Diamond Offshore Drilling (DODRW) 10-K 11 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 07, 2020	Jun. 28, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	DO
Entity Registrant Name	DIAMOND OFFSHORE DRILLING, INC.
Entity Central Index Key	0000949039
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		137,703,910
Entity Public Float			$ 572,749,915
Title of 12(b) Security	Common Stock, $0.01 par value per share
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity File Number	1-13926
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	76-0321760
Entity Address, Address Line One	15415 Katy Freeway
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77094
City Area Code	281
Local Phone Number	492-5300
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Documents Incorporated by Reference	Portions of the definitive proxy statement relating to the 2020 Annual Meeting of Stockholders of Diamond Offshore Drilling, Inc., which will be filed within 120 days of December 31, 2019, are incorporated by reference in Part III of this report.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 156,281	$ 154,073
Marketable securities		299,849
Accounts receivable, net of allowance for bad debts	250,856	168,620
Prepaid expenses and other current assets	68,658	163,396
Asset held for sale	1,000
Total current assets	476,795	785,938
Drilling and other property and equipment, net of accumulated depreciation	5,152,828	5,184,222
Other assets	204,421	65,534
Total assets	5,834,044	6,035,694
Current liabilities:
Accounts payable	68,586	43,933
Accrued liabilities	210,780	172,228
Taxes payable	23,228	20,685
Total current liabilities	302,594	236,846
Long-term debt	1,975,741	1,973,922
Deferred tax liability	47,528	104,380
Other liabilities	275,971	135,893
Total liabilities	2,601,834	2,451,041
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock (par value $0.01, 25,000,000 shares authorized, none issued and outstanding)
Common stock (par value $0.01, 500,000,000 shares authorized; 144,781,766 shares issued and 137,703,910 shares outstanding at December 31, 2019; 144,383,662 shares issued and 137,438,353 shares outstanding at December 31, 2018)	1,448	1,444
Additional paid-in capital	2,024,347	2,018,143
Retained earnings	1,412,201	1,769,415
Accumulated other comprehensive (loss) gain	(18)	21
Treasury stock, at cost (7,077,856 and 6,945,309 shares of common stock at December 31, 2019 and 2018, respectively)	(205,768)	(204,370)
Total stockholders’ equity	3,232,210	3,584,653
Total liabilities and stockholders’ equity	$ 5,834,044	$ 6,035,694

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	144,781,766	144,383,662
Common stock, shares outstanding	137,703,910	137,438,353
Treasury stock, shares	7,077,856	6,945,309

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Total revenues	$ 980,644	$ 1,083,215	$ 1,485,746
Operating expenses:
Depreciation	355,596	331,789	348,695
General and administrative	67,878	85,351	74,505
Impairment of assets		27,225	99,313
Restructuring and separation costs		5,041	14,146
Loss (gain) on disposition of assets	1,072	241	(10,500)
Total operating expenses	1,262,974	1,195,398	1,361,867
Operating (loss) income	(282,330)	(112,183)	123,879
Other income (expense):
Interest income	6,382	8,477	2,473
Interest expense, net of amounts capitalized	(122,832)	(123,240)	(113,528)
Loss on extinguishment of senior notes			(35,366)
Foreign currency transaction loss	(3,936)	(379)	(1,128)
Other, net	702	700	2,230
Loss before income tax benefit	(402,014)	(226,625)	(21,440)
Income tax benefit	44,800	46,353	39,786
Net (loss) income	$ (357,214)	$ (180,272)	$ 18,346
(Loss) earnings per share:
Basic	$ (2.60)	$ (1.31)	$ 0.13
Diluted	$ (2.60)	$ (1.31)	$ 0.13
Weighted-average shares outstanding:
Shares of common stock	137,652	137,399	137,213
Dilutive potential shares of common stock			52
Total weighted-average shares outstanding	137,652	137,399	137,265
Contract Drilling [Member]
Revenues:
Total revenues	$ 934,934	$ 1,059,973	$ 1,451,219
Operating expenses:
Contract drilling, excluding depreciation	793,412	722,834	801,964
Reimbursable Expenses [Member]
Revenues:
Total revenues	45,710	23,242	34,527
Operating expenses:
Contract drilling, excluding depreciation	$ 45,016	$ 22,917	$ 33,744

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income or Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (357,214)	$ (180,272)	$ 18,346
Derivative financial instruments:
Reclassification adjustment for gain included in net (loss) income	(7)	(6)	(6)
Investments in marketable securities:
Unrealized holding gain on investments	23	69
Reclassification adjustment for gain included in net (loss) income	(55)	(37)
Total other comprehensive (loss) gain	(39)	26	(6)
Comprehensive (loss) income	$ (357,253)	$ (180,246)	$ 18,340

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Gains (Losses) [Member]	Treasury Stock [Member]
Beginning Balance at Dec. 31, 2016	$ 3,750,134	$ 1,440	$ 2,004,514	$ 1,946,765	$ 1	$ (202,586)
Beginning Balance, shares at Dec. 31, 2016		143,997,757				6,828,094
Impact of change in accounting principle at Dec. 31, 2016			634	(634)
Adjusted balance at Dec. 31, 2016	3,750,134	$ 1,440	2,005,148	1,946,131	1	$ (202,586)
Adjusted balance, shares at Dec. 31, 2016		143,997,757				6,828,094
Net (loss) income	18,346			18,346
Anti-dilution adjustment	20			20
Stock-based compensation, net of tax	5,767	$ 1	6,249			$ (483)
Stock-based compensation, net of tax, shares		87,535				29,416
Net loss on derivative financial instruments	(6)				(6)
Ending Balance at Dec. 31, 2017	3,774,261	$ 1,441	2,011,397	1,964,497	(5)	$ (203,069)
Ending Balance, shares at Dec. 31, 2017		144,085,292				6,857,510
Impact of change in accounting principle at Dec. 31, 2017	(14,812)			(14,812)
Adjusted balance at Dec. 31, 2017	3,759,449	$ 1,441	2,011,397	1,949,685	(5)	$ (203,069)
Adjusted balance, shares at Dec. 31, 2017		144,085,292				6,857,510
Net (loss) income	(180,272)			(180,272)
Anti-dilution adjustment	2			2
Stock options exercised, shares		3,773
Stock-based compensation, net of tax	5,448	$ 3	6,746			$ (1,301)
Stock-based compensation, net of tax, shares		294,597				87,799
Net loss on derivative financial instruments	(6)				(6)
Net gain (loss) on investments	32				32
Ending Balance at Dec. 31, 2018	3,584,653	$ 1,444	2,018,143	1,769,415	21	$ (204,370)
Ending Balance, shares at Dec. 31, 2018		144,383,662				6,945,309
Net (loss) income	(357,214)			(357,214)
Stock-based compensation, net of tax	4,810	$ 4	6,204			$ (1,398)
Stock-based compensation, net of tax, shares		398,104				132,547
Net loss on derivative financial instruments	(7)				(7)
Net gain (loss) on investments	(32)				(32)
Ending Balance at Dec. 31, 2019	$ 3,232,210	$ 1,448	$ 2,024,347	$ 1,412,201	$ (18)	$ (205,768)
Ending Balance, shares at Dec. 31, 2019		144,781,766				7,077,856

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net (loss) income	$ (357,214)	$ (180,272)	$ 18,346
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation	355,596	331,789	348,695
Loss on impairment of assets		27,225	99,313
Loss on extinguishment of senior notes			35,366
Restructuring and separation costs		1,478	14,146
Loss (gain) on disposition of assets	1,072	241	(10,500)
Deferred tax provision	(56,908)	(75,993)	(72,127)
Stock-based compensation expense	6,208	6,749	6,250
Contract liabilities, net	27,578	183	8,676
Contract assets, net	2,625	(6,221)
Deferred contract costs, net	59,141	22,765	46,337
Long-term employee remuneration programs	3,169	547	3,801
Other assets, noncurrent	52	(1,307)	(326)
Other liabilities, noncurrent	6,514	(3,217)	(963)
Other	2,380	1,013	3,907
Changes in operating assets and liabilities:
Accounts receivable	(37,832)	87,970	(11,049)
Prepaid expenses and other current assets	(1,170)	6,211	(1,291)
Accounts payable and accrued liabilities	3,897	(7,587)	19,803
Taxes payable	(6,019)	20,484	(14,576)
Net cash provided by operating activities	9,089	232,058	493,808
Investing activities:
Capital expenditures (including rig construction)	(326,090)	(222,406)	(139,581)
Proceeds from disposition of assets, net of disposal costs	16,217	70,067	15,196
Proceeds from sale and maturities of marketable securities	2,300,000	1,600,000	35
Purchase of marketable securities	(1,996,996)	(1,895,997)
Net cash used in investing activities	(6,869)	(448,336)	(124,350)
Financing activities:
Redemption of senior notes			(500,000)
Payment of debt extinguishment costs			(34,395)
Proceeds from issuance of senior notes			496,360
Repayment of short-term borrowings, net			(104,200)
Debt issuance costs and arrangement fees	(12)	(5,651)	(7,263)
Other		(35)	(156)
Net cash used in financing activities	(12)	(5,686)	(149,654)
Net change in cash and cash equivalents	2,208	(221,964)	219,804
Cash and cash equivalents, beginning of year	154,073	376,037	156,233
Cash and cash equivalents, end of year	$ 156,281	$ 154,073	$ 376,037

General Information

General Information	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
General Information	1. General Information Diamond Offshore Drilling, Inc. provides contract drilling services to the energy industry around the globe with a fleet of 15 offshore drilling rigs, consisting of four drillships and 11 semisubmersible rigs, including two rigs that are currently cold stacked. Our current fleet excludes the Ocean Confidence Unless the context otherwise requires, references in these Notes to “Diamond Offshore,” “we,” “us” or “our” mean Diamond Offshore Drilling, Inc. and our consolidated subsidiaries. We were incorporated in Delaware in 1989. As of February 7, 2020, Loews Corporation, or Loews, owned approximately 53% of the outstanding shares of our common stock. Principles of Consolidation Our consolidated financial statements include the accounts of Diamond Offshore Drilling, Inc. and our wholly-owned subsidiaries after elimination of intercompany transactions and balances. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States, or U.S., or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amount of revenues and expenses during the reporting period. Actual results could differ from those estimated. Changes in Accounting Principles Leases. Leases We adopted ASU 2016-02 effective January 1, 2019 using an optional transition method requiring leases existing at, or entered into after, January 1, 2019 to be recognized and measured under the new accounting standard. Prior period amounts have not been adjusted and continue to be reflected in accordance with our historical accounting for leases. In our adoption of ASU 2016-02, we also utilized a transition practical expedient package whereby we did not reassess (i) whether any of our expired or existing contracts contain a lease, (ii) the classification for any expired or existing leases and (iii) initial direct costs for any existing leases. The adoption of this standard resulted in the recording of operating lease assets and offsetting operating lease liabilities of $146.8 million as of January 1, 2019, with no related impact on our annual Consolidated Statement of Stockholders’ Equity. See Note 11. Upon adoption of ASU 2016-02, we concluded that our drilling contracts contain a lease component for the use of our drilling rigs based on the updated definition of a lease. However, ASU 2016-02 provides for a practical expedient for lessors whereby, under certain circumstances, the lessor may combine the lease and non-lease components and account for the combined component in accordance with the accounting treatment for the predominant component. We have determined that our current drilling contracts qualify for this practical expedient and have combined the lease and service components of our standard drilling contracts. We continue to account for the combined component under ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606 ) and its related amendments . Revenue Recognition Revenue from Contracts with Customers We adopted ASU 2014-09 and its related amendments, or collectively Topic 606, effective January 1, 2018 using the modified retrospective implementation method. Accordingly, we have applied the five-step method outlined in Topic 606 for determining when and how revenue is recognized to all contracts that were not completed as of the date of adoption. Revenues for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts have not been adjusted and continue to be reported under the previous revenue recognition guidance. For contracts that were modified before the effective date, we have considered the modification guidance within the new standard and determined that the revenue recognized and contract balances recorded prior to adoption for such contracts were not impacted. While Topic 606 requires additional disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers, its adoption has not had a material impact on the measurement or recognition of our revenues. Our adoption of ASU 2014-09 represents a change in accounting principle and therefore, we have recorded the cumulative effect of adopting Topic 606 as an increase to opening retained earnings on January 1, 2018. This adjustment represents an accrual for the earned portion of demobilization revenue expected to be received for contracts not completed as of December 31, 2017, which was not recordable under previous revenue recognition guidance until completion of the demobilization activities. See Note 2. Income Taxes Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory, amended the guidance in Topic 740 with respect to the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. We have evaluated our historical intra-group transactions for impact under the provisions of ASU 2016-16 and adopted the guidance thereof effective January 1, 2018 using the modified retrospective approach. We recorded the $17.4 million cumulative effect of applying the new standard as a decrease to opening retained earnings with an offset to deferred income tax liability. See Note 14. Stock-Based Compensation Compensation - Stock Compensation (Topic 718) , or ASU 2016-09, which required We adopted ASU 2016-09 on January 1, 2017 using a modified retrospective approach and have elected to account for forfeitures of share-based awards in the period in which such forfeitures occur . The adoption Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments 49 periods beginning after December 15, 2019 . We adopted ASU 2016-13 effective January 1, 2020 by applying a modified retrospective method and the impact was not material to our consolidated financial statements. Cash and Cash Equivalents We consider short-term, highly liquid investments that have an original maturity of three months or less and deposits in money market mutual funds that are readily convertible into cash to be cash equivalents. The effect of exchange rate changes on cash balances held in foreign currencies was not material for the years ended December 31, 2019, 2018 and 2017. Provision for Bad Debts Prior to the adoption of ASU 2016-13, we have historically recorded a provision for bad debts on a case-by-case basis when facts and circumstances indicated that a customer receivable may not be collectible. In establishing these reserves, we considered historical and other factors that predicted collectability of such customer receivables, including write-offs, recoveries and the monitoring of credit quality. Such provision was reported as a component of “Operating expense” in our Consolidated Statements of Operations. See Note 4. Drilling and Other Property and Equipment We carry our drilling and other property and equipment at cost, less accumulated depreciation. Maintenance and routine repairs are charged to income currently while replacements and betterments that upgrade or increase the functionality of our existing equipment and that significantly extend the useful life of an existing asset are capitalized. Significant judgments, assumptions and estimates may be required in determining whether or not such replacements and betterments meet the criteria for capitalization and in determining useful lives and salvage values of such assets. Changes in these judgments, assumptions and estimates could produce results that differ from those reported. During the years ended December 31, 2019 and 2018, we capitalized $343.8 million and $243.6 million, respectively, in replacements and betterments of our drilling fleet. Costs incurred for major rig upgrades and/or the construction of rigs are accumulated in construction work-in-progress, with no depreciation recorded on the additions, until the month the upgrade or newbuild is completed and the rig is placed in service. Upon retirement or sale of a rig, the cost and related accumulated depreciation are removed from the respective accounts and any gains or losses are reported in our Consolidated Statements of Operations as “Loss (gain) on disposition of assets.” Depreciation is recognized up to applicable salvage values by applying the straight-line method over the remaining estimated useful lives from the year the asset is placed in service. Drilling rigs and equipment are depreciated over their estimated useful lives ranging from 3 to 30 years. Capitalized Interest We capitalize interest cost for rig construction and other qualifying projects. A reconciliation of our total interest cost to “Interest expense, net of amounts capitalized” as reported in our Consolidated Statements of Operations is as follows (in thousands): For the Year Ended December 31, 2019 2018 2017 Total interest cost including amortization of debt issuance costs $ 122,832 $ 123,816 $ 113,618 Capitalized interest — (576 ) (90 ) Total interest expense as reported $ 122,832 $ 123,240 $ 113,528 50 Impairment of Long-Lived Assets We evaluate our property and equipment for impairment whenever changes in circumstances indicate that the carrying amount of an asset may not be recoverable (such as, but not limited to, cold stacking a rig, the expectation of cold stacking a rig in the near term, contracted backlog of less than one year for a rig, a decision to retire or scrap a rig, or excess spending over budget on a newbuild, construction project or major rig upgrade). We utilize an undiscounted probability-weighted cash flow analysis in testing an asset for potential impairment. Our assumptions and estimates underlying this analysis include the following: • dayrate by rig; • utilization rate by rig if active, warm stacked or cold stacked (expressed as the actual percentage of time per year that the rig would be used at certain dayrates); • the per day operating cost for each rig if active, warm stacked or cold stacked; • the estimated annual cost for rig replacements and/or enhancement programs; • the estimated maintenance, inspection or other reactivation costs associated with a rig returning to work; • salvage value for each rig; and • estimated proceeds that may be received on disposition of each rig. Based on these assumptions, we develop a matrix for each rig under evaluation using multiple utilization/dayrate scenarios, to each of which we have assigned a probability of occurrence. We arrive at a projected probability-weighted cash flow for each rig based on the respective matrix and compare such amount to the carrying value of the asset to assess recoverability. The underlying assumptions and assigned probabilities of occurrence for utilization and dayrate scenarios are developed using a methodology that examines historical data for each rig, which considers the rig’s age, rated water depth and other attributes and then assesses its future marketability in light of the current and projected market environment at the time of assessment. Other assumptions, such as operating, maintenance, inspection and reactivation costs, are estimated using historical data adjusted for known developments, cost projections for re-entry of rigs into the market and future events that are anticipated by management at the time of the assessment. Management’s assumptions are necessarily subjective and are an inherent part of our asset impairment evaluation , Fair Value of Financial Instruments We believe that the carrying amount of our current financial instruments approximates fair value because of the short maturity of these instruments. See Note 7. 51 Debt Issuance Costs Deferred costs associated with our credit facilities are presented in “Other assets” in our Consolidated Balance Sheets at December 31, 2019 and 2018 and amortized as interest expense over the respective terms of the credit facilities. During 2018, we paid $5.7 million in debt issuance and arrangement fees in connection with our credit facilities. Deferred costs associated with our senior notes are presented in our Consolidated Balance Sheets at December 31, 2019 and 2018 as a reduction to the related long-term debt and are amortized over the respective terms of the related debt. See Note 9. Income Taxes We account for income taxes in accordance with accounting standards that require the recognition of the amount of taxes payable or refundable for the current year and an asset and liability approach in recognizing the amount of deferred tax liabilities and assets for the future tax consequences of events that have been currently recognized in our financial statements or tax returns. In each of our tax jurisdictions we recognize a current tax liability or asset for the estimated taxes payable or refundable on tax returns for the current year and a deferred tax asset or liability for the estimated future tax effects attributable to temporary differences and carryforwards. Deferred tax assets are reduced by a valuation allowance, if necessary, which is determined by the amount of any tax benefits that, based on available evidence, are not expected to be realized under a “more likely than not” approach. Deferred tax assets and liabilities are classified as noncurrent in a classified statement of financial position. We make judgments regarding future events and related estimates especially as they pertain to the forecasting of our effective tax rate, the potential realization of deferred tax assets such as utilization of foreign tax credits, and exposure to the disallowance of items deducted on tax returns upon audit. We record both interest and penalties related to accrued uncertain tax positions in “Income tax benefit” in our Consolidated Statements of Operations. Liabilities for uncertain tax positions, including any interest and penalties, are denominated in the currency of the related tax jurisdiction and are revalued for changes in currency exchange rates. The revaluation of such liabilities for uncertain tax positions is reported in “Income tax benefit” in our Consolidated Statements of Operations. See Note 14. Comprehensive (Loss) Income Comprehensive (loss) income is the change in equity of a business enterprise during a period from transactions and other events and circumstances except those transactions resulting from investments by owners and distributions to owners. Comprehensive (loss) income for the three years ended December 31, 2019, 2018 and 2017 includes net (loss) income and unrealized holding gains and losses on marketable securities and financial derivatives designated as cash flow accounting hedges. Foreign Currency Our functional currency is the U.S. dollar. Transactions incurred in currencies other than the U.S. dollar are subject to gains or losses due to fluctuations in those currencies. We report foreign currency transaction gains and losses as “Foreign currency transaction (loss) gain” in our Consolidated Statements of Operations. The revaluation of assets and liabilities related to foreign income taxes, including deferred tax assets and liabilities and uncertain tax positions, including any interest and/or penalties, is reported in “Income tax benefit” in our Consolidated Statements of Operations.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	2. Revenue from Contracts with Customers The activities that primarily drive the revenue earned from our contract drilling services includes (i) providing a drilling rig and the crew and supplies necessary to operate the rig, (ii) mobilizing and demobilizing the rig to and from the drill site and (iii) performing rig preparation activities and/or modifications required for the contract. Consideration received for performing these activities may consist of dayrate drilling revenue, mobilization and demobilization revenue, contract preparation revenue and reimbursement revenue. We account for these integrated services provided within our drilling contracts as a single performance obligation satisfied over time and comprised of a series of distinct time increments in which we provide drilling services. Consideration for activities that are not distinct within the context of our contracts and do not correspond to a distinct time increment within the contract term are allocated across the single performance obligation and recognized ratably over the initial term of the contract (which is the period we estimate to be benefited from the corresponding activities and generally ranges from two to 60 months). Consideration for activities that correspond to a distinct time increment within the contract term is recognized in the period when the services are performed. The total transaction price is determined for each individual contract by estimating both fixed and variable consideration expected to be earned over the term of the contract. See below for further discussion regarding the allocation of the transaction price to the remaining performance obligations. The amount estimated for variable consideration may be constrained (reduced) and is only included in the transaction price to the extent that it is probable that a significant reversal of previously recognized revenue will not occur throughout the term of the contract. When determining if variable consideration should be constrained, management considers whether there are factors outside of our control that could result in a significant reversal of revenue as well as the likelihood and magnitude of a potential reversal of revenue. These estimates are re-assessed each reporting period as required. Dayrate Drilling Revenue. Our drilling contracts generally provide for payment on a dayrate basis, with higher rates for periods when the drilling unit is operating and lower rates or zero rates for periods when drilling operations are interrupted or restricted. The dayrate invoices billed to the customer are typically determined based on the varying rates applicable to the specific activities performed on an hourly basis. Such dayrate consideration is allocated to the distinct hourly increment it relates to within the contract term, and therefore, recognized in line with the contractual rate billed for the services provided for any given hour. Mobilization/Demobilization Revenue. We may receive fees (on either a fixed lump-sum or variable dayrate basis) for the mobilization and demobilization of our rigs. These activities are not considered to be distinct within the context of the contract and therefore, the associated revenue is allocated to the overall performance obligation and recognized ratably over the initial term of the related drilling contract. We record a contract liability for mobilization fees received, which is amortized ratably to contract drilling revenue as services are rendered over the initial term of the related drilling contract. Demobilization revenue expected to be received upon contract completion is estimated as part of the overall transaction price at contract inception and recognized in earnings ratably over the initial term of the contract with an offset to an accretive contract asset. In some contracts, there is uncertainty as to the likelihood and amount of expected demobilization revenue to be received. For example, contractual provisions may require that a rig demobilize a certain distance before the demobilization revenue is payable or the amount may vary dependent upon whether or not the rig has additional contracted work within a certain distance from the wellsite. Therefore, the estimate for such revenue may be constrained, as described above, depending on the facts and circumstances pertaining to the specific contract. We assess the likelihood of receiving such revenue based on our past experience and knowledge of market conditions. Contract Preparation Revenue. Some of our drilling contracts require downtime before the start of the contract to prepare the rig to meet customer requirements. At times, we may be compensated by the customer for such work (on either a fixed lump-sum or variable dayrate basis). These activities are not considered to be distinct within the context of the contract. We record a contract liability for contract preparation fees received, which is amortized ratably to contract drilling revenue over the initial term of the related drilling contract. 53 Capital Modification Revenue . From time to time, we may receive fees from our customers for capital improvements or upgrades to our rigs to meet contractual requirements (on either a fixed lump-sum or variable dayrate basis). The activities related to these capital modifications are not considered to be distinct within the context of our contracts. We record a contract liability for such fees and recognize them ratably as contract drilling revenue over the initial term of the related drilling contract. Revenues Related to Reimbursable Expenses . We generally receive reimbursements from our customers for the purchase of supplies, equipment, personnel services and other services provided at their request in accordance with a drilling contract or other agreement. Such reimbursable revenue is variable and subject to uncertainty, as the amounts received and timing thereof are highly dependent on factors outside of our influence. Accordingly, reimbursable revenue is fully constrained and not included in the total transaction price until the uncertainty is resolved, which typically occurs when the related costs are incurred on behalf of a customer. We are generally considered a principal in such transactions and record the associated revenue at the gross amount billed to the customer, as “Revenues related to reimbursable expenses” in our Consolidated Statements of Operations. Such amounts are recognized ratably over the period within the contract term during which the corresponding goods and services are to be consumed. Contract Balances Accounts receivable are recognized when the right to consideration becomes unconditional based upon contractual billing schedules. Payment terms on invoiced amounts are typically 30 days. Contract asset balances consist primarily of demobilization revenue that we expect to receive and is recognized ratably throughout the contract term, but invoiced upon completion of the demobilization activities. Once the demobilization revenue is invoiced, the corresponding contract asset is transferred to accounts receivable. Contract assets may also include amounts recognized in advance of amounts invoiced due to the blending of rates when a contract has operating dayrates that increase over the initial contract term. Contract liabilities include payments received for mobilization as well as rig preparation and upgrade activities which are allocated to the overall performance obligation and recognized ratably over the initial term of the contract. Contract liabilities may also include amounts invoiced in advance of amounts recognized due to the blending of rates when a contract has operating dayrates that decrease over the initial contract term. Contract balances are netted at a contract level, such that deferred revenue for mobilization, contract preparation and capital modifications (contract liabilities) is netted with any accrued demobilization revenue (contract asset) for each applicable contract. The following table provides information about receivables, contract assets and contract liabilities from our contracts with customers (in thousands): December 31, 2019 December 31, 2018 Trade receivables $ 199,572 $ 160,478 Current contract assets (1) 6,314 6,832 Noncurrent contract assets (1) — 2,107 Current contract liabilities (deferred revenue) (1) (9,573 ) (2,803 ) Noncurrent contract liabilities (deferred revenue) (1) (38,531 ) (17,723 ) (1) Contract assets and contract liabilities may reflect balances that have been netted together on a contract basis. Net current contract asset and liability balances are included in “Prepaid expenses and other current assets” and “Accrued liabilities,” respectively, and net noncurrent contract asset and liability balances are included in “Other assets” and “Other liabilities,” respectively, in our Consolidated Balance Sheets as of December 31, 2019 and 2018. 54 Significant changes in the contract assets and the contract liabilities balances during the period are as follows (in thousands): Net Contract Balances December 31, 2019 2018 Contract assets, beginning of period $ 8,939 $ 2,718 Contract liabilities, beginning of period (20,526 ) (20,343 ) Net balance at beginning of period (11,587 ) (17,625 ) Decrease due to amortization of revenue that was included in the beginning contract liability balance 6,952 19,026 Increase due to cash received, excluding amounts recognized as revenue during the period (34,529 ) (19,353 ) Increase due to revenue recognized during the period but contingent on future performance 3,537 7,114 Decrease due to transfer to receivables during the period (5,119 ) (893 ) Adjustments (1,044 ) 144 Net balance at end of period $ (41,790 ) $ (11,587 ) Contract assets at end of period $ 6,314 $ 8,939 Contract liabilities at end of period (48,104 ) (20,526 ) Deferred Contract Costs Certain direct and incremental costs incurred for upfront preparation, initial mobilization and modifications of contracted rigs represent costs of fulfilling a contract as they relate directly to a contract, enhance resources that will be used in satisfying our performance obligations in the future and are expected to be recovered. Such costs are deferred and amortized ratably to contract drilling expense as services are rendered over the initial term of the related drilling contract. Such deferred contract costs in the amount of $20.0 million and $4.0 million are reported in “Prepaid expenses and other current assets” and “Other assets,” respectively, in our Consolidated Balance Sheets at December 31, 2019. Deferred contract costs in the amount of $70.0 million and $13.1 million are reported in “Prepaid expenses and other current assets” and “Other assets,” respectively, in our Consolidated Balance Sheets at December 31, 2018. During the years ended December 31, 2019 and 2018, the amount of amortization of such costs was $96.0 million and $67.7 million, respectively. There was no impairment loss in relation to capitalized costs. Costs incurred for the demobilization of rigs at contract completion are recognized as incurred during the demobilization process. Costs incurred for rig modifications or upgrades required for a contract, which are considered to be capital improvements, are capitalized as drilling and other property and equipment and depreciated over the estimated useful life of the improvement. Transaction Price Allocated to Remaining Performance Obligations The following table reflects revenue expected to be recognized in the future related to unsatisfied performance obligations as of December 31, 2019 (in thousands): For the Years Ending December 31, 2020 2021 2022 Total Mobilization and contract preparation revenue $ 2,268 $ 630 $ 124 $ 3,022 Capital modification revenue 9,028 1,777 — 10,805 Blended rate revenue 27,848 9,114 — 36,962 Total $ 39,144 $ 11,521 $ 124 $ 50,789 55 The revenue included above consists of expected fixed m obilization and upgrade revenue for both wholly and partially unsatisfied performance obligations as well as expected variable m obilization and upgrade revenue for partially unsatisfied performance obligations, which has been estimated for purposes of allocating across the entire corresponding performance obligations. Revenue expected to be recognized in the future related to the blending of rates when a contract has operating dayrates that decrease over the initial contract term is also included. The amounts are derived from the specific terms within drilling contracts that contain such provisions, and the expected timing for recognition of such revenue is based on the estimated start date and duration of each respective contract based on information known at December 31, 2019 . The actual timing of recognition of such amounts may vary due to factors outside of our control. We have applied the disclosure practical expedient in Topic 606 and have not included estimated variable consideration related to wholly unsatisfied performance obligations or to distinct future time increments within our contracts, including dayrate revenue .

Asset Impairments

Asset Impairments	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Asset Impairments	3. Asset Impairments 2019 Impairment Evaluation. At December 31, 2019, we evaluated three drilling rigs with indicators of impairment. Based on our assumptions and analysis at that time, we determined that the undiscounted probability-weighted cash flow of each of these rigs was in excess of its carrying value. As a result, we concluded that no impairment of these rigs had occurred at December 31, 2019. 2018 Impairment. During 2018, we recorded an impairment loss of $27.2 million to recognize a reduction in fair value of the . We estimated the fair value of the impaired rig using a market approach based on a signed agreement to sell the rig, less estimated costs to sell. We considered this valuation approach to be a Level 3 fair value measurement due to the level of estimation involved as the sale had not yet been completed at the time of our analysis. 2017 Impairments. During 2017, we evaluated ten of our drilling rigs with indicators of impairment and determined that the carrying values of three rigs were impaired (we collectively refer to these three rigs as the 2017 Impaired Rigs). We estimated the fair value of two of the 2017 Impaired Rigs using an income approach, whereby the fair value of each rig was estimated based on a calculation of the rig’s future net cash flows. These calculations utilized significant unobservable inputs, including estimated proceeds that may be received on ultimate disposition of each rig. The fair value of the remaining 2017 Impaired Rig was estimated using a market approach, which required us to estimate the value that would be received for the rig in the principal or most advantageous market for that rig in an orderly transaction between market participants. This estimate was primarily based on an indicative bid to purchase the rig at that time, as well as our evaluation of other market data points. Our fair value estimates were representative of Level 3 fair value measurements due to the significant level of estimation involved and the lack of transparency as to the inputs used. We recorded aggregate impairment losses of $99.3 million for the year ended December 31, 2017 related to our 2017 Impaired Rigs. See Note 1.

Supplemental Financial Informat

Supplemental Financial Information	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Supplemental Financial Information	4. Supplemental Financial Information Consolidated Balance Sheets Information Accounts receivable, net of allowance for bad debts, consists of the following (in thousands): December 31, 2019 2018 Trade receivables $ 199,572 $ 160,478 Federal income tax receivable 38,574 — Value added tax receivables 17,716 13,237 Related party receivables 166 174 Other 287 190 256,315 174,079 Allowance for bad debts (5,459 ) (5,459 ) Total $ 250,856 $ 168,620 There was no change in our provision for bad debts for each of the years ended December 31, 2019, 2018 and 2017. See Note 7 for a discussion of our policy regarding uncollectible accounts. Prepaid expenses and other current assets consist of the following (in thousands): December 31, 2019 2018 Deferred contract costs $ 20,019 $ 70,021 Rig spare parts and supplies 18,250 20,256 Prepaid taxes 12,475 54,412 Current contract assets 6,314 6,832 Prepaid rig costs 2,990 5,247 Prepaid insurance 2,892 2,742 Prepaid software costs 2,319 1,531 Other 3,399 2,355 Total $ 68,658 $ 163,396 Accrued liabilities consist of the following (in thousands): December 31, 2019 2018 Accrued capital project/upgrade costs $ 56,603 $ 37,379 Payroll and benefits 42,494 47,564 Rig operating expenses 37,969 42,323 Interest payable 28,234 28,234 Current operating lease liability (1) 20,030 — Deferred revenue 9,573 2,803 Personal injury and other claims 7,074 5,544 Shorebase and administrative costs 5,275 6,217 Other 3,528 2,164 Total $ 210,780 $ 172,228 (1) 57 Consolidated Statements of Cash Flows Information Noncash investing activities excluded from the Consolidated Statements of Cash Flows and other supplemental cash flow information is as follows (in thousands): December 31, 2019 2018 2017 Accrued but unpaid capital expenditures at period end $ 56,603 $ 37,234 $ 3,698 Common stock withheld for payroll tax obligations (1) 1,398 1,301 483 Cash interest payments 113,063 113,063 97,096 Cash income taxes paid (refunded), net: Foreign 17,821 9,286 43,999 U.S. federal 1,001 (7,389 ) — State (15 ) 2 94 (1) Represents the cost of 132,547, 87,799 and 29,416 shares of common stock withheld to satisfy the payroll tax obligation incurred as a result of the vesting of restricted stock units in 2019, 2018 and 2017, respectively. These costs are presented as a deduction from stockholders’ equity in “Treasury stock” in our Consolidated Balance Sheets at December 31, 2019, 2018 and 2017, respectively

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	5. Stock-Based Compensation We have an Equity Incentive Compensation Plan, or Equity Plan, for our officers, independent contractors, employees and non-employee directors, which is designed to encourage stock ownership by such persons. Under the Equity Plan, we may grant both time-vesting and performance-vesting awards, which are earned on the achievement of certain performance criteria. The following types of awards may be granted under the Equity Plan: • Stock options (including incentive stock options and nonqualified stock options); • Stock appreciation rights, or SARs; • Restricted stock; • Restricted stock units, or RSUs; • Performance shares or units; and • Other stock-based awards (including dividend equivalents). A maximum of 7,500,000 shares of our common stock is available for the grant or settlement of awards under the Equity Plan, subject to adjustment for certain business transactions and changes in capital structure. Vesting conditions and other terms and conditions of awards under the Equity Plan are determined by our Board of Directors or the compensation committee of our Board of Directors, subject to the terms of the Equity Plan. RSUs may be issued with performance-vesting or time-vesting features. Except for RSUs issued to our Chief Executive Officer, RSUs are not participating securities, and the holders of such awards have no right to receive regular dividends if or when declared. However, we have not paid a dividend to stockholders since 2015. Total compensation cost recognized for all awards under the Equity Plan (or its predecessor) for the years ended December 31, 2019, 2018 and 2017 was $6.2 million, $6.8 million and $8.7 million, respectively. Tax benefits recognized for the years ended December 31, 2019, 2018 and 2017 related thereto were $0.5 million, $0.8 million and $2.6 million, respectively. As of December 31, 2019 there was $6.6 million of total unrecognized compensation cost related to non-vested awards under the Equity Plan, which we expect to recognize over a weighted average period of two years. 58 Time- Vesting A wards SARs . Currently, SARs awarded under the Equity Plan generally vest immediately and expire in ten years. The exercise price per share of SARs awarded under the Equity Plan may not be less than the fair market value of our common stock on the date of grant. The fair value of SARs granted under the Equity Plan (or its predecessor) during each of the years ended December 31, 2019, 2018 and 2017 was estimated using the Black Scholes pricing model with the following weighted average assumptions: Year Ended December 31, 2019 2018 2017 Expected life of SARs (in years) 7 7 7 Expected volatility 39.35 % 32.10 % 31.70 % Risk free interest rate 2.11 % 2.56 % 2.09 % The expected life of SARs is based on historical data as is the expected volatility. Risk free interest rates are determined using the U.S. Treasury yield curve at time of grant with a term equal to the expected life of the SARs. A summary of SARs activity under the Equity Plan as of December 31, 2019 and changes during the year then ended is as follows: Number of Awards Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (In Thousands) Awards outstanding at January 1, 2019 1,029,082 $ 54.08 Granted 28,000 $ 8.57 Expired (134,852 ) $ 71.46 Awards outstanding at December 31, 2019 922,230 $ 50.19 3.6 $ — Awards exercisable at December 31, 2019 922,230 $ 50.19 3.6 $ — The weighted-average grant date fair values per share of awards granted during the years ended December 31, 2019, 2018 and 2017 were $3.75, $7.11 and $5.61, respectively. The total intrinsic value of awards exercised during the years ended December 31, 2019, 2018 and 2017 was $0, $0.1 million and $0, respectively. The total fair value of awards vested during the years ended December 31, 2019, 2018 and 2017 was $0.1 million, $0.7 million and $1.2 million, respectively. Restricted Stock Units . RSUs are contractual rights to receive shares of our common stock in the future if the applicable vesting conditions are met. In 2019, 2018 and 2017, we granted an aggregate of 310,700, 135,759 and 276,085 time-vesting RSUs, respectively. One-half of each annual grant of time-vesting RSUs will vest two years from the date of grant and the remaining 50% will vest three years from the date of grant, conditioned upon continued employment through the applicable vesting date. The fair value of time-vesting RSUs granted under the Equity Plan was estimated based on the fair market value of our common stock on the date of grant. 59 A summary of activity for time-vesting RSUs under the Equity Plan as of December 31, 2019 and changes during the year then ended is as follows: Number of Awards Weighted -Average Grant Date Fair Value Per Share Nonvested awards at January 1, 2019 422,059 $ 16.57 Granted 310,700 $ 10.47 Vested (174,774 ) $ 18.20 Forfeited (24,382 ) $ 13.42 Nonvested awards at December 31, 2019 533,603 $ 12.58 The total fair value of time-vesting RSUs vested during the years ended December 31, 2019, 2018 and 2017 was $1.9 million, $1.9 million and $1.1 million, respectively. Performance-Vesting Awards Restricted Stock Units . In 2019, 2018 and 2017, we granted an aggregate of 190,634, 194,563 and 370,616 performance-vesting RSUs, respectively, which will vest upon achievement of certain performance goals as set forth in the individual award agreements over the three-year performance period beginning on January 1 in the year of grant. The shares of our common stock to be received upon the vesting of the performance-vesting RSUs will be delivered no later than March 15 of the year following completion of the three-year performance period. The fair value of performance-vesting RSUs granted under the Equity Plan to employees was estimated based on the fair market value of our common stock on the date of grant. A summary of activity for performance-vesting RSUs under the Equity Plan as of December 31, 2019 and changes during the year then ended is as follows: Number of Awards Weighted -Average Grant Date Fair Value Per Share Nonvested awards at January 1, 2019 741,973 $ 17.53 Granted 190,634 $ 10.49 Vested (223,330 ) $ 21.44 Nonvested awards at December 31, 2019 709,277 $ 14.41 The total grant date fair value of the performance-vesting RSUs that vested during the years ended December 31, 2019, 2018 and 2017 was $2.3 million, $2.5 million and $0.3 million, respectively.

(Loss) Earnings Per Share

(Loss) Earnings Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
(Loss) Earnings Per Share	6. (Loss) Earnings Per Share We present basic and diluted (loss) earnings per share on our Consolidated Statements of Operations. Basic (loss) earnings per share excludes dilution and is computed by dividing net (loss) income by the weighted-average number of common shares outstanding for the period. Diluted (loss) earnings per share reflects the potential dilution that could occur if securities or other contracts to issue common stock (common share equivalents) were exercised or converted into common stock, unless the effect would be antidilutive. For all periods in which we experience a net loss, all shares of common stock issuable upon exercise of outstanding stock appreciation rights and vesting of outstanding restricted stock units have been excluded from the calculation of weighted-average shares because their inclusion would be antidilutive. 60 The following table sets forth the share effects of stock-based awards exc luded from the computation of diluted (loss) earnings per share (in thousands). Year Ended December 31, 2019 2018 2017 Employee and director: SARs 982 1,133 1,315 RSUs 1,205 1,153 757

Financial Instruments and Fair

Financial Instruments and Fair Value Disclosures	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Disclosures	7. Financial Instruments and Fair Value Disclosures Concentrations of Credit and Market Risk Financial instruments that potentially subject us to significant concentrations of credit or market risk consist primarily of periodic temporary investments of excess cash, trade accounts receivable and investments in debt securities. We generally place our excess cash investments in U.S. Treasury Bills and U.S. government-backed short-term money market instruments through several financial institutions. We periodically evaluate the relative credit standing of these financial institutions as part of our investment strategy. Concentrations of credit risk with respect to our trade accounts receivable are limited, primarily due to the entities comprising our customer base. Since the market for our services is the offshore oil and gas industry, this customer base consists primarily of major and independent oil and gas companies, as well as government-owned oil companies. We believe that we have potentially significant concentrations of credit risk on the basis of the limited number of our rigs currently contracted and the smaller population of customers, as several customers have contracted for multiple rigs. In general, before working for a customer with whom we have not had a prior business relationship and/or whose financial stability may be uncertain to us, we perform a credit review on that company. Based on that analysis, we may require that the customer present a letter of credit, prepay or provide other credit enhancements. Historically, we have recorded a provision for bad debts on a case-by-case basis when facts and circumstances indicated that a customer receivable may not be collectible. Losses on our trade receivables have been infrequent occurrences. Fair Values Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy prescribed by GAAP requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value: Level 1 Quoted prices for identical instruments in active markets. Level 2 Quoted market prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. Level 3 Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. Level 3 assets and liabilities generally include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation or for which there is a lack of transparency as to the inputs used. 61 Certain of our assets and liabilities are required to be measured at fair value on a recurring basis in accordance with GAAP. In addition, certain assets and liabilities may be recorded at fair value on a nonrecurring basis. Generally, we record assets at fair value on a nonrecurring basis as a result of impairment charges. We recorded an impairment charge related to one of our drilling rigs, which w as measured at fair value on a nonrecurring basis in 2018 , and have presented the aggregate loss in “Impairment of assets” in our Consolidated Statements of Operations for the year ended December 31, 201 8. Assets measured at fair value are summarized below (in thousands). December 31, 2019 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value Recurring fair value measurements: Money market funds $ 135,300 $ — $ — $ 135,300 Total short-term investments $ 135,300 $ — $ — $ 135,300 December 31, 2018 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value Total Losses for Year Ended (1) Recurring fair value measurements: U.S. Treasury bills $ 299,900 $ — $ — $ 299,900 Money market funds 135,800 — — 135,800 Short-term investments $ 435,700 $ — $ — $ 435,700 Nonrecurring fair value measurements: Impaired assets $ — $ — $ — $ — $ 27,225 ( 1 ) Represents impairment loss of $27.2 million recognized during 2018 related to a drilling rig whose carrying value was impaired and was subsequently sold. See Note 3. We believe that the carrying amounts of our other financial assets and liabilities (excluding long-term debt), which are not measured at fair value in our Consolidated Balance Sheets, approximate fair value based on the following assumptions: • Cash and cash equivalents -- The carrying amounts approximate fair value because of the short maturity of these instruments. • Accounts receivable and accounts payable -- The carrying amounts approximate fair value based on the nature of the instruments. 62 Our senior notes are not measured at fair value; however, under the GAAP fair value hierarchy, our long-term debt would be considered Level 2 liabilities. The fair value of our senior notes was derived using a third-party pricing service at December 31, 2019 and 2018. We perform control procedures over information we obtain from pricing services and brokers to test whether prices received represent a reasonable estimate of fair value. These procedures include the review of pricing service or broker pricing methodologies and comparing fair value estimates to actual trade activity executed in the market for these instruments occurring generally within a 10-day period of the report date. Fair values and related carrying values of our senior notes (see Note 9) are shown below (in millions). December 31, 2019 December 31, 2018 Fair Value Carrying Value Fair Value Carrying Value 3.45% Senior Notes due 2023 $ 212.5 $ 249.6 $ 185.0 $ 249.5 7.875% Senior Notes due 2025 435.0 497.1 415.0 496.8 5.70% Senior Notes due 2039 292.5 497.3 305.0 497.2 4.875% Senior Notes due 2043 408.8 749.0 416.3 748.9 We have estimated the fair value amounts by using appropriate valuation methodologies and information available to management. Considerable judgment is required in developing these estimates, and accordingly, no assurance can be given that the estimated values are indicative of the amounts that would be realized in a free market exchange.

Drilling and Other Property and

Drilling and Other Property and Equipment	12 Months Ended
	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Drilling and Other Property and Equipment	8. Drilling and Other Property and Equipment Cost and accumulated depreciation of drilling and other property and equipment are summarized as follows (in thousands): December 31, 2019 2018 Drilling rigs and equipment $ 8,004,489 $ 8,210,824 Land and buildings 64,267 63,757 Office equipment and other 92,289 91,819 Cost 8,161,045 8,366,400 Less: accumulated depreciation (3,008,217 ) (3,182,178 ) Drilling and other property and equipment, net $ 5,152,828 $ 5,184,222 During 2019, we recognized an aggregate pre-tax loss of $1.1 million on the disposal of assets, which included a pre-tax gain on the sale of the Ocean Guardian Ocean Confidence

Credit Agreements and Senior No

Credit Agreements and Senior Notes	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Credit Agreements and Senior Notes	9. Credit Agreements and Senior Notes Credit Agreements In September 2012, we entered into a syndicated 5-year revolving credit agreement, which, as amended as of August 18, 2016, provided for a $1.5 billion senior unsecured revolving credit facility for general corporate purposes. On October 2, 2018, we entered into Amendment No. 6 and Consent to Credit Agreement and Successor Agency Agreement, or the Amendment, which amended our 5-year revolving credit agreement, dated as of September 28, 2012, as amended (we refer to such credit agreement as the Amended Credit Facility). Among other things, the Amendment reduced the aggregate principal amount of commitments under the credit facility to $325.0 million, of which $100.0 million of the commitments matured in 2019. The remaining $225.0 million of commitments mature on October 22, 2020 and are available, subject to the terms of the Amended Credit Facility, for revolving loans. On October 2, 2018, Diamond Offshore Drilling, Inc., or DODI, as the U.S. borrower, and our subsidiary Diamond Foreign Asset Company, or DFAC, as the foreign borrower, entered into a senior 5-year revolving credit 63 agreement with a syndicate of lenders and Wells Fargo Bank, National Association, as administrative agent (we refer to such credit agreement as the $ 950 Million Credit Facility ) . The maximum amount of borrowings available under the $950 Million Credit Facility is $950.0 million and may be used for general corporate purposes, including investments, acquisitions and capital expenditures. The $950 Million Credit Facility, which matures on October 2, 2023 , provides for a swingline subfacility of $ 100.0 million and a letter of credit subfacility of $ 250.0 million . The entire amount of borrowings available under the $950 Million Credit Facility is available for loans to DFAC, and a portion of such amount is available for loans to DODI, based on a ratio as specified in the $950 Million Credit Facility. The obligations of DODI and DFAC under the $950 Million Credit Facility are each guaranteed by certain subsidiaries of DODI and DFAC, respectively, and 65% of the equity interest in DFAC is pledged as collateral for the obligations under the $950 Million Credit Facility. The $950 Million Credit Facility includes restrictions on borrowing if, after giving effect to any such borrowings and the application of the proceeds thereof, the aggregate amount of available cash, as defined in the $950 Million Credit Facility, would exceed $500.0 million. In addition, the ability to borrow revolving loans under the $950 Million Credit Facility is conditioned on there being no unused commitments to advance loans under the Amended Credit Facility. We refer to the Amended Credit Facility and $950 Million Credit Facility collectively as the Credit Agreements. At December 31, 2019, we had no borrowings outstanding under the Credit Agreements, however, in January 2020, a $6.0 million financial letter of credit was issued under the $950 Million Credit Facility in support of a previously issued surety bond. As of February 7, 2020, there was approximately $1.2 billion available under the Credit Agreements in the aggregate, subject to their respective terms Covenants The Amended Credit Facility contains customary covenants, including, but not limited to, maintenance of a ratio of consolidated indebtedness to total capitalization, as defined in the Amended Credit Facility, of not more than 60% at the end of each fiscal quarter, as well as limitations on liens; mergers, consolidations, liquidation and dissolution; changes in lines of business; swap agreements; transactions with affiliates; and subsidiary indebtedness. The $950 Million Credit Facility contains certain financial covenants, including (i) maintenance of a ratio of consolidated indebtedness to total capitalization not to exceed 60% at the end of each fiscal quarter, (ii) maintenance of a ratio of not less than 80% at the end of each fiscal quarter of (A) the aggregate value of certain rigs directly wholly owned by the borrowers and subsidiary guarantors to (B) the aggregate value of substantially all rigs owned by us and (iii) maintenance of a ratio of not less than 3:00 to 1:00 at the end of each fiscal quarter of (A) the sum of the aggregate value of all marketed rigs, as defined in the $950 Million Credit Facility, wholly owned directly by DFAC and certain foreign guarantors, as specified in the $950 Million Credit Facility, plus the value of the Ocean Valiant The $950 Million Credit Facility also contains additional covenants generally applicable to DODI and its subsidiaries that we consider usual and customary for an agreement of this type, including a limit on the payment of dividends if certain minimum cash balances are not maintained. The Credit Agreements provide for customary events of default including, among others, a cross-default provision with respect to DODI’s and its subsidiaries’ other indebtedness in excess of $100.0 million. At December 31, 2019, we were in compliance with all covenant requirements under the Credit Agreements. Interest Rates and Fees Revolving loans under the Credit Agreements bear interest, at our option, at a rate per annum based on either an alternate base rate, or ABR, or a Eurodollar Rate, as defined in the applicable Credit Agreement, plus the applicable interest margin for an ABR loan or a Eurodollar loan (determined based on our credit ratings). Swingline loans under the $950 Million Credit Facility bear interest, at our option, at a rate per annum equal to (i) the ABR plus the applicable 64 interest margin for ABR loans or (ii) the daily one-month Eurodollar Rate plus the applicable interest margin for Eurodollar loans. Under the Credit Agreements, we also pay, based on our current long-term credit ratings, and as applicable, other customary fees including, but not limited to, a commitment fee on the unused commitments under each of the Credit Agreements and a fronting fee to the issuing bank for each letter of credit. Participation fees for letters of credit are dependent upon the type of letter of credit issued. The following summarizes the interest rate margins and fees payable under the Credit Agreements, based on our current long-term credit ratings: Amended Credit Facility $950 Million Credit Facility Revolving Loans: ABR 0.25% over the greater of (i) the prime rate, (ii) the federal funds rate plus 0.50% and (iii) the daily one-month Eurodollar Rate plus 1.00% 3.25% over the greater of (i) the prime rate, (ii) the federal funds rate plus 0.50% and (iii) the daily one-month Eurodollar Rate plus 1.00% Eurodollar 1.25% over specified LIBOR 4.25% over specified LIBOR Swingline Loans N/A At our option, at a rate per annum equal to (i) the ABR plus the applicable interest margin for ABR loans or (ii) the daily one-month Eurodollar Rate plus the applicable interest margin for Eurodollar loans Letter of credit participation fees: Performance letters of credit N/A 2.125% per annum All other letters of credit N/A 4.25% per annum Commitment fee on unused commitments under credit agreement 0.20% per annum 0.70% per annum Favorable changes in our current credit ratings could lower the interest rate margins and fees that we pay under the Credit Agreements; however, current interest rates and fees under the Credit Agreements will apply should there be any further downgrade in our credit ratings. Senior Notes At December 31, 2019, our senior notes were comprised of the following debt issues (dollars in millions): Semiannual Principal Interest Rate Interest Payment Debt Issue Amount Maturity Date Coupon Effective Dates 3.45% Senior Notes due 2023 $ 250.0 November 1, 2023 3.45 % 3.50 % May 1 and November 1 7.875% Senior Notes due 2025 $ 500.0 August 15, 2025 7.875 % 8.00 % February 15 and August 15 5.70% Senior Notes due 2039 $ 500.0 October 15, 2039 5.70 % 5.75 % April 15 and October 15 4.875% Senior Notes due 2043 $ 750.0 November 1, 2043 4.875 % 4.89 % May 1 and November 1 65 At December 31, 2019 and 2018, the carrying value of our senior notes, net of unamortized discount and debt issuance costs, was as follows (in thousands): December 31, 2019 2018 3.45% Senior Notes due 2023 $ 248,759 $ 248,455 7.875% Senior Notes due 2025 491,655 490,491 5.70% Senior Notes due 2039 493,316 493,139 4.875% Senior Notes due 2043 742,011 741,837 Total senior notes, net $ 1,975,741 $ 1,973,922 As of December 31, 2019, the aggregate annual maturity of our senior notes, excluding net unamortized discounts and debt issuance costs of $7.0 million and $17.3 million, respectively, was as follows (in thousands): Aggregate Principal Amount Year Ending December 31, 2020 $ — 2021 — 2022 — 2023 250,000 2024 — Thereafter 1,750,000 Total maturities of senior notes $ 2,000,000 Notes Redemption . In August 2017, we redeemed all of our outstanding 5.875% senior notes due 2019, or 2019 Notes, for a redemption price of $543.0 million in the aggregate, including accrued and unpaid interest to the date of redemption. We accounted for the redemption as an extinguishment of debt and reported a corresponding loss of $35.4 million in our Consolidated Statements of Operations. Senior Notes Due 2025 . In August 2017, we issued $500.0 million aggregate principal amount of unsecured 7.875% senior notes due 2025, or 2025 Notes, and received net proceeds of $489.1 million after deduction of underwriter discounts, commissions and expenses. We used the net proceeds from the 2025 Notes, together with cash on hand, to fund the redemption of our previously outstanding 2019 Notes. The 2025 Notes are unsecured obligations of DODI, and rank equally in right of payment to all of its existing and future senior indebtedness, and are structurally subordinated to all existing and future obligations of our subsidiaries. We have the right to redeem some or all of the 2025 Notes at any time or from time to time, on at least 15 days but not more than 60 days prior written notice, at the applicable redemption price specified in the governing indenture, plus accrued and unpaid interest to, but excluding, the date of redemption Senior Notes Due 2023 and 2043 . Our 3.45% Senior Notes due 2023 and 4.875% Senior Notes due 2043 are unsecured and unsubordinated obligations of DODI, and rank equally in right of payment to all of its existing and future unsecured and unsubordinated indebtedness, and are effectively subordinated to all existing and future obligations of our subsidiaries. We have the right to redeem all or a portion of these notes for cash at any time or from time to time, on at least 15 days 60 days Senior Notes Due 2039 . Our 5.70% Senior Notes due 2039 are unsecured and unsubordinated obligations of DODI, and rank equally in right of payment to all of its existing and future unsecured and unsubordinated indebtedness, and are effectively subordinated to all existing and future obligations of our subsidiaries. We have the right to redeem all or a portion of these notes for cash at any time or from time to time, on at least 15 days but not more than 60 days prior written notice, at the redemption price specified in the governing indenture plus accrued and unpaid interest to the date of redemption. 66 The 2025 Notes, 3.45% Senior Notes due 2023, 4.875% Senior Notes due 2043 and 5.70% Senior Notes due 2039 contain customary covenants including limitations on liens, mergers, consolidations and certain sales of assets and on entering into sale and lease-back transactions covering a drilling rig or drillship, as specified in each governing indenture. As of December 31, 2019, we were in compliance with all of these covenants.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Various claims have been filed against us in the ordinary course of business, including claims by offshore workers alleging personal injuries. With respect to each claim or exposure, we have made an assessment, in accordance with GAAP, of the probability that the resolution of the matter would ultimately result in a loss. When we determine that an unfavorable resolution of a matter is probable and such amount of loss can be determined, we record a liability for the amount of the estimated loss at the time that both of these criteria are met. Our management believes that we have recorded adequate accruals for any liabilities that may reasonably be expected to result from these claims. Asbestos Litigation . We are one of several unrelated defendants in lawsuits filed in Louisiana state courts alleging that defendants manufactured, distributed or utilized drilling mud containing asbestos and, in our case, allowed such drilling mud to have been utilized aboard our drilling rigs. The plaintiffs seek, among other things, an award of unspecified compensatory and punitive damages. The manufacture and use of asbestos-containing drilling mud had already ceased before we acquired any of the drilling rigs addressed in these lawsuits. We believe that we are not liable for the damages asserted in the lawsuits pursuant to the terms of our 1989 asset purchase agreement with Diamond M Corporation. We are unable to estimate our potential exposure, if any, to these lawsuits at this time but do not believe that our ultimate liability, if any, resulting from this litigation will have a material effect on our financial condition, results of operations and cash flows, including negative cash flows. Non-Income Tax and Related Claims . We have received assessments related to, or otherwise have exposure to, non-income tax items such as sales-and-use tax, value-added tax, ad valorem tax, custom duties, and other similar taxes in various taxing jurisdictions. We have determined that we have a probable loss for these taxes and the related penalties and interest and, accordingly, have recorded a $16.1 million and $12.3 million liability at December 31, 2019 and 2018, respectively. We intend to defend these matters vigorously; however, the ultimate outcome of these assessments and exposures could result in additional taxes, interest and penalties for which the fully assessed amounts would have a material adverse effect on our financial statements Other Litigation. We have been named in various other claims, lawsuits or threatened actions that are incidental to the ordinary course of our business, including a claim by one of our customers in Brazil, Petróleo Brasileiro S.A., or Petrobras, that it will seek to recover from its contractors, including us, any taxes, penalties, interest and fees that it must pay to the Brazilian tax authorities for our applicable portion of withholding taxes related to Petrobras’ charter agreements with its contractors. We intend to defend these matters vigorously; however, litigation is inherently unpredictable, and the ultimate outcome or effect of any claim, lawsuit or action cannot be predicted with certainty. As a result, there can be no assurance as to the ultimate outcome of any litigation matter. Any claims against us, whether meritorious or not, could cause us to incur significant costs and expenses and require significant amounts of management and operational time and resources. In the opinion of our management, no such pending or known threatened claims, actions or proceedings against us are expected to have a material adverse effect on our consolidated financial position, results of operations or cash flows. Personal Injury Claims . Under our current insurance policies, our deductibles for marine liability insurance coverage with respect to personal injury claims not related to named windstorms in the U.S. Gulf of Mexico, which primarily result from Jones Act liability in the U.S. Gulf of Mexico, are $5.0 million for the first occurrence and vary in amounts ranging between $5.0 million and, if aggregate claims exceed certain thresholds, up to $100.0 million for each subsequent occurrence, depending on the nature, severity and frequency of claims that might arise during the policy year. Our deductibles for personal injury claims arising due to named windstorms in the U.S. Gulf of Mexico are $25.0 million for the first occurrence and vary in amounts ranging between $25.0 million and, if 67 aggregate claims exceed certain thresholds, up to $ 100.0 million for each subsequent occurrence, depending on the nature, severity and frequency of claims that might arise during the policy year. The Jones Act is a federal law that permits seamen to seek compensation for certain injuries during the course of their employment on a vessel and governs the liability of vessel operators and marine employers for the work-related injury or death of an employee. We engage outside consultants to assist us in estimating our aggregate liability for personal injury claims based on our historical losses and utilizing various actuarial models. We allocate a portion of the aggregate liability to “Accrued liabilities” based on an estimate of claims expected to be paid within the next twelve months with the residual recorded as “Other liabilities.” At December 31, 2019, our estimated liability for personal injury claims was $17.4 million, of which $6.4 million and $11.0 million were recorded in “Accrued liabilities” and “Other liabilities,” respectively, in our Consolidated Balance Sheets. At December 31, 2018, our estimated liability for personal injury claims was $27.9 million, of which $5.2 million and $22.7 million were recorded in “Accrued liabilities” and “Other liabilities,” respectively, in our Consolidated Balance Sheets. The eventual settlement or adjudication of these claims could differ materially from our estimated amounts due to uncertainties such as: • the severity of personal injuries claimed; • significant changes in the volume of personal injury claims; • the unpredictability of legal jurisdictions where the claims will ultimately be litigated; • inconsistent court decisions; and • the risks and lack of predictability inherent in personal injury litigation. Purchase Obligations . At December 31, 2019, we had no purchase obligations for major rig upgrades or any other significant obligations, except for those related to our direct rig operations, which arise during the normal course of business. Services Agreement . In February 2016, we entered into a ten-year Future commitments under the contractual services agreements are estimated to be approximately $39 million per year or an estimated $250 million in the aggregate over the remaining term of the agreements. In addition, we lease Well Control Equipment for our drillships under ten-year operating leases. See Note 11. Letters of Credit and Other. We were contingently liable as of December 31, 2019 in the amount of $37.1 million under certain tax, performance, supersedeas, VAT and customs bonds and letters of credit. Agreements relating to approximately $28.5 million of customs, tax, VAT and supersedeas bonds can require collateral at any time, while the remaining agreements, aggregating $8.6 million, cannot require collateral except in events of default. As of December 31, 2019, we had not been required to make any collateral deposits with respect to these agreements. However, in January 2020, we were required to issue a $6.0 million financial letter of credit as collateral in support of our outstanding surety bonds

Leases and Lease Commitments

Leases and Lease Commitments	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases and Lease Commitments	11. Leases and Lease Commitments Our leasing activities primarily consist of operating leases for shorebase offices, office and information technology equipment, employee housing, vehicles, onshore storage yards and certain rig equipment and tools. Our leases have terms ranging from one month to ten years, some of which include options to extend the lease for up to five years and/or to terminate the lease within one year. Additionally, we are participants in four sale and leaseback arrangements with a subsidiary of Baker Hughes pursuant to the 2016 sale of Well Control Equipment on our drillships and corresponding agreements to lease back that equipment under ten-year five-year 68 of prepaid rent, which was being amortized over the respective terms of the leases. On January 1, 2019, as a result of the adoption of ASU 2016-02, the aggregate remaining prepaid rent balances of $ 3.9 million and $ 10.6 million, previously recorded as “Prepaid expenses and other current assets” and “Other assets,” respectively, were reclassified to a right-of-use lease asset within “Other assets” in our Consolidated Balance Sheets and continue to be amortized over the remaining terms of the leases. In applying ASU 2016-02, we utilized an exemption for short-term leases whereby we did not record leases with terms of one year or less on the balance sheet. We have also made an accounting policy election not to separate lease components from non-lease components for each of our classes of underlying assets, except for subsea equipment, which includes the Well Control Equipment discussed above. At inception, the consideration for the overall Well Control Equipment arrangement was allocated between the lease and service components based on an estimation of stand-alone selling price of each component, which maximized observable inputs. The costs associated with the service portion of the agreement are accounted for separately from the cost attributable to the equipment leases based on that allocation and thus, are not included in our right-of-use lease asset or lease liability balances. The non-lease components for each of our other classes of assets generally relate to maintenance, monitoring and security services and are not separated from their respective lease components. See Note 10. The lease term used for calculating our right-of-use assets and lease liabilities is determined by considering the noncancelable lease term, as well as any extension options that we are reasonably certain to exercise. The determination to include option periods is generally made by considering the activity in the region or for the rig corresponding to the respective lease, among other contract-based and market-based factors. We have used our incremental borrowing rate to discount future lease payments as the rate implicit in our leases is not readily determinable. To arrive at our incremental borrowing rate, we consider our unsecured borrowings and then adjust those rates to assume full collateralization and to factor in the individual lease term and payment structure. Total operating lease expense for the year ended December 31, 2019 was $39.7 million of which $3.4 million related to short-term leases. Total operating lease expense for the years ended December 31, 2018 and 2017 was $30.1 million and $30.6 million, respectively. Supplemental information related to leases is as follows (in thousands, except weighted-average data): Year Ended December 31, 2019 Operating cash flows used for operating leases $ 39,561 Right-of-use assets obtained in exchange for lease liabilities 26,248 Weighted-average remaining lease term 6.7 years Weighted-average discount rate 8.68 % Future minimum rental payments under noncancelable operating leases as of December 31, 2018 were as follows (in thousands): 2019 $ 28,373 2020 27,144 2021 26,565 2022 26,281 2023 26,280 Thereafter 64,062 Total lease payments $ 198,705 69 Maturities of lease liabilities as of December 31, 2019 are as follows (in thousands): 2020 $ 32,888 2021 30,548 2022 29,973 2023 29,499 2024 29,580 Thereafter 51,784 Total lease payments 204,272 Less: interest (50,348 ) Total lease liability $ 153,924 Amounts recognized in Consolidated Balance Sheets: Accrued liabilities $ 20,030 Other liabilities 133,894 Total operating lease liability $ 153,924 Operating lease assets, including prepaid rent balances related to the Baker Hughes transaction, totaling $169.2 million are included in “Other assets” in our Consolidated Balance Sheets as of December 31, 2019. As of December 31, 2019, we had an additional operating lease for mooring equipment to be used on a rig that had not yet commenced. The agreement, which commenced in January 2020, provides for fixed lease payments of approximately $5 million in the aggregate to be paid over a lease term of 5 years.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related-Party Transactions	12. Related-Party Transactions Transactions with Loews. We are party to a services agreement with Loews, or the Services Agreement, pursuant to which Loews performs certain administrative and technical services on our behalf. Such services include internal auditing services and advice and assistance with respect to obtaining insurance. Under the Services Agreement, we are required to reimburse Loews for (i) allocated personnel cost (such as salaries, employee benefits and payroll taxes) of the Loews personnel actually providing such services and (ii) all out-of-pocket expenses related to the provision of such services. The Services Agreement may be terminated at our option upon 30 days’ notice to Loews and at the option of Loews upon six months’ notice to us. In addition, we have agreed to indemnify Loews for all claims and damages arising from the provision of services under the Services Agreement unless due to the gross negligence or willful misconduct of Loews. We were charged $0.7 million, $0.6 million and $1.0 million by Loews for these support functions during the years ended December 31, 2019, 2018 and 2017, respectively.

Restructuring and Separation Co

Restructuring and Separation Costs	12 Months Ended
	Dec. 31, 2019
Restructuring And Related Activities [Abstract]
Restructuring and Separation Costs	13. Restructuring and Separation Costs In late 2017, in response to expectations at the time that a recovery of the offshore drilling market would not occur in the near term, combined with changes to the size and composition of our drilling fleet since 2015, we reviewed our global cost and organizational structure, including the way in which we market our services in certain countries. As a result, our management approved and initiated a reduction in workforce at our onshore bases and corporate facilities, as well as the negotiation of a termination of our agency agreement in Brazil. We incurred $14.1 million in restructuring and employee separation related costs during 2017, including $11.5 million related to the termination of our Brazilian agency agreement. During 2018, we incurred an additional $5.0 million in severance and related costs for redundant employees identified in 2018 in connection with the restructuring plan and paid $12.4 million in previously accrued costs. During 2019, all remaining obligations under the restructuring plan were settled.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	14. Income Taxes Several of our rigs are owned by Swiss branches of entities incorporated in the U.K. that have historically been taxed under a special tax regime pursuant to Swiss corporate income tax rules. On September 3, 2019, the Swiss federal government, along with the Canton of Zug, enacted tax legislation, which we refer to as Swiss Tax Reform, effective as of January 1, 2020. Swiss Tax Reform significantly changed Swiss corporate income tax rules by, 70 among other things, abolishing special tax regimes. The legislation also provides transition rules under which companies can maintain their current basis of taxation through January 1, 2022. The abolition of special tax regimes will require us to determine our Swiss tax liability on a net income basis beginning on January 1, 2022, thus also requiring deferred taxes to be computed on the difference between the Swiss tax basis and U.S. GAAP basis of certain items, including property, plant and equipment. There are still many uncertainties in the application of Swiss Tax Reform, including the values to be used to measure depreciable property. Therefore, we have recorded a $74.2 million net deferred tax asset for the difference in basis of certain of our rigs between Swiss tax and U.S. GAAP, offset, where appropriate, by a reserve for an uncertain tax position. As further clarification is issued by the Swiss tax authorities, deferred tax balances and the reserve for uncertain tax positions may need to be adjusted. The potential changes could have a material effect on our consolidated financial statements. In 2019, the Internal Revenue Service, or IRS, issued final regulations with respect to the calculation of the toll charge associated with the deemed repatriation of previously deferred earnings of our non-U.S. subsidiaries, or Transition Tax, in response to the Tax Cuts and Jobs Act enacted in 2017, commonly referred to as the Tax Reform Act. Based on the new regulations, we recorded a net tax benefit of $14.2 million in the second quarter of 2019, primarily to reverse a previously recorded uncertain tax position related to the Transition Tax. Consequently, our revised net tax benefit associated with the Tax Reform Act is $34.5 million, which now consists of (i) a $38.0 million charge relating to the one-time mandatory repatriation of previously deferred earnings of certain non-US subsidiaries that are owned either wholly or partially by our U.S. subsidiaries, inclusive of the utilization of certain tax attributes and (ii) a $72.5 million credit resulting from the determination and re-measurement of our net U.S. deferred tax liabilities at the lower corporate income tax rate. Our income tax expense is a function of the mix between our domestic and international pre-tax earnings or losses, the mix of international tax jurisdictions in which we operate and recognition of valuation allowances for deferred tax assets for which the tax benefits are not likely to be realized. Certain of our rigs are owned and operated, directly or indirectly, by DFAC. Our management has determined that we will no longer permanently reinvest foreign earnings. The components of income tax expense (benefit) are as follows (in thousands): Year Ended December 31, 2019 2018 2017 Federal – current $ (13,810 ) $ 20,107 $ 6,994 State – current 19 2 95 Foreign – current 25,899 9,531 25,252 Total current 12,108 29,640 32,341 Federal – deferred (67,015 ) (75,279 ) (85,066 ) Foreign – deferred 10,107 (714 ) 12,939 Total deferred (56,908 ) (75,993 ) (72,127 ) Total $ (44,800 ) $ (46,353 ) $ (39,786 ) 71 The difference between actual income tax expense and the tax provision computed by applying the statutory federal income tax rate to income before taxes is attributable to the following (in thousands): Year Ended December 31, 2019 2018 2017 (Loss) income before income tax expense: U.S. $ (339,072 ) $ (266,855 ) $ (241,178 ) Foreign (62,942 ) 40,230 219,738 $ (402,014 ) $ (226,625 ) $ (21,440 ) Expected income tax benefit at federal statutory rate $ (84,423 ) $ (47,591 ) $ (7,504 ) Effect of tax rate changes (74,168 ) 1,763 (74,294 ) Mandatory repatriation of earnings pursuant to Tax Reform Act — — 94,194 Effect of foreign operations 3,129 15 (42,102 ) Valuation allowance 11,650 11,929 (41,492 ) Uncertain tax positions, settlements and adjustments relating to prior years 96,960 (15,777 ) 31,726 Other 2,052 3,308 (314 ) Income tax benefit $ (44,800 ) $ (46,353 ) $ (39,786 ) Deferred Income Taxes. Significant components of our deferred income tax assets and liabilities are as follows (in thousands): December 31, 2019 2018 Deferred tax assets: Net operating loss carryforwards, or NOLs $ 253,973 $ 209,679 Foreign tax credits 43,026 43,225 Disallowed interest deduction 40,777 16,248 Worker’s compensation and other current accruals 6,250 8,375 Deferred deductions 12,345 10,481 Deferred revenue 7,209 — Operating lease liability 5,461 — Other 4,367 6,380 Total deferred tax assets 373,408 294,388 Valuation allowance (186,620 ) (174,970 ) Net deferred tax assets 186,788 119,418 Deferred tax liabilities: Property, plant and equipment (225,643 ) (212,251 ) Mobilization (2,245 ) (11,012 ) Right-of-use assets (5,461 ) — Other (967 ) (535 ) Total deferred tax liabilities (234,316 ) (223,798 ) Net deferred tax liability $ (47,528 ) $ (104,380 ) Net Operating Loss Carryforwards . As of December 31, 2019, we recorded a deferred tax asset of $254.0 million for the benefit of NOL carryforwards, comprised of $149.4 million related to our U.S. losses and $104.6 million related to our international operations. Approximately $154.7 million of this deferred tax asset relates to NOL carryforwards that have an indefinite life. The remaining $99.3 million relates to NOL carryforwards in several of our foreign subsidiaries, as well as in the U.S. Unless utilized, these NOL carryforwards will expire between 2021 and 2038. 72 Foreign Tax Credits. As of December 31, 2019, we recorded a deferred tax asset of $43.0 million for the benefit of foreign tax credits in the U.S., all of which will expire, Valuation Allowances. Changes in Accounting Principles - As of December 31, 2019, valuation allowances aggregating $186.6 million have been recorded for our net operating losses, foreign tax credits and other deferred tax assets for which the tax benefits are not likely to be realized. Unrecognized Tax Benefits. Our income tax returns are subject to review and examination in the various jurisdictions in which we operate, and we are currently contesting various tax assessments. We accrue for income tax contingencies, or uncertain tax positions, that we believe are not likely to be realized. A rollforward of the beginning and ending amount of unrecognized tax benefits, excluding interest and penalties, is as follows (in thousands): For the Year Ended December 31, 2019 2018 2017 Balance, beginning of period $ (55,943 ) $ (81,864 ) $ (34,970 ) Additions for current year tax positions (85,970 ) (2,906 ) (51,260 ) Additions for prior year tax positions (2,113 ) (20,943 ) (2,938 ) Reductions for prior year tax positions 23,267 49,175 623 Reductions related to statute of limitation expirations 1,875 595 6,681 Balance, end of period $ (118,884 ) $ (55,943 ) $ (81,864 ) The addition for current year tax positions in 2019 is due to a recent change in Switzerland tax legislation. Due to the uncertainties regarding the application of Swiss Tax Reform, including the values to be used to measure depreciable property, a liability for an uncertain tax position was recorded in the amount of $ 86.2 million. The $23.3 million reduction for prior year tax positions is mainly due to reversal of an uncertain tax position recorded for the one-time mandatory repatriation provision of the Tax Reform Act, following final regulations issued by the IRS in June 2019. The $20.9 million addition for prior year tax positions in 2018 and the $51.3 million addition for current year tax positions in 2017, as well as the $49.2 million reduction for prior year tax positions in 2018 are all primarily due to uncertainty associated with the enactment of the Tax Reform Act and subsequent clarification issued by the IRS related to the positions in question. At December 31, 2019, $0.5 million, $91.1 million and $58.3 million of the net liability for uncertain tax positions were reflected in “Other assets,” “Deferred tax liability” and “Other liabilities,” respectively, in our Consolidated Balance Sheets. At December 31, 2018, $1.2 million, $7.5 million and $75.3 million of the net liability for uncertain tax positions were reflected in “Other assets,” “Deferred tax liability” and “Other liabilities,” respectively, in our Consolidated Balance Sheets. Of the net unrecognized tax benefits at December 31, 2019, 2018 and 2017, $148.8 million, $81.6 million and $101.9 million, respectively, would affect the effective tax rates if recognized. At December 31, 2019, the amount of accrued interest and penalties related to uncertain tax positions was $4.0 million and $16.5 million, respectively. At December 31, 2018, the amount of accrued interest and penalties related to uncertain tax positions was $3.2 million and $16.3 million, respectively. 73 Interest expense recognized during the years ended December 31, 2019, 2018 and 2017 related to uncertain tax positions was $1.0 million, $0.1 million and $0.5 million, respectively. Penalties recognized during the years ended December 31, 2019, 2018 and 2017 related to uncertain tax positions were $0.3 million, $0.6 million and $(1.7) million, respectively. We expect the statute of limitations for the 2013 through 2015 tax years to expire in 2020 for various of our subsidiaries operating in Ireland, Malaysia and Mexico. We anticipate that the related unrecognized tax benefit will decrease by $5.1 million at that time. Tax Returns and Examinations. We file income tax returns in the U.S. federal jurisdiction, various state jurisdictions and various foreign jurisdictions. Tax years that remain subject to examination by these jurisdictions include the year 2000 and the years 2009 to 2018. We are currently under audit in Australia, Brazil, Egypt, Equatorial Guinea, Malaysia, Mexico, Nicaragua, Qatar and the United Kingdom, or U.K. We do not anticipate that any adjustments resulting from the tax audit of any of these years will have a material impact on our consolidated results of operations, financial condition or cash flows.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Postemployment Benefits [Abstract]
Employee Benefit Plans	15. Employee Benefit Plans Defined Contribution Plans We maintain defined contribution retirement plans for our U.S., U.K., and third-country national, or TCN, employees. The plan for our U.S. employees, or the 401k Plan, is designed to qualify under Section 401(k) of the Code. Under the 401k Plan, each participant may elect to defer taxation on a portion of his or her eligible earnings, as defined by the 401k Plan, by directing his or her employer to withhold a percentage of such earnings. A participating employee may also elect to make after-tax contributions to the 401k Plan. During 2019, 2018 and 2017, we matched 100% of the first 5% of each employee’s qualifying annual compensation contributed to the 401k Plan on a pre-tax or Roth elective deferral basis in each respective year. Participants are fully vested in the employer match immediately upon enrollment in the 401k Plan. For the years ended December 31, 2019, 2018 and 2017, our provision for contributions was $9.1 million, $8.0 million and $8.9 million, respectively. The defined contribution retirement plan for our U.K. employees provides that we make annual contributions in an amount equal to the employee's contributions generally up to a maximum percentage of the employee's defined compensation per year. Our contribution during 2019, 2018 and 2017 for employees working in the U.K. sector of the North Sea was 6% of the employee’s defined compensation. Our provision for contributions was $2.1 million, $1.5 million and $1.4 million for the years ended December 31, 2019, 2018 and 2017, respectively. The defined contribution retirement plan for our TCN employees, or International Savings Plan, is similar to the 401k Plan. During 2019, 2018 and 2017, we matched 5% of each employee’s compensation contributed to the International Savings Plan in each respective year, and our provision for contributions was $0.4 million in each of the years ended December 31, 2019, 2018 and 2017. Deferred Compensation and Supplemental Executive Retirement Plan Our Amended and Restated Diamond Offshore Management Company Supplemental Executive Retirement Plan, or Supplemental Plan, provides benefits to a select group of our management or other highly compensated employees to compensate such employees for any portion of the applicable percentage of the base salary contribution and/or matching contribution under the 401k Plan that could not be contributed to that plan because of limitations within the Code. Our provision for contributions to the Supplemental Plan for 2019, 2018 and 2017 was approximately $0.1 million in each respective year.

Segments and Geographic Area An

Segments and Geographic Area Analysis	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segments and Geographic Area Analysis	16. Segments and Geographic Area Analysis Although we provide contract drilling services with different types of offshore drilling rigs and also provide such services in many geographic locations, we have aggregated these operations into one reportable segment based on the similarity of economic characteristics due to the nature of the revenue-earning process as it relates to the offshore drilling industry over the operating lives of our drilling rigs. 74 Our drilling rigs are highly mobile and may be moved to other markets throughout the world in response to market conditions or customer needs. At December 31, 2019, our active drilling rigs were located offshore three countries in addition to the United States. Revenues by geographic area are presented by attributing revenues to the individual country or areas where the services were performed. The following tables provide information about disaggregated revenue by equipment-type and country (in thousands): Year Ended December 31, 2019 Total Contract Drilling Revenues (1) Revenues Related to Reimbursable Expenses Total United States $ 507,759 $ 7,881 $ 515,640 Brazil 191,519 83 191,602 United Kingdom 149,724 14,036 163,760 Australia 85,932 23,710 109,642 Total $ 934,934 $ 45,710 $ 980,644 (1) Year Ended December 31, 2018 Floater Rigs Jack-up Rigs (1) Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 628,574 $ 8,413 $ 636,987 $ 7,436 $ 644,423 Brazil 170,839 — 170,839 (26 ) 170,813 United Kingdom 84,749 — 84,749 7,738 92,487 Australia 53,170 — 53,170 7,612 60,782 Malaysia 114,228 — 114,228 (210 ) 114,018 Other countries (2) — — — 692 692 Total $ 1,051,560 $ 8,413 $ 1,059,973 $ 23,242 $ 1,083,215 (1) (2) Year Ended December 31, 2017 Floater Rigs Jack-up Rigs Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 619,655 $ — $ 619,655 $ 10,940 $ 630,595 Brazil 280,798 — 280,798 (311 ) 280,487 United Kingdom 171,146 — 171,146 6,424 177,570 Australia 125,568 — 125,568 15,385 140,953 Malaysia 164,984 — 164,984 1,988 166,972 Trinidad 67,924 — 67,924 — 67,924 Other countries (1) — 21,144 21,144 101 21,245 Total $ 1,430,075 $ 21,144 $ 1,451,219 $ 34,527 $ 1,485,746 (1) 75 The following table presents our long-lived tangible assets by country as of December 31, 2019, 2018 and 2017. A substantial portion of our assets is comprised of rigs that are mobile, and therefore asset locations at the end of the period are not necessarily indicative of the geographic distribution of the earnings generated by such assets during the periods and may vary from period to period due to the relocation of rigs. In circumstances where our drilling rigs were in transit at the end of a calendar year, they have been presented in the tables below within the country in which they were expected to operate (in thousands). December 31, 2019 2018 (1) 2017 (1) Drilling and other property and equipment, net: United States $ 2,227,934 $ 2,245,989 $ 2,300,956 International: United Kingdom 1,061,585 1,083,540 133,525 Brazil 883,607 923,355 923,398 Australia 570,964 242,929 629,436 Singapore 404,420 366,798 17 Malaysia 2,037 318,191 1,084,793 Other countries (2) 2,281 3,420 189,516 2,924,894 2,938,233 2,960,685 Total $ 5,152,828 $ 5,184,222 $ 5,261,641 (1) (2) rilling and other property and equipment, net of accumulated depreciation Major Customers Our customer base includes major and independent oil and gas companies and government-owned oil companies. Revenues from our major customers for the years ended December 31, 2019, 2018 and 2017 that contributed more than 10% of our total revenues are as follows: Year Ended December 31, Customer 2019 2018 2017 Hess Corporation 28.9 % 25.0 % 16.0 % Occidental (formerly Anadarko) 20.6 % 33.8 % 24.9 % Petróleo Brasileiro S.A. 19.5 % 15.8 % 18.9 % BP 3.1 % 10.5 % 15.8 %

Unaudited Quarterly Financial D

Unaudited Quarterly Financial Data	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Data	17. Unaudited Quarterly Financial Data Unaudited summarized financial data by quarter for the years ended December 31, 2019 and 2018 is shown below (in thousands). First Second Third Fourth Quarter Quarter Quarter Quarter 2019 Revenues $ 233,542 $ 216,706 $ 254,020 $ 276,376 Operating loss (49,127 ) (111,500 ) (72,834 ) (48,869 ) Loss before income tax expense (77,390 ) (141,342 ) (102,610 ) (80,672 ) Net loss (73,328 ) (113,988 ) (95,128 ) (74,770 ) Net loss per share, basic and diluted $ (0.53 ) $ (0.83 ) $ (0.69 ) $ (0.54 ) 2018 Revenues $ 295,510 $ 268,861 $ 286,322 $ 232,522 Operating income (loss) (1) 512 (52,375 ) (23,043 ) (37,277 ) Loss before income tax expense (25,142 ) (79,286 ) (55,894 ) (66,303 ) Net income (loss) 19,321 (69,274 ) (51,112 ) (79,207 ) Net income (loss) per share, basic and diluted $ 0.14 $ (0.50 ) $ (0.37 ) $ (0.58 ) (1) During the second quarter of 2018, we recognized an impairment loss of $27.2 million to write down the carrying value of the Ocean Scepter to its estimated recoverable amount. See Note 3.

General Information (Policies)

General Information (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation Our consolidated financial statements include the accounts of Diamond Offshore Drilling, Inc. and our wholly-owned subsidiaries after elimination of intercompany transactions and balances.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States, or U.S., or GAAP, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amount of revenues and expenses during the reporting period. Actual results could differ from those estimated.
Changes in Accounting Principles	Changes in Accounting Principles Leases. Leases We adopted ASU 2016-02 effective January 1, 2019 using an optional transition method requiring leases existing at, or entered into after, January 1, 2019 to be recognized and measured under the new accounting standard. Prior period amounts have not been adjusted and continue to be reflected in accordance with our historical accounting for leases. In our adoption of ASU 2016-02, we also utilized a transition practical expedient package whereby we did not reassess (i) whether any of our expired or existing contracts contain a lease, (ii) the classification for any expired or existing leases and (iii) initial direct costs for any existing leases. The adoption of this standard resulted in the recording of operating lease assets and offsetting operating lease liabilities of $146.8 million as of January 1, 2019, with no related impact on our annual Consolidated Statement of Stockholders’ Equity. See Note 11. Upon adoption of ASU 2016-02, we concluded that our drilling contracts contain a lease component for the use of our drilling rigs based on the updated definition of a lease. However, ASU 2016-02 provides for a practical expedient for lessors whereby, under certain circumstances, the lessor may combine the lease and non-lease components and account for the combined component in accordance with the accounting treatment for the predominant component. We have determined that our current drilling contracts qualify for this practical expedient and have combined the lease and service components of our standard drilling contracts. We continue to account for the combined component under ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606 ) and its related amendments . Revenue Recognition Revenue from Contracts with Customers We adopted ASU 2014-09 and its related amendments, or collectively Topic 606, effective January 1, 2018 using the modified retrospective implementation method. Accordingly, we have applied the five-step method outlined in Topic 606 for determining when and how revenue is recognized to all contracts that were not completed as of the date of adoption. Revenues for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts have not been adjusted and continue to be reported under the previous revenue recognition guidance. For contracts that were modified before the effective date, we have considered the modification guidance within the new standard and determined that the revenue recognized and contract balances recorded prior to adoption for such contracts were not impacted. While Topic 606 requires additional disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers, its adoption has not had a material impact on the measurement or recognition of our revenues. Our adoption of ASU 2014-09 represents a change in accounting principle and therefore, we have recorded the cumulative effect of adopting Topic 606 as an increase to opening retained earnings on January 1, 2018. This adjustment represents an accrual for the earned portion of demobilization revenue expected to be received for contracts not completed as of December 31, 2017, which was not recordable under previous revenue recognition guidance until completion of the demobilization activities. See Note 2. Income Taxes Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory, amended the guidance in Topic 740 with respect to the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. We have evaluated our historical intra-group transactions for impact under the provisions of ASU 2016-16 and adopted the guidance thereof effective January 1, 2018 using the modified retrospective approach. We recorded the $17.4 million cumulative effect of applying the new standard as a decrease to opening retained earnings with an offset to deferred income tax liability. See Note 14. Stock-Based Compensation Compensation - Stock Compensation (Topic 718) , or ASU 2016-09, which required We adopted ASU 2016-09 on January 1, 2017 using a modified retrospective approach and have elected to account for forfeitures of share-based awards in the period in which such forfeitures occur . The adoption
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments 49 periods beginning after December 15, 2019 . We adopted ASU 2016-13 effective January 1, 2020 by applying a modified retrospective method and the impact was not material to our consolidated financial statements.
Cash and Cash Equivalents	Cash and Cash Equivalents We consider short-term, highly liquid investments that have an original maturity of three months or less and deposits in money market mutual funds that are readily convertible into cash to be cash equivalents. The effect of exchange rate changes on cash balances held in foreign currencies was not material for the years ended December 31, 2019, 2018 and 2017.
Provision for Bad Debts	Provision for Bad Debts Prior to the adoption of ASU 2016-13, we have historically recorded a provision for bad debts on a case-by-case basis when facts and circumstances indicated that a customer receivable may not be collectible. In establishing these reserves, we considered historical and other factors that predicted collectability of such customer receivables, including write-offs, recoveries and the monitoring of credit quality. Such provision was reported as a component of “Operating expense” in our Consolidated Statements of Operations. See Note 4.
Drilling and Other Property and Equipment	Drilling and Other Property and Equipment We carry our drilling and other property and equipment at cost, less accumulated depreciation. Maintenance and routine repairs are charged to income currently while replacements and betterments that upgrade or increase the functionality of our existing equipment and that significantly extend the useful life of an existing asset are capitalized. Significant judgments, assumptions and estimates may be required in determining whether or not such replacements and betterments meet the criteria for capitalization and in determining useful lives and salvage values of such assets. Changes in these judgments, assumptions and estimates could produce results that differ from those reported. During the years ended December 31, 2019 and 2018, we capitalized $343.8 million and $243.6 million, respectively, in replacements and betterments of our drilling fleet. Costs incurred for major rig upgrades and/or the construction of rigs are accumulated in construction work-in-progress, with no depreciation recorded on the additions, until the month the upgrade or newbuild is completed and the rig is placed in service. Upon retirement or sale of a rig, the cost and related accumulated depreciation are removed from the respective accounts and any gains or losses are reported in our Consolidated Statements of Operations as “Loss (gain) on disposition of assets.” Depreciation is recognized up to applicable salvage values by applying the straight-line method over the remaining estimated useful lives from the year the asset is placed in service. Drilling rigs and equipment are depreciated over their estimated useful lives ranging from 3 to 30 years.
Capitalized Interest	Capitalized Interest We capitalize interest cost for rig construction and other qualifying projects. A reconciliation of our total interest cost to “Interest expense, net of amounts capitalized” as reported in our Consolidated Statements of Operations is as follows (in thousands): For the Year Ended December 31, 2019 2018 2017 Total interest cost including amortization of debt issuance costs $ 122,832 $ 123,816 $ 113,618 Capitalized interest — (576 ) (90 ) Total interest expense as reported $ 122,832 $ 123,240 $ 113,528
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets We evaluate our property and equipment for impairment whenever changes in circumstances indicate that the carrying amount of an asset may not be recoverable (such as, but not limited to, cold stacking a rig, the expectation of cold stacking a rig in the near term, contracted backlog of less than one year for a rig, a decision to retire or scrap a rig, or excess spending over budget on a newbuild, construction project or major rig upgrade). We utilize an undiscounted probability-weighted cash flow analysis in testing an asset for potential impairment. Our assumptions and estimates underlying this analysis include the following: • dayrate by rig; • utilization rate by rig if active, warm stacked or cold stacked (expressed as the actual percentage of time per year that the rig would be used at certain dayrates); • the per day operating cost for each rig if active, warm stacked or cold stacked; • the estimated annual cost for rig replacements and/or enhancement programs; • the estimated maintenance, inspection or other reactivation costs associated with a rig returning to work; • salvage value for each rig; and • estimated proceeds that may be received on disposition of each rig. Based on these assumptions, we develop a matrix for each rig under evaluation using multiple utilization/dayrate scenarios, to each of which we have assigned a probability of occurrence. We arrive at a projected probability-weighted cash flow for each rig based on the respective matrix and compare such amount to the carrying value of the asset to assess recoverability. The underlying assumptions and assigned probabilities of occurrence for utilization and dayrate scenarios are developed using a methodology that examines historical data for each rig, which considers the rig’s age, rated water depth and other attributes and then assesses its future marketability in light of the current and projected market environment at the time of assessment. Other assumptions, such as operating, maintenance, inspection and reactivation costs, are estimated using historical data adjusted for known developments, cost projections for re-entry of rigs into the market and future events that are anticipated by management at the time of the assessment. Management’s assumptions are necessarily subjective and are an inherent part of our asset impairment evaluation ,
Fair Value of Financial Instruments	Fair Value of Financial Instruments We believe that the carrying amount of our current financial instruments approximates fair value because of the short maturity of these instruments. See Note 7.
Debt Issuance Costs	Debt Issuance Costs Deferred costs associated with our credit facilities are presented in “Other assets” in our Consolidated Balance Sheets at December 31, 2019 and 2018 and amortized as interest expense over the respective terms of the credit facilities. During 2018, we paid $5.7 million in debt issuance and arrangement fees in connection with our credit facilities. Deferred costs associated with our senior notes are presented in our Consolidated Balance Sheets at December 31, 2019 and 2018 as a reduction to the related long-term debt and are amortized over the respective terms of the related debt. See Note 9.
Income Taxes	Income Taxes We account for income taxes in accordance with accounting standards that require the recognition of the amount of taxes payable or refundable for the current year and an asset and liability approach in recognizing the amount of deferred tax liabilities and assets for the future tax consequences of events that have been currently recognized in our financial statements or tax returns. In each of our tax jurisdictions we recognize a current tax liability or asset for the estimated taxes payable or refundable on tax returns for the current year and a deferred tax asset or liability for the estimated future tax effects attributable to temporary differences and carryforwards. Deferred tax assets are reduced by a valuation allowance, if necessary, which is determined by the amount of any tax benefits that, based on available evidence, are not expected to be realized under a “more likely than not” approach. Deferred tax assets and liabilities are classified as noncurrent in a classified statement of financial position. We make judgments regarding future events and related estimates especially as they pertain to the forecasting of our effective tax rate, the potential realization of deferred tax assets such as utilization of foreign tax credits, and exposure to the disallowance of items deducted on tax returns upon audit. We record both interest and penalties related to accrued uncertain tax positions in “Income tax benefit” in our Consolidated Statements of Operations. Liabilities for uncertain tax positions, including any interest and penalties, are denominated in the currency of the related tax jurisdiction and are revalued for changes in currency exchange rates. The revaluation of such liabilities for uncertain tax positions is reported in “Income tax benefit” in our Consolidated Statements of Operations. See Note 14.
Comprehensive (Loss) Income	Comprehensive (Loss) Income Comprehensive (loss) income is the change in equity of a business enterprise during a period from transactions and other events and circumstances except those transactions resulting from investments by owners and distributions to owners. Comprehensive (loss) income for the three years ended December 31, 2019, 2018 and 2017 includes net (loss) income and unrealized holding gains and losses on marketable securities and financial derivatives designated as cash flow accounting hedges.
Foreign Currency	Foreign Currency Our functional currency is the U.S. dollar. Transactions incurred in currencies other than the U.S. dollar are subject to gains or losses due to fluctuations in those currencies. We report foreign currency transaction gains and losses as “Foreign currency transaction (loss) gain” in our Consolidated Statements of Operations. The revaluation of assets and liabilities related to foreign income taxes, including deferred tax assets and liabilities and uncertain tax positions, including any interest and/or penalties, is reported in “Income tax benefit” in our Consolidated Statements of Operations.
Revenue from Contracts with Customers	Revenue from Contracts with Customers The activities that primarily drive the revenue earned from our contract drilling services includes (i) providing a drilling rig and the crew and supplies necessary to operate the rig, (ii) mobilizing and demobilizing the rig to and from the drill site and (iii) performing rig preparation activities and/or modifications required for the contract. Consideration received for performing these activities may consist of dayrate drilling revenue, mobilization and demobilization revenue, contract preparation revenue and reimbursement revenue. We account for these integrated services provided within our drilling contracts as a single performance obligation satisfied over time and comprised of a series of distinct time increments in which we provide drilling services. Consideration for activities that are not distinct within the context of our contracts and do not correspond to a distinct time increment within the contract term are allocated across the single performance obligation and recognized ratably over the initial term of the contract (which is the period we estimate to be benefited from the corresponding activities and generally ranges from two to 60 months). Consideration for activities that correspond to a distinct time increment within the contract term is recognized in the period when the services are performed. The total transaction price is determined for each individual contract by estimating both fixed and variable consideration expected to be earned over the term of the contract. See below for further discussion regarding the allocation of the transaction price to the remaining performance obligations. The amount estimated for variable consideration may be constrained (reduced) and is only included in the transaction price to the extent that it is probable that a significant reversal of previously recognized revenue will not occur throughout the term of the contract. When determining if variable consideration should be constrained, management considers whether there are factors outside of our control that could result in a significant reversal of revenue as well as the likelihood and magnitude of a potential reversal of revenue. These estimates are re-assessed each reporting period as required. Dayrate Drilling Revenue. Our drilling contracts generally provide for payment on a dayrate basis, with higher rates for periods when the drilling unit is operating and lower rates or zero rates for periods when drilling operations are interrupted or restricted. The dayrate invoices billed to the customer are typically determined based on the varying rates applicable to the specific activities performed on an hourly basis. Such dayrate consideration is allocated to the distinct hourly increment it relates to within the contract term, and therefore, recognized in line with the contractual rate billed for the services provided for any given hour. Mobilization/Demobilization Revenue. We may receive fees (on either a fixed lump-sum or variable dayrate basis) for the mobilization and demobilization of our rigs. These activities are not considered to be distinct within the context of the contract and therefore, the associated revenue is allocated to the overall performance obligation and recognized ratably over the initial term of the related drilling contract. We record a contract liability for mobilization fees received, which is amortized ratably to contract drilling revenue as services are rendered over the initial term of the related drilling contract. Demobilization revenue expected to be received upon contract completion is estimated as part of the overall transaction price at contract inception and recognized in earnings ratably over the initial term of the contract with an offset to an accretive contract asset. In some contracts, there is uncertainty as to the likelihood and amount of expected demobilization revenue to be received. For example, contractual provisions may require that a rig demobilize a certain distance before the demobilization revenue is payable or the amount may vary dependent upon whether or not the rig has additional contracted work within a certain distance from the wellsite. Therefore, the estimate for such revenue may be constrained, as described above, depending on the facts and circumstances pertaining to the specific contract. We assess the likelihood of receiving such revenue based on our past experience and knowledge of market conditions. Contract Preparation Revenue. Some of our drilling contracts require downtime before the start of the contract to prepare the rig to meet customer requirements. At times, we may be compensated by the customer for such work (on either a fixed lump-sum or variable dayrate basis). These activities are not considered to be distinct within the context of the contract. We record a contract liability for contract preparation fees received, which is amortized ratably to contract drilling revenue over the initial term of the related drilling contract. 53 Capital Modification Revenue . From time to time, we may receive fees from our customers for capital improvements or upgrades to our rigs to meet contractual requirements (on either a fixed lump-sum or variable dayrate basis). The activities related to these capital modifications are not considered to be distinct within the context of our contracts. We record a contract liability for such fees and recognize them ratably as contract drilling revenue over the initial term of the related drilling contract. Revenues Related to Reimbursable Expenses . We generally receive reimbursements from our customers for the purchase of supplies, equipment, personnel services and other services provided at their request in accordance with a drilling contract or other agreement. Such reimbursable revenue is variable and subject to uncertainty, as the amounts received and timing thereof are highly dependent on factors outside of our influence. Accordingly, reimbursable revenue is fully constrained and not included in the total transaction price until the uncertainty is resolved, which typically occurs when the related costs are incurred on behalf of a customer. We are generally considered a principal in such transactions and record the associated revenue at the gross amount billed to the customer, as “Revenues related to reimbursable expenses” in our Consolidated Statements of Operations. Such amounts are recognized ratably over the period within the contract term during which the corresponding goods and services are to be consumed. Contract Balances Accounts receivable are recognized when the right to consideration becomes unconditional based upon contractual billing schedules. Payment terms on invoiced amounts are typically 30 days. Contract asset balances consist primarily of demobilization revenue that we expect to receive and is recognized ratably throughout the contract term, but invoiced upon completion of the demobilization activities. Once the demobilization revenue is invoiced, the corresponding contract asset is transferred to accounts receivable. Contract assets may also include amounts recognized in advance of amounts invoiced due to the blending of rates when a contract has operating dayrates that increase over the initial contract term. Contract liabilities include payments received for mobilization as well as rig preparation and upgrade activities which are allocated to the overall performance obligation and recognized ratably over the initial term of the contract. Contract liabilities may also include amounts invoiced in advance of amounts recognized due to the blending of rates when a contract has operating dayrates that decrease over the initial contract term. Contract balances are netted at a contract level, such that deferred revenue for mobilization, contract preparation and capital modifications (contract liabilities) is netted with any accrued demobilization revenue (contract asset) for each applicable contract. The following table provides information about receivables, contract assets and contract liabilities from our contracts with customers (in thousands): December 31, 2019 December 31, 2018 Trade receivables $ 199,572 $ 160,478 Current contract assets (1) 6,314 6,832 Noncurrent contract assets (1) — 2,107 Current contract liabilities (deferred revenue) (1) (9,573 ) (2,803 ) Noncurrent contract liabilities (deferred revenue) (1) (38,531 ) (17,723 ) (1) Contract assets and contract liabilities may reflect balances that have been netted together on a contract basis. Net current contract asset and liability balances are included in “Prepaid expenses and other current assets” and “Accrued liabilities,” respectively, and net noncurrent contract asset and liability balances are included in “Other assets” and “Other liabilities,” respectively, in our Consolidated Balance Sheets as of December 31, 2019 and 2018. 54 Significant changes in the contract assets and the contract liabilities balances during the period are as follows (in thousands): Net Contract Balances December 31, 2019 2018 Contract assets, beginning of period $ 8,939 $ 2,718 Contract liabilities, beginning of period (20,526 ) (20,343 ) Net balance at beginning of period (11,587 ) (17,625 ) Decrease due to amortization of revenue that was included in the beginning contract liability balance 6,952 19,026 Increase due to cash received, excluding amounts recognized as revenue during the period (34,529 ) (19,353 ) Increase due to revenue recognized during the period but contingent on future performance 3,537 7,114 Decrease due to transfer to receivables during the period (5,119 ) (893 ) Adjustments (1,044 ) 144 Net balance at end of period $ (41,790 ) $ (11,587 ) Contract assets at end of period $ 6,314 $ 8,939 Contract liabilities at end of period (48,104 ) (20,526 ) Deferred Contract Costs Certain direct and incremental costs incurred for upfront preparation, initial mobilization and modifications of contracted rigs represent costs of fulfilling a contract as they relate directly to a contract, enhance resources that will be used in satisfying our performance obligations in the future and are expected to be recovered. Such costs are deferred and amortized ratably to contract drilling expense as services are rendered over the initial term of the related drilling contract. Such deferred contract costs in the amount of $20.0 million and $4.0 million are reported in “Prepaid expenses and other current assets” and “Other assets,” respectively, in our Consolidated Balance Sheets at December 31, 2019. Deferred contract costs in the amount of $70.0 million and $13.1 million are reported in “Prepaid expenses and other current assets” and “Other assets,” respectively, in our Consolidated Balance Sheets at December 31, 2018. During the years ended December 31, 2019 and 2018, the amount of amortization of such costs was $96.0 million and $67.7 million, respectively. There was no impairment loss in relation to capitalized costs. Costs incurred for the demobilization of rigs at contract completion are recognized as incurred during the demobilization process. Costs incurred for rig modifications or upgrades required for a contract, which are considered to be capital improvements, are capitalized as drilling and other property and equipment and depreciated over the estimated useful life of the improvement. Transaction Price Allocated to Remaining Performance Obligations The following table reflects revenue expected to be recognized in the future related to unsatisfied performance obligations as of December 31, 2019 (in thousands): For the Years Ending December 31, 2020 2021 2022 Total Mobilization and contract preparation revenue $ 2,268 $ 630 $ 124 $ 3,022 Capital modification revenue 9,028 1,777 — 10,805 Blended rate revenue 27,848 9,114 — 36,962 Total $ 39,144 $ 11,521 $ 124 $ 50,789 55 The revenue included above consists of expected fixed m obilization and upgrade revenue for both wholly and partially unsatisfied performance obligations as well as expected variable m obilization and upgrade revenue for partially unsatisfied performance obligations, which has been estimated for purposes of allocating across the entire corresponding performance obligations. Revenue expected to be recognized in the future related to the blending of rates when a contract has operating dayrates that decrease over the initial contract term is also included. The amounts are derived from the specific terms within drilling contracts that contain such provisions, and the expected timing for recognition of such revenue is based on the estimated start date and duration of each respective contract based on information known at December 31, 2019 . The actual timing of recognition of such amounts may vary due to factors outside of our control. We have applied the disclosure practical expedient in Topic 606 and have not included estimated variable consideration related to wholly unsatisfied performance obligations or to distinct future time increments within our contracts, including dayrate revenue .

General Information (Tables)

General Information (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Reconciliation of Total Interest Cost to Interest Expense	A reconciliation of our total interest cost to “Interest expense, net of amounts capitalized” as reported in our Consolidated Statements of Operations is as follows (in thousands): For the Year Ended December 31, 2019 2018 2017 Total interest cost including amortization of debt issuance costs $ 122,832 $ 123,816 $ 113,618 Capitalized interest — (576 ) (90 ) Total interest expense as reported $ 122,832 $ 123,240 $ 113,528

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue From Contract With Customer [Abstract]
Summary of Information about Receivables, Contract Assets and Contract Liabilities from Contracts with Customers	The following table provides information about receivables, contract assets and contract liabilities from our contracts with customers (in thousands): December 31, 2019 December 31, 2018 Trade receivables $ 199,572 $ 160,478 Current contract assets (1) 6,314 6,832 Noncurrent contract assets (1) — 2,107 Current contract liabilities (deferred revenue) (1) (9,573 ) (2,803 ) Noncurrent contract liabilities (deferred revenue) (1) (38,531 ) (17,723 ) (1) Contract assets and contract liabilities may reflect balances that have been netted together on a contract basis. Net current contract asset and liability balances are included in “Prepaid expenses and other current assets” and “Accrued liabilities,” respectively, and net noncurrent contract asset and liability balances are included in “Other assets” and “Other liabilities,” respectively, in our Consolidated Balance Sheets as of December 31, 2019 and 2018.
Summary of Significant Changes in Contract Assets and Contract Liabilities Balances	Significant changes in the contract assets and the contract liabilities balances during the period are as follows (in thousands): Net Contract Balances December 31, 2019 2018 Contract assets, beginning of period $ 8,939 $ 2,718 Contract liabilities, beginning of period (20,526 ) (20,343 ) Net balance at beginning of period (11,587 ) (17,625 ) Decrease due to amortization of revenue that was included in the beginning contract liability balance 6,952 19,026 Increase due to cash received, excluding amounts recognized as revenue during the period (34,529 ) (19,353 ) Increase due to revenue recognized during the period but contingent on future performance 3,537 7,114 Decrease due to transfer to receivables during the period (5,119 ) (893 ) Adjustments (1,044 ) 144 Net balance at end of period $ (41,790 ) $ (11,587 ) Contract assets at end of period $ 6,314 $ 8,939 Contract liabilities at end of period (48,104 ) (20,526 )
Summary of Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations	The following table reflects revenue expected to be recognized in the future related to unsatisfied performance obligations as of December 31, 2019 (in thousands): For the Years Ending December 31, 2020 2021 2022 Total Mobilization and contract preparation revenue $ 2,268 $ 630 $ 124 $ 3,022 Capital modification revenue 9,028 1,777 — 10,805 Blended rate revenue 27,848 9,114 — 36,962 Total $ 39,144 $ 11,521 $ 124 $ 50,789

Supplemental Financial Inform_2

Supplemental Financial Information (Tables)	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accounts Receivable, Net of Allowance for Doubtful Accounts	Accounts receivable, net of allowance for bad debts, consists of the following (in thousands): December 31, 2019 2018 Trade receivables $ 199,572 $ 160,478 Federal income tax receivable 38,574 — Value added tax receivables 17,716 13,237 Related party receivables 166 174 Other 287 190 256,315 174,079 Allowance for bad debts (5,459 ) (5,459 ) Total $ 250,856 $ 168,620
Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): December 31, 2019 2018 Deferred contract costs $ 20,019 $ 70,021 Rig spare parts and supplies 18,250 20,256 Prepaid taxes 12,475 54,412 Current contract assets 6,314 6,832 Prepaid rig costs 2,990 5,247 Prepaid insurance 2,892 2,742 Prepaid software costs 2,319 1,531 Other 3,399 2,355 Total $ 68,658 $ 163,396
Accrued Liabilities	Accrued liabilities consist of the following (in thousands): December 31, 2019 2018 Accrued capital project/upgrade costs $ 56,603 $ 37,379 Payroll and benefits 42,494 47,564 Rig operating expenses 37,969 42,323 Interest payable 28,234 28,234 Current operating lease liability (1) 20,030 — Deferred revenue 9,573 2,803 Personal injury and other claims 7,074 5,544 Shorebase and administrative costs 5,275 6,217 Other 3,528 2,164 Total $ 210,780 $ 172,228
Noncash Investing and Financing Activities	Noncash investing activities excluded from the Consolidated Statements of Cash Flows and other supplemental cash flow information is as follows (in thousands): December 31, 2019 2018 2017 Accrued but unpaid capital expenditures at period end $ 56,603 $ 37,234 $ 3,698 Common stock withheld for payroll tax obligations (1) 1,398 1,301 483 Cash interest payments 113,063 113,063 97,096 Cash income taxes paid (refunded), net: Foreign 17,821 9,286 43,999 U.S. federal 1,001 (7,389 ) — State (15 ) 2 94 (1) Represents the cost of 132,547, 87,799 and 29,416 shares of common stock withheld to satisfy the payroll tax obligation incurred as a result of the vesting of restricted stock units in 2019, 2018 and 2017, respectively. These costs are presented as a deduction from stockholders’ equity in “Treasury stock” in our Consolidated Balance Sheets at December 31, 2019, 2018 and 2017, respectively

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Summary of Activity Under Stock Plan	The fair value of SARs granted under the Equity Plan (or its predecessor) during each of the years ended December 31, 2019, 2018 and 2017 was estimated using the Black Scholes pricing model with the following weighted average assumptions: Year Ended December 31, 2019 2018 2017 Expected life of SARs (in years) 7 7 7 Expected volatility 39.35 % 32.10 % 31.70 % Risk free interest rate 2.11 % 2.56 % 2.09 %
Weighted Average Assumptions Used in Estimating Fair Value of Options and SARs	A summary of SARs activity under the Equity Plan as of December 31, 2019 and changes during the year then ended is as follows: Number of Awards Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (In Thousands) Awards outstanding at January 1, 2019 1,029,082 $ 54.08 Granted 28,000 $ 8.57 Expired (134,852 ) $ 71.46 Awards outstanding at December 31, 2019 922,230 $ 50.19 3.6 $ — Awards exercisable at December 31, 2019 922,230 $ 50.19 3.6 $ —
Time-vesting RSUs [Member]
Summary of Restricted Stock Units Awarded Under Equity Plan	A summary of activity for time-vesting RSUs under the Equity Plan as of December 31, 2019 and changes during the year then ended is as follows: Number of Awards Weighted -Average Grant Date Fair Value Per Share Nonvested awards at January 1, 2019 422,059 $ 16.57 Granted 310,700 $ 10.47 Vested (174,774 ) $ 18.20 Forfeited (24,382 ) $ 13.42 Nonvested awards at December 31, 2019 533,603 $ 12.58
Performance-Vesting RSUs [Member]
Summary of Restricted Stock Units Awarded Under Equity Plan	A summary of activity for performance-vesting RSUs under the Equity Plan as of December 31, 2019 and changes during the year then ended is as follows: Number of Awards Weighted -Average Grant Date Fair Value Per Share Nonvested awards at January 1, 2019 741,973 $ 17.53 Granted 190,634 $ 10.49 Vested (223,330 ) $ 21.44 Nonvested awards at December 31, 2019 709,277 $ 14.41

(Loss) Earnings Per Share (Tabl

(Loss) Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Securities Excluded from Computations of Diluted (Loss) Earnings Per Share	The following table sets forth the share effects of stock-based awards exc luded from the computation of diluted (loss) earnings per share (in thousands). Year Ended December 31, 2019 2018 2017 Employee and director: SARs 982 1,133 1,315 RSUs 1,205 1,153 757

Financial Instruments and Fai_2

Financial Instruments and Fair Value Disclosures (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value on Recurring and Nonrecurring Basis	Assets measured at fair value are summarized below (in thousands). December 31, 2019 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value Recurring fair value measurements: Money market funds $ 135,300 $ — $ — $ 135,300 Total short-term investments $ 135,300 $ — $ — $ 135,300 December 31, 2018 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value Total Losses for Year Ended (1) Recurring fair value measurements: U.S. Treasury bills $ 299,900 $ — $ — $ 299,900 Money market funds 135,800 — — 135,800 Short-term investments $ 435,700 $ — $ — $ 435,700 Nonrecurring fair value measurements: Impaired assets $ — $ — $ — $ — $ 27,225 ( 1 ) Represents impairment loss of $27.2 million recognized during 2018 related to a drilling rig whose carrying value was impaired and was subsequently sold. See Note 3.
Fair Values and Related Carrying Values of Our Debt Instruments	Fair values and related carrying values of our senior notes (see Note 9) are shown below (in millions). December 31, 2019 December 31, 2018 Fair Value Carrying Value Fair Value Carrying Value 3.45% Senior Notes due 2023 $ 212.5 $ 249.6 $ 185.0 $ 249.5 7.875% Senior Notes due 2025 435.0 497.1 415.0 496.8 5.70% Senior Notes due 2039 292.5 497.3 305.0 497.2 4.875% Senior Notes due 2043 408.8 749.0 416.3 748.9

Drilling and Other Property a_2

Drilling and Other Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Summary of Cost and Accumulated Depreciation of Drilling and Other Property and Equipment	Cost and accumulated depreciation of drilling and other property and equipment are summarized as follows (in thousands): December 31, 2019 2018 Drilling rigs and equipment $ 8,004,489 $ 8,210,824 Land and buildings 64,267 63,757 Office equipment and other 92,289 91,819 Cost 8,161,045 8,366,400 Less: accumulated depreciation (3,008,217 ) (3,182,178 ) Drilling and other property and equipment, net $ 5,152,828 $ 5,184,222

Credit Agreements and Senior _2

Credit Agreements and Senior Notes (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Summary of Interest Rate Margins and Fees Payable Under the Amended and New Credit Agreements	The following summarizes the interest rate margins and fees payable under the Credit Agreements, based on our current long-term credit ratings: Amended Credit Facility $950 Million Credit Facility Revolving Loans: ABR 0.25% over the greater of (i) the prime rate, (ii) the federal funds rate plus 0.50% and (iii) the daily one-month Eurodollar Rate plus 1.00% 3.25% over the greater of (i) the prime rate, (ii) the federal funds rate plus 0.50% and (iii) the daily one-month Eurodollar Rate plus 1.00% Eurodollar 1.25% over specified LIBOR 4.25% over specified LIBOR Swingline Loans N/A At our option, at a rate per annum equal to (i) the ABR plus the applicable interest margin for ABR loans or (ii) the daily one-month Eurodollar Rate plus the applicable interest margin for Eurodollar loans Letter of credit participation fees: Performance letters of credit N/A 2.125% per annum All other letters of credit N/A 4.25% per annum Commitment fee on unused commitments under credit agreement 0.20% per annum 0.70% per annum
Summary of Senior Notes	At December 31, 2019, our senior notes were comprised of the following debt issues (dollars in millions): Semiannual Principal Interest Rate Interest Payment Debt Issue Amount Maturity Date Coupon Effective Dates 3.45% Senior Notes due 2023 $ 250.0 November 1, 2023 3.45 % 3.50 % May 1 and November 1 7.875% Senior Notes due 2025 $ 500.0 August 15, 2025 7.875 % 8.00 % February 15 and August 15 5.70% Senior Notes due 2039 $ 500.0 October 15, 2039 5.70 % 5.75 % April 15 and October 15 4.875% Senior Notes due 2043 $ 750.0 November 1, 2043 4.875 % 4.89 % May 1 and November 1
Summary of Carrying Value of Senior Notes, Net of Unamortized Discount and Debt Issuance Costs	At December 31, 2019 and 2018, the carrying value of our senior notes, net of unamortized discount and debt issuance costs, was as follows (in thousands): December 31, 2019 2018 3.45% Senior Notes due 2023 $ 248,759 $ 248,455 7.875% Senior Notes due 2025 491,655 490,491 5.70% Senior Notes due 2039 493,316 493,139 4.875% Senior Notes due 2043 742,011 741,837 Total senior notes, net $ 1,975,741 $ 1,973,922
Aggregate Maturities of Senior Notes, Excluding Net Unamortized Discounts and Debt Issuance Costs	As of December 31, 2019, the aggregate annual maturity of our senior notes, excluding net unamortized discounts and debt issuance costs of $7.0 million and $17.3 million, respectively, was as follows (in thousands): Aggregate Principal Amount Year Ending December 31, 2020 $ — 2021 — 2022 — 2023 250,000 2024 — Thereafter 1,750,000 Total maturities of senior notes $ 2,000,000

Leases and Lease Commitments (T

Leases and Lease Commitments (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Supplemental Information Related to Leases	Supplemental information related to leases is as follows (in thousands, except weighted-average data): Year Ended December 31, 2019 Operating cash flows used for operating leases $ 39,561 Right-of-use assets obtained in exchange for lease liabilities 26,248 Weighted-average remaining lease term 6.7 years Weighted-average discount rate 8.68 %
Schedule of Future Minimum Rental Payment Under Non-Cancelable Operating Leases	Future minimum rental payments under noncancelable operating leases as of December 31, 2018 were as follows (in thousands): 2019 $ 28,373 2020 27,144 2021 26,565 2022 26,281 2023 26,280 Thereafter 64,062 Total lease payments $ 198,705
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of December 31, 2019 are as follows (in thousands): 2020 $ 32,888 2021 30,548 2022 29,973 2023 29,499 2024 29,580 Thereafter 51,784 Total lease payments 204,272 Less: interest (50,348 ) Total lease liability $ 153,924 Amounts recognized in Consolidated Balance Sheets: Accrued liabilities $ 20,030 Other liabilities 133,894 Total operating lease liability $ 153,924

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components of Income Tax Expense (Benefit)	The components of income tax expense (benefit) are as follows (in thousands): Year Ended December 31, 2019 2018 2017 Federal – current $ (13,810 ) $ 20,107 $ 6,994 State – current 19 2 95 Foreign – current 25,899 9,531 25,252 Total current 12,108 29,640 32,341 Federal – deferred (67,015 ) (75,279 ) (85,066 ) Foreign – deferred 10,107 (714 ) 12,939 Total deferred (56,908 ) (75,993 ) (72,127 ) Total $ (44,800 ) $ (46,353 ) $ (39,786 )
Difference Between Actual Income Tax Expense and Tax Provision Computed by Applying Statutory Federal Income Tax Rate to Income Before Taxes	The difference between actual income tax expense and the tax provision computed by applying the statutory federal income tax rate to income before taxes is attributable to the following (in thousands): Year Ended December 31, 2019 2018 2017 (Loss) income before income tax expense: U.S. $ (339,072 ) $ (266,855 ) $ (241,178 ) Foreign (62,942 ) 40,230 219,738 $ (402,014 ) $ (226,625 ) $ (21,440 ) Expected income tax benefit at federal statutory rate $ (84,423 ) $ (47,591 ) $ (7,504 ) Effect of tax rate changes (74,168 ) 1,763 (74,294 ) Mandatory repatriation of earnings pursuant to Tax Reform Act — — 94,194 Effect of foreign operations 3,129 15 (42,102 ) Valuation allowance 11,650 11,929 (41,492 ) Uncertain tax positions, settlements and adjustments relating to prior years 96,960 (15,777 ) 31,726 Other 2,052 3,308 (314 ) Income tax benefit $ (44,800 ) $ (46,353 ) $ (39,786 )
Components of Deferred Income Tax Assets and Liabilities	Deferred Income Taxes. Significant components of our deferred income tax assets and liabilities are as follows (in thousands): December 31, 2019 2018 Deferred tax assets: Net operating loss carryforwards, or NOLs $ 253,973 $ 209,679 Foreign tax credits 43,026 43,225 Disallowed interest deduction 40,777 16,248 Worker’s compensation and other current accruals 6,250 8,375 Deferred deductions 12,345 10,481 Deferred revenue 7,209 — Operating lease liability 5,461 — Other 4,367 6,380 Total deferred tax assets 373,408 294,388 Valuation allowance (186,620 ) (174,970 ) Net deferred tax assets 186,788 119,418 Deferred tax liabilities: Property, plant and equipment (225,643 ) (212,251 ) Mobilization (2,245 ) (11,012 ) Right-of-use assets (5,461 ) — Other (967 ) (535 ) Total deferred tax liabilities (234,316 ) (223,798 ) Net deferred tax liability $ (47,528 ) $ (104,380 )
Summary of Rollforward of Beginning and Ending Amount of Unrecognized Tax Benefits, Excluding Interest and Penalties	A rollforward of the beginning and ending amount of unrecognized tax benefits, excluding interest and penalties, is as follows (in thousands): For the Year Ended December 31, 2019 2018 2017 Balance, beginning of period $ (55,943 ) $ (81,864 ) $ (34,970 ) Additions for current year tax positions (85,970 ) (2,906 ) (51,260 ) Additions for prior year tax positions (2,113 ) (20,943 ) (2,938 ) Reductions for prior year tax positions 23,267 49,175 623 Reductions related to statute of limitation expirations 1,875 595 6,681 Balance, end of period $ (118,884 ) $ (55,943 ) $ (81,864 )

Segments and Geographic Area _2

Segments and Geographic Area Analysis (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Summary of Information About Disaggregated Revenue by Equipment type and Country	The following tables provide information about disaggregated revenue by equipment-type and country (in thousands): Year Ended December 31, 2019 Total Contract Drilling Revenues (1) Revenues Related to Reimbursable Expenses Total United States $ 507,759 $ 7,881 $ 515,640 Brazil 191,519 83 191,602 United Kingdom 149,724 14,036 163,760 Australia 85,932 23,710 109,642 Total $ 934,934 $ 45,710 $ 980,644 (1) Year Ended December 31, 2018 Floater Rigs Jack-up Rigs (1) Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 628,574 $ 8,413 $ 636,987 $ 7,436 $ 644,423 Brazil 170,839 — 170,839 (26 ) 170,813 United Kingdom 84,749 — 84,749 7,738 92,487 Australia 53,170 — 53,170 7,612 60,782 Malaysia 114,228 — 114,228 (210 ) 114,018 Other countries (2) — — — 692 692 Total $ 1,051,560 $ 8,413 $ 1,059,973 $ 23,242 $ 1,083,215 (1) (2) Year Ended December 31, 2017 Floater Rigs Jack-up Rigs Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 619,655 $ — $ 619,655 $ 10,940 $ 630,595 Brazil 280,798 — 280,798 (311 ) 280,487 United Kingdom 171,146 — 171,146 6,424 177,570 Australia 125,568 — 125,568 15,385 140,953 Malaysia 164,984 — 164,984 1,988 166,972 Trinidad 67,924 — 67,924 — 67,924 Other countries (1) — 21,144 21,144 101 21,245 Total $ 1,430,075 $ 21,144 $ 1,451,219 $ 34,527 $ 1,485,746 (1)
Long-Lived Tangible Assets by Country	The following table presents our long-lived tangible assets by country as of December 31, 2019, 2018 and 2017. A substantial portion of our assets is comprised of rigs that are mobile, and therefore asset locations at the end of the period are not necessarily indicative of the geographic distribution of the earnings generated by such assets during the periods and may vary from period to period due to the relocation of rigs. In circumstances where our drilling rigs were in transit at the end of a calendar year, they have been presented in the tables below within the country in which they were expected to operate (in thousands). December 31, 2019 2018 (1) 2017 (1) Drilling and other property and equipment, net: United States $ 2,227,934 $ 2,245,989 $ 2,300,956 International: United Kingdom 1,061,585 1,083,540 133,525 Brazil 883,607 923,355 923,398 Australia 570,964 242,929 629,436 Singapore 404,420 366,798 17 Malaysia 2,037 318,191 1,084,793 Other countries (2) 2,281 3,420 189,516 2,924,894 2,938,233 2,960,685 Total $ 5,152,828 $ 5,184,222 $ 5,261,641 (1) (2) rilling and other property and equipment, net of accumulated depreciation
Revenues from Major Customers that Contributed More than 10% of Total Revenues	Revenues from our major customers for the years ended December 31, 2019, 2018 and 2017 that contributed more than 10% of our total revenues are as follows: Year Ended December 31, Customer 2019 2018 2017 Hess Corporation 28.9 % 25.0 % 16.0 % Occidental (formerly Anadarko) 20.6 % 33.8 % 24.9 % Petróleo Brasileiro S.A. 19.5 % 15.8 % 18.9 % BP 3.1 % 10.5 % 15.8 %

Unaudited Quarterly Financial_2

Unaudited Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Data	Unaudited summarized financial data by quarter for the years ended December 31, 2019 and 2018 is shown below (in thousands). First Second Third Fourth Quarter Quarter Quarter Quarter 2019 Revenues $ 233,542 $ 216,706 $ 254,020 $ 276,376 Operating loss (49,127 ) (111,500 ) (72,834 ) (48,869 ) Loss before income tax expense (77,390 ) (141,342 ) (102,610 ) (80,672 ) Net loss (73,328 ) (113,988 ) (95,128 ) (74,770 ) Net loss per share, basic and diluted $ (0.53 ) $ (0.83 ) $ (0.69 ) $ (0.54 ) 2018 Revenues $ 295,510 $ 268,861 $ 286,322 $ 232,522 Operating income (loss) (1) 512 (52,375 ) (23,043 ) (37,277 ) Loss before income tax expense (25,142 ) (79,286 ) (55,894 ) (66,303 ) Net income (loss) 19,321 (69,274 ) (51,112 ) (79,207 ) Net income (loss) per share, basic and diluted $ 0.14 $ (0.50 ) $ (0.37 ) $ (0.58 ) (1) During the second quarter of 2018, we recognized an impairment loss of $27.2 million to write down the carrying value of the Ocean Scepter to its estimated recoverable amount. See Note 3.

General Information - Additiona

General Information - Additional Information (Detail) $ in Thousands	Jan. 01, 2018USD ($)	Dec. 31, 2019USD ($)Rig	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Feb. 07, 2020	Jan. 01, 2019USD ($)	Jan. 01, 2017USD ($)	Dec. 31, 2016USD ($)
Significant Accounting Policies [Line Items]
Number of offshore rigs owned | Rig		15
Operating lease assets		$ 169,200
Operating lease liabilities		$ 153,924
Impact of change in accounting principle				$ (14,812)
Period considered to treat short-term, highly liquid investments as cash equivalents		three months or less
Amount capitalized for asset replacements and betterments		$ 343,800	$ 243,600
Debt issuance costs and arrangement fees		$ 12	$ 5,651	7,263
Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful life for drilling rigs and equipment		3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful life for drilling rigs and equipment		30 years
Retained Earnings [Member]
Significant Accounting Policies [Line Items]
Impact of change in accounting principle				$ (14,812)				$ (634)
Additional Paid-in Capital [Member]
Significant Accounting Policies [Line Items]
Impact of change in accounting principle								$ 634
ASU 2016-02 [Member]
Significant Accounting Policies [Line Items]
Operating lease assets						$ 146,800
Operating lease liabilities						$ 146,800
ASU 2016-16 [Member]
Significant Accounting Policies [Line Items]
Reduction in retained earnings	$ 17,400
ASU, No. 2016-09 [Member] | Retained Earnings [Member]
Significant Accounting Policies [Line Items]
Impact of change in accounting principle							$ (600)
ASU, No. 2016-09 [Member] | Additional Paid-in Capital [Member]
Significant Accounting Policies [Line Items]
Impact of change in accounting principle							$ 600
Subsequent Event [Member]
Significant Accounting Policies [Line Items]
Outstanding common stock owned by loews corporation					53.00%
Ultra-deepwater Drillship [Member]
Significant Accounting Policies [Line Items]
Number of offshore rigs owned | Rig		4
Semisubmersible Rigs [Member]
Significant Accounting Policies [Line Items]
Number of offshore rigs owned | Rig		11
Cold Stacked Rigs [Member]
Significant Accounting Policies [Line Items]
Number of offshore rigs owned | Rig		2

General Information - Reconcili

General Information - Reconciliation of Total Interest Cost to Interest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Costs Incurred [Abstract]
Total interest cost including amortization of debt issuance costs	$ 122,832	$ 123,816	$ 113,618
Capitalized interest		(576)	(90)
Total interest expense as reported	$ 122,832	$ 123,240	$ 113,528

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue From Contract With Customers [Line Items]
Payment terms on invoiced amounts	30 days
Deferred contract costs	$ 20,019,000	$ 70,021,000
Contract costs amortization	96,000,000	67,700,000
Contract costs impairment loss	0
Prepaid Expenses and Other Current Assets [Member]
Revenue From Contract With Customers [Line Items]
Deferred contract costs	20,000,000	70,000,000
Other Assets [Member]
Revenue From Contract With Customers [Line Items]
Deferred contract costs	$ 4,000,000	$ 13,100,000
Minimum [Member]
Revenue From Contract With Customers [Line Items]
Initial term of contract	2 months
Maximum [Member]
Revenue From Contract With Customers [Line Items]
Initial term of contract	60 months

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Summary of Information about Receivables, Contract Assets and Contract Liabilities from Contracts with Customers (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Trade receivables	$ 199,572	$ 160,478
Current contract assets	6,314	6,832
Noncurrent contract assets		2,107
Current contract liabilities (deferred revenue)	(9,573)	(2,803)
Noncurrent contract liabilities (deferred revenue)	$ (38,531)	$ (17,723)

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Summary of Significant Changes in Contract Assets and Contract Liabilities Balances (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Contract assets, beginning of period	$ 8,939	$ 2,718
Contract liabilities, beginning of period	(20,526)	(20,343)
Net balance at beginning of period	(11,587)	(17,625)
Decrease due to amortization of revenue that was included in the beginning contract liability balance	6,952	19,026
Increase due to cash received, excluding amounts recognized as revenue during the period	(34,529)	(19,353)
Increase due to revenue recognized during the period but contingent on future performance	3,537	7,114
Decrease due to transfer to receivables during the period	(5,119)	(893)
Adjustments	(1,044)	144
Net balance at end of period	(41,790)	(11,587)
Contract assets at end of period	6,314	8,939
Contract liabilities at end of period	$ (48,104)	$ (20,526)

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Summary of Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 50,789
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue remaining performance obligation	$ 39,144
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue remaining performance obligation	$ 11,521
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year
Revenue remaining performance obligation	$ 124
Mobilization and Contract Preparation Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	3,022
Mobilization and Contract Preparation Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	2,268
Mobilization and Contract Preparation Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	630
Mobilization and Contract Preparation Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	124
Capital Modification Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	10,805
Capital Modification Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	9,028
Capital Modification Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	1,777
Blended Rate Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	36,962
Blended Rate Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	27,848
Blended Rate Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 9,114

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Summary of Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations (Detail 1) $ in Thousands	Dec. 31, 2019USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 50,789
Mobilization and Contract Preparation Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	3,022
Capital Modification Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	10,805
Blended Rate Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 36,962

Assets Impairments - Additional

Assets Impairments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019USD ($)Rig	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)Rig
Schedule Of Asset Impairment Charges [Line Items]
Loss on impairment of assets | $		$ 27,225,000	$ 99,313,000
2019 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment | Rig	3
Loss on impairment of assets | $	$ 0
2018 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Loss on impairment of assets | $		$ 27,200,000
Impaired long-lived assets held and used, method for determining fair value		We estimated the fair value of the impaired rig using a market approach based on a signed agreement to sell the rig, less estimated costs to sell. We considered this valuation approach to be a Level 3 fair value measurement due to the level of estimation involved as the sale had not yet been completed at the time of our analysis.
2017 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment | Rig			10
Loss on impairment of assets | $			$ 99,300,000
Number of rigs impaired | Rig			3
Number of rigs impaired based on income approach | Rig			2

Supplemental Financial Inform_3

Supplemental Financial Information - Accounts Receivable, Net of Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Receivables [Abstract]
Trade receivables	$ 199,572	$ 160,478
Federal income tax receivable	38,574
Value added tax receivables	17,716	13,237
Related party receivables	166	174
Other	287	190
Receivables Gross Current, Total	256,315	174,079
Allowance for bad debts	(5,459)	(5,459)
Total	$ 250,856	$ 168,620

Supplemental Financial Inform_4

Supplemental Financial Information - Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Deferred contract costs	$ 20,019	$ 70,021
Rig spare parts and supplies	18,250	20,256
Prepaid taxes	12,475	54,412
Current contract assets	6,314	6,832
Prepaid rig costs	2,990	5,247
Prepaid insurance	2,892	2,742
Prepaid software costs	2,319	1,531
Other	3,399	2,355
Total	$ 68,658	$ 163,396

Supplemental Financial Inform_5

Supplemental Financial Information - Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued capital project/upgrade costs	$ 56,603	$ 37,379
Payroll and benefits	42,494	47,564
Rig operating expenses	37,969	42,323
Interest payable	28,234	28,234
Current operating lease liability	20,030
Deferred revenue	9,573	2,803
Personal injury and other claims	7,074	5,544
Shorebase and administrative costs	5,275	6,217
Other	3,528	2,164
Total	$ 210,780	$ 172,228

Supplemental Financial Inform_6

Supplemental Financial Information - Noncash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Accrued but unpaid capital expenditures at period end	$ 56,603	$ 37,234	$ 3,698
Common stock withheld for payroll tax obligations	1,398	1,301	483
Cash interest payments	113,063	113,063	97,096
Foreign [Member]
Cash income taxes paid (refunded), net:
Cash income taxes paid, net of refunds	17,821	9,286	43,999
U.S. Federal [Member]
Cash income taxes paid (refunded), net:
Cash income taxes paid, net of refunds	1,001	(7,389)
State [Member]
Cash income taxes paid (refunded), net:
Cash income taxes paid, net of refunds	$ (15)	$ 2	$ 94

Supplemental Financial Inform_7

Supplemental Financial Information - Noncash Investing and Financing Activities (Parenthetical) (Detail) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted Stock [Member]
Condensed Financial Statements, Captions [Line Items]
Number of shares of common stock withheld	132,547	87,799	29,416

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration (in years)	10 years
Weighted-average grant date fair values of awards granted	$ 3.75	$ 7.11	$ 5.61
Intrinsic value of awards exercised	$ 0	$ 100,000	$ 0
Fair value of awards vested	100,000	700,000	1,200,000
Time-vesting RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	$ 1,900,000	$ 1,900,000	$ 1,100,000
Number of Equity Instruments Awarded in Period	310,700	135,759	276,085
Time-vesting RSUs [Member] | Two Years from the Date of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of RSUs vesting	50.00%
Time-vesting RSUs [Member] | Three Year from the Date of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of RSUs vesting	50.00%
Performance-Vesting RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of awards vested	$ 2,300,000	$ 2,500,000	$ 300,000
Number of Equity Instruments Awarded in Period	190,634	194,563	370,616
Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost recognized for awards under the Equity Plan	$ 6,200,000	$ 6,800,000	$ 8,700,000
Tax benefits recognized	500,000	$ 800,000	$ 2,600,000
Unrecognized compensation cost related to nonvested awards under the Equity Plan	$ 6,600,000
Expected weighted average period to recognized compensation cost related to nonvested awards under the Equity Plan	2 years
Equity Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock available for issuance	7,500,000

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Assumptions Used in Estimating Fair Value of Options and SARs (Detail) - Stock Appreciation Rights (SARs) [Member]	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of SARs (in years)	7 years	7 years	7 years
Expected volatility	39.35%	32.10%	31.70%
Risk free interest rate	2.11%	2.56%	2.09%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity Under Stock Plan (Detail) - Stock Appreciation Rights (SARs) [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards Outstanding, Beginning Balance | shares	1,029,082
Number of Awards, granted | shares	28,000
Number of Awards, expired | shares	(134,852)
Number of Awards, Outstanding, Ending Balance | shares	922,230
Number of Awards, exercisable | shares	922,230
Weighted-Average Exercise Price Outstanding, Beginning Balance | $ / shares	$ 54.08
Weighted-Average Exercise Price, granted | $ / shares	8.57
Weighted-Average Exercise Price, expired | $ / shares	71.46
Weighted-Average Exercise Price Outstanding, Ending Balance | $ / shares	50.19
Weighted-Average Exercise Price Outstanding, exercisable | $ / shares	$ 50.19
Weighted-Average Remaining Contractual Term, outstanding	3 years 7 months 6 days
Weighted-Average Remaining Contractual Term, exercisable	3 years 7 months 6 days
Aggregate Intrinsic Value, outstanding | $	$ 0
Aggregate Intrinsic Value, exercisable | $	$ 0

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Restricted Stock Units Awarded Under Equity Plan (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Time-vesting RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards, Nonvested, Beginning Balance	422,059
Number of Awards, granted	310,700	135,759	276,085
Number of Awards, vested	(174,774)
Number of Awards, forfeited	(24,382)
Number of Awards, Nonvested, Ending Balance	533,603	422,059
Weighted-Average Grant Date Fair Value Per Share, Nonvested, Beginning Balance	$ 16.57
Weighted-Average Grant Date Fair Value Per Share, granted	10.47
Weighted-Average Grant Date Fair Value Per Share, vested	18.20
Weighted-Average Grant Date Fair Value Per Share, forfeited	13.42
Weighted-Average Grant Date Fair Value Per Share, Nonvested, Ending Balance	$ 12.58	$ 16.57
Performance-Vesting RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards, Nonvested, Beginning Balance	741,973
Number of Awards, granted	190,634	194,563	370,616
Number of Awards, vested	(223,330)
Number of Awards, Nonvested, Ending Balance	709,277	741,973
Weighted-Average Grant Date Fair Value Per Share, Nonvested, Beginning Balance	$ 17.53
Weighted-Average Grant Date Fair Value Per Share, granted	10.49
Weighted-Average Grant Date Fair Value Per Share, vested	21.44
Weighted-Average Grant Date Fair Value Per Share, Nonvested, Ending Balance	$ 14.41	$ 17.53

(Loss) Earnings Per Share - Sec

(Loss) Earnings Per Share - Securities Excluded from Computations of Diluted (Loss) Earnings Per Share (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Appreciation Rights (SARs) [Member]
Employee and director:
Securities excluded from computation of diluted (loss) earning per share	982	1,133	1,315
Restricted Stock Units (RSUs) [Member]
Employee and director:
Securities excluded from computation of diluted (loss) earning per share	1,205	1,153	757

Financial Instruments and Fai_3

Financial Instruments and Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring and Nonrecurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment of assets	$ 27,225	$ 99,313
Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	435,700		$ 135,300
Fair Value Measurements, Recurring [Member] | U.S. Treasury Bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	299,900
Nonrecurring Fair Value Measurements [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment of assets	27,225
Level 1 [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	435,700		135,300
Level 1 [Member] | Fair Value Measurements, Recurring [Member] | U.S. Treasury Bills [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	299,900
Money Market Funds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	135,800		135,300
Money Market Funds [Member] | Level 1 [Member] | Fair Value Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total short-term investments	$ 135,800		$ 135,300

Financial Instruments and Fai_4

Financial Instruments and Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring and Nonrecurring Basis (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment of assets	$ 27,225	$ 99,313
2018 Impaired Rigs [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment of assets	$ 27,200

Financial Instruments and Fai_5

Financial Instruments and Fair Value Disclosures - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Measurement period for determining fair value of debt instruments	10 days

Financial Instruments and Fai_6

Financial Instruments and Fair Value Disclosures - Fair Value and Related Carrying Values of Our Debt Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
3.45% Senior Notes due 2023 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 212.5	$ 185
Carrying Value	249.6	249.5
7.875% Senior Notes due 2025 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	435	415
Carrying Value	497.1	496.8
5.70% Senior Notes due 2039 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	292.5	305
Carrying Value	497.3	497.2
4.875% Senior Notes due 2043 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	408.8	416.3
Carrying Value	$ 749	$ 748.9

Financial Instruments and Fai_7

Financial Instruments and Fair Value Disclosures - Fair Value and Related Carrying Values of Our Debt Instruments (Parenthetical) (Detail)	Dec. 31, 2019	Dec. 31, 2018
3.45% Senior Notes due 2023 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate of senior notes	3.45%	3.45%
7.875% Senior Notes due 2025 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate of senior notes	7.875%	7.875%
5.70% Senior Notes due 2039 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate of senior notes	5.70%	5.70%
4.875% Senior Notes due 2043 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate of senior notes	4.875%	4.875%

Drilling and Other Property a_3

Drilling and Other Property and Equipment - Summary of Cost and Accumulated Depreciation of Drilling and Other Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment	$ 8,161,045	$ 8,366,400
Less: accumulated depreciation	(3,008,217)	(3,182,178)
Drilling and other property and equipment, net	5,152,828	5,184,222	$ 5,261,641
Drilling Rigs and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	8,004,489	8,210,824
Land and Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	64,267	63,757
Office Equipment and Other [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 92,289	$ 91,819

Drilling and Other Property a_4

Drilling and Other Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Gain (loss) on disposition of assets		$ (1,072)	$ (241)	$ 10,500
Asset held for sale		1,000
Semisubmersible Rig [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on disposition of assets		14,300
Asset held for sale		1,000
Semisubmersible Rig [Member] | Forecast [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on disposition of assets	$ 3,500
Other Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Gain (loss) on disposition of assets		$ (15,400)

Credit Agreements and Senior _3

Credit Agreements and Senior Notes - Credit Agreement - Additional Information (Detail) - USD ($)	Oct. 02, 2018	Feb. 07, 2020	Jan. 20, 2020	Dec. 31, 2019	Sep. 30, 2012
Debt Instrument [Line Items]
Borrowings outstanding				$ 0
Subsequent Event [Member]
Debt Instrument [Line Items]
Remaining amount available under Credit Agreement		$ 1,200,000,000
Amended Credit Agreement [Member]
Debt Instrument [Line Items]
Amount available for general purposes	$ 325,000,000				$ 1,500,000,000
Amended Credit Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Consolidated indebtedness to total capitalization	60.00%
Amended Credit Agreement [Member] | Credit Facility Mature on March 17, 2019 [Member]
Debt Instrument [Line Items]
Amount available for general purposes	$ 100,000,000
Amended Credit Agreement [Member] | Credit facility Mature on October 22, 2020 [Member]
Debt Instrument [Line Items]
Remaining amount available under Credit Agreement	$ 225,000,000
Credit facility, maturity	Oct. 22, 2020
950 Million Credit Agreement [Member]
Debt Instrument [Line Items]
Amount available for general purposes	$ 950,000,000
Credit facility, maturity	Oct. 2, 2023
Credit facility, term	5 years
Required ratio of value of marketed rigs to total commitments	3
Excess of other indebtedness	$ 100,000,000
950 Million Credit Agreement [Member] | Financial Letter of Credit [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Line of credit issued			$ 6,000,000
950 Million Credit Agreement [Member] | Minimum [Member]
Debt Instrument [Line Items]
Aggregate amount of available cash	$ 500,000,000
Required ratio of value of rigs owned by borrower to total rigs owned by entity	80.00%
950 Million Credit Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Consolidated indebtedness to total capitalization	60.00%
950 Million Credit Agreement [Member] | Diamond Foreign Assets Corporation [Member]
Debt Instrument [Line Items]
Equity interest pledged as collateral on borrowing	65.00%
950 Million Credit Agreement [Member] | Letter Of Credit Subfacility [Member]
Debt Instrument [Line Items]
Amount available for general purposes	$ 250,000,000
950 Million Credit Agreement [Member] | Swingline Sub Facility [Member]
Debt Instrument [Line Items]
Amount available for general purposes	$ 100,000,000

Credit Agreements and Senior _4

Credit Agreements and Senior Notes - Summary of Interest Rate Margins and Fees Payable Under the Amended and New Credit Agreements (Detail)	12 Months Ended
	Dec. 31, 2019
Amended Credit Agreement [Member]
Schedule of Debt Instruments [Line Items]
Commitment fee on unused commitments under credit agreement	0.20%
Amended Credit Agreement [Member] | ABR Loans [Member]
Schedule of Debt Instruments [Line Items]
Debt instruments interest rate description	0.25% over the greater of (i) the prime rate, (ii) the federal funds rate plus 0.50% and (iii) the daily one-month Eurodollar Rate plus 1.00%
Interest margin	0.25%
Amended Credit Agreement [Member] | Eurodollar Loans [Member]
Schedule of Debt Instruments [Line Items]
Debt instruments interest rate description	1.25% over specified LIBOR
Interest margin	1.25%
Amended Credit Agreement [Member] | Federal Funds Rate [Member]
Schedule of Debt Instruments [Line Items]
Basis point increase	0.50%
Amended Credit Agreement [Member] | Swingline Loans Facility [Member]
Schedule of Debt Instruments [Line Items]
Debt instruments interest rate description	N/A
Amended Credit Agreement [Member] | Eurodollar [Member]
Schedule of Debt Instruments [Line Items]
Basis point increase	1.00%
950 Million Credit Agreement [Member]
Schedule of Debt Instruments [Line Items]
Commitment fee on unused commitments under credit agreement	0.70%
950 Million Credit Agreement [Member] | ABR Loans [Member]
Schedule of Debt Instruments [Line Items]
Debt instruments interest rate description	3.25% over the greater of (i) the prime rate, (ii) the federal funds rate plus 0.50% and (iii) the daily one-month Eurodollar Rate plus 1.00%
Interest margin	3.25%
950 Million Credit Agreement [Member] | Eurodollar Loans [Member]
Schedule of Debt Instruments [Line Items]
Debt instruments interest rate description	4.25% over specified LIBOR
Interest margin	4.25%
950 Million Credit Agreement [Member] | Federal Funds Rate [Member]
Schedule of Debt Instruments [Line Items]
Basis point increase	0.50%
950 Million Credit Agreement [Member] | Swingline Loans Facility [Member]
Schedule of Debt Instruments [Line Items]
Debt instruments interest rate description	At our option, at a rate per annum equal to (i) the ABR plus the applicable interest margin for ABR loans or (ii) the daily one-month Eurodollar Rate plus the applicable interest margin for Eurodollar loans
950 Million Credit Agreement [Member] | Performance Letters of Credit [Member]
Schedule of Debt Instruments [Line Items]
Performance letters of credit	2.125%
950 Million Credit Agreement [Member] | All Other Letters of Credit [Member]
Schedule of Debt Instruments [Line Items]
Performance letters of credit	4.25%
950 Million Credit Agreement [Member] | Eurodollar [Member]
Schedule of Debt Instruments [Line Items]
Basis point increase	1.00%

Credit Agreements and Senior _5

Credit Agreements and Senior Notes - Summary of Senior Notes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2017
3.45% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Principal Amount	$ 250
Maturity Date	Nov. 1, 2023
Interest rate Coupon, senior notes	3.45%	3.45%
Interest rate Effective, senior notes	3.50%
Semiannual Interest Payment Dates	May 1 and November 1
7.875% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Principal Amount	$ 500		$ 500
Maturity Date	Aug. 15, 2025
Interest rate Coupon, senior notes	7.875%	7.875%
Interest rate Effective, senior notes	8.00%
Semiannual Interest Payment Dates	February 15 and August 15
5.70% Senior Notes due 2039 [Member]
Debt Instrument [Line Items]
Principal Amount	$ 500
Maturity Date	Oct. 15, 2039
Interest rate Coupon, senior notes	5.70%	5.70%
Interest rate Effective, senior notes	5.75%
Semiannual Interest Payment Dates	April 15 and October 15
4.875% Senior Notes due 2043 [Member]
Debt Instrument [Line Items]
Principal Amount	$ 750
Maturity Date	Nov. 1, 2043
Interest rate Coupon, senior notes	4.875%	4.875%
Interest rate Effective, senior notes	4.89%
Semiannual Interest Payment Dates	May 1 and November 1

Credit Agreements and Senior _6

Credit Agreements and Senior Notes - Summary of Senior Notes (Parenthetical) (Detail)	Dec. 31, 2019	Dec. 31, 2018
3.45% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	3.45%	3.45%
7.875% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	7.875%	7.875%
5.70% Senior Notes due 2039 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	5.70%	5.70%
4.875% Senior Notes due 2043 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	4.875%	4.875%

Credit Agreements and Senior _7

Credit Agreements and Senior Notes - Summary of Carrying Value of Senior Notes, Net of Unamortized Discount and Debt Issuance Costs (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Senior Notes	$ 1,975,741	$ 1,973,922
3.45% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Senior Notes	248,759	248,455
7.875% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Senior Notes	491,655	490,491
5.70% Senior Notes due 2039 [Member]
Debt Instrument [Line Items]
Senior Notes	493,316	493,139
4.875% Senior Notes due 2043 [Member]
Debt Instrument [Line Items]
Senior Notes	$ 742,011	$ 741,837

Credit Agreements and Senior _8

Credit Agreements and Senior Notes - Summary of Carrying Value of Senior Notes, Net of Unamortized Discount and Debt Issuance Costs (Parenthetical) (Detail)	Dec. 31, 2019	Dec. 31, 2018
3.45% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	3.45%	3.45%
7.875% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	7.875%	7.875%
5.70% Senior Notes due 2039 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	5.70%	5.70%
4.875% Senior Notes due 2043 [Member]
Debt Instrument [Line Items]
Interest rate of senior notes	4.875%	4.875%

Credit Agreements and Senior _9

Credit Agreements and Senior Notes - Senior Notes - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2017	Dec. 31, 2019	Dec. 31, 2017
Debt Instrument [Line Items]
Unamortized discounts, net		$ 7,000
Debt issuance costs, net		17,300
Loss on extinguishment of senior notes			$ (35,366)
Proceeds from issuance of senior notes			$ 496,360
5.875% Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Redemption of outstanding senior notes	$ 543,000
Loss on extinguishment of senior notes	35,400
7.875% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Aggregate principal amount of senior unsecured notes	500,000	$ 500,000
Proceeds from issuance of senior notes	$ 489,100
7.875% Senior Notes due 2025 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		15 days
7.875% Senior Notes due 2025 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		60 days
3.45% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Aggregate principal amount of senior unsecured notes		$ 250,000
3.45% Senior Notes due 2023 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		15 days
3.45% Senior Notes due 2023 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		60 days
4.875% Senior Notes due 2043 [Member]
Debt Instrument [Line Items]
Aggregate principal amount of senior unsecured notes		$ 750,000
4.875% Senior Notes due 2043 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		15 days
4.875% Senior Notes due 2043 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		60 days
5.70% Senior Notes due 2039 [Member]
Debt Instrument [Line Items]
Aggregate principal amount of senior unsecured notes		$ 500,000
5.70% Senior Notes due 2039 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		15 days
5.70% Senior Notes due 2039 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Notice period for redemption of senior notes		60 days

Credit Agreements and Senior_10

Credit Agreements and Senior Notes - Aggregate Maturities of Senior Notes, Excluding Net Unamortized Discounts and Debt Issuance Costs (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Debt Disclosure [Abstract]
2020	$ 0
2021	0
2022	0
2023	250,000
2024	0
Thereafter	1,750,000
Total maturities of senior notes	$ 2,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Feb. 29, 2016	Dec. 31, 2019	Jan. 31, 2020	Dec. 31, 2018
Contingencies And Commitments [Line Items]
Estimated sales tax and related penalties and interest		$ 16,100,000		$ 12,300,000
Deductible for marine liability coverage including personal injury claims, per first occurrence		5,000,000
Range of deductible for liability coverage for personal injury claims, lower limit		5,000,000
Range of deductible for liability coverage for personal injury claims, upper limit		100,000,000
Purchase obligations		0
Maturity of service arrangement	10 years
Annual payments due under service agreement		39,000,000
Total remaining payments due under service agreement		250,000,000
Total Contingent Liabilities Under Letters of Credit and Bonds [Member]
Contingencies And Commitments [Line Items]
Contingent liability under letters of credit and other bonds		37,100,000
Potentially Collateralized Contingent Liability Under Letters Of Credit and Bonds [Member]
Contingencies And Commitments [Line Items]
Contingent liability under letters of credit and other bonds		28,500,000
Uncollateralized Contingent Liability Under Letters of Credit and Bonds [Member]
Contingencies And Commitments [Line Items]
Contingent liability under letters of credit and other bonds		8,600,000
Collateralized Contingent Liability Under Financial Letters of Credit and Surety Bond [Member] | Subsequent Event [Member]
Contingencies And Commitments [Line Items]
Contingent liability under letters of credit and other bonds			$ 6,000,000
Windstorms in U.S. Gulf of Mexico [Member]
Contingencies And Commitments [Line Items]
Deductible for marine liability coverage including personal injury claims, per first occurrence		25,000,000
Range of deductible for liability coverage for personal injury claims, lower limit		25,000,000
Range of deductible for liability coverage for personal injury claims, upper limit		100,000,000
Personal Injury Claims [Member]
Contingencies And Commitments [Line Items]
Personal injury claims recorded		17,400,000		27,900,000
Personal Injury Claims [Member] | Accrued Liabilities [Member]
Contingencies And Commitments [Line Items]
Personal injury claims recorded		6,400,000		5,200,000
Personal Injury Claims [Member] | Other Liabilities [Member]
Contingencies And Commitments [Line Items]
Personal injury claims recorded		$ 11,000,000		$ 22,700,000

Leases and Leases Commitments -

Leases and Leases Commitments - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Lessee Lease Description [Line Items]
Options to extend the leases	5 years
Operating cash flows used for operating leases	$ 39,561
Total operating lease expense	39,700	$ 30,100	$ 30,600
Short-term leases expense	3,400
Operating lease assets	$ 169,200
Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List	us-gaap:OtherAssetsMember
Mooring Equipment [Member]
Lessee Lease Description [Line Items]
Operating lease payments, lease not yet commenced	$ 5,000
Lease term of lease expected to commence	5 years
ASU 2016-02 [Member]
Lessee Lease Description [Line Items]
Operating lease assets				$ 146,800
ASU 2016-02 [Member] | Sale and Lease-back Equipment [Member]
Lessee Lease Description [Line Items]
Operating lease term	10 years
Options to extend the leases	5 years
Operating cash flows used for operating leases	$ 26,000
Sale lease back transaction renewal term description	renewal options for two successive five-year periods.
ASU 2016-02 [Member] | Prepaid Expenses and Other Current Assets [Member]
Lessee Lease Description [Line Items]
Prepaid rent				3,900
ASU 2016-02 [Member] | Other Assets [Member]
Lessee Lease Description [Line Items]
Prepaid rent				$ 10,600
Minimum [Member]
Lessee Lease Description [Line Items]
Operating lease term	1 month
Maximum [Member]
Lessee Lease Description [Line Items]
Operating lease term	10 years
Options to terminate the leases	1 year

Leases and Leases Commitments_2

Leases and Leases Commitments - Supplemental Information Related to Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating cash flows used for operating leases	$ 39,561
Right-of-use assets obtained in exchange for lease liabilities	$ 26,248
Weighted-average remaining lease term	6 years 8 months 12 days
Weighted-average discount rate	8.68%

Leases and Leases Commitments_3

Leases and Leases Commitments - Schedule of Future Minimum Rental Payment Under Non-Cancelable Operating Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 28,373
2020	27,144
2021	26,565
2022	26,281
2023	26,280
Thereafter	64,062
Total lease payments	$ 198,705

Leases and Leases Commitments_4

Leases and Leases Commitments - Schedule of Maturities of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 32,888
2021	30,548
2022	29,973
2023	29,499
2024	29,580
Thereafter	51,784
Total lease payments	204,272
Less: interest	(50,348)
Operating lease liabilities	153,924
Amounts recognized in Consolidated Balance Sheets:
Accrued liabilities	$ 20,030
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesMember
Other liabilities	$ 133,894
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesMember
Total operating lease liability	$ 153,924

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Terms and conditions of service agreement with Loews	The Services Agreement may be terminated at our option upon 30 days’ notice to Loews and at the option of Loews upon six months’ notice to us.
Services Agreement with Loews [Member]
Related Party Transaction [Line Items]
Related party transaction expenses	$ 0.7	$ 0.6	$ 1

Restructuring and Separation _2

Restructuring and Separation Costs - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Accrued costs associated with restructuring plan		$ 1,478	$ 14,146
Restructuring and employee separation related costs		5,041	14,146
Payment of accrued costs associated with restructuring plan		12,400
Restructuring a cost description	We incurred $14.1 million in restructuring and employee separation related costs during 2017, including $11.5 million related to the termination of our Brazilian agency agreement. During 2018, we incurred an additional $5.0 million in severance and related costs for redundant employees identified in 2018 in connection with the restructuring plan and paid $12.4 million in previously accrued costs.
Termination of Brazilian Agency Agreement [Member]
Restructuring Cost and Reserve [Line Items]
Accrued costs associated with restructuring plan			$ 11,500
Severance Payments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and employee separation related costs		$ 5,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Net deferred tax asset and offsetting valuation allowance for swiss tax reform		$ 74,200
Net tax benefit related to tax law change	$ 14,200	23,267	$ 49,175	$ 623
Charge relating to previously deferred earnings of certain non-US subsidiaries		7,209
Revised net tax benefit associated with tax reform act	34,500
Unrecorded tax liability		95,000
Net operating loss carryforwards, or NOLs		253,973	209,679
Deferred tax asset relates to NOL carryforwards		154,700
Net operating loss carryforwards to expire		$ 99,300
Net operating loss carryforwards expiring years		2021 and 2038
Deferred tax assets for foreign tax credits		$ 43,026	43,225
Valuation allowance of net operating losses		186,600
Net liability for uncertain tax positions		118,884	55,943	81,864	$ 34,970
Net increase in uncertain tax positions from prior years		2,113	20,943	2,938
Addition to current year tax positions		85,970	2,906	51,260
Net unrecognized tax benefits that would affect the effective tax rate		148,800	81,600	101,900
Accrued interest on uncertain tax positions		4,000	3,200
Accrued penalties on uncertain tax positions		16,500	16,300
Interest expense recognized related to uncertain tax positions		1,000	100	500
Penalties recognized related to uncertain tax positions		300	600	(1,700)
Tax Year 2013 [Member]
Income Tax Contingency [Line Items]
Decrease in unrecognized tax benefit		5,100
Other Assets [Member]
Income Tax Contingency [Line Items]
Net liability for uncertain tax positions		500	1,200
Deferred Tax Liability [Member]
Income Tax Contingency [Line Items]
Net liability for uncertain tax positions		91,100	7,500
Other Liabilities [Member]
Income Tax Contingency [Line Items]
Net liability for uncertain tax positions		58,300	75,300
Retained Earnings [Member]
Income Tax Contingency [Line Items]
Valuation allowance reduced		6,200
Deferred Tax Assets Including Net Operating Losses, Foreign Tax Credits and Other [Member]
Income Tax Contingency [Line Items]
Change in valuation allowance		30,700	35,200	37,900
Releases of Valuation Allowances in Various Jurisdictions [Member]
Income Tax Contingency [Line Items]
Change in valuation allowance		19,000	$ 23,300	$ 79,400
United States [Member]
Income Tax Contingency [Line Items]
Deferred tax assets for foreign tax credits		43,000
Diamond Foreign Assets Corporation [Member]
Income Tax Contingency [Line Items]
Withholding income tax		400
U.S. Federal [Member]
Income Tax Contingency [Line Items]
Tax credit resulting from remeasurement of net U.S. deferred tax liabilities	72,500
Net operating loss carryforwards, or NOLs		149,400
Foreign [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards, or NOLs		104,600
Switzerland Tax Legislation [Member]
Income Tax Contingency [Line Items]
Net liability for uncertain tax positions		$ 86,200
Mandatory Repatriation [Member] | U.S. Federal [Member]
Income Tax Contingency [Line Items]
Charge relating to previously deferred earnings of certain non-US subsidiaries	$ 38,000
Foreign Tax Credit Carryforwards [Member] | United States [Member]
Income Tax Contingency [Line Items]
Foreign tax credits expiration periods		between 2020 to 2030

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal – current	$ (13,810)	$ 20,107	$ 6,994
State – current	19	2	95
Foreign – current	25,899	9,531	25,252
Total current	12,108	29,640	32,341
Federal – deferred	(67,015)	(75,279)	(85,066)
Foreign – deferred	10,107	(714)	12,939
Total deferred	(56,908)	(75,993)	(72,127)
Income tax benefit	$ (44,800)	$ (46,353)	$ (39,786)

Income Taxes - Difference Betwe

Income Taxes - Difference Between Actual Income Tax Expense and Tax Provision Computed by Applying Statutory Federal Income Tax Rate to Income Before Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
(Loss) income before income tax expense:
U.S.	$ (339,072)	$ (266,855)	$ (241,178)
Foreign	(62,942)	40,230	219,738
Worldwide	(402,014)	(226,625)	(21,440)
Expected income tax benefit at federal statutory rate	(84,423)	(47,591)	(7,504)
Effect of tax rate changes	(74,168)	1,763	(74,294)
Mandatory repatriation of earnings pursuant to Tax Reform Act			94,194
Effect of foreign operations	3,129	15	(42,102)
Valuation allowance	11,650	11,929	(41,492)
Uncertain tax positions, settlements and adjustments relating to prior years	96,960	(15,777)	31,726
Other	2,052	3,308	(314)
Income tax benefit	$ (44,800)	$ (46,353)	$ (39,786)

Income Taxes - Components of De

Income Taxes - Components of Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards, or NOLs	$ 253,973	$ 209,679
Foreign tax credits	43,026	43,225
Disallowed interest deduction	40,777	16,248
Worker’s compensation and other current accruals	6,250	8,375
Deferred deductions	12,345	10,481
Deferred revenue	7,209
Operating lease liability	5,461
Other	4,367	6,380
Total deferred tax assets	373,408	294,388
Valuation allowance	(186,620)	(174,970)
Net deferred tax assets	186,788	119,418
Deferred tax liabilities:
Property, plant and equipment	(225,643)	(212,251)
Mobilization	(2,245)	(11,012)
Right-of-use assets	(5,461)
Other	(967)	(535)
Total deferred tax liabilities	(234,316)	(223,798)
Net deferred tax liability	$ (47,528)	$ (104,380)

Income Taxes - Summary of Rollf

Income Taxes - Summary of Rollforward of Beginning and Ending Amount of Unrecognized Tax Benefits, Excluding Interest and Penalties (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Balance, beginning of period		$ (55,943)	$ (81,864)	$ (34,970)
Additions for current year tax positions		(85,970)	(2,906)	(51,260)
Additions for prior year tax positions		(2,113)	(20,943)	(2,938)
Reductions for prior year tax positions	$ 14,200	23,267	49,175	623
Reductions related to statute of limitation expirations		1,875	595	6,681
Balance, end of period		$ (118,884)	$ (55,943)	$ (81,864)

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Provision for contributions to the Supplemental Plan	$ 0.1	$ 0.1	$ 0.1
US Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employers percentage matching of first 5% of each employee's qualifying annual compensation	100.00%	100.00%	100.00%
Defined Contribution Plan, Matching Contribution per employee by the company	5.00%	5.00%	5.00%
Defined contribution plan, cost recognized	$ 9.1	$ 8	$ 8.9
UK Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost recognized	$ 2.1	$ 1.5	$ 1.4
UK Plan [Member] | U. K. Sector of North Sea [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Matching Contribution by the company	6.00%	6.00%	6.00%
International Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Matching Contribution per employee by the company	5.00%	5.00%	5.00%
Defined contribution plan, cost recognized	$ 0.4	$ 0.4	$ 0.4

Segments and Geographic Area _3

Segments and Geographic Area Analysis - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019SegmentCountry	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	1
Number of countries with rigs | Country	3
Customer Concentration Risk [Member] | Revenues [Member]
Segment Reporting Information [Line Items]
Concentration risk benchmark	contributed more than 10% of our total revenues
Concentration risk percentage	10.00%	10.00%	10.00%

Segments and Geographic Area _4

Segments and Geographic Area Analysis - Summary of Information about Disaggregated Revenue by Equipment-type and Country (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 276,376	$ 254,020	$ 216,706	$ 233,542	$ 232,522	$ 286,322	$ 268,861	$ 295,510	$ 980,644	$ 1,083,215	$ 1,485,746
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues									934,934	1,059,973	1,451,219
Contract Drilling [Member] | Floater Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										1,051,560	1,430,075
Contract Drilling [Member] | Jack-up Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										8,413	21,144
Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues									45,710	23,242	34,527
United States [Member]
Segment Reporting Information [Line Items]
Total revenues									515,640	644,423	630,595
United States [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues									507,759	636,987	619,655
United States [Member] | Contract Drilling [Member] | Floater Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										628,574	619,655
United States [Member] | Contract Drilling [Member] | Jack-up Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										8,413
United States [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues									7,881	7,436	10,940
Brazil [Member]
Segment Reporting Information [Line Items]
Total revenues									191,602	170,813	280,487
Brazil [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues									191,519	170,839	280,798
Brazil [Member] | Contract Drilling [Member] | Floater Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										170,839	280,798
Brazil [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues									83	(26)	(311)
United Kingdom [Member]
Segment Reporting Information [Line Items]
Total revenues									163,760	92,487	177,570
United Kingdom [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues									149,724	84,749	171,146
United Kingdom [Member] | Contract Drilling [Member] | Floater Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										84,749	171,146
United Kingdom [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues									14,036	7,738	6,424
Australia [Member]
Segment Reporting Information [Line Items]
Total revenues									109,642	60,782	140,953
Australia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues									85,932	53,170	125,568
Australia [Member] | Contract Drilling [Member] | Floater Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										53,170	125,568
Australia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues									$ 23,710	7,612	15,385
Malaysia [Member]
Segment Reporting Information [Line Items]
Total revenues										114,018	166,972
Malaysia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues										114,228	164,984
Malaysia [Member] | Contract Drilling [Member] | Floater Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues										114,228	164,984
Malaysia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues										(210)	1,988
Other Countries [Member]
Segment Reporting Information [Line Items]
Total revenues										692	21,245
Other Countries [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues											21,144
Other Countries [Member] | Contract Drilling [Member] | Jack-up Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues											21,144
Other Countries [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues										$ 692	101
Trinidad [Member]
Segment Reporting Information [Line Items]
Total revenues											67,924
Trinidad [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues											67,924
Trinidad [Member] | Contract Drilling [Member] | Floater Rigs [Member]
Segment Reporting Information [Line Items]
Total revenues											$ 67,924

Segments and Geographic Area _5

Segments and Geographic Area Analysis - Summary of Information about Disaggregated Revenue by Equipment-type and Country (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other Countries [Member] | Maximum [Member] | Revenues [Member]
Segment Reporting Information [Line Items]
Concentration risk percentage	5.00%	5.00%

Segments and Geographic Area _6

Segments and Geographic Area Analysis - Long-Lived Tangible Assets by Country (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	$ 5,152,828	$ 5,184,222	$ 5,261,641
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	2,227,934	2,245,989	2,300,956
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	1,061,585	1,083,540	133,525
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	883,607	923,355	923,398
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	570,964	242,929	629,436
Singapore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	404,420	366,798	17
Malaysia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	2,037	318,191	1,084,793
Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	2,281	3,420	189,516
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling and other property and equipment, net	$ 2,924,894	$ 2,938,233	$ 2,960,685

Segments and Geographic Area _7

Segments and Geographic Area Analysis - Long-Lived Tangible Assets by Country (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Impairment of assets	$ 27,225	$ 99,313
Other Countries [Member] | Drilling and Other Property and Equipment , Net of Accumulated Depreciation [Member] | Maximum [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk percentage	5.00%

Segments and Geographic Area _8

Segments and Geographic Area Analysis - Revenues from Major Customers that Contributed More than 10% of Total Revenues (Detail) - Revenues [Member] - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	10.00%	10.00%	10.00%
Hess Corporation [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	28.90%	25.00%	16.00%
Occidental (formerly Anadarko) [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	20.60%	33.80%	24.90%
Petrobras Brasileiro S.A. [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	19.50%	15.80%	18.90%
BP [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	3.10%	10.50%	15.80%

Unaudited Quarterly Financial_3

Unaudited Quarterly Financial Data - Unaudited Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Revenues	$ 276,376	$ 254,020	$ 216,706	$ 233,542	$ 232,522	$ 286,322	$ 268,861	$ 295,510	$ 980,644	$ 1,083,215	$ 1,485,746
Operating income (loss)	(48,869)	(72,834)	(111,500)	(49,127)	(37,277)	(23,043)	(52,375)	512	(282,330)	(112,183)	123,879
Loss before income tax expense	(80,672)	(102,610)	(141,342)	(77,390)	(66,303)	(55,894)	(79,286)	(25,142)	(402,014)	(226,625)	(21,440)
Net (loss) income	$ (74,770)	$ (95,128)	$ (113,988)	$ (73,328)	$ (79,207)	$ (51,112)	$ (69,274)	$ 19,321	$ (357,214)	$ (180,272)	$ 18,346
Net income (loss) per share, basic and diluted	$ (0.54)	$ (0.69)	$ (0.83)	$ (0.53)	$ (0.58)	$ (0.37)	$ (0.50)	$ 0.14

Unaudited Quarterly Financial_4

Unaudited Quarterly Financial Data - Unaudited Quarterly Financial Data (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Quarterly Financial Data [Line Items]
Impairment of assets		$ 27,225	$ 99,313
Ocean Scepter [Member]
Schedule Of Quarterly Financial Data [Line Items]
Impairment of assets	$ 27,200