware (the “DGCL”), continued its existence under the DGCL as a corporation organized in the State of Delaware. As a result, the statutory tax rate for the 2020, 2019 and 2018 reconciliation of income tax expense is the U.S. statutory tax rate of 21%. (2) The effective tax rate during the years ended December 31, 2020, 2019 and 2018, were impacted by (gains) and losses of $(2.9) million, $132.1 million and $261.2 million, respectively, incurred in jurisdictions in which we are not subject to taxes and therefore do not generate any income tax benefits or where there are valuation allowances offsetting the corresponding deferred tax assets. The effective tax rate for the United States is approximately 7%, 12% and 84% for the years ended December 31, 2020, 2019 and 2018, respectively. The effective tax rate in the United States is impacted by the effect of non-deductible expenditures and equity-based compensation tax shortfalls and tax windfalls equal to the difference between the income tax benefit recognized for financial statement reporting purposes compared to the income tax benefit realized for tax return purposes. For the years ended December 31, 2020 and December 31, 2019, our effective tax rate in the United States is impacted by valuation allowances on a portion of our deferred tax assets totaling $96.6 million and $6.8 million, respectively. The effective tax rate for Ghana is approximately 35%, 29% and 36% for the years ended December 31, 2020, 2019 and 2018, respectively. The effective tax rate in Ghana is impacted by non-deductible expenditures. The effective tax rate for years ended December 31, 2018 and 2019, is impacted by amounts associated with damage to the turret bearing, which we expect to recover from insurance proceeds. Any such insurance recoveries would not be subject to income tax. The effective tax rate for Equatorial Guinea is approximately 34% and 37% for the years ended December 31, 2020 and 2019 and is impacted by non-deductible expenditures. Our operations in other foreign jurisdictions have a 0% effective tax rate because they reside in countries with a 0% statutory rate or we have incurred losses in those countries and have full valuation allowances against the corresponding net deferred tax assets. Deferred tax assets and liabilities, which are computed on the estimated income tax effect of temporary differences between financial and tax bases in assets and liabilities, are determined using the tax rates expected to be in effect when taxes are actually paid or recovered. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. The tax effects of significant temporary differences giving rise to deferred tax assets and liabilities are as follows: December 31, 2020 2019 (In thousands) Deferred tax assets: Foreign capitalized operating expenses $ 152,106 $ 175,330 Foreign net operating losses 32,762 19,576 United States net operating losses 113,427 58,903 United States deferred interest expense — 15,426 Equity compensation 14,089 13,700 Unrealized derivative losses 3,482 1,471 Asset retirement obligation and other 41,759 43,159 Total deferred tax assets 357,625 327,565 Valuation allowance (288,288) (201,749) Total deferred tax assets, net 69,337 125,816 Deferred tax liabilities: Depletion, depreciation and amortization related to property and equipment (642,956) (746,258) Unrealized derivative gains — — Total deferred tax liabilities (642,956) (746,258) Net deferred tax liability $ (573,619) $ (620,442) The Company has foreign net operating loss carryforwards of $105.9 million. Of these losses, we expect $0.5 million, $15.5 million, $0.6 million, $2.1 million, $1.2 million and $43.5 million to expire in 2021, 2022, 2023, 2024, 2025, and 2026 respectively, and $42.5 million do not expire. All of these losses currently have offsetting valuation allowances. The Company has $540.1 million of United States net operating loss that will not expire. The Company is open to tax examinations in the United States for federal income tax return years 2017 through 2019 and in Ghana to federal income tax return years 2014 through 2019. As of December 31, 2020, 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.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Net Income (Loss) Per Share In the calculation of basic net income per share, participating securities are allocated earnings based on actual dividend distributions received plus a proportionate share of undistributed net income, if any. We calculate basic net income per share under the two‑class method. Diluted net income (loss) per share is calculated under both the two-class method and the treasury stock method and the more dilutive of the two calculations is presented. The computation of diluted net income (loss) per share reflects the potential dilution that could occur if all outstanding awards under our LTIP were converted into shares of common stock or resulted in the issuance of shares of common stock that would then share in the earnings of the Company. During periods in which the Company realizes a loss from continuing operations securities would not be dilutive to net loss per share and conversion into shares of common stock is assumed not to occur. Basic net income (loss) per share is computed as (i) net income (loss), (ii) less income allocable to participating securities (iii) divided by weighted average basic shares outstanding. The Company’s diluted net income (loss) per share is computed as (i) basic net income (loss), (ii) plus diluted adjustments to income allocable to participating securities (iii) divided by weighted average diluted shares outstanding. Years Ended December 31, 2020 2019 2018 (In thousands, except per share data) Numerator: Net loss allocable to common stockholders $ (411,586) $ (55,777) $ (93,991) Denominator: Weighted average number of shares outstanding: Basic 405,212 401,368 404,585 Restricted stock awards and units(1)(2) — — — Diluted 405,212 401,368 404,585 Net loss per share: Basic $ (1.02) $ (0.14) $ (0.23) Diluted $ (1.02) $ (0.14) $ (0.23) ______________________________________ (1) Our service vesting restricted stock awards represent participating securities because they participate in non-forfeitable 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 (loss) per share calculation. Our service vesting restricted stock awards do not participate in undistributed net losses because they are not contractually obligated to do so and, therefore, are excluded from the basic net income (loss) per share calculation in periods we are in a net loss position. All restricted stock awards were fully vested in January 2018. (2) For the years ended December 31, 2020, 2019 and 2018, we excluded 6.1 million, 15.3 million and 10.6 million outstanding restricted stock awards and restricted stock units, respectively, from the computations of diluted net income per share because the effect would have been anti‑dilutive. All restricted stock awards were fully vested in January 2018.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies From time to time, 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. The Jubilee Field in Ghana covers an area within both the WCTP and DT petroleum contract areas. It was agreed the Jubilee Field would be unitized for optimal resource recovery. Kosmos and its partners executed a comprehensive unitization and unit operating agreement, the Jubilee UUOA, to unitize the Jubilee Field and govern each party’s respective rights and duties in the Jubilee Unit, which was effective July 16, 2009. Pursuant to the terms of the Jubilee UUOA, the tract participations are subject to a process of redetermination. The initial redetermination process was completed on October 14, 2011. As a result of the initial redetermination process, our Unit Interest is 24.1%. These consolidated financial statements are based on these redetermined tract participations. Our unit interest may change in the future should another redetermination occur. The Greater Tortue Ahmeyim Unit, which includes the Ahmeyim discovery in Mauritania Block C8 and the Guembeul discovery in the Senegal Saint Louis Offshore Profond Block, straddles the border between Mauritania and Senegal. To optimize resource recovery in this field, we entered into the GTA UUOA in February 2019 with the governments of Mauritania and Senegal. The GTA UUOA governs interests in and development of the Greater Tortue Ahmeyim Field and created the Greater Tortue Ahmeyim Unit from portions of the Mauritania Block C8 and the Senegal Saint Louis Offshore Profond Block areas. These interest percentages are subject to redetermination of the participating interests in the Greater Tortue Ahmeyim Field pursuant to the terms of the GTA UUOA. These consolidated financial statements are based our current payment interest on development activities in the Greater Tortue Ahmeyim Unit of 26.7%. Our unit interest may change in the future should a redetermination occur. We currently have a commitment to drill two exploration wells and approximately 1,000 square kilometer 3D seismic acquisition requirement in Mauritania. In South Africa, as of December 31, 2020, we had 2D seismic acquisition requirements of approximately 500 line kilometers, which was acquired in January 2021. Performance Obligations As of December 31, 2020 and 2019, the Company had performance bonds totaling $195.5 million and $222 million, respectively, for our supplemental bonding requirements stipulated by the BOEM and $7.1 million and $3.7 million, respectively, to other operators related to costs anticipated for the plugging and abandonment of certain wells and the removal of certain facilities in our U.S. Gulf of Mexico fields. As of December 31, 2020 and 2019, we had zero cash collateral against these secured performance bonds. Dividends On March 26, 2020, the quarterly cash dividend of $0.0452 per common share was paid to stockholders of record as of March 5, 2020. In March 2020, in response to economic conditions, including oil price volatility and the impact of COVID-19 pandemic, the Board of Directors decided to suspend the dividend. During the year ended December 31, 2019 we declared and issued cash dividends to stockholders totaling $0.1808 per common share.

Additional Financial Informatio

Additional Financial Information	12 Months Ended
	Dec. 31, 2020
Additional Financial Information
Additional Financial Information	Additional Financial Information Accrued Liabilities Accrued liabilities consisted of the following: December 31, 2020 2019 (In thousands) Accrued liabilities: Exploration, development and production $ 89,162 $ 152,490 Revenue payable 15,079 32,482 Current asset retirement obligations 7,255 4,527 General and administrative expenses 4,988 44,575 Interest 23,725 33,584 Income taxes 37,344 103,566 Taxes other than income 2,815 3,375 Derivatives 17,475 4,837 Other 5,417 1,268 $ 203,260 $ 380,704 Gain on sale of assets During the year ended December 31, 2020, we recognized a $92.1 million gain related to the farm down of interests in blocks offshore Sao Tome & Principe, Suriname and Namibia to Shell. During the year ended December 31, 2019, we recognized a $10.5 million gain related to the farm-out of Blocks 6 and 11 offshore Sao Tome and Principe. During the year ended December 31, 2018, we recognized a $7.7 million gain related to the farm-out of Blocks EG-21, S, and W offshore Equatorial Guinea to Trident. Facilities Insurance Modifications, net Facilities insurance modifications, net consists of costs associated with the long-term solution to convert the Jubilee FPSO to a permanently spread moored facility, net of any insurance reimbursements. Other Expenses, net Other expenses, net incurred during the period is comprised of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Loss on disposal of inventory $ 8,607 $ 4,590 $ 280 Gain on insurance settlements — (3,509) — Loss on asset retirement obligations liability settlements 1,966 193 — Restructuring charges 16,474 11,528 — Other, net 10,755 11,846 (6,781) Other expenses, net $ 37,802 $ 24,648 $ (6,501) The restructuring charges are for employee severance and related benefit costs incurred as part of a corporate reorganization. Included in Other, net are expenditures arising from Tullow Ghana Limited’s contract with Seadrill for use of the West Leo drilling rig once partner-approved 2016 work program objectives were concluded. Tullow charged such expenditures to the Deepwater Tano (“DT”) joint account. Kosmos disputed through arbitration that these expenditures were chargeable to the DT joint account on the basis that the Seadrill West Leo drilling rig contract was not approved by the DT operating committee pursuant to the DT Joint Operating Agreement. In July 2018, the International Chamber of Commerce ("ICC") issued its Final Award in the arbitration in favor of Kosmos. As a result, we recovered from Tullow Ghana Limited disputed charges in the amount of $12.9 million in 2018 in the form of cash payments and offsets against other unrelated joint venture costs, which include amounts previously paid under protest as well as certain costs and fees incurred pursuing the arbitration. Equity Method Investments - Equatorial Guinea As part of our acquisition of KTIPI in 2017, a corporate joint venture entity in which we owned a 50% interest until January 2019, we acquired an indirect participating interest in Block G offshore Equatorial Guinea. The objective of this transaction was to acquire the Ceiba Field and Okume Complex with the intent to optimize production and increase reserves. Below is a summary of financial information for KTIPI presented on a 100% basis for 2018. The financial information for 2019 is presented as part of our consolidated financial statements based on our direct 40.375% ownership in the Ceiba Field and Okume Complex. December 31, 2018 (In thousands) Assets Total current assets $ 149,950 Property and equipment, net 271,627 Other assets 21 Total assets $ 421,598 Liabilities and shareholders' deficit Total current liabilities $ 226,311 Total long term liabilities 536,178 Shareholders' deficit: Total shareholders' deficit (340,891) Total liabilities and shareholders' deficit $ 421,598 Year Ended December 31, 2018 (In thousands) Revenues and other income: Oil and gas revenue $ 721,299 Other income (477) Total revenues and other income 720,822 Costs and expenses: Oil and gas production 147,685 Depletion and depreciation 126,983 Other expenses, net 429 Total costs and expenses 275,097 Income before income taxes 445,725 Income tax expense 156,981 Net income $ 288,744 Kosmos' share of net income $ 144,372 Basis difference amortization(1) 71,491 Equity in earnings - KTIPI $ 72,881 ______________________________________ (1) The basis difference, which is associated with oil and gas properties and subject to amortization, has been allocated to the Ceiba Field and Okume Complex. We amortize the basis difference using the unit-of-production method. Effective as of January 1, 2019, our outstanding shares in KTIPI were transferred to Trident in exchange for a 40.375% undivided interest in the Ceiba Field and Okume Complex. As a result, our interest in the Ceiba Field and Okume Complex is accounted for under the proportionate consolidation method of accounting going forward. This transaction was accounted for as an asset acquisition. The carrying value of the equity method investment was allocated to the undivided interest acquired and net working capital based on the estimated relative fair value of the acquired assets. The estimated fair value measurements of oil and gas assets acquired and liabilities assumed are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair value of oil and gas properties and asset retirement obligations were measured using the discounted cash flow technique of valuation. Significant inputs to the valuation of oil and gas properties include estimates of: (i) reserves, (ii) future operating and development costs, (iii) future commodity prices, (iv) future plugging and abandonment costs, (v) estimated future cash flows, and (vi) a market-based weighted average cost of capital rate. Carrying Value Allocation (in thousands) Assets acquired: Proved oil and gas properties $ 372,144 Unproved oil and gas properties 103,909 Prepaids and other 7,273 Total assets acquired $ 483,326 Liabilities assumed: Asset retirement obligations $ 114,395 Deferred tax liabilities 247,636 Accrued liabilities and other 69,399 Total liabilities assumed $ 431,430 Carrying value: Equity method investment carrying value at December 31, 2018 $ 51,896

Business Segment Information

Business Segment Information	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Business Segment Information	Business Segment Information Kosmos is engaged in a single line of business, which is the exploration and development of oil and gas. At December 31, 2020, the Company had operations in four geographic reporting segments: Ghana, Equatorial Guinea, Mauritania/Senegal and the U.S. Gulf of Mexico. To assess performance of the reporting segments, the Chief Operating Decision Maker ("CODM") reviews capital expenditures. Capital expenditures, as defined by the Company, may not be comparable to similarly titled measures used by other companies and should be considered in conjunction with our consolidated financial statements and notes thereto. Financial information for each area is presented below: Ghana Equatorial Guinea Mauritania / Senegal U.S. Gulf of Mexico Corporate & Other Eliminations Total (in thousands) Year ended December 31, 2020 Revenues and other income: Oil and gas revenue 366,515 $ 152,501 $ — $ 285,017 $ — $ — $ 804,033 Gain on sale of assets — — — 84 92,079 — 92,163 Other income, net 2 — — 280 120,135 (120,415) 2 Total revenues and other income 366,517 152,501 — 285,381 212,214 (120,415) 896,198 Costs and expenses: Oil and gas production 169,357 80,813 — 88,307 — — 338,477 Facilities insurance modifications, net 13,161 — — — — — 13,161 Exploration expenses 182 8,290 8,189 26,792 41,163 — 84,616 General and administrative 13,506 4,865 7,464 12,607 129,801 (96,101) 72,142 Depletion, depreciation and amortization 235,772 64,786 61 181,898 3,345 — 485,862 Impairment of long-lived assets — — — 153,959 — — 153,959 Interest and other financing costs, net(1) 54,530 (1,248) (27,339) 17,373 73,612 (7,134) 109,794 Derivatives, net — — — — 17,180 — 17,180 Other expenses, net (27,925) 2,281 4,829 54,485 21,312 (17,180) 37,802 Total costs and expenses 458,583 159,787 (6,796) 535,421 286,413 (120,415) 1,312,993 Income (loss) before income taxes (92,066) (7,286) 6,796 (250,040) (74,199) — (416,795) Income tax expense (benefit) (30,486) 2,428 — 26,061 (3,212) — (5,209) Net income (loss) $ (61,580) $ (9,714) $ 6,796 $ (276,101) $ (70,987) $ — $ (411,586) Consolidated capital expenditures $ 44,146 $ 38,126 $ 126,803 $ 123,197 $ (58,293) $ — $ 273,979 As of December 31, 2020 Property and equipment, net $ 1,293,372 $ 426,365 $ 580,920 $ 998,204 $ 22,052 $ — $ 3,320,913 Total assets $ 1,397,802 $ 689,222 $ 823,411 $ 3,171,851 $ 12,654,827 $ (14,869,520) $ 3,867,593 ______________________________________ (1) Interest expense is recorded based on actual third-party and intercompany debt agreements. Capitalized interest is recorded on the business unit where the assets reside. Ghana Equatorial Guinea Mauritania / Senegal U.S. Gulf of Mexico Corporate & Other Eliminations Total (in thousands) Year ended December 31, 2019 Revenues and other income: Oil and gas revenue $ 738,909 $ 300,547 $ — $ 459,960 $ — $ — $ 1,499,416 Gain on sale of assets — — — — 10,528 — 10,528 Other income, net 5 — — 1,194 155,866 (157,100) (35) Total revenues and other income 738,914 300,547 — 461,154 166,394 (157,100) 1,509,909 Costs and expenses: Oil and gas production 188,207 90,607 — 123,799 — — 402,613 Facilities insurance modifications, net (24,254) — — — — — (24,254) Exploration expenses 204 13,350 11,181 115,765 40,455 — 180,955 General and administrative 18,618 6,643 8,222 25,456 159,539 (108,468) 110,010 Depletion, depreciation and amortization 268,866 75,565 62 214,592 4,776 — 563,861 Interest and other financing costs, net(1) 72,226 (634) (26,537) 21,266 95,887 (7,134) 155,074 Derivatives, net — — — 30,387 41,498 — 71,885 Other expenses, net 40,382 (563) 12,056 2,691 11,580 (41,498) 24,648 Total costs and expenses 564,249 184,968 4,984 533,956 353,735 (157,100) 1,484,792 Income (loss) before income taxes 174,665 115,579 (4,984) (72,802) (187,341) — 25,117 Income tax expense (benefit) 50,293 49,192 — (8,419) (10,172) — 80,894 Net income (loss) $ 124,372 $ 66,387 $ (4,984) $ (64,383) $ (177,169) $ — $ (55,777) Consolidated capital expenditures $ 98,285 $ 63,798 $ 12,556 $ 232,891 $ 33,206 $ — $ 440,736 As of December 31, 2019 Property and equipment, net $ 1,487,114 $ 464,420 $ 438,800 $ 1,216,453 $ 35,545 $ — $ 3,642,332 Total assets $ 1,654,266 $ 650,607 $ 581,317 $ 3,251,420 $ 12,144,312 $ (13,964,690) $ 4,317,232 ______________________________________ (1) Interest expense is recorded based on actual third-party and intercompany debt agreements. Capitalized interest is recorded on the business unit where the assets reside. Ghana Equatorial Guinea(1) Mauritania / Senegal U.S. Gulf of Mexico(2) Corporate & Other Eliminations(3) Total (in thousands) Year ended December 31, 2018 Revenues and other income: Oil and gas revenue $ 739,070 $ 360,649 $ — $ 147,596 $ — $ (360,649) $ 886,666 Gain on sale of assets — 7,666 — — — — 7,666 Other income, net (17) (238) — 11 150,635 (142,354) 8,037 Total revenues and other income 739,053 368,077 — 147,607 150,635 (503,003) 902,369 Costs and expenses: Oil and gas production 189,104 73,843 — 30,470 5,153 (73,843) 224,727 Facilities insurance modifications, net 6,955 — — — — — 6,955 Exploration expenses 58,276 38,164 7,262 66,962 131,180 (352) 301,492 General and administrative 19,342 5,351 5,220 10,534 168,542 (109,133) 99,856 Depletion, depreciation and amortization 265,805 134,983 61 59,835 4,134 (134,983) 329,835 Interest and other financing costs, net(4) 86,738 (12) (25,386) 7,487 39,483 (7,134) 101,176 Derivatives, net — — — (57,615) 26,185 — (31,430) Gain on equity method investments, net — — — — — (72,881) (72,881) Other expenses, net 16,414 (814) (23) 598 3,510 (26,186) (6,501) Total costs and expenses 642,634 251,515 (12,866) 118,271 378,187 (424,512) 953,229 Income (loss) before income taxes 96,419 116,562 12,866 29,336 (227,552) (78,491) (50,860) Income tax expense (benefit) 34,494 78,491 — 6,163 2,474 (78,491) 43,131 Net income (loss) $ 61,925 $ 38,071 $ 12,866 $ 23,173 $ (230,026) $ — $ (93,991) Consolidated capital expenditures $ 105,942 $ 32,156 $ 11,962 $ 95,993 $ 139,381 $ — $ 385,434 As of December 31, 2018 Property and equipment, net $ 1,698,194 $ 3,919 $ 411,448 $ 1,308,670 $ 37,470 $ — $ 3,459,701 Total assets $ 1,930,071 $ 55,302 $ 536,620 $ 3,512,989 $ 10,349,488 $ (12,296,281) $ 4,088,189 ______________________________________ (1) Includes our proportionate share of our equity method investment in KTIPI, including our basis difference which is reflected in depletion, depreciation and amortization for the year ended December 31, 2018, except for capital expenditures. See Note 16 - Additional Financial Information for additional information regarding our equity method investments. (2) Represents activity commencing September 14, 2018, the DGE acquisition date. (3) Includes elimination of proportionate consolidation amounts recorded for KTIPI to reconcile to (Gain) loss on equity method investments, net as reported in the consolidated statements of operations. (4) Interest expense is recorded based on actual third-party and intercompany debt agreements. Capitalized interest is recorded on the business unit where the assets reside. Years Ended December 31, 2020 2019 2018 (In thousands) Consolidated capital expenditures: Consolidated Statements of Cash Flows - Investing activities: Oil and gas assets $ 377,491 $ 340,217 $ 213,806 Other property 2,102 11,796 7,935 Adjustments: Changes in capital accruals (42,315) 33,717 26,669 Exploration expense, excluding unsuccessful well costs and leasehold impairments(1) 61,459 93,142 178,293 Capitalized interest (25,013) (28,077) (28,331) Proceeds on sale of assets (99,337) (16,713) (13,703) Other (408) 6,654 765 Total consolidated capital expenditures $ 273,979 $ 440,736 $ 385,434 ______________________________________ (1) Unsuccessful well costs are included in oil and gas assets when incurred.

Supplemental Quarterly Financia

Supplemental Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Supplemental Quarterly Financial Information (Unaudited)	Supplemental Quarterly Financial Information (Unaudited) Quarter Ended March 31, June 30, September 30, December 31, (In thousands, except per share data) 2020 Revenues and other income $ 177,781 $ 127,314 $ 224,787 $ 366,316 Costs and expenses 295,005 374,130 261,279 382,579 Net income (loss) (182,767) (199,391) (37,384) 7,956 Net income (loss) per share: Basic(1) (0.45) (0.49) (0.09) 0.02 Diluted(1) (0.45) (0.49) (0.09) 0.02 2019 Revenues and other income $ 296,790 $ 395,934 $ 356,970 $ 460,215 Costs and expenses 358,370 346,495 317,435 462,492 Net income (loss) (52,906) 16,837 16,065 (35,773) Net income (loss) per share: Basic(1) (0.13) 0.04 0.04 (0.09) Diluted(1) (0.13) 0.04 0.04 (0.09) _______________________________ (1) The sum of the quarterly earnings per share information may not add to the annual earnings per share information as a result of rounding.

Condensed Parent Company Financ

Condensed Parent Company Financial Statements	12 Months Ended
	Dec. 31, 2020
Condensed Financial Information Disclosure [Abstract]
Schedule I - Condensed Parent Company Financial Statements	Schedule I—Condensed Parent Company Financial Statements Under the terms of agreements governing the indebtedness of subsidiaries of Kosmos Energy Ltd. for 2020, 2019 and 2018 (collectively “KEL,” the “Parent Company”), such subsidiaries may be restricted from making dividend payments, loans or advances to KEL. Schedule I of Article 5‑04 of Regulation S‑X requires the condensed financial information of the Parent Company to be filed when the restricted net assets of consolidated subsidiaries exceed 25 percent of consolidated net assets as of the end of the most recently completed fiscal year. The following condensed parent‑only financial statements of KEL have been prepared in accordance with Rule 12‑04, Schedule I of Regulation S‑X and included herein. The Parent Company’s 100% investment in its subsidiaries has been recorded using the equity basis of accounting in the accompanying condensed parent‑only financial statements. The condensed financial statements should be read in conjunction with the consolidated financial statements of Kosmos Energy Ltd. and subsidiaries and notes thereto. The terms “Kosmos,” the “Company,” and similar terms refer to Kosmos Energy Ltd. and its wholly-owned subsidiaries, unless the context indicates otherwise. Certain prior period amounts have been reclassified to conform with the current year presentation. Such reclassifications had no impact on our reported net income, current assets, total assets, current liabilities, total liabilities or shareholders equity. KOSMOS ENERGY LTD. CONDENSED PARENT COMPANY BALANCE SHEETS (In thousands, except share data) December 31, 2020 2019 Assets Current assets: Cash and cash equivalents $ 1,166 $ 6,422 Receivables from subsidiaries — 3,819 Prepaid expenses and other 908 428 Derivatives—related party 2,502 — Total current assets 4,576 10,669 Investment in subsidiaries at equity 1,034,226 1,159,560 Long-term note receivable from subsidiary 176,540 518,844 Deferred financing costs, net of accumulated amortization of $17,296 and $14,681 at December 31, 2020 and December 31, 2019, respectively 3,706 6,321 Derivatives—related party 140 — Restricted cash 305 305 Long-term deferred tax asset 18,687 17,265 Total assets $ 1,238,180 $ 1,712,964 Liabilities and shareholders’ equity Current liabilities: Accounts payable $ 153 $ — Accounts payable to subsidiaries 38,558 — Accrued liabilities 14,157 11,942 Derivatives 2,502 — Total current liabilities 55,370 11,942 Long-term debt, net 741,606 640,856 Long-term note payable to subsidiary — 217,000 Derivatives 140 — Other long-term liabilities 910 1,464 Shareholders’ equity: Preference shares, $0.01 par value; 200,000,000 authorized shares; zero issued at December 31, 2020 and December 31, 2019 — — Common stock, $0.01 par value; 2,000,000,000 authorized shares; 449,718,317 and 445,779,367 issued at December 31, 2020 and December 31, 2019, respectively 4,497 4,458 Additional paid-in capital 2,307,220 2,297,221 Accumulated deficit (1,634,556) (1,222,970) Treasury stock, at cost, 44,263,269 shares at December 31, 2020 and 2019, respectively (237,007) (237,007) Total shareholders’ equity 440,154 841,702 Total liabilities and shareholders’ equity $ 1,238,180 $ 1,712,964 CONDENSED PARENT COMPANY STATEMENTS OF OPERATIONS (In thousands) Years Ended December 31, 2020 2019 2018 Revenues and other income: Oil and gas revenue $ — $ — $ — Other income—related party 2,642 — — Total revenues and other income 2,642 — — Costs and expenses: General and administrative 40,162 40,840 47,279 General and administrative recoveries—related party 4,112 (30,822) (36,197) Interest and other financing costs, net 59,200 86,104 66,055 Interest and other financing costs, net—related party (5,889) (7,144) (7,941) Derivatives, net 2,642 — — Other expenses, net — 10 49 Equity in (earnings) losses of subsidiaries 315,423 (15,064) 23,614 Total costs and expenses 415,650 73,924 92,859 Loss before income taxes (413,008) (73,924) (92,859) Income tax expense (1,422) (18,147) 1,132 Net loss $ (411,586) $ (55,777) $ (93,991) Dividends declared per common share $ 0.0452 $ 0.1808 $ — CONDENSED PARENT COMPANY STATEMENTS OF CASH FLOWS (In thousands) Years Ended December 31, 2020 2019 2018 Operating activities Net loss $ (411,586) $ (55,777) $ (93,991) Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Equity in (earnings) losses of subsidiaries 315,423 (15,064) 23,614 Equity-based compensation 32,706 32,370 35,230 Depreciation and amortization 8,644 5,039 7,292 Deferred income taxes (1,422) (18,397) 1,132 Other income—related party (2,642) — — Change in fair value on derivatives 2,642 — — Loss on extinguishment of debt — 22,913 — Other — — 268 Changes in assets and liabilities: Decrease in receivables 856 427 1,234 (Increase) decrease in prepaid expenses and other (480) (115) (23) (Increase) decrease due to/from related party 162,897 43,974 (42,163) Increase (decrease) in accounts payable and accrued liabilities 2,509 (8,754) 816 Net cash provided by (used in) operating activities 109,547 6,616 (66,591) Investing activities Investment in subsidiaries (190,089) 287,972 (36,192) Net cash provided by (used in) investing activities (190,089) 287,972 (36,192) Financing activities Borrowings under long-term debt 100,000 — 400,000 Payments on long-term debt — (325,000) (75,000) Net proceeds from issuance of senior notes — 641,875 — Redemption of senior secured notes — (535,338) — Purchase of treasury stock / tax withholdings (4,947) (1,983) (206,051) Dividends (19,271) (72,599) — Deferred financing costs (496) (1,897) (9,382) Net cash provided by (used in) financing activities 75,286 (294,942) 109,567 Net increase (decrease) in cash and cash equivalents (5,256) (354) 6,784 Cash, cash equivalents and restricted cash at beginning of period 6,727 7,081 297 Cash, cash equivalents and restricted cash at end of period $ 1,471 $ 6,727 $ 7,081 Non-cash activity: Issuance of common stock for related party receivable $ — $ — $ 307,944

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	Valuation and Qualifying Accounts For the Years Ended December 31, 2020, 2019 and 2018 Additions Description Balance January 1, Charged to Costs and Expenses Charged To Other Accounts Deductions From Reserves Balance December 31, 2020 Allowance for credit losses $ 2,748 $ 1,800 $ 1,127 $ — $ 5,675 Allowance for deferred tax assets $ 201,749 $ 86,539 $ — $ — $ 288,288 2019 Allowance for doubtful receivables $ 1,211 $ 1,324 $ 228 $ (15) $ 2,748 Allowance for deferred tax assets $ 156,860 $ 44,889 $ — $ — $ 201,749 2018 Allowance for doubtful receivables $ — $ 1,211 $ — $ — $ 1,211 Allowance for deferred tax assets $ 93,525 $ 63,335 $ — $ — $ 156,860 Schedules other than Schedule I and Schedule II have been omitted because they are not applicable or the required information is presented in the consolidated financial statements or the notes to consolidated financial statements.

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Kosmos Energy Ltd. and its wholly-owned subsidiaries. They also include the Company’s share of the undivided interest in certain assets, liabilities, revenues and expenses. Investments in corporate joint ventures, which we exercise significant influence over, are accounted for using the equity method of accounting. All intercompany transactions have been eliminated. Investments in companies that are partially owned by the Company are integral to the Company’s operations. The other parties, who also have an equity interest in these companies, are independent third parties that share in the business results according to their ownership. Kosmos does not invest in these companies in order to remove liabilities from its balance sheet.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the disclosures of contingent assets and liabilities. These estimates could change materially if different information or assumptions were used. We base our assumptions and estimates on historical experience and other sources that we believe to be reasonable at the time. Actual results could differ from these estimates.
Reclassifications	Reclassifications Certain prior period amounts have been reclassified to conform with the current year presentation. Such reclassifications had no significant impact on our reported net loss, current assets, total assets, current liabilities, total liabilities, shareholders’ equity or cash flows, except as disclosed related to the adoption of recent accounting pronouncements.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted CashCash and cash equivalents includes demand deposits and funds invested in highly liquid instruments with original maturities of three months or less at the date of purchase. When our net leverage ratio exceeds 2.50x, we are required under the Facility 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 7.125% Senior Notes plus the Corporate Revolver or the Facility, whichever is greater. As of December 31, 2020, we exceeded this ratio and restricted approximately $28.5 million in cash to meet our requirements in January 2021.In accordance with certain of our petroleum contracts, we have posted letters of credit related to performance guarantees for our minimum work obligations. Certain of 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.
Receivables	ReceivablesOur receivables consist of joint interest billings, oil and gas sales, related party and other receivables. For our oil sales receivable in Ghana, we require a letter of credit to be posted to secure the outstanding receivable. Receivables from joint interest owners are stated at amounts due, net of any allowances for doubtful accounts. As required by ASU 2016-13, "Measurement of Credit Losses on Financial Instruments", we determine our allowance based on historical experience, current conditions and reasonable and supportable forecasts by considering the length of time past due, future net revenues of the debtor’s ownership interest in oil and natural gas properties we operate, and the owner’s ability to pay its obligation, among other things.
Inventories	InventoriesThe 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 net realizable value. We recorded write downs of $8.6 million, $4.6 million and $0.3 million during the years ended December 31, 2020, 2019 and 2018 for materials and supplies inventories as Other expenses, net in the consolidated statements of operations and other in the consolidated statements of cash flows.Hydrocarbon inventory is carried at the lower of cost, using the weighted average cost method, or net realizable value. 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.
Leases	Leases In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” ASU 2016-02 was issued to increase transparency and comparability across organizations by recognizing substantially all leases on the balance sheet through the concept of right-of-use lease assets and liabilities. Under prior accounting guidance, lessees did not recognize lease assets or liabilities for leases classified as operating leases. The ASU was effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years with early adoption permitted. In July 2018, the FASB issued ASU 2018-11, which added a transition option permitting entities to apply the provisions of the new standard at its adoption date instead of the earliest comparative period presented in the consolidated financial statements. Under this transition option, comparative reporting would not be required, and the provisions of the standard would be applied prospectively to leases in effect at the date of adoption. The Company adopted the guidance prospectively during the first quarter of 2019. As part of our adoption, we elected not to reassess historical lease classification, recognize short-term leases on our balance sheet, nor separate lease and non-lease components for our real estate leases. The adoption and implementation of this ASU resulted in a $21.7 million increase in assets and liabilities related to our leasing activities, which primarily consists of office leases. Our adoption of ASU 2016-02 did not impact retained earnings or other components of equity as of December 31, 2018. We account for leases in accordance with ASC Topic 842, Leases, (“ASC 842”). We determine if an arrangement is a lease at contract inception. A lease exists when a contract conveys to the customer the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. The definition of a lease embodies two conditions: (1) there is an identified asset in the contract that is land or a depreciable asset (i.e., property, plant, and equipment), and (2) the customer has the right to control the use of the identified asset. In the normal course of business, the Company enters into various lease agreements for real estate and equipment related to its exploration, development and production activities that are currently accounted for as operating leases. Operating leases are included in Other assets, Accrued liabilities, and Other long-term liabilities on our consolidated balance sheets. The lease liabilities are initially and subsequently measured at the present value of the unpaid lease payments at the lease commencement date. Key estimates and judgments include how we determined: (1) the discount rate we use to discount the unpaid lease payments to present value; (2) lease term; and (3) lease payments. 1. ASC 842 requires a lessee to discount its unpaid lease payments using the interest rate implicit in the lease or, if that rate cannot be readily determined, its incremental borrowing rate. As most of our leases where we are the lessee do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. Our incremental borrowing rate for a lease is the rate of interest we would have to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. 2. The lease term for all of our leases includes the non-cancellable period of the lease plus any additional periods covered by either an option to extend (or not to terminate) the lease that we are reasonably certain to exercise, or an option to extend (or not to terminate) the lease controlled by the lessor. 3. Lease payments included in the measurement of the lease asset or liability comprise the following: fixed payments (including in-substance fixed payments), variable payments that depend on index or rate, and the exercise price of a lessee option to purchase the underlying asset if we are reasonably certain to exercise. Amounts expected to be payable under residual value guarantee are also lease payments included in the measurement of the lease liability. The Right-of-use ("ROU") asset is initially measured at cost, which comprises the initial amount of the lease liability adjusted for lease payments made at or before the lease commencement date, plus any initial direct costs incurred less any lease incentives received. For operating leases, the ROU asset is subsequently measured throughout the lease term at the carrying amount of the lease liability, plus initial direct costs, plus (minus) any prepaid (accrued) lease payments, less the unamortized balance of lease incentives received. Lease expense for lease payments is recognized on a straight-line basis over the lease term. We monitor for events or changes in circumstances that require a reassessment of a lease. When a reassessment results in the re-measurement of a lease liability, a corresponding adjustment is made to the carrying amount of the corresponding ROU asset unless doing so would reduce the carrying amount of the ROU asset to an amount less than zero. In that case, the amount of the adjustment that would result in a negative ROU asset balance is recorded in profit or loss. We have lease agreements which include lease and non-lease components. We have elected to combine lease and non-lease components for all lease contracts. We have elected not to recognize ROU assets and lease liabilities for all short-term leases that have a lease term of 12 months or less. We recognize the lease payments associated with our short-term leases as an expense on a straight-line basis over the lease term.
Exploration and Development Costs	Exploration and Development Costs The Company follows the successful efforts method of accounting for its oil and gas properties. Acquisition costs for proved and unproved properties are capitalized when incurred. Costs of unproved properties are transferred to proved properties when a determination that proved reserves have been found. Exploration costs, including geological and geophysical costs and costs of carrying unproved properties, are expensed as incurred. Exploratory drilling costs are capitalized when incurred. If exploratory wells are determined to be commercially unsuccessful or dry holes, the applicable costs are expensed and recorded in exploration expense on the consolidated statement of operations. Costs incurred to drill and equip development wells, including unsuccessful development wells, are capitalized. Costs incurred to operate and maintain wells and equipment and to lift oil and natural gas to the surface are expensed as oil and gas production expense. The Company evaluates unproved property periodically for impairment. The impairment assessment considers results of exploration activities, commodity price outlooks, planned future sales or expiration of all or a portion of such projects. If it is determined that future appraisal drilling or development activities are unlikely to occur, the associated capitalized costs are recorded as exploration expense in the consolidated statement of operations.
Depletion, Depreciation and Amortization	Depletion, Depreciation and Amortization Proved properties and support equipment and facilities are depleted using the unit‑of‑production method based on estimated proved oil and natural gas reserves. Capitalized exploratory drilling costs that result in a discovery of proved reserves and development costs are depleted using the unit‑of‑production method based on estimated proved developed oil and natural gas reserves for the related field. Depreciation and amortization of other property is computed using the straight-line method over the assets’ estimated useful lives (not to exceed the lease term for leasehold improvements), ranging from one Years Leasehold improvements 1 to 8 Office furniture, fixtures and computer equipment 3 to 7 Vehicles 5 Amortization of deferred financing costs is computed using the straight‑line method over the life of the related debt.
Capitalized Interest	Capitalized Interest Interest costs from external borrowings are capitalized on major projects with an expected construction period of one year or longer. Capitalized interest is added to the cost of the underlying asset and is depleted on the unit‑of‑production method in the same manner as the underlying assets.
Asset Retirement Obligations	Asset Retirement Obligations The Company accounts for asset retirement obligations as required by ASC 410—Asset Retirement and Environmental Obligations. Under these standards, the fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. If a reasonable estimate of fair value cannot be made in the period the asset retirement obligation is incurred, the liability is recognized when a reasonable estimate of fair value can be made. If a tangible long‑lived asset with an existing asset retirement obligation is acquired, a liability for that obligation is recognized at the asset’s acquisition or in service date. In addition, a liability for the fair value of a conditional asset retirement obligation is recorded if the fair value of the liability can be reasonably estimated. We capitalize the asset retirement costs by increasing the carrying amount of the related long‑lived asset by the same amount as the liability. We record increases in the discounted abandonment liability resulting from the passage of time in depletion, depreciation and amortization in the consolidated statement of operations. Estimating the future restoration and removal costs requires management to make estimates and judgments because most of the removal obligations are many years in the future and contracts and regulations often have vague descriptions of what constitutes removal. Additionally, asset removal technologies and costs are constantly changing, as are regulatory, political, environmental, safety and public relations considerations. Inherent in the present value calculation are numerous assumptions and judgments including the ultimate settlement amounts, inflation factors, credit adjusted discount rates, timing of settlement and changes in the legal, regulatory, environmental and political environments. To the extent future revisions to these assumptions impact the present value of the existing asset retirement obligations, a corresponding adjustment is made to the oil and gas property balance.
Impairment of Long-lived Assets	Impairment of Long‑lived Assets We review our long‑lived assets for impairment when changes in circumstances indicate that the carrying amount of an asset may not be recoverable. ASC 360 — Property, Plant and Equipment requires an impairment loss to be recognized if the carrying amount of a long‑lived asset is not recoverable and exceeds its fair value. The carrying amount of a long‑lived asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. That assessment shall be based on the carrying amount of the asset at the date it is tested for recoverability, whether in use or under development. Assets to be disposed of and assets not expected to provide any future service potential to us are recorded at the lower of carrying amount or fair value. Oil and gas properties are grouped in accordance with ASC 932 — Extractive Activities-Oil and Gas. The basis for grouping is a reasonable aggregation of properties typically by field or by logical grouping of assets with significant shared infrastructure. For long-lived assets whereby the carrying value exceeds the estimated future undiscounted cash flows, the carrying amount is reduced to fair value. Fair value is generally estimated using the income approach described in the ASC 820 — Fair Value Measurement. If applicable, we utilize prices and other relevant information generated by market transactions involving assets and liabilities that are identical or comparable to the item being measured as the basis for determining fair value. The expected future cash flows used for impairment reviews and related fair value measurements are typically based on judgmental assessments of future production, pricing estimates, capital and operating costs, market-based weighted average cost of capital, and risk adjustment factors applied to reserves. These assumptions are applied to develop future cash flow projections that are then discounted to estimated fair value, using a market-based weighted-average cost of capital. Although we base the fair value estimate of each asset group on assumptions we believe to be reasonable, those assumptions are inherently unpredictable and uncertain, and actual results could differ from the estimate. Negative revisions of estimated reserve quantities, increases in future cost estimates, divestiture of a significant component of the asset group, or sustained decreases in crude oil prices could lead to a reduction in expected future cash flows and possibly an additional impairment of long-lived assets in future periods.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging ActivitiesWe utilize oil derivative contracts to mitigate our exposure to commodity price risk associated with our anticipated future oil production. These derivative contracts consist of collars, put options, call options and swaps. We also have used interest rate derivative contracts to mitigate our exposure to interest rate fluctuations related to our long‑term debt. Our derivative financial instruments are recorded on the balance sheet as either assets or liabilities and are measured at fair value. We do not apply hedge accounting to our derivative contracts.
Estimates of Proved Oil and Natural Gas Reserves	Estimates of Proved Oil and Natural Gas Reserves Reserve quantities and the related estimates of future net cash flows affect our periodic calculations of depletion and assessment of impairment of our oil and natural gas properties. Proved oil and natural gas reserves are the estimated quantities of crude oil, natural gas and natural gas liquids that geological and engineering data demonstrate with reasonable certainty to be recoverable in future periods from known reservoirs under existing economic and operating conditions. As additional proved reserves are discovered, reserve quantities and future cash flows will be estimated by independent petroleum consultants and prepared in accordance with guidelines established by the SEC and the FASB. The accuracy of these reserve estimates is a function of: • the engineering and geological interpretation of available data; • estimates of the amount and timing of future operating cost, production taxes, development cost and workover cost; • the accuracy of various mandated economic assumptions; and • the judgments of the persons preparing the estimates.
Revenue Recognition	Revenue Recognition We recognize revenues on the volumes of hydrocarbons sold to a purchaser. The volumes sold may be more or less than the volumes to which we are entitled based on our ownership interest in the property. These differences result in a condition known in the industry as a production imbalance. A receivable or liability is recognized only to the extent that we have an imbalance on a specific property greater than the expected remaining proved reserves on such property. As of December 31, 2020 and 2019, we had no oil and gas imbalances recorded in our consolidated financial statements. Our oil and gas revenues are recognized when hydrocarbons have been sold to a purchaser at a fixed or determinable price, title has transferred and collection is probable. Certain revenues are based on provisional price contracts which contain an embedded derivative that is required to be separated from the host contract for accounting purposes. The host contract is the receivable from oil sales at the spot price on the date of sale. The embedded derivative, which is not designated as a hedge, is marked to market through oil and gas revenue each period until the final settlement occurs, which generally is limited to the month after the sale.
Equity-based Compensation	Equity‑based Compensation For equity‑based compensation awards, compensation expense is recognized in the Company’s financial statements over the awards’ vesting periods based on their grant date fair value. The Company utilizes (i) the closing stock price on the date of grant to determine the fair value of service vesting restricted stock awards and restricted stock units and (ii) a Monte Carlo simulation to determine the fair value of restricted stock awards and restricted stock units with a combination of market and service vesting criteria. Forfeitures are recognized in the period in which they occur.
Restructuring Charges	Restructuring Charges The Company accounts for restructuring charges and related termination benefits in accordance with ASC 712-Compensation-Nonretirement Postemployment Benefits. Under this standard, the costs associated with termination benefits are recorded during the period in which the liability is incurred. During the years ended December 31, 2020 and 2019, we
Treasury Stock	Treasury Stock We record treasury stock purchases at cost. Our treasury purchases are from our employees that surrendered shares to the Company to satisfy their statutory tax withholding requirements and are not part of a formal stock repurchase plan. Our treasury stock consists of a share repurchase in 2018 and forfeited restricted stock awards granted under our long‑term incentive plan.
Income Taxes	Income Taxes The Company accounts for income taxes as required by ASC 740—Income Taxes. Under this method, deferred income taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. On a quarterly basis, management evaluates the need for and adequacy of valuation allowances based on the expected realizability of the deferred tax assets and adjusts the amount of such allowances, if necessary. We recognize tax benefits from uncertain tax positions only if it is more likely than not that the tax position will be sustained upon examination by the tax authorities, based on the technical merits of the position. Accordingly, we measure tax benefits from such positions based on the most likely outcome to be realized.
Foreign Currency Translation	Foreign Currency Translation The U.S. dollar is the functional currency for all of the Company’s material foreign operations. Foreign currency transaction gains and losses and adjustments resulting from translating monetary assets and liabilities denominated in foreign currencies are included in other expenses. Cash balances held in foreign currencies are not significant, and as such, the effect of exchange rate changes is not material to any reporting period.
Concentration of Credit Risk	Concentration of Credit RiskOur revenue can be materially affected by current economic conditions and the price of oil. However, based on the current demand for crude oil and the fact that alternative purchasers are readily available, we believe that the loss of our marketing agent and/or any of the purchasers identified by our marketing agent would not have a long‑term material adverse effect on our financial position or results of international operations. For our U.S. Gulf of Mexico operations, crude oil and natural gas are transported to customers using third-party pipelines.
Recent Accounting Standards	Recent Accounting Standards Recently Adopted In June 2016, ASU 2016-13, "Measurement of Credit Losses on Financial Instruments," was issued requiring measurement of all expected credit losses for certain types of financial instruments, including trade receivables, held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. This standard was effective January 1, 2020. We assessed all receivable positions for expected credit losses through the implementation of ASU 2016-13, current expected credit loss standard (CECL). Our receivables are collectible in the original term of the underlying agreements and current expected credit losses under the CECL standard are not significant. Not Yet Adopted

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of cash and cash equivalents	December 31, 2020 2019 2018 (In thousands) Cash and cash equivalents $ 149,027 $ 224,502 $ 173,515 Restricted cash - current 195 4,302 4,527 Restricted cash - long-term 542 542 7,574 Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows $ 149,764 $ 229,346 $ 185,616
Schedule of estimated useful lives of other property	Depreciation and amortization of other property is computed using the straight-line method over the assets’ estimated useful lives (not to exceed the lease term for leasehold improvements), ranging from one Years Leasehold improvements 1 to 8 Office furniture, fixtures and computer equipment 3 to 7 Vehicles 5
Schedule of oil and gas revenue	Oil and gas revenue is composed of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Revenues from contract with customer - Equatorial Guinea $ 149,033 $ 297,831 $ — Revenues from contract with customer - Ghana 375,603 740,464 741,033 Revenues from contract with customers - U.S. Gulf of Mexico 285,017 459,960 147,596 Provisional oil sales contracts (5,620) 1,161 (1,963) Oil and gas revenue $ 804,033 $ 1,499,416 $ 886,666

Acquisitions and Divestitures (

Acquisitions and Divestitures (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	Purchase Price Allocation (in thousands) Fair value of assets acquired: Proved oil and gas properties $ 1,037,511 Unproved oil and gas properties 298,159 Accounts receivable and other 180,989 Total assets acquired $ 1,516,659 Fair value of liabilities assumed: Accrued liabilities and other $ 126,530 Asset retirement obligations 74,482 Derivative liabilities 40,265 Total liabilities assumed $ 241,277 Purchase price: Cash consideration paid $ 952,586 Fair value of common stock(1) 307,944 Transaction related costs 14,852 Total purchase price $ 1,275,382 ______________________________________ (1) Based on 34,993,585 shares of common stock issued at a price of $8.80 per share, which was the opening Kosmos common stock price on September 14, 2018, the closing date of the acquisition.

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of property and equipment	Property and equipment is stated at cost and consisted of the following: December 31, 2020 2019 (In thousands) Oil and gas properties: Proved properties $ 5,369,737 $ 4,904,648 Unproved properties 495,390 814,065 Total oil and gas properties 5,865,127 5,718,713 Accumulated depletion (2,554,851) (2,093,962) Oil and gas properties, net 3,310,276 3,624,751 Other property 59,949 61,598 Accumulated depreciation (49,312) (44,017) Other property, net 10,637 17,581 Property and equipment, net $ 3,320,913 $ 3,642,332

Suspended Well Costs (Tables)

Suspended Well Costs (Tables)	12 Months Ended
	Dec. 31, 2020
Oil and Gas Exploration and Production Industries Disclosures [Abstract]
Schedule of capitalized exploratory well costs	The following table reflects the Company’s capitalized exploratory well costs on drilled wells as of and during the years ended December 31, 2020, 2019 and 2018. Years Ended December 31, 2020 2019 2018 (In thousands) Beginning balance $ 445,790 $ 367,665 $ 410,113 Additions to capitalized exploratory well costs pending the determination of proved reserves 4,001 78,125 10,518 Additions associated with the acquisition of DGE — — 26,224 Reclassification due to determination of proved reserves(1) (263,502) — (26,224) Capitalized exploratory well costs charged to expense(2) — — (52,966) Ending balance $ 186,289 $ 445,790 $ 367,665 ______________________________________ (1) Represents the reclassification of exploratory well costs associated with the Greater Tortue Ahmeyim Unit as a result of the execution of the Tortue Phase 1 SPA in February 2020 and Nearly Headless Nick well costs associated with the DGE acquisition in 2018. As of December 31, 2020, due to pricing revisions related to the decrease in commodity prices during the year the Greater Tortue Ahmeyim Unit did not have proved reserves recognition. (2) Primarily related to Akasa and Wawa wells as we wrote off $38.1 million and $13.6 million, respectively, of previously capitalized exploratory well costs to exploration expense during the third quarter of 2018. These impairments are included in our Ghana segment.
Schedule of aging of capitalized exploratory well costs and number of projects for which exploratory well costs were capitalized for more than one year	The following table provides 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: Years Ended December 31, 2020 2019 2018 (In thousands, except well counts) Exploratory well costs capitalized for a period of one year or less $ — $ 29,121 $ — Exploratory well costs capitalized for a period of one to two years 28,692 78,245 299,253 Exploratory well costs capitalized for a period of three years or longer 157,597 338,424 68,412 Ending balance $ 186,289 $ 445,790 $ 367,665 Number of projects that have exploratory well costs that have been capitalized for a period greater than one year 3 3 3

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of components of lease cost	The components of lease cost for the years ended December 31, 2020 and 2019 is as follows: December 31, 2020 2019 (In thousands) Operating lease cost $ 5,869 $ 5,480 Short-term lease cost(1) 13,705 15,874 Total lease cost $ 19,574 $ 21,354 __________________________________ (1) Includes $12.6 million and $13.9 million during the years ended December 31, 2020 and 2019, respectively, of costs associated with short-term drilling contracts. The table below presents supplemental cash flow information related to leases during the years ended December 31, 2020 and 2019: December 31, 2020 2019 (In thousands) Operating cash flows for operating leases $ 5,225 $ 5,082 Investing cash flows for operating leases(1) 12,586 13,855 __________________________________ (1) Represents costs associated with short-term drilling contracts.
Schedule of other information leases	Other information related to operating leases at December 31, 2020 and 2019, is as follows: December 31 2020 2019 (In thousands, except lease term and discount rate) Balance sheet classifications Other assets (right-of-use assets) $ 19,799 $ 20,008 Accrued liabilities (current maturities of leases) 1,405 1,139 Other long-term liabilities (non-current maturities of leases) 22,771 22,240 Weighted average remaining lease term 8.4 years 8.8 years Weighted average discount rate 9.8 % 9.8 %
Schedule of future minimum rental commitments	Future minimum rental commitments under our leases at December 31, 2020, are as follows: Operating Leases(1) (In thousands) 2021 $ 3,307 2022 4,216 2023 4,287 2024 4,358 2025 4,429 Thereafter 15,470 Total undiscounted lease payments $ 36,067 Less: Imputed interest (11,891) Total lease liabilities $ 24,176 __________________________________ (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.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of debt	December 31, 2020 2019 (In thousands) Outstanding debt principal balances: Facility $ 1,200,000 $ 1,400,000 Corporate Revolver 100,000 — Senior Notes 650,000 650,000 GoM Term Loan 200,000 — Total 2,150,000 2,050,000 Unamortized deferred financing costs and discounts(1) (38,569) (41,937) Total debt, net 2,111,431 2,008,063 Less: Current maturities of long-term debt (7,500) — Long-term debt, net $ 2,103,931 $ 2,008,063 ________________________________________ (1) Includes $25.6 million and $32.8 million of unamortized deferred financing costs related to the Facility; $8.4 million and $9.1 million of unamortized deferred financing costs and discounts related to the Senior Notes; and $4.6 million and zero of unamortized deferred financing costs related to the GoM Term Loan as of December 31, 2020 and December 31, 2019, respectively.
Schedule of redemption price	On or after April 4, 2022, 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 April 4, 2022, but before April 4, 2023 103.6 % On or after April 4, 2023, but before April 4, 2024 101.8 % On or after April 4, 2024 and thereafter 100.0 %
Schedule of estimated repayments of debt	At December 31, 2020, the estimated repayments of debt during the five years and thereafter are as follows: Payments Due by Year Total 2021 2022 2023 2024 2025 Thereafter (In thousands) Principal debt repayments(1) $ 2,150,000 $ 7,500 $ 258,571 $ 458,571 $ 458,572 $ 316,786 $ 650,000 _______________________________________ (1) Includes the scheduled maturities for the $650.0 million aggregate principal amount of Senior Notes and borrowings under the Facility, Corporate Revolver and GoM Term Loan. The scheduled maturities of debt related to the Facility as of December 31, 2020 are based on our level of borrowings and our estimated future available borrowing base commitment levels in future periods. Any increases or decreases in the level of borrowings or increases or decreases in the available borrowing base would impact the scheduled maturities of debt during the next five years and thereafter.
Schedule of interest and other financing costs, net	Interest and other financing costs, net incurred during the period comprised of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Interest expense $ 119,857 $ 145,507 $ 114,134 Amortization—deferred financing costs 9,347 9,257 9,379 Loss on extinguishment of debt 2,902 24,794 4,324 Capitalized interest (25,013) (28,077) (28,331) Deferred interest 2,402 1,919 (1,138) Interest income (4,773) (3,692) (3,455) Other, net 5,072 5,366 6,263 Interest and other financing costs, net $ 109,794 $ 155,074 $ 101,176

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
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 prices per Bbl for those contracts as of December 31, 2020. Volumes and weighted average prices are net of any offsetting derivative contracts entered into. Weighted Average Price per Bbl Term Type of Contract Index MBbl Net Deferred Premium Payable/(Receivable) Swap Sold Put Floor Ceiling 2021: January — December Swaps with sold puts Dated Brent 6,000 $ — $ 53.96 $ 42.92 $ — $ — January — June Swaps with sold puts NYMEX WTI 1,000 — 47.75 37.50 — — January — December Three-way collars Dated Brent 4,000 0.34 — 33.13 40.63 52.60 January — December Three-way collars NYMEX WTI 1,000 1.00 — 37.50 45.00 55.00 January — December Sold calls(1) Dated Brent 7,000 — — — — 70.09 2022: January — December Sold calls(1) Dated Brent 1,581 — — — — 60.00 ______________________________________ (1) Represents call option contracts sold to counterparties to enhance other derivative positions.
Schedule of derivative instruments by balance sheet location	The following tables disclose the Company’s derivative instruments as of December 31, 2020 and 2019 and gain/(loss) from derivatives during the years ended December 31, 2020, 2019 and 2018. Estimated Fair Value Asset (Liability) December 31, Type of Contract Balance Sheet Location 2020 2019 (In thousands) Derivatives not designated as hedging instruments: Derivative assets: Commodity Derivatives assets—current $ 15,414 $ 12,856 Provisional oil sales Receivables: Oil sales (677) (3,287) Commodity Derivatives assets—long-term 964 2,302 Derivative liabilities: Commodity Derivatives liabilities—current (28,009) (8,914) Commodity Derivatives liabilities—long-term (8,069) (11,478) Total derivatives not designated as hedging instruments $ (20,377) $ (8,521)
Schedule of derivative instruments by location of gain/(loss)	Amount of Gain/(Loss) Years Ended December 31, Type of Contract Location of Gain/(Loss) 2020 2019 2018 (In thousands) Derivatives not designated as hedging instruments: Commodity(1) Oil and gas revenue $ (5,620) $ 1,161 $ (1,963) Commodity Derivatives, net (17,180) (71,885) 31,430 Interest rate Interest expense — — 493 Total derivatives not designated as hedging instruments $ (22,800) $ (70,724) $ 29,960 ______________________________________ (1) Amounts represent the change in fair value of our provisional oil sales contracts.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of company's assets and liabilities that are measured at fair value on a recurring basis	The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2020 and 2019, for each fair value hierarchy level: Fair Value Measurements Using: Quoted Prices in Active Markets for Identical Assets Significant Other Significant Unobservable Inputs (Level 1) (Level 2) (Level 3) Total (In thousands) December 31, 2020 Assets: Commodity derivatives $ — $ 16,378 $ — $ 16,378 Provisional oil sales — (677) — (677) Liabilities: Commodity derivatives — (36,078) — (36,078) Total $ — $ (20,377) $ — $ (20,377) December 31, 2019 Assets: Commodity derivatives $ — $ 15,158 $ — $ 15,158 Provisional oil sales — (3,287) — (3,287) Liabilities: Commodity derivatives — (20,392) — (20,392) Total $ — $ (8,521) $ — $ (8,521)
Schedule of carrying values and fair values of financial instruments that are not carried at fair value	The following table presents the carrying values and fair values at December 31, 2020 and 2019: December 31, 2020 December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value (In thousands) Senior Notes $ 643,524 $ 613,412 $ 642,550 $ 664,957 GoM Term Loan 200,000 200,000 — — Corporate Revolver 100,000 100,000 — — Facility 1,200,000 1,200,000 1,400,000 1,400,000 Total $ 2,143,524 $ 2,113,412 $ 2,042,550 $ 2,064,957

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]
Schedule of changes in asset retirement obligations	The following table summarizes the changes in the Company’s asset retirement obligations: December 31, 2020 2019 (In thousands) Asset retirement obligations: Beginning asset retirement obligations $ 235,053 $ 151,953 Additions associated with Equatorial Guinea - Ceiba Field and Okume Complex — 114,395 Liabilities incurred during period 3,436 11,218 Liabilities settled during period (2,782) (7,156) Revisions in estimated retirement obligations (3,736) (49,471) Accretion expense 19,450 14,114 Ending asset retirement obligations $ 251,421 $ 235,053

Equity-based Compensation (Tabl

Equity-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of plan activity	The following table reflects the outstanding restricted stock awards as of December 31, 2020: Service Vesting Restricted Stock Awards Weighted- Average Grant-Date Fair Value Market / Service Vesting Restricted Stock Awards Weighted- Average Grant-Date Fair Value (In thousands) (In thousands) Outstanding at December 31, 2017: 220 $ 8.64 — $ — Granted — — — — Forfeited — — — — Vested (220) 8.64 — — Outstanding at December 31, 2018: — — — — There has been no additional restricted stock activity subsequent to December 31, 2018. The following table reflects the outstanding restricted stock units as of December 31, 2020: Service Vesting Weighted- Average Grant-Date Fair Value Market / Service Vesting Restricted Stock Units Weighted-Average Grant-Date Fair Value (In thousands) (In thousands) Outstanding at December 31, 2017: 4,183 $ 6.39 8,452 $ 11.26 Granted 2,402 7.07 8,111 12.38 Forfeited (229) 6.40 (302) 8.95 Vested (2,241) 6.95 (9,545) 13.75 Outstanding at December 31, 2018: 4,115 6.42 6,716 9.02 Granted 3,228 5.01 3,195 6.02 Forfeited (591) 5.90 (813) 7.93 Vested (2,021) 5.95 (1,300) 6.32 Outstanding at December 31, 2019: 4,731 5.71 7,798 8.42 Granted 3,481 5.48 3,394 8.37 Forfeited (1,187) 6.12 (726) 8.03 Vested (2,185) 5.91 (2,607) 9.47 Outstanding at December 31, 2020: 4,840 5.34 7,859 8.11

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of components of income (loss) before income taxes	The components of loss before income taxes were as follows: Years Ended December 31, 2020 2019 2018 (In thousands) United States $ (338,746) $ (149,919) $ 41,026 Bermuda — — (73,979) Foreign—other (78,049) 175,036 (17,907) Income (loss) before income taxes $ (416,795) $ 25,117 $ (50,860)
Schedule of components of the provision for income taxes attributable to the entity's income (loss) before income taxes	The components of the provision for income taxes attributable to our income (loss) before income taxes consist of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Current: United States $ (12,208) $ 185 $ 122 Bermuda — — — Foreign—other 49,586 171,079 33,864 Total current 37,378 171,264 33,986 Deferred: United States 34,831 (18,776) 8,514 Bermuda — — — Foreign—other (77,418) (71,594) 631 Total deferred (42,587) (90,370) 9,145 Income tax expense (benefit) $ (5,209) $ 80,894 $ 43,131
Schedule of reconciliation of income tax expense and the reported effective tax rate	Our reconciliation of income tax expense (benefit) computed by applying our statutory rate and the reported effective tax rate on income or (loss) from continuing operations is as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Tax at statutory rate(1) $ (87,527) $ 5,275 $ (10,681) Foreign income (loss) taxed at different rates (1,771) 32,690 5,013 Net non-taxable expense / insurance recoveries — (13,352) 3,256 West Leo arbitration settlement — — (2,834) Non-deductible insurance premiums — 2,625 — Non-deductible compensation 890 3,545 2,643 Deferred tax liability - undistributed earnings — — (2,565) Non-deductible and other items 387 3,998 656 Equity earnings - net of tax — — (15,305) Tax shortfall (windfall) on equity-based compensation, net 1,175 1,224 (387) Change in valuation allowance 86,539 44,889 63,335 U.S. tax loss carryback rate differential (4,902) — — Total tax expense $ (5,209) $ 80,894 $ 43,131 Effective tax rate(2) 1 % 322 % 85 % ______________________________________ (1) On December 28, 2018, we changed our jurisdiction of incorporation from Bermuda to the State of Delaware. Kosmos Energy Ltd. discontinued as a Bermuda exempted company pursuant to Section 132G of the Companies Act 1981 of Bermuda and, pursuant to Section 265 of the General Corporation Law of the State of Delaware (the “DGCL”), continued its existence under the DGCL as a corporation organized in the State of Delaware. As a result, the statutory tax rate for the 2020, 2019 and 2018 reconciliation of income tax expense is the U.S. statutory tax rate of 21%.
Schedule of tax effects of significant temporary differences to deferred tax assets and liabilities	The tax effects of significant temporary differences giving rise to deferred tax assets and liabilities are as follows: December 31, 2020 2019 (In thousands) Deferred tax assets: Foreign capitalized operating expenses $ 152,106 $ 175,330 Foreign net operating losses 32,762 19,576 United States net operating losses 113,427 58,903 United States deferred interest expense — 15,426 Equity compensation 14,089 13,700 Unrealized derivative losses 3,482 1,471 Asset retirement obligation and other 41,759 43,159 Total deferred tax assets 357,625 327,565 Valuation allowance (288,288) (201,749) Total deferred tax assets, net 69,337 125,816 Deferred tax liabilities: Depletion, depreciation and amortization related to property and equipment (642,956) (746,258) Unrealized derivative gains — — Total deferred tax liabilities (642,956) (746,258) Net deferred tax liability $ (573,619) $ (620,442)

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of reconciliation between net income (loss) and the amounts used to compute basic and diluted net income (loss) per share and the weighted average shares outstanding used to compute basic and diluted net income (loss) per share	Years Ended December 31, 2020 2019 2018 (In thousands, except per share data) Numerator: Net loss allocable to common stockholders $ (411,586) $ (55,777) $ (93,991) Denominator: Weighted average number of shares outstanding: Basic 405,212 401,368 404,585 Restricted stock awards and units(1)(2) — — — Diluted 405,212 401,368 404,585 Net loss per share: Basic $ (1.02) $ (0.14) $ (0.23) Diluted $ (1.02) $ (0.14) $ (0.23) ______________________________________ (1) Our service vesting restricted stock awards represent participating securities because they participate in non-forfeitable 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 (loss) per share calculation. Our service vesting restricted stock awards do not participate in undistributed net losses because they are not contractually obligated to do so and, therefore, are excluded from the basic net income (loss) per share calculation in periods we are in a net loss position. All restricted stock awards were fully vested in January 2018. (2) For the years ended December 31, 2020, 2019 and 2018, we excluded 6.1 million, 15.3 million and 10.6 million outstanding restricted stock awards and restricted stock units, respectively, from the computations of diluted net income per share because the effect would have been anti‑dilutive. All restricted stock awards were fully vested in January 2018.

Additional Financial Informat_2

Additional Financial Information (Tables)	12 Months Ended
	Dec. 31, 2020
Additional Financial Information
Schedule of accrued liabilities	Accrued liabilities consisted of the following: December 31, 2020 2019 (In thousands) Accrued liabilities: Exploration, development and production $ 89,162 $ 152,490 Revenue payable 15,079 32,482 Current asset retirement obligations 7,255 4,527 General and administrative expenses 4,988 44,575 Interest 23,725 33,584 Income taxes 37,344 103,566 Taxes other than income 2,815 3,375 Derivatives 17,475 4,837 Other 5,417 1,268 $ 203,260 $ 380,704
Schedule of other expenses, net incurred	Other expenses, net incurred during the period is comprised of the following: Years Ended December 31, 2020 2019 2018 (In thousands) Loss on disposal of inventory $ 8,607 $ 4,590 $ 280 Gain on insurance settlements — (3,509) — Loss on asset retirement obligations liability settlements 1,966 193 — Restructuring charges 16,474 11,528 — Other, net 10,755 11,846 (6,781) Other expenses, net $ 37,802 $ 24,648 $ (6,501)
Summary of financial information of KTIPI	Below is a summary of financial information for KTIPI presented on a 100% basis for 2018. The financial information for 2019 is presented as part of our consolidated financial statements based on our direct 40.375% ownership in the Ceiba Field and Okume Complex. December 31, 2018 (In thousands) Assets Total current assets $ 149,950 Property and equipment, net 271,627 Other assets 21 Total assets $ 421,598 Liabilities and shareholders' deficit Total current liabilities $ 226,311 Total long term liabilities 536,178 Shareholders' deficit: Total shareholders' deficit (340,891) Total liabilities and shareholders' deficit $ 421,598 Year Ended December 31, 2018 (In thousands) Revenues and other income: Oil and gas revenue $ 721,299 Other income (477) Total revenues and other income 720,822 Costs and expenses: Oil and gas production 147,685 Depletion and depreciation 126,983 Other expenses, net 429 Total costs and expenses 275,097 Income before income taxes 445,725 Income tax expense 156,981 Net income $ 288,744 Kosmos' share of net income $ 144,372 Basis difference amortization(1) 71,491 Equity in earnings - KTIPI $ 72,881 ______________________________________ (1) The basis difference, which is associated with oil and gas properties and subject to amortization, has been allocated to the Ceiba Field and Okume Complex. We amortize the basis difference using the unit-of-production method.
Schedule of Asset Acquisitions	The estimated fair value measurements of oil and gas assets acquired and liabilities assumed are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair value of oil and gas properties and asset retirement obligations were measured using the discounted cash flow technique of valuation. Significant inputs to the valuation of oil and gas properties include estimates of: (i) reserves, (ii) future operating and development costs, (iii) future commodity prices, (iv) future plugging and abandonment costs, (v) estimated future cash flows, and (vi) a market-based weighted average cost of capital rate. Carrying Value Allocation (in thousands) Assets acquired: Proved oil and gas properties $ 372,144 Unproved oil and gas properties 103,909 Prepaids and other 7,273 Total assets acquired $ 483,326 Liabilities assumed: Asset retirement obligations $ 114,395 Deferred tax liabilities 247,636 Accrued liabilities and other 69,399 Total liabilities assumed $ 431,430 Carrying value: Equity method investment carrying value at December 31, 2018 $ 51,896

Business Segment Information (T

Business Segment Information (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Schedule of Business Segment Information	Ghana Equatorial Guinea Mauritania / Senegal U.S. Gulf of Mexico Corporate & Other Eliminations Total (in thousands) Year ended December 31, 2020 Revenues and other income: Oil and gas revenue 366,515 $ 152,501 $ — $ 285,017 $ — $ — $ 804,033 Gain on sale of assets — — — 84 92,079 — 92,163 Other income, net 2 — — 280 120,135 (120,415) 2 Total revenues and other income 366,517 152,501 — 285,381 212,214 (120,415) 896,198 Costs and expenses: Oil and gas production 169,357 80,813 — 88,307 — — 338,477 Facilities insurance modifications, net 13,161 — — — — — 13,161 Exploration expenses 182 8,290 8,189 26,792 41,163 — 84,616 General and administrative 13,506 4,865 7,464 12,607 129,801 (96,101) 72,142 Depletion, depreciation and amortization 235,772 64,786 61 181,898 3,345 — 485,862 Impairment of long-lived assets — — — 153,959 — — 153,959 Interest and other financing costs, net(1) 54,530 (1,248) (27,339) 17,373 73,612 (7,134) 109,794 Derivatives, net — — — — 17,180 — 17,180 Other expenses, net (27,925) 2,281 4,829 54,485 21,312 (17,180) 37,802 Total costs and expenses 458,583 159,787 (6,796) 535,421 286,413 (120,415) 1,312,993 Income (loss) before income taxes (92,066) (7,286) 6,796 (250,040) (74,199) — (416,795) Income tax expense (benefit) (30,486) 2,428 — 26,061 (3,212) — (5,209) Net income (loss) $ (61,580) $ (9,714) $ 6,796 $ (276,101) $ (70,987) $ — $ (411,586) Consolidated capital expenditures $ 44,146 $ 38,126 $ 126,803 $ 123,197 $ (58,293) $ — $ 273,979 As of December 31, 2020 Property and equipment, net $ 1,293,372 $ 426,365 $ 580,920 $ 998,204 $ 22,052 $ — $ 3,320,913 Total assets $ 1,397,802 $ 689,222 $ 823,411 $ 3,171,851 $ 12,654,827 $ (14,869,520) $ 3,867,593 ______________________________________ (1) Interest expense is recorded based on actual third-party and intercompany debt agreements. Capitalized interest is recorded on the business unit where the assets reside. Ghana Equatorial Guinea Mauritania / Senegal U.S. Gulf of Mexico Corporate & Other Eliminations Total (in thousands) Year ended December 31, 2019 Revenues and other income: Oil and gas revenue $ 738,909 $ 300,547 $ — $ 459,960 $ — $ — $ 1,499,416 Gain on sale of assets — — — — 10,528 — 10,528 Other income, net 5 — — 1,194 155,866 (157,100) (35) Total revenues and other income 738,914 300,547 — 461,154 166,394 (157,100) 1,509,909 Costs and expenses: Oil and gas production 188,207 90,607 — 123,799 — — 402,613 Facilities insurance modifications, net (24,254) — — — — — (24,254) Exploration expenses 204 13,350 11,181 115,765 40,455 — 180,955 General and administrative 18,618 6,643 8,222 25,456 159,539 (108,468) 110,010 Depletion, depreciation and amortization 268,866 75,565 62 214,592 4,776 — 563,861 Interest and other financing costs, net(1) 72,226 (634) (26,537) 21,266 95,887 (7,134) 155,074 Derivatives, net — — — 30,387 41,498 — 71,885 Other expenses, net 40,382 (563) 12,056 2,691 11,580 (41,498) 24,648 Total costs and expenses 564,249 184,968 4,984 533,956 353,735 (157,100) 1,484,792 Income (loss) before income taxes 174,665 115,579 (4,984) (72,802) (187,341) — 25,117 Income tax expense (benefit) 50,293 49,192 — (8,419) (10,172) — 80,894 Net income (loss) $ 124,372 $ 66,387 $ (4,984) $ (64,383) $ (177,169) $ — $ (55,777) Consolidated capital expenditures $ 98,285 $ 63,798 $ 12,556 $ 232,891 $ 33,206 $ — $ 440,736 As of December 31, 2019 Property and equipment, net $ 1,487,114 $ 464,420 $ 438,800 $ 1,216,453 $ 35,545 $ — $ 3,642,332 Total assets $ 1,654,266 $ 650,607 $ 581,317 $ 3,251,420 $ 12,144,312 $ (13,964,690) $ 4,317,232 ______________________________________ (1) Interest expense is recorded based on actual third-party and intercompany debt agreements. Capitalized interest is recorded on the business unit where the assets reside. Ghana Equatorial Guinea(1) Mauritania / Senegal U.S. Gulf of Mexico(2) Corporate & Other Eliminations(3) Total (in thousands) Year ended December 31, 2018 Revenues and other income: Oil and gas revenue $ 739,070 $ 360,649 $ — $ 147,596 $ — $ (360,649) $ 886,666 Gain on sale of assets — 7,666 — — — — 7,666 Other income, net (17) (238) — 11 150,635 (142,354) 8,037 Total revenues and other income 739,053 368,077 — 147,607 150,635 (503,003) 902,369 Costs and expenses: Oil and gas production 189,104 73,843 — 30,470 5,153 (73,843) 224,727 Facilities insurance modifications, net 6,955 — — — — — 6,955 Exploration expenses 58,276 38,164 7,262 66,962 131,180 (352) 301,492 General and administrative 19,342 5,351 5,220 10,534 168,542 (109,133) 99,856 Depletion, depreciation and amortization 265,805 134,983 61 59,835 4,134 (134,983) 329,835 Interest and other financing costs, net(4) 86,738 (12) (25,386) 7,487 39,483 (7,134) 101,176 Derivatives, net — — — (57,615) 26,185 — (31,430) Gain on equity method investments, net — — — — — (72,881) (72,881) Other expenses, net 16,414 (814) (23) 598 3,510 (26,186) (6,501) Total costs and expenses 642,634 251,515 (12,866) 118,271 378,187 (424,512) 953,229 Income (loss) before income taxes 96,419 116,562 12,866 29,336 (227,552) (78,491) (50,860) Income tax expense (benefit) 34,494 78,491 — 6,163 2,474 (78,491) 43,131 Net income (loss) $ 61,925 $ 38,071 $ 12,866 $ 23,173 $ (230,026) $ — $ (93,991) Consolidated capital expenditures $ 105,942 $ 32,156 $ 11,962 $ 95,993 $ 139,381 $ — $ 385,434 As of December 31, 2018 Property and equipment, net $ 1,698,194 $ 3,919 $ 411,448 $ 1,308,670 $ 37,470 $ — $ 3,459,701 Total assets $ 1,930,071 $ 55,302 $ 536,620 $ 3,512,989 $ 10,349,488 $ (12,296,281) $ 4,088,189 ______________________________________ (1) Includes our proportionate share of our equity method investment in KTIPI, including our basis difference which is reflected in depletion, depreciation and amortization for the year ended December 31, 2018, except for capital expenditures. See Note 16 - Additional Financial Information for additional information regarding our equity method investments. (2) Represents activity commencing September 14, 2018, the DGE acquisition date. (3) Includes elimination of proportionate consolidation amounts recorded for KTIPI to reconcile to (Gain) loss on equity method investments, net as reported in the consolidated statements of operations. (4) Interest expense is recorded based on actual third-party and intercompany debt agreements. Capitalized interest is recorded on the business unit where the assets reside. Years Ended December 31, 2020 2019 2018 (In thousands) Consolidated capital expenditures: Consolidated Statements of Cash Flows - Investing activities: Oil and gas assets $ 377,491 $ 340,217 $ 213,806 Other property 2,102 11,796 7,935 Adjustments: Changes in capital accruals (42,315) 33,717 26,669 Exploration expense, excluding unsuccessful well costs and leasehold impairments(1) 61,459 93,142 178,293 Capitalized interest (25,013) (28,077) (28,331) Proceeds on sale of assets (99,337) (16,713) (13,703) Other (408) 6,654 765 Total consolidated capital expenditures $ 273,979 $ 440,736 $ 385,434 ______________________________________ (1) Unsuccessful well costs are included in oil and gas assets when incurred.

Supplemental Quarterly Financ_2

Supplemental Quarterly Financial Information (Unaudited) (Table)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of Supplemental Quarterly Financial Information (Unaudited)	Quarter Ended March 31, June 30, September 30, December 31, (In thousands, except per share data) 2020 Revenues and other income $ 177,781 $ 127,314 $ 224,787 $ 366,316 Costs and expenses 295,005 374,130 261,279 382,579 Net income (loss) (182,767) (199,391) (37,384) 7,956 Net income (loss) per share: Basic(1) (0.45) (0.49) (0.09) 0.02 Diluted(1) (0.45) (0.49) (0.09) 0.02 2019 Revenues and other income $ 296,790 $ 395,934 $ 356,970 $ 460,215 Costs and expenses 358,370 346,495 317,435 462,492 Net income (loss) (52,906) 16,837 16,065 (35,773) Net income (loss) per share: Basic(1) (0.13) 0.04 0.04 (0.09) Diluted(1) (0.13) 0.04 0.04 (0.09) _______________________________ (1) The sum of the quarterly earnings per share information may not add to the annual earnings per share information as a result of rounding.

Organization (Details)

Organization (Details)	12 Months Ended
	Dec. 31, 2020segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reportable geographic areas	4

Accounting Policies - Cash, Cas

Accounting Policies - Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 149,027	$ 224,502	$ 173,515
Restricted cash - current	195	4,302	4,527
Restricted cash - long-term	542	542	7,574
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$ 149,764	$ 229,346	$ 185,616	$ 304,986

Accounting Policies - Narrative

Accounting Policies - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2021	Jan. 01, 2019
Cash, Cash Equivalents and Restricted Cash
Restricted cash - current	$ 195,000	$ 4,302,000	$ 4,527,000
Restricted cash - long-term	542,000	542,000	7,574,000
Receivables
Allowance for doubtful accounts	5,700,000	2,700,000
Inventories
Materials and supplies inventory	127,500,000	112,300,000
Hydrocarbons inventory	1,500,000	2,100,000
Write down of materials and supplies	8,607,000	4,590,000	280,000
Leases
Operating lease asset	19,799,000	20,008,000
Lease liability	24,176,000
Revenue Recognition
Oil and gas imbalances	0	0
Restructuring Charges
Restructuring charges	$ 16,474,000	$ 11,528,000	$ 0
Accounting Standards Update 2016-02
Leases
Operating lease asset					$ 21,700,000
Lease liability					$ 21,700,000
Sales Revenue | Customer Concentration Risk
Concentration of Credit Risk
Concentration risk percentage	23.00%	20.00%	11.00%
Minimum
Depletion, Depreciation and Amortization
Estimated useful lives	1 year
Maximum
Depletion, Depreciation and Amortization
Estimated useful lives	8 years
Capitalized Interest | Minimum
Capitalized Interest
Expected construction period for capitalization of interest costs on major projects	1 year
Restricted Cash | Petroleum Agreements - Performance Guarantees
Cash, Cash Equivalents and Restricted Cash
Restricted cash - current	$ 200,000	$ 4,300,000
Restricted cash - long-term	300,000	300,000
Restricted Cash | Non-Petroleum Agreements
Cash, Cash Equivalents and Restricted Cash
Restricted cash - long-term	$ 200,000	$ 200,000
Facility
Cash, Cash Equivalents and Restricted Cash
Net leverage ratio	2.50
Facility Interest Or Senior Notes Plus The Corporate Revolver
Cash, Cash Equivalents and Restricted Cash
Period for contractual future interest payments	6 months
Facility Interest Or Senior Notes Plus The Corporate Revolver | Subsequent Event
Cash, Cash Equivalents and Restricted Cash
Restricted cash - current				$ 28,500,000
7.125% Senior Notes Due 2026
Cash, Cash Equivalents and Restricted Cash
Interest rate	7.125%

Accounting Policies - Useful Li

Accounting Policies - Useful Lives (Details)	12 Months Ended
	Dec. 31, 2020
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	1 year
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	8 years
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	1 year
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	8 years
Office furniture, fixtures and computer equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Office furniture, fixtures and computer equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	7 years
Vehicles
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years

Accounting Policies - Summary o

Accounting Policies - Summary of Oil and Gas Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Provisional oil sales contracts	$ (22,800)	$ (70,724)	$ 29,960
Oil and gas revenue	804,033	1,499,416	886,666
Equatorial Guinea
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	149,033	297,831	0
Ghana
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	375,603	740,464	741,033
Gulf of Mexico
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	285,017	459,960	147,596
Oil and Gas Revenue
Disaggregation of Revenue [Line Items]
Provisional oil sales contracts	(5,620)	1,161	(1,963)
Oil and gas revenue	$ 804,033	$ 1,499,416	$ 886,666

Acquisitions and Divestitures -

Acquisitions and Divestitures - 2020 Transactions (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2020USD ($)well
Acquisitions and Divestitures
Proceeds on sale of assets		$ 99,118	$ 15,000	$ 13,703
Gain on sale of assets		92,163	$ 10,528	$ 7,666
Farm Down Agreement | Blocks Offshore Sao Tome And Principe, Suriname, Namibia, And South Africa
Acquisitions and Divestitures
Amount of cash consideration to be received for frontier exploration portfolio					$ 96,000
Farm Down Agreement | Blocks Offshore Sao Tome and Principe Suriname and Namibia
Acquisitions and Divestitures
Future contingent consideration					$ 50,000
Proceeds on sale of assets	$ 95,000
Gain on sale of assets		92,100
Number of wells | well					4
Farm Down Agreement | Blocks Offshore Sao Tome and Principe Suriname and Namibia | Maximum
Acquisitions and Divestitures
Future contingent consideration					$ 100,000
Farm Down Agreement | South Africa
Acquisitions and Divestitures
Amount of cash consideration to be received for frontier exploration portfolio	$ 1,000	$ 1,000

Acquisitions and Divestitures_2

Acquisitions and Divestitures - 2019 Transactions (Details) $ in Thousands	1 Months Ended				12 Months Ended
	Nov. 30, 2019	Sep. 30, 2019km²meter	Mar. 31, 2019	Jun. 30, 2018km²	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Gain on sale of assets | $					$ 92,163	$ 10,528	$ 7,666
Block 11
Business Acquisition [Line Items]
Participating interest percentage	35.00%
Block 6
Business Acquisition [Line Items]
Participating interest percentage	25.00%
Farm-in Agreement | Block EG-24
Business Acquisition [Line Items]
Participation interest acquired			80.00%	40.00%
Area of petroleum exploration | km²				3,500
Initial exploration period				3 years
Farm-in Agreement | Block EG-24 | Guinea Equatorial De Petroleos
Business Acquisition [Line Items]
Carried participating interest			20.00%	20.00%
Percentage converted from carried to participating			20.00%	20.00%
Farm-in Agreement | Northern Cape Ultra Deep Block
Business Acquisition [Line Items]
Participation interest acquired		45.00%
Area of petroleum exploration | km²		6,930
Initial exploration period		2 years
Farm-in Agreement | Northern Cape Ultra Deep Block | Minimum
Business Acquisition [Line Items]
Water depths | meter		2,500
Farm-in Agreement | Northern Cape Ultra Deep Block | Maximum
Business Acquisition [Line Items]
Water depths | meter		3,100
Farm-out Agreement | Block 11 | Shell Sao Tome and Principe B.V.
Business Acquisition [Line Items]
Participating interest percentage	30.00%
Farm-out Agreement | Block 6 | Shell Sao Tome and Principe B.V.
Business Acquisition [Line Items]
Participating interest percentage	20.00%
Farm-out Agreement | Blocks 6 and 11
Business Acquisition [Line Items]
Gain on sale of assets | $						$ 10,500

Acquisitions and Divestitures_3

Acquisitions and Divestitures - 2018 Transactions Narrative (Details)	1 Months Ended					4 Months Ended
	Mar. 31, 2019	Oct. 31, 2018company	Sep. 30, 2018USD ($)	Jun. 30, 2018km²	Mar. 31, 2018km²block	Dec. 31, 2018USD ($)	Nov. 30, 2018USD ($)	Feb. 28, 2018USD ($)
Business Acquisition [Line Items]
Number of companies in alliance | company		2
Facility
Business Acquisition [Line Items]
Additional commitments						$ 100,000,000	$ 100,000,000	$ 500,000,000
Revolving Credit Facility | Facility
Business Acquisition [Line Items]
Additional commitments			$ 200,000,000
Deep Gulf Energy, LP
Business Acquisition [Line Items]
Total purchase price			1,275,382,000
Cash consideration paid			952,586,000
Fair value of common stock			307,944,000
Transaction related costs			14,852,000
Revenue of acquiree since acquisition date						147,600,000
Operating expenses of acquiree since acquisition date						$ 30,500,000
Deep Gulf Energy, LP | Common Stock
Business Acquisition [Line Items]
Fair value of common stock			$ 307,900,000
Blocks 10 and 13 | Petroleum Agreement
Business Acquisition [Line Items]
Participating interest percentage					35.00%
Area of petroleum exploration | km²					13,600
Initial exploration period					4 years
First sub exploration period					4 years
3D seismic requirements (in square kilometers) | km²					13,500
Number of blocks | block					2
Blocks 10 and 13 | Petroleum Agreement | BP
Business Acquisition [Line Items]
Participating interest percentage					50.00%
Blocks 10 and 13 | Petroleum Agreement | ANP STP
Business Acquisition [Line Items]
Carried participating interest					15.00%
Block EG-24 | Farm-in Agreement
Business Acquisition [Line Items]
Area of petroleum exploration | km²				3,500
Initial exploration period				3 years
First sub exploration period				4 years
3D seismic requirements (in square kilometers) | km²				3,000
Participation interest acquired	80.00%			40.00%
Block EG-24 | Farm-in Agreement | Guinea Equatorial De Petroleos
Business Acquisition [Line Items]
Carried participating interest	20.00%			20.00%
Percentage converted from carried to participating	20.00%			20.00%

Acquisitions and Divestitures_4

Acquisitions and Divestitures - 2018 Transactions Schedule (Details) - Deep Gulf Energy, LP - USD ($) $ / shares in Units, $ in Thousands	Sep. 14, 2018	Sep. 30, 2018
Fair value of assets acquired:
Proved oil and gas properties		$ 1,037,511
Unproved oil and gas properties		298,159
Accounts receivable and other		180,989
Total assets acquired		1,516,659
Fair value of liabilities assumed:
Accrued liabilities and other		126,530
Asset retirement obligations		74,482
Derivative liabilities		40,265
Total liabilities assumed		241,277
Cash consideration paid		952,586
Fair value of common stock		307,944
Transaction related costs		14,852
Total purchase price		1,275,382
Common Stock
Fair value of liabilities assumed:
Fair value of common stock		$ 307,900
Common shares issued (in shares)	34,993,585
Common Stock
Fair value of liabilities assumed:
Share price (in dollars per share)	$ 8.80

Joint Interest Billings and N_2

Joint Interest Billings and Notes Receivables (Details) $ in Thousands	1 Months Ended	9 Months Ended
	Feb. 28, 2019USD ($)agreement	Sep. 30, 2015	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Joint interest billings
Joint interest billings, net			$ 26,002	$ 81,424
Long-term receivables			117,497	43,430
Carry Advance Agreements | National Oil Companies Of Mauritania And Senegal
Joint interest billings
Long-term receivables			96,300	27,400
Number of agreements | agreement	2
Share of development costs to be financed, up to	$ 239,700
TEN Discoveries | GNPC
Joint interest billings
Joint interest billings, net			5,800	14,000
Long-term receivables			$ 21,200	$ 16,000
GNPC | TEN Discoveries
Joint interest billings
GNPC's paying interest		5.00%

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Oil and gas properties:
Proved properties	$ 5,369,737				$ 5,369,737	$ 4,904,648
Unproved properties	495,390				495,390	814,065
Total oil and gas properties	5,865,127				5,865,127	5,718,713
Accumulated depletion	(2,554,851)				(2,554,851)	(2,093,962)
Oil and gas properties, net	3,310,276				3,310,276	3,624,751
Other property	59,949				59,949	61,598
Accumulated depreciation	(49,312)				(49,312)	(44,017)
Other property, net	10,637				10,637	17,581
Property and equipment, net	3,320,913				3,320,913	3,642,332	$ 3,459,701
Depletion expense					460,900	542,900	316,300
Depreciation expense					5,500	6,900	4,600
Impairment of long-lived assets	$ 3,200	$ 0	$ 0	$ 150,800	$ 153,959	$ 0	$ 0

Suspended Well Costs - Schedule

Suspended Well Costs - Schedule of Suspended Well Costs (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2020USD ($)project	Dec. 31, 2019USD ($)project	Dec. 31, 2018USD ($)project
Reconciliation of capitalized exploratory well costs on completed wells
Beginning balance		$ 445,790	$ 367,665	$ 410,113
Additions to capitalized exploratory well costs pending the determination of proved reserves		4,001	78,125	10,518
Additions associated with the acquisition of DGE		0	0	26,224
Reclassification due to determination of proved reserves		(263,502)	0	(26,224)
Capitalized exploratory well costs charged to expense		0	0	(52,966)
Ending balance		186,289	445,790	367,665
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					$ 0	$ 29,121	$ 0
Exploratory well costs capitalized for a period of one to two years					28,692	78,245	299,253
Exploratory well costs capitalized for a period of three years or longer					157,597	338,424	68,412
Ending balance		$ 186,289	$ 367,665	$ 367,665	$ 186,289	$ 445,790	$ 367,665
Number of projects that have exploratory well costs that have been capitalized for a period greater than one year | project					3	3	3
Akasa Discovery
Reconciliation of capitalized exploratory well costs on completed wells
Capitalized exploratory well costs charged to expense	$ (38,100)
Wawa Discovery
Reconciliation of capitalized exploratory well costs on completed wells
Capitalized exploratory well costs charged to expense	$ (13,600)

Suspended Well Costs - Narrativ

Suspended Well Costs - Narrative (Details)	1 Months Ended
	Sep. 30, 2019km
Yakaar and Teranga Discoveries
Capitalized Contract Cost [Line Items]
Distance from Yakaar-2 well to Yakaar-1 exploration well	9

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease, Cost [Abstract]
Operating lease cost	$ 5,869	$ 5,480
Short-term lease cost	13,705	15,874
Total lease cost	$ 19,574	$ 21,354
Balance sheet classifications
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets	us-gaap:OtherAssets
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Other assets (right-of-use assets)	$ 19,799	$ 20,008
Accrued liabilities (current maturities of leases)	1,405	1,139
Other long-term liabilities (non-current maturities of leases)	$ 22,771	$ 22,240
Weighted average remaining lease term	8 years 4 months 24 days	8 years 9 months 18 days
Weighted average discount rate	9.80%	9.80%
Operating cash flows for operating leases	$ 5,225	$ 5,082
Investing cash flows for operating leases	12,586	13,855
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2021	3,307
2022	4,216
2023	4,287
2024	4,358
2025	4,429
Thereafter	15,470
Total undiscounted lease payments	36,067
Less: Imputed interest	(11,891)
Total lease liabilities	24,176
Short-Term Drilling Contracts
Lease, Cost [Abstract]
Short-term lease cost	$ 12,600	$ 13,900
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, initial term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, initial term	10 years

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Outstanding debt principal	$ 2,150,000	$ 2,050,000
Unamortized issuance costs and discount	(38,569)	(41,937)
Total debt, net	2,111,431	2,008,063
Current maturities of long-term debt	(7,500)	0
Long-term debt, net	2,103,931	2,008,063
Senior Notes
Debt Instrument [Line Items]
Unamortized issuance costs and discount	(8,400)	(9,100)
Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding debt principal	1,200,000	1,400,000
Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Unamortized issuance costs and discount	(25,600)	(32,800)
Corporate Revolver | Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding debt principal	100,000	0
7.125% Senior Notes Due 2026 | Senior Notes
Debt Instrument [Line Items]
Outstanding debt principal	650,000	650,000
GoM Term Loan | Secured Debt
Debt Instrument [Line Items]
Outstanding debt principal	200,000	0
Unamortized issuance costs and discount	$ (4,600)	$ 0

Debt - Facility (Details)

Debt - Facility (Details)

1 Months Ended

3 Months Ended

12 Months Ended

Apr. 30, 2019USD ($)

Dec. 31, 2020USD ($)

Dec. 31, 2020USD ($)

Oct. 31, 2020USD ($)

Sep. 30, 2020

Apr. 30, 2020USD ($)

Mar. 31, 2020USD ($)

Dec. 31, 2019USD ($)

Jan. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Nov. 30, 2018USD ($)

Feb. 28, 2018USD ($)

Debt Instrument [Line Items]

Restricted cash

$ 195,000

$ 195,000

$ 4,302,000

$ 4,527,000

Facility

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 1,600,000,000

$ 1,500,000,000

$ 1,600,000,000

$ 1,700,000,000

$ 1,600,000,000

$ 1,500,000,000

Additional commitments

$ 100,000,000

$ 100,000,000

$ 500,000,000

Commitment reduction

$ 100,000,000

Available borrowing base

$ 1,320,000,000

Repayments of Debt

$ 250,000,000

Net leverage ratio

2.50

2.50

Field life cover ratio

1.30

Loan life cover ratio

1.10

Interest cover ratio

2.25

Facility Interest Or Senior Notes Plus The Corporate Revolver

Debt Instrument [Line Items]

Interval period for payment of interest

6 months

Revolving Credit Facility | Facility

Debt Instrument [Line Items]

Interval period for payment of interest

6 months

Amount outstanding

$ 1,200,000,000

$ 1,200,000,000

Undrawn availability

120,000,000

$ 120,000,000

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

30.00%

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

20.00%

Availability period of revolving-credit

1 month

Amount outstanding under letters of credit

$ 0

$ 0

Revolving Credit Facility | Facility | Stated Period

Debt Instrument [Line Items]

Debt cover ratio

4.75

Revolving Credit Facility | Facility | Normal Period

Debt Instrument [Line Items]

Debt cover ratio

3.5

Revolving Credit Facility | Facility | LIBOR | Minimum

Debt Instrument [Line Items]

Applicable margin

3.25%

Revolving Credit Facility | Facility | LIBOR | Maximum

Debt Instrument [Line Items]

Applicable margin

4.50%

Debt - Corporate Revolver (Deta

Debt - Corporate Revolver (Details)	1 Months Ended	12 Months Ended
	Aug. 31, 2018USD ($)	Dec. 31, 2020USD ($)	Sep. 30, 2020	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Net deferred financing costs		$ 3,706,000		$ 6,321,000
Revolving Credit Facility | Corporate Revolver
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 400,000,000
Reduction in margin	1.00%
Applicable margin	5.00%
Commitment fee percentage	30.00%	30.00%
Net deferred financing costs		$ 3,700,000
Amount outstanding		100,000,000
Undrawn availability		$ 300,000,000
Interval period for payment of interest		6 months
Interest cover ratio			2.25
Revolving Credit Facility | Corporate Revolver | Stated Period
Debt Instrument [Line Items]
Debt cover ratio		4.75
Revolving Credit Facility | Corporate Revolver | Normal Period
Debt Instrument [Line Items]
Debt cover ratio		3.5
Revolving Credit Facility | Corporate Revolver | LIBOR
Debt Instrument [Line Items]
Applicable margin		5.00%

Debt - Letter of Credit Facilit

Debt - Letter of Credit Facility (Details)	Jun. 30, 2016	Jul. 31, 2016	Dec. 31, 2019USD ($)letter_of_credit	Jul. 31, 2019USD ($)letter_of_credit	Dec. 31, 2018USD ($)	Jul. 31, 2018USD ($)	Feb. 28, 2018USD ($)
Revolving Letter of Credit Facility
Debt Instrument [Line Items]
Applicable margin	0.50%	0.80%
Commitment fee percentage		0.65%
Maximum borrowing capacity					$ 20,000,000	$ 40,000,000	$ 73,000,000
Amount outstanding				$ 3,100,000
Number of letters of credit | letter_of_credit				5
Letter of Credit Arrangement
Debt Instrument [Line Items]
Amount outstanding			$ 20,400,000
Number of letters of credit | letter_of_credit			2

Debt - Senior Notes (Details)

Debt - Senior Notes (Details) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2014
Debt Instrument [Line Items]
Loss on extinguishment of debt		$ 2,902,000	$ 24,794,000	$ 4,324,000
7.875% Senior Notes Due 2021 | Senior Notes
Debt Instrument [Line Items]
Debt redeemed	$ 543,800,000
Loss on extinguishment of debt	22,900,000
Interest rate					7.875%
7.125% Senior Notes Due 2026
Debt Instrument [Line Items]
Interest rate		7.125%
7.125% Senior Notes Due 2026 | Senior Notes
Debt Instrument [Line Items]
Debt, face amount	$ 650,000,000
Interest rate	7.125%
Proceeds, net of offering discounts and deferred financing costs	$ 640,000,000
Redemption price percentage following change of control	101.00%
Redemption price percentage following sell of certain assets	100.00%
7.125% Senior Notes Due 2026 | Any Time Prior to April 4, 2022 | Senior Notes
Debt Instrument [Line Items]
Maximum percentage of principal amount available to be redeemed with proceeds from equity offerings	40.00%
Redemption price percentage	107.10%
7.125% Senior Notes Due 2026 | Any Time Prior to April 4, 2022 with Make-whole Premium | Senior Notes
Debt Instrument [Line Items]
Redemption price, as a percent of the of principal amount	100.00%

Debt - Redemption Prices (Detai

Debt - Redemption Prices (Details) - Senior Notes - 7.125% Senior Notes Due 2026	1 Months Ended
	Apr. 30, 2019
On or after April 4, 2022, but before April 4, 2023
Debt Instrument [Line Items]
Redemption price, as a percent of the of principal amount	103.60%
On or after April 4, 2023, but before April 4, 2024
Debt Instrument [Line Items]
Redemption price, as a percent of the of principal amount	101.80%
On or after April 4, 2024 and thereafter
Debt Instrument [Line Items]
Redemption price, as a percent of the of principal amount	100.00%

Debt - Production Prepayment Ag

Debt - Production Prepayment Agreement, net (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Advances under production prepayment agreement		$ 50,000	$ 0	$ 0
Trafigura
Debt Instrument [Line Items]
Advances under production prepayment agreement	$ 50,000

Debt - GoM Term Loan (Details)

Debt - GoM Term Loan (Details) - GoM Term Loan - Secured Debt	1 Months Ended
	Sep. 30, 2020USD ($)
Debt Instrument [Line Items]
Debt term	5 years
Debt, face amount	$ 200,000,000
Proceeds from debt, net of issuance costs	197,700,000
Additional incremental commitments	$ 100,000,000
Debt instrument, interest rate, effective percentage	6.00%
Trafigura
Debt Instrument [Line Items]
Debt, face amount	$ 50,000,000
Beal Bank
Debt Instrument [Line Items]
Debt, face amount	$ 150,000,000

Debt - Maturities (Details)

Debt - Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Scheduled maturities of debt during the five year period and thereafter
Total	$ 2,150,000	$ 2,050,000
2021	7,500
2022	258,571
2023	458,571
2024	458,572
2025	316,786
Thereafter	650,000
Debt Instrument [Line Items]
Outstanding debt principal	2,150,000	2,050,000
Senior Notes | 7.125% Senior Notes Due 2026
Scheduled maturities of debt during the five year period and thereafter
Total	650,000	650,000
Debt Instrument [Line Items]
Outstanding debt principal	$ 650,000	$ 650,000

Debt - Debt Interest (Details)

Debt - Debt Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Interest expense	$ 119,857	$ 145,507	$ 114,134
Amortization—deferred financing costs	9,347	9,257	9,379
Loss on extinguishment of debt	2,902	24,794	4,324
Capitalized interest	(25,013)	(28,077)	(28,331)
Deferred interest	2,402	1,919	(1,138)
Interest income	(4,773)	(3,692)	(3,455)
Other, net	5,072	5,366	6,263
Interest and other financing costs, net	$ 109,794	$ 155,074	$ 101,176

Derivative Financial Instrume_3

Derivative Financial Instruments - Oil Derivative Contracts (Details)	12 Months Ended
	Dec. 31, 2020$ / bblMBbls
Dated Brent | January 2021 - December 2021 | Swaps with sold puts
Derivative Financial Instruments
Volume (mbbls) | MBbls	6,000
Weighted Average Price per Bbl [Abstract]
Net deferred premium payable/(receivable) (usd per bbll)	0
Swap (usd per bbl)	53.96
Sold Put (usd per bbl)	42.92
Floor (usd per bbl)	0
Ceiling (usd per bbl)	0
Dated Brent | January 2021 - December 2021 | Three-way collars
Derivative Financial Instruments
Volume (mbbls) | MBbls	4,000
Weighted Average Price per Bbl [Abstract]
Net deferred premium payable/(receivable) (usd per bbll)	0.34
Swap (usd per bbl)	0
Sold Put (usd per bbl)	33.13
Floor (usd per bbl)	40.63
Ceiling (usd per bbl)	52.60
Dated Brent | January 2021 - December 2021 | Sold calls
Derivative Financial Instruments
Volume (mbbls) | MBbls	7,000
Weighted Average Price per Bbl [Abstract]
Net deferred premium payable/(receivable) (usd per bbll)	0
Swap (usd per bbl)	0
Sold Put (usd per bbl)	0
Floor (usd per bbl)	0
Ceiling (usd per bbl)	70.09
Dated Brent | January 2022 - December 2022 | Sold calls
Derivative Financial Instruments
Volume (mbbls) | MBbls	1,581
Weighted Average Price per Bbl [Abstract]
Net deferred premium payable/(receivable) (usd per bbll)	0
Swap (usd per bbl)	0
Sold Put (usd per bbl)	0
Floor (usd per bbl)	0
Ceiling (usd per bbl)	60
NYMEX WTI | January 2021 - December 2021 | Three-way collars
Derivative Financial Instruments
Volume (mbbls) | MBbls	1,000
Weighted Average Price per Bbl [Abstract]
Net deferred premium payable/(receivable) (usd per bbll)	1
Swap (usd per bbl)	0
Sold Put (usd per bbl)	37.50
Floor (usd per bbl)	45
Ceiling (usd per bbl)	55
NYMEX WTI | January 2021 - June 2021 | Swaps with sold puts
Derivative Financial Instruments
Volume (mbbls) | MBbls	1,000
Weighted Average Price per Bbl [Abstract]
Net deferred premium payable/(receivable) (usd per bbll)	0
Swap (usd per bbl)	47.75
Sold Put (usd per bbl)	37.50
Floor (usd per bbl)	0
Ceiling (usd per bbl)	0

Derivative Financial Instrume_4

Derivative Financial Instruments - Narrative (Details) - Dated Brent - Three-way collars - January 2022 - December 2022 - Subsequent Event	1 Months Ended
	Feb. 28, 2021$ / bblMBbls
Derivative Financial Instruments
Volume (mbbls) | MBbls	1,500
Sold Put (usd per bbl)	40
Floor (usd per bbl)	50
Ceiling (usd per bbl)	70

Derivative Financial Instrume_5

Derivative Financial Instruments - Derivative Instruments and Gain/(Loss) from Derivatives (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Derivative instruments, Balance Sheet Location
Derivatives assets—current	$ 15,414	$ 12,856
Derivatives assets—long-term	964	2,302
Derivatives liabilities—current	(28,009)	(8,914)
Derivatives liabilities—long-term	(8,069)	(11,478)
Not designated as hedging instruments
Derivative instruments, Balance Sheet Location
Total derivatives not designated as hedging instruments	(20,377)	(8,521)
Commodity derivatives | Not designated as hedging instruments
Derivative instruments, Balance Sheet Location
Derivatives assets—current	15,414	12,856
Derivatives assets—long-term	964	2,302
Derivatives liabilities—current	(28,009)	(8,914)
Derivatives liabilities—long-term	(8,069)	(11,478)
Provisional Oil Sales | Receivables: Oil sales | Not designated as hedging instruments
Derivative instruments, Balance Sheet Location
Derivatives assets—current	$ (677)	$ (3,287)

Derivative Financial Instrume_6

Derivative Financial Instruments - Location of Gain (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative instruments, Location of Gain/(Loss)
Derivative, not designated as hedge, gain (loss)	$ (22,800)	$ (70,724)	$ 29,960
Commodity derivatives | Oil and gas revenue
Derivative instruments, Location of Gain/(Loss)
Derivative, not designated as hedge, gain (loss)	(5,620)	1,161	(1,963)
Commodity derivatives | Derivatives, net
Derivative instruments, Location of Gain/(Loss)
Derivative, not designated as hedge, gain (loss)	(17,180)	(71,885)	31,430
Interest rate contracts | Interest expense
Derivative instruments, Location of Gain/(Loss)
Derivative, not designated as hedge, gain (loss)	$ 0	$ 0	$ 493

Fair Value Measurements (Detail

Fair Value Measurements (Details) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Liabilities:
Impairment of long-lived assets	$ 3,200	$ 0	$ 0	$ 150,800	$ 153,959	$ 0	$ 0
Carrying Value
Liabilities:
Long-term debt	2,143,524				2,143,524	2,042,550
Fair Value
Liabilities:
Long-term debt	2,113,412				2,113,412	2,064,957
7.125% Senior Notes Due 2026 | Senior Notes | Carrying Value
Liabilities:
Long-term debt	643,524				643,524	642,550
7.125% Senior Notes Due 2026 | Senior Notes | Fair Value
Liabilities:
Long-term debt	613,412				613,412	664,957
GoM Term Loan | Secured Debt | Carrying Value
Liabilities:
Long-term debt	200,000				200,000	0
GoM Term Loan | Secured Debt | Fair Value
Liabilities:
Long-term debt	200,000				200,000	0
Corporate Revolver | Revolving Credit Facility | Carrying Value
Liabilities:
Long-term debt	100,000				100,000	0
Corporate Revolver | Revolving Credit Facility | Fair Value
Liabilities:
Long-term debt	100,000				100,000	0
Facility | Revolving Credit Facility | Carrying Value
Liabilities:
Long-term debt	1,200,000				1,200,000	1,400,000
Facility | Revolving Credit Facility | Fair Value
Liabilities:
Long-term debt	1,200,000				1,200,000	1,400,000
Recurring basis
Liabilities:
Total derivatives not designated as hedging instruments	(20,377)				(20,377)	(8,521)
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Total derivatives not designated as hedging instruments	0				0	0
Recurring basis | Significant Other Observable Inputs (Level 2)
Liabilities:
Total derivatives not designated as hedging instruments	(20,377)				(20,377)	(8,521)
Recurring basis | Significant Unobservable Inputs (Level 3)
Liabilities:
Total derivatives not designated as hedging instruments	0				0	0
Recurring basis | Commodity derivatives
Assets:
Derivative asset, fair value	16,378				16,378	15,158
Liabilities:
Derivative liability, fair value	(36,078)				(36,078)	(20,392)
Recurring basis | Commodity derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset, fair value	0				0	0
Liabilities:
Derivative liability, fair value	0				0	0
Recurring basis | Commodity derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset, fair value	16,378				16,378	15,158
Liabilities:
Derivative liability, fair value	(36,078)				(36,078)	(20,392)
Recurring basis | Commodity derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset, fair value	0				0	0
Liabilities:
Derivative liability, fair value	0				0	0
Recurring basis | Provisional Oil Sales
Assets:
Derivative asset, fair value	(677)				(677)	(3,287)
Recurring basis | Provisional Oil Sales | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset, fair value	0				0	0
Recurring basis | Provisional Oil Sales | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset, fair value	(677)				(677)	(3,287)
Recurring basis | Provisional Oil Sales | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset, fair value	0				0	$ 0
Nonrecurring
Liabilities:
Proved oil and gas reserves, fair value	$ 243,700				$ 243,700
Nonrecurring | Valuation Technique, Discounted Cash Flow | Measurement input, discount rate
Liabilities:
Long-Lived Assets, Measurement Input	0.10				0.10

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Dec. 31, 2020	Dec. 31, 2019
Asset retirement obligations:
Beginning asset retirement obligations	$ 151,953	$ 235,053	$ 151,953
Liabilities incurred during period		3,436	11,218
Liabilities settled during period		(2,782)	(7,156)
Revisions in estimated retirement obligations		(3,736)	(49,471)
Accretion expense		19,450	14,114
Ending asset retirement obligations		251,421	235,053
Ceiba Field and Okume Complex Acquisition
Asset retirement obligations:
Liabilities incurred during period	$ 114,395
Ownership percentage	40.375%
Equatorial Guinea
Asset retirement obligations:
Additions associated with Equatorial Guinea - Ceiba Field and Okume Complex		$ 0	$ 114,395

Equity-based Compensation - Nar

Equity-based Compensation - Narrative (Details) - USD ($)	1 Months Ended			12 Months Ended
	Jan. 31, 2021	Jan. 31, 2018	Jan. 31, 2015	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity-based Compensation
Net tax shortfall (windfall) related to equity-based compensation				$ 890,000	$ 3,545,000	$ 2,643,000
LTIP
Equity-based Compensation
Additional shares authorized (in shares)		11,000,000	15,000,000
Number of shares authorized (in shares)				50,500,000
Number of shares remaining available for grant (in shares)				6,500,000
Compensation expense recognized				$ 32,700,000	32,400,000	35,200,000
Tax benefit				4,700,000	4,900,000	6,600,000
Net tax shortfall (windfall) related to equity-based compensation				$ 1,300,000	1,200,000	(400,000)
LTIP | Minimum
Equity-based Compensation
Vesting period				3 years
LTIP | Restricted Stock Awards and Restricted Stock Units
Equity-based Compensation
Fair value of awards vested				$ 26,000,000	$ 20,300,000	$ 85,100,000
LTIP | Market/Service Vesting Restricted Stock Awards
Equity-based Compensation
Granted (in dollars per share)						$ 0
LTIP | Market/Service Vesting Restricted Stock Units
Equity-based Compensation
Granted (in dollars per share)				$ 8.37	$ 6.02	12.38
LTIP | Market/Service Vesting Restricted Stock Units | Subsequent Event
Equity-based Compensation
Granted (in shares)	6,700,000
LTIP | Market/Service Vesting Restricted Stock Units | Minimum
Equity-based Compensation
Granted (in dollars per share)				$ 1.06
Expected volatility				44.00%
Risk-free interest rate				0.80%
Expected quarterly dividends (in dollars per share)				$ 0.045
LTIP | Market/Service Vesting Restricted Stock Units | Maximum
Equity-based Compensation
Vesting percentage of the awards granted				200.00%
Granted (in dollars per share)				$ 12.96
Expected volatility				52.00%
Risk-free interest rate				2.50%
Expected quarterly dividends (in dollars per share)				$ 0.050
LTIP | Service Vesting Restricted Stock Units
Equity-based Compensation
Granted (in dollars per share)				$ 5.48	$ 5.01	$ 7.07
LTIP | Service Vesting Restricted Stock Units | Subsequent Event
Equity-based Compensation
Granted (in shares)	2,500,000
LTIP | Restricted stock units
Equity-based Compensation
Compensation expense not yet recognized				$ 22,900,000
Weighted average period over which compensation expense is to be recognized				1 year 8 months 12 days
LTIP | Restricted stock units | Subsequent Event
Equity-based Compensation
Compensation expense not yet recognized	$ 32,200,000
Weighted average period over which compensation expense is to be recognized	3 years

Equity-based Compensation - Sch

Equity-based Compensation - Schedule of Awards (Details) - LTIP - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Service Vesting Restricted Stock Awards
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)		0	220
Granted (in shares)			0
Forfeited (in shares)			0
Vested (in shares)			(220)
Outstanding at the end of the period (in shares)			0
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)		$ 0	$ 8.64
Granted (in dollars per share)			0
Forfeited (in dollars per share)			0
Vested (in dollars per share)			8.64
Outstanding at the end of the period (in dollars per share)			$ 0
Market/Service Vesting Restricted Stock Awards
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)		0	0
Granted (in shares)			0
Forfeited (in shares)			0
Vested (in shares)			0
Outstanding at the end of the period (in shares)			0
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)		$ 0	$ 0
Granted (in dollars per share)			0
Forfeited (in dollars per share)			0
Vested (in dollars per share)			0
Outstanding at the end of the period (in dollars per share)			$ 0
Service Vesting Restricted Stock Units
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)	4,731	4,115	4,183
Granted (in shares)	3,481	3,228	2,402
Forfeited (in shares)	(1,187)	(591)	(229)
Vested (in shares)	(2,185)	(2,021)	(2,241)
Outstanding at the end of the period (in shares)	4,840	4,731	4,115
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)	$ 5.71	$ 6.42	$ 6.39
Granted (in dollars per share)	5.48	5.01	7.07
Forfeited (in dollars per share)	6.12	5.90	6.40
Vested (in dollars per share)	5.91	5.95	6.95
Outstanding at the end of the period (in dollars per share)	$ 5.34	$ 5.71	$ 6.42
Market/Service Vesting Restricted Stock Units
Outstanding unvested awards activity
Outstanding at the beginning of the period (in shares)	7,798	6,716	8,452
Granted (in shares)	3,394	3,195	8,111
Forfeited (in shares)	(726)	(813)	(302)
Vested (in shares)	(2,607)	(1,300)	(9,545)
Outstanding at the end of the period (in shares)	7,859	7,798	6,716
Weighted-Average Grant-Date Fair Value
Outstanding at beginning of the period (in dollars per share)	$ 8.42	$ 9.02	$ 11.26
Granted (in dollars per share)	8.37	6.02	12.38
Forfeited (in dollars per share)	8.03	7.93	8.95
Vested (in dollars per share)	9.47	6.32	13.75
Outstanding at the end of the period (in dollars per share)	$ 8.11	$ 8.42	$ 9.02

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Tax benefit from cares act		$ 4,900
Income tax refund claim from Cares act		$ 12,200
Effective tax rate			1.00%	322.00%	85.00%
Change in valuation allowance			$ 86,539	$ 44,889	$ 63,335
Federal statutory income tax rate percent			21.00%	21.00%	21.00%
Foreign net operating loss carryforwards			$ 105,900
Foreign net operating loss carryforwards expiring in 2021			500
Foreign net operating loss carryforwards expiring in 2022			15,500
Foreign net operating loss carryforwards expiring in 2023			600
Foreign net operating loss carryforwards expiring in 2024			2,100
Foreign net operating loss carryforwards expiring in 2025			1,200
Foreign net operating loss carryforwards expiring in 2026			43,500
Foreign net operating loss carryforwards not expiring			$ 42,500
Ceiba Field and Okume Complex Acquisition
Income Taxes
Ownership percentage	40.375%
United States
Income Taxes
Effective tax rate			7.00%	12.00%	84.00%
Change in valuation allowance			$ 96,600	$ 6,800
Foreign net operating loss carryforwards not expiring			$ 540,100
Ghana
Income Taxes
Effective tax rate			35.00%	29.00%	36.00%
Equatorial Guinea
Income Taxes
Effective tax rate			34.00%	37.00%
Foreign—other
Income Taxes
Effective tax rate			0.00%
Federal statutory income tax rate percent			0.00%

Income Taxes - Components of In

Income Taxes - Components of Income (Loss) and Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Income (loss) before income taxes	$ (416,795)	$ 25,117	$ (50,860)
Components of the provision for income taxes attributable to income (loss) before income taxes
Current	37,378	171,264	33,986
Deferred	(42,587)	(90,370)	9,145
Income tax expense (benefit)	(5,209)	80,894	43,131
Reconciliation of income tax expense and the reported effective tax rate
Tax at statutory rate	(87,527)	5,275	(10,681)
Foreign income (loss) taxed at different rates	(1,771)	32,690	5,013
Net non-taxable expense / insurance recoveries	0	(13,352)	3,256
West Leo arbitration settlement	0	0	(2,834)
Non-deductible insurance premiums	0	2,625	0
Non-deductible compensation	890	3,545	2,643
Deferred tax liability - undistributed earnings	0	0	(2,565)
Non-deductible and other items	387	3,998	656
Equity earnings - net of tax	0	0	(15,305)
Tax shortfall (windfall) on equity-based compensation, net	1,175	1,224	(387)
Change in valuation allowance	86,539	44,889	63,335
U.S. tax loss carryback rate differential	(4,902)	0	0
Income tax expense (benefit)	$ (5,209)	$ 80,894	$ 43,131
Effective tax rate	1.00%	322.00%	85.00%
Federal statutory income tax rate percent	21.00%	21.00%	21.00%
Impact of (gains) losses incurred in jurisdictions in which company is not subject to taxes on effective tax rate	$ (2,900)	$ 132,100	$ 261,200
United States
Income Taxes
Income (loss) before income taxes	(338,746)	(149,919)	41,026
Components of the provision for income taxes attributable to income (loss) before income taxes
Current	(12,208)	185	122
Deferred	34,831	(18,776)	8,514
Bermuda
Income Taxes
Income (loss) before income taxes	0	0	(73,979)
Components of the provision for income taxes attributable to income (loss) before income taxes
Current	0	0	0
Deferred	0	0	0
Foreign—other
Income Taxes
Income (loss) before income taxes	(78,049)	175,036	(17,907)
Components of the provision for income taxes attributable to income (loss) before income taxes
Current	49,586	171,079	33,864
Deferred	$ (77,418)	$ (71,594)	$ 631

Income Taxes - Deferred Taxes (

Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Foreign capitalized operating expenses	$ 152,106	$ 175,330
Foreign net operating losses	32,762	19,576
United States net operating losses	113,427	58,903
United States deferred interest expense	0	15,426
Equity compensation	14,089	13,700
Unrealized derivative losses	3,482	1,471
Asset retirement obligation and other	41,759	43,159
Total deferred tax assets	357,625	327,565
Valuation allowance	(288,288)	(201,749)
Total deferred tax assets, net	69,337	125,816
Deferred tax liabilities:
Depletion, depreciation and amortization related to property and equipment	(642,956)	(746,258)
Unrealized derivative gains	0	0
Total deferred tax liabilities	(642,956)	(746,258)
Net deferred tax liability	$ (573,619)	$ (620,442)

Net Income (Loss) Per Share (De

Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss allocable to common stockholders	$ 7,956	$ (37,384)	$ (199,391)	$ (182,767)	$ (35,773)	$ 16,065	$ 16,837	$ (52,906)	$ (411,586)	$ (55,777)	$ (93,991)
Weighted average number of shares outstanding:
Basic (in shares)									405,212	401,368	404,585
Restricted stock awards and units (in shares)									0	0	0
Diluted (in shares)									405,212	401,368	404,585
Net loss per share:
Basic (in dollars per share)	$ 0.02	$ (0.09)	$ (0.49)	$ (0.45)	$ (0.09)	$ 0.04	$ 0.04	$ (0.13)	$ (1.02)	$ (0.14)	$ (0.23)
Diluted (in dollars per share)	$ 0.02	$ (0.09)	$ (0.49)	$ (0.45)	$ (0.09)	$ 0.04	$ 0.04	$ (0.13)	$ (1.02)	$ (0.14)	$ (0.23)
Outstanding restricted stock awards and units excluded from the computations of diluted net income per share (in shares)									6,100	15,300	10,600

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ / shares in Units, $ in Millions	Oct. 14, 2011	Mar. 26, 2020$ / shares	Feb. 28, 2019	Dec. 31, 2020USD ($)km²meterwell$ / shares	Dec. 31, 2019USD ($)$ / shares
Commitments and contingencies
Dividends declared per common stock (in dollars per share) | $ / shares		$ 0.0452		$ 0.0452	$ 0.1808
Mauritania
Commitments and contingencies
Number of exploration wells | well				2
3D seismic requirements (in square kilometers) | km²				1,000
South Africa
Commitments and contingencies
2D seismic requirements | meter				500
U.S. Gulf of Mexico | Surety Bond
Commitments and contingencies
Cash collateral				$ 0	$ 0
U.S. Gulf of Mexico | Bureau Of Ocean Energy Management | Surety Bond
Commitments and contingencies
Required performance bonds				195.5	222
U.S. Gulf of Mexico | Third Party | Surety Bond
Commitments and contingencies
Required performance bonds				$ 7.1	$ 3.7
Jubilee UUOA
Commitments and contingencies
Unit interest after redetermination process (as a percent)	24.10%
GTA UUOA
Commitments and contingencies
Payment interest on development activities			26.70%

Additional Financial Informat_3

Additional Financial Information - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued liabilities:
Exploration, development and production	$ 89,162	$ 152,490
Revenue payable	15,079	32,482
Current asset retirement obligations	7,255	4,527
General and administrative expenses	4,988	44,575
Interest	23,725	33,584
Income taxes	37,344	103,566
Taxes other than income	2,815	3,375
Derivatives	17,475	4,837
Other	5,417	1,268
Accrued liabilities	$ 203,260	$ 380,704

Additional Financial Informat_4

Additional Financial Information - Narrative (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Jul. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Gain on sale of assets			$ 92,163	$ 10,528	$ 7,666
Recoveries		$ 12,900
Ceiba Field and Okume Complex Acquisition
Schedule of Equity Method Investments [Line Items]
Ownership percentage	40.375%
Kosmos-Trident International Petroleum Inc.
Schedule of Equity Method Investments [Line Items]
Ownership percentage					50.00%
Summary of financial information					100.00%
Farm Down Agreement | Blocks Offshore Sao Tome and Principe Suriname and Namibia
Schedule of Equity Method Investments [Line Items]
Gain on sale of assets			$ 92,100
Farm-out Agreement | Blocks 6 and 11
Schedule of Equity Method Investments [Line Items]
Gain on sale of assets				$ 10,500
Farm-out Agreement | Block EG-21 and Block S and Block W
Schedule of Equity Method Investments [Line Items]
Gain on sale of assets					$ 7,700

Additional Financial Informat_5

Additional Financial Information - Other Expenses, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Additional Financial Information
Loss on disposal of inventory	$ 8,607	$ 4,590	$ 280
Gain on insurance settlements	0	(3,509)	0
Loss on asset retirement obligations liability settlements	1,966	193	0
Restructuring charges	16,474	11,528	0
Other, net	10,755	11,846	(6,781)
Other expenses, net	$ 37,802	$ 24,648	$ (6,501)

Additional Financial Informat_6

Additional Financial Information - Summary of Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Total current assets	$ 400,291				$ 566,557				$ 400,291	$ 566,557
Property and equipment, net	3,320,913				3,642,332				3,320,913	3,642,332	$ 3,459,701
Other assets	23,680				22,969				23,680	22,969
Total assets	3,867,593				4,317,232				3,867,593	4,317,232	4,088,189
Liabilities and stockholders’ equity
Total current liabilities	460,199				539,101				460,199	539,101
Total long term liabilities	2,967,240				2,936,429				2,967,240	2,936,429
Shareholders' deficit:
Total shareholders' deficit	440,154				841,702				440,154	841,702	941,478	$ 897,112
Total liabilities and stockholders’ equity	3,867,593				4,317,232				3,867,593	4,317,232
Revenues and other income:
Oil and gas revenue									804,033	1,499,416	886,666
Other income, net									2	(35)	8,037
Total revenues and other income	366,316	$ 224,787	$ 127,314	$ 177,781	460,215	$ 356,970	$ 395,934	$ 296,790	896,198	1,509,909	902,369
Costs and expenses:
Oil and gas production									338,477	402,613	224,727
Depletion and depreciation									485,862	563,861	329,835
Other expenses, net									(37,802)	(24,648)	6,501
Total costs and expenses	382,579	261,279	374,130	295,005	462,492	317,435	346,495	358,370	1,312,993	1,484,792	953,229
Income (loss) before income taxes									(416,795)	25,117	(50,860)
Income tax expense (benefit)									(5,209)	80,894	43,131
Net income (loss)	$ 7,956	$ (37,384)	$ (199,391)	$ (182,767)	$ (35,773)	$ 16,065	$ 16,837	$ (52,906)	(411,586)	(55,777)	(93,991)
Equity in earnings - KTIPI									$ 0	$ 0	72,881
Kosmos-Trident International Petroleum Inc. | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Assets
Total current assets											149,950
Property and equipment, net											271,627
Other assets											21
Total assets											421,598
Liabilities and stockholders’ equity
Total current liabilities											226,311
Total long term liabilities											536,178
Shareholders' deficit:
Total shareholders' deficit											(340,891)
Total liabilities and stockholders’ equity											421,598
Revenues and other income:
Oil and gas revenue											721,299
Other income, net											(477)
Total revenues and other income											720,822
Costs and expenses:
Oil and gas production											147,685
Depletion and depreciation											126,983
Other expenses, net											429
Total costs and expenses											275,097
Income (loss) before income taxes											445,725
Income tax expense (benefit)											156,981
Net income (loss)											288,744
Kosmos' share of net income											144,372
Basis difference amortization											71,491
Equity in earnings - KTIPI											$ 72,881

Additional Financial Informat_7

Additional Financial Information - Asset Acquisition (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Asset retirement obligations		$ 3,436	$ 11,218
Ceiba Field and Okume Complex Acquisition
Schedule of Equity Method Investments [Line Items]
Proved oil and gas properties	$ 372,144
Unproved oil and gas properties	103,909
Prepaids and other	7,273
Total assets acquired	483,326
Asset retirement obligations	114,395
Deferred tax liabilities	247,636
Accrued liabilities and other	69,399
Total liabilities assumed	$ 431,430
Equity method investment carrying value				$ 51,896

Business Segment Information -

Business Segment Information - Financial Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment									4
Oil and gas revenue									$ 804,033	$ 1,499,416	$ 886,666
Gain on sale of assets									92,163	10,528	7,666
Other income, net									2	(35)	8,037
Total revenues and other income	$ 366,316	$ 224,787	$ 127,314	$ 177,781	$ 460,215	$ 356,970	$ 395,934	$ 296,790	896,198	1,509,909	902,369
Oil and gas production									338,477	402,613	224,727
Facilities insurance modifications, net									13,161	(24,254)	6,955
Exploration expenses									84,616	180,955	301,492
General and administrative									72,142	110,010	99,856
Depletion, depreciation and amortization									485,862	563,861	329,835
Impairment of long-lived assets	3,200	0	0	150,800					153,959	0	0
Interest and other financing costs, net									109,794	155,074	101,176
Derivatives, net									17,180	71,885	(31,430)
Gain on equity method investments, net									0	0	72,881
Other expenses, net									37,802	24,648	(6,501)
Total costs and expenses	382,579	261,279	374,130	295,005	462,492	317,435	346,495	358,370	1,312,993	1,484,792	953,229
Income (loss) before income taxes									(416,795)	25,117	(50,860)
Income tax expense (benefit)									(5,209)	80,894	43,131
Net income (loss)	7,956	$ (37,384)	$ (199,391)	$ (182,767)	(35,773)	$ 16,065	$ 16,837	$ (52,906)	(411,586)	(55,777)	(93,991)
Consolidated capital expenditures									273,979	440,736	385,434
Property and equipment, net	3,320,913				3,642,332				3,320,913	3,642,332	3,459,701
Total assets	3,867,593				4,317,232				3,867,593	4,317,232	4,088,189
Corporate & Other
Segment Reporting Information [Line Items]
Oil and gas revenue									0	0	0
Gain on sale of assets									92,079	10,528	0
Other income, net									120,135	155,866	150,635
Total revenues and other income									212,214	166,394	150,635
Oil and gas production									0	0	5,153
Facilities insurance modifications, net									0	0	0
Exploration expenses									41,163	40,455	131,180
General and administrative									129,801	159,539	168,542
Depletion, depreciation and amortization									3,345	4,776	4,134
Impairment of long-lived assets									0
Interest and other financing costs, net									73,612	95,887	39,483
Derivatives, net									17,180	41,498	26,185
Gain on equity method investments, net											0
Other expenses, net									21,312	11,580	3,510
Total costs and expenses									286,413	353,735	378,187
Income (loss) before income taxes									(74,199)	(187,341)	(227,552)
Income tax expense (benefit)									(3,212)	(10,172)	2,474
Net income (loss)									(70,987)	(177,169)	(230,026)
Consolidated capital expenditures									(58,293)	33,206	139,381
Property and equipment, net	22,052				35,545				22,052	35,545	37,470
Total assets	12,654,827				12,144,312				12,654,827	12,144,312	10,349,488
Eliminations
Segment Reporting Information [Line Items]
Oil and gas revenue									0	0	(360,649)
Gain on sale of assets									0	0	0
Other income, net									(120,415)	(157,100)	(142,354)
Total revenues and other income									(120,415)	(157,100)	(503,003)
Oil and gas production									0	0	(73,843)
Facilities insurance modifications, net									0	0	0
Exploration expenses									0	0	(352)
General and administrative									(96,101)	(108,468)	(109,133)
Depletion, depreciation and amortization									0	0	(134,983)
Impairment of long-lived assets									0
Interest and other financing costs, net									(7,134)	(7,134)	(7,134)
Derivatives, net									0	0	0
Gain on equity method investments, net											72,881
Other expenses, net									(17,180)	(41,498)	(26,186)
Total costs and expenses									(120,415)	(157,100)	(424,512)
Income (loss) before income taxes									0	0	(78,491)
Income tax expense (benefit)									0	0	(78,491)
Net income (loss)									0	0	0
Consolidated capital expenditures									0	0	0
Property and equipment, net	0				0				0	0	0
Total assets	(14,869,520)				(13,964,690)				(14,869,520)	(13,964,690)	(12,296,281)
Ghana | Operating Segments
Segment Reporting Information [Line Items]
Oil and gas revenue									366,515	738,909	739,070
Gain on sale of assets									0	0	0
Other income, net									2	5	(17)
Total revenues and other income									366,517	738,914	739,053
Oil and gas production									169,357	188,207	189,104
Facilities insurance modifications, net									13,161	(24,254)	6,955
Exploration expenses									182	204	58,276
General and administrative									13,506	18,618	19,342
Depletion, depreciation and amortization									235,772	268,866	265,805
Impairment of long-lived assets									0
Interest and other financing costs, net									54,530	72,226	86,738
Derivatives, net									0	0	0
Gain on equity method investments, net											0
Other expenses, net									(27,925)	40,382	16,414
Total costs and expenses									458,583	564,249	642,634
Income (loss) before income taxes									(92,066)	174,665	96,419
Income tax expense (benefit)									(30,486)	50,293	34,494
Net income (loss)									(61,580)	124,372	61,925
Consolidated capital expenditures									44,146	98,285	105,942
Property and equipment, net	1,293,372				1,487,114				1,293,372	1,487,114	1,698,194
Total assets	1,397,802				1,654,266				1,397,802	1,654,266	1,930,071
Equatorial Guinea | Operating Segments
Segment Reporting Information [Line Items]
Oil and gas revenue									152,501	300,547	360,649
Gain on sale of assets									0	0	7,666
Other income, net									0	0	(238)
Total revenues and other income									152,501	300,547	368,077
Oil and gas production									80,813	90,607	73,843
Facilities insurance modifications, net									0	0	0
Exploration expenses									8,290	13,350	38,164
General and administrative									4,865	6,643	5,351
Depletion, depreciation and amortization									64,786	75,565	134,983
Impairment of long-lived assets									0
Interest and other financing costs, net									(1,248)	(634)	(12)
Derivatives, net									0	0	0
Gain on equity method investments, net											0
Other expenses, net									2,281	(563)	(814)
Total costs and expenses									159,787	184,968	251,515
Income (loss) before income taxes									(7,286)	115,579	116,562
Income tax expense (benefit)									2,428	49,192	78,491
Net income (loss)									(9,714)	66,387	38,071
Consolidated capital expenditures									38,126	63,798	32,156
Property and equipment, net	426,365				464,420				426,365	464,420	3,919
Total assets	689,222				650,607				689,222	650,607	55,302
Mauritania / Senegal | Operating Segments
Segment Reporting Information [Line Items]
Oil and gas revenue									0	0	0
Gain on sale of assets									0	0	0
Other income, net									0	0	0
Total revenues and other income									0	0	0
Oil and gas production									0	0	0
Facilities insurance modifications, net									0	0	0
Exploration expenses									8,189	11,181	7,262
General and administrative									7,464	8,222	5,220
Depletion, depreciation and amortization									61	62	61
Impairment of long-lived assets									0
Interest and other financing costs, net									(27,339)	(26,537)	(25,386)
Derivatives, net									0	0	0
Gain on equity method investments, net											0
Other expenses, net									4,829	12,056	(23)
Total costs and expenses									(6,796)	4,984	(12,866)
Income (loss) before income taxes									6,796	(4,984)	12,866
Income tax expense (benefit)									0	0	0
Net income (loss)									6,796	(4,984)	12,866
Consolidated capital expenditures									126,803	12,556	11,962
Property and equipment, net	580,920				438,800				580,920	438,800	411,448
Total assets	823,411				581,317				823,411	581,317	536,620
U.S. Gulf of Mexico | Operating Segments
Segment Reporting Information [Line Items]
Oil and gas revenue									285,017	459,960	147,596
Gain on sale of assets									84	0	0
Other income, net									280	1,194	11
Total revenues and other income									285,381	461,154	147,607
Oil and gas production									88,307	123,799	30,470
Facilities insurance modifications, net									0	0	0
Exploration expenses									26,792	115,765	66,962
General and administrative									12,607	25,456	10,534
Depletion, depreciation and amortization									181,898	214,592	59,835
Impairment of long-lived assets									153,959
Interest and other financing costs, net									17,373	21,266	7,487
Derivatives, net									0	30,387	(57,615)
Gain on equity method investments, net											0
Other expenses, net									54,485	2,691	598
Total costs and expenses									535,421	533,956	118,271
Income (loss) before income taxes									(250,040)	(72,802)	29,336
Income tax expense (benefit)									26,061	(8,419)	6,163
Net income (loss)									(276,101)	(64,383)	23,173
Consolidated capital expenditures									123,197	232,891	95,993
Property and equipment, net	998,204				1,216,453				998,204	1,216,453	1,308,670
Total assets	$ 3,171,851				$ 3,251,420				$ 3,171,851	$ 3,251,420	$ 3,512,989

Business Segment Information _2

Business Segment Information - Consolidated Capital Expenditures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting [Abstract]
Oil and gas assets	$ 377,491	$ 340,217	$ 213,806
Other property	2,102	11,796	7,935
Changes in capital accruals	(42,315)	33,717	26,669
Exploration expense, excluding unsuccessful well costs and leasehold impairments	61,459	93,142	178,293
Capitalized interest	(25,013)	(28,077)	(28,331)
Proceeds on sale of assets	(99,337)	(16,713)	(13,703)
Other	(408)	6,654	765
Consolidated capital expenditures	$ 273,979	$ 440,736	$ 385,434

Supplemental Quarterly Financ_3

Supplemental Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenues and other income	$ 366,316	$ 224,787	$ 127,314	$ 177,781	$ 460,215	$ 356,970	$ 395,934	$ 296,790	$ 896,198	$ 1,509,909	$ 902,369
Costs and expenses	382,579	261,279	374,130	295,005	462,492	317,435	346,495	358,370	1,312,993	1,484,792	953,229
Net loss	$ 7,956	$ (37,384)	$ (199,391)	$ (182,767)	$ (35,773)	$ 16,065	$ 16,837	$ (52,906)	$ (411,586)	$ (55,777)	$ (93,991)
Net loss per share:
Basic (in dollars per share)	$ 0.02	$ (0.09)	$ (0.49)	$ (0.45)	$ (0.09)	$ 0.04	$ 0.04	$ (0.13)	$ (1.02)	$ (0.14)	$ (0.23)
Diluted (in dollars per share)	$ 0.02	$ (0.09)	$ (0.49)	$ (0.45)	$ (0.09)	$ 0.04	$ 0.04	$ (0.13)	$ (1.02)	$ (0.14)	$ (0.23)

Condensed Parent Company Fina_2

Condensed Parent Company Financial Statements - Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 149,027	$ 224,502	$ 173,515
Prepaid expenses and other	27,870	36,192
Total current assets	400,291	566,557
Deferred financing costs, net of accumulated amortization of $17,296 and $14,681 at December 31, 2020 and December 31, 2019, respectively	3,706	6,321
Restricted cash	542	542	7,574
Long-term deferred tax asset	0	32,779
Total assets	3,867,593	4,317,232	4,088,189
Current liabilities:
Accounts payable	221,430	149,483
Accrued liabilities	203,260	380,704
Derivatives	28,009	8,914
Total current liabilities	460,199	539,101
Long-term debt, net	2,103,931	2,008,063
Derivatives	8,069	11,478
Other long-term liabilities	37,455	33,141
Stockholders’ equity:
Preference shares, $0.01 par value; 200,000,000 authorized shares; zero issued at December 31, 2020 and December 31, 2019	0	0
Common stock, $0.01 par value; 2,000,000,000 authorized shares; 449,718,317 and 445,779,367 issued at December 31, 2020 and December 31, 2019, respectively	4,497	4,458
Additional paid-in capital	2,307,220	2,297,221
Accumulated deficit	(1,634,556)	(1,222,970)
Treasury stock, at cost, 44,263,269 shares at December 31, 2020 and December 31, 2019, respectively	(237,007)	(237,007)
Total stockholders’ equity	440,154	841,702	$ 941,478	$ 897,112
Total liabilities and stockholders’ equity	3,867,593	4,317,232
Parent Company
Current assets:
Cash and cash equivalents	1,166	6,422
Receivables from subsidiaries	0	3,819
Prepaid expenses and other	908	428
Derivatives—related party	2,502	0
Total current assets	4,576	10,669
Investment in subsidiaries at equity	1,034,226	1,159,560
Long-term note receivable from subsidiary	176,540	518,844
Deferred financing costs, net of accumulated amortization of $17,296 and $14,681 at December 31, 2020 and December 31, 2019, respectively	3,706	6,321
Derivatives—related party	140	0
Restricted cash	305	305
Long-term deferred tax asset	18,687	17,265
Total assets	1,238,180	1,712,964
Current liabilities:
Accounts payable	153	0
Accounts payable to subsidiaries	38,558	0
Accrued liabilities	14,157	11,942
Derivatives	2,502	0
Total current liabilities	55,370	11,942
Long-term debt, net	741,606	640,856
Long-term note payable to subsidiary	0	217,000
Derivatives	140	0
Other long-term liabilities	910	1,464
Stockholders’ equity:
Preference shares, $0.01 par value; 200,000,000 authorized shares; zero issued at December 31, 2020 and December 31, 2019	0	0
Common stock, $0.01 par value; 2,000,000,000 authorized shares; 449,718,317 and 445,779,367 issued at December 31, 2020 and December 31, 2019, respectively	4,497	4,458
Additional paid-in capital	2,307,220	2,297,221
Accumulated deficit	(1,634,556)	(1,222,970)
Treasury stock, at cost, 44,263,269 shares at December 31, 2020 and December 31, 2019, respectively	(237,007)	(237,007)
Total stockholders’ equity	440,154	841,702
Total liabilities and stockholders’ equity	$ 1,238,180	$ 1,712,964

Condensed Parent Company Fina_3

Condensed Parent Company Financial Statements - Balance Sheet - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred financing costs, accumulated amortization	$ 17,296	$ 14,681
Preference shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preference shares, authorized shares (in shares)	200,000,000	200,000,000
Preference shares, issued shares (in shares)	0	0
Common shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, authorized shares (in shares)	2,000,000,000	2,000,000,000
Common shares, issued shares (in shares)	449,718,317	445,779,367
Treasury stock shares (in shares)	44,263,269	44,263,269
Parent Company
Condensed Balance Sheet Statements, Captions [Line Items]
Deferred financing costs, accumulated amortization	$ 17,296	$ 14,681
Preference shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preference shares, authorized shares (in shares)	200,000,000	200,000,000
Preference shares, issued shares (in shares)	0	0
Common shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, authorized shares (in shares)	2,000,000,000	2,000,000,000
Common shares, issued shares (in shares)	449,718,317	445,779,367
Treasury stock shares (in shares)	44,263,269	44,263,269

Condensed Parent Company Fina_4

Condensed Parent Company Financial Statements - Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Mar. 26, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues and other income:
Oil and gas revenue										$ 804,033	$ 1,499,416	$ 886,666
Total revenues and other income		$ 366,316	$ 224,787	$ 127,314	$ 177,781	$ 460,215	$ 356,970	$ 395,934	$ 296,790	896,198	1,509,909	902,369
Costs and expenses:
General and administrative										72,142	110,010	99,856
Interest and other financing costs, net										109,794	155,074	101,176
Derivatives, net										17,180	71,885	(31,430)
Other expenses, net										37,802	24,648	(6,501)
Total costs and expenses		382,579	261,279	374,130	295,005	462,492	317,435	346,495	358,370	1,312,993	1,484,792	953,229
Income (loss) before income taxes										(416,795)	25,117	(50,860)
Income tax expense (benefit)										(5,209)	80,894	43,131
Net income (loss)		$ 7,956	$ (37,384)	$ (199,391)	$ (182,767)	$ (35,773)	$ 16,065	$ 16,837	$ (52,906)	$ (411,586)	$ (55,777)	(93,991)
Dividends declared per common share (in dollars per share)	$ 0.0452									$ 0.0452	$ 0.1808
Parent Company
Revenues and other income:
Oil and gas revenue										$ 0	$ 0	0
Other income—related party										2,642	0	0
Total revenues and other income										2,642	0	0
Costs and expenses:
General and administrative										40,162	40,840	47,279
General and administrative recoveries—related party										4,112	(30,822)	(36,197)
Interest and other financing costs, net										59,200	86,104	66,055
Interest and other financing costs, net—related party										(5,889)	(7,144)	(7,941)
Derivatives, net										2,642	0	0
Other expenses, net										0	10	49
Equity in (earnings) losses of subsidiaries										315,423	(15,064)	23,614
Total costs and expenses										415,650	73,924	92,859
Income (loss) before income taxes										(413,008)	(73,924)	(92,859)
Income tax expense (benefit)										(1,422)	(18,147)	1,132
Net income (loss)										$ (411,586)	$ (55,777)	$ (93,991)
Dividends declared per common share (in dollars per share)										$ 0.0452	$ 0.1808	$ 0

Condensed Parent Company Fina_5

Condensed Parent Company Financial Statements - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ 7,956	$ (37,384)	$ (199,391)	$ (182,767)	$ (35,773)	$ 16,065	$ 16,837	$ (52,906)	$ (411,586)	$ (55,777)	$ (93,991)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity-based compensation									32,706	32,370	35,230
Depreciation and amortization									495,209	573,118	339,214
Deferred income taxes									(42,587)	(90,370)	9,145
Change in fair value of derivatives									22,800	67,436	(29,960)
Loss on extinguishment of debt									2,902	24,794	4,324
Other									15,922	9,069	2,820
Changes in assets and liabilities:
Decrease in receivables									92,093	(29,735)	175,954
(Increase) decrease in prepaid expenses and other									7,882	34,586	(18,731)
Net cash provided by (used in) operating activities									196,145	628,150	260,491
Investing activities
Net cash provided by (used in) investing activities									(345,587)	(363,931)	(985,138)
Financing activities
Net proceeds from issuance of senior notes									0	641,875	0
Redemption of senior secured notes									0	(535,338)	0
Purchase of treasury stock / tax withholdings									(4,947)	(1,983)	(206,051)
Dividends									(19,271)	(72,599)	0
Deferred financing costs									(5,922)	(2,444)	(38,672)
Net cash provided by (used in) financing activities									69,860	(220,489)	605,277
Net increase (decrease) in cash, cash equivalents and restricted cash									(79,582)	43,730	(119,370)
Cash, cash equivalents and restricted cash at end of period				229,346				185,616	229,346	185,616	304,986
Cash, cash equivalents and restricted cash at beginning of period	149,764				229,346				149,764	229,346	185,616
Parent Company
Operating activities
Net loss									(411,586)	(55,777)	(93,991)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in (earnings) losses of subsidiaries									315,423	(15,064)	23,614
Equity-based compensation									32,706	32,370	35,230
Depreciation and amortization									8,644	5,039	7,292
Deferred income taxes									(1,422)	(18,397)	1,132
Other income—related party									(2,642)	0	0
Change in fair value of derivatives									2,642	0	0
Loss on extinguishment of debt									0	22,913	0
Other									0	0	268
Changes in assets and liabilities:
Decrease in receivables									856	427	1,234
(Increase) decrease in prepaid expenses and other									(480)	(115)	(23)
(Increase) decrease due to/from related party									162,897	43,974	(42,163)
Increase (decrease) in accounts payable and accrued liabilities									2,509	(8,754)	816
Net cash provided by (used in) operating activities									109,547	6,616	(66,591)
Investing activities
Investment in subsidiaries									(190,089)	287,972	(36,192)
Net cash provided by (used in) investing activities									(190,089)	287,972	(36,192)
Financing activities
Borrowings under long-term debt									100,000	0	400,000
Payments on long-term debt									0	(325,000)	(75,000)
Net proceeds from issuance of senior notes									0	641,875	0
Redemption of senior secured notes									0	(535,338)	0
Purchase of treasury stock / tax withholdings									(4,947)	(1,983)	(206,051)
Dividends									(19,271)	(72,599)	0
Deferred financing costs									(496)	(1,897)	(9,382)
Net cash provided by (used in) financing activities									75,286	(294,942)	109,567
Net increase (decrease) in cash, cash equivalents and restricted cash									(5,256)	(354)	6,784
Cash, cash equivalents and restricted cash at end of period				$ 6,727				$ 7,081	6,727	7,081	297
Cash, cash equivalents and restricted cash at beginning of period	$ 1,471				$ 6,727				1,471	6,727	7,081
Non-cash activity:
Issuance of common stock for related party receivable									$ 0	$ 0	$ 307,944

Valuation and Qualifying Acco_2

Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for credit losses
Changes in valuation and qualifying Accounts
Balance at the beginning of the period	$ 2,748	$ 1,211	$ 0
Charged to Costs and Expenses	1,800	1,324	1,211
Charged To Other Accounts	1,127	228	0
Deductions From Reserves	0	(15)	0
Balance at the end of the period	5,675	2,748	1,211
Allowance for deferred tax assets
Changes in valuation and qualifying Accounts
Balance at the beginning of the period	201,749	156,860	93,525
Charged to Costs and Expenses	86,539	44,889	63,335
Charged To Other Accounts	0	0	0
Deductions From Reserves	0	0	0
Balance at the end of the period	$ 288,288	$ 201,749	$ 156,860