Diamond Offshore Drilling (DODRW) 10-Q 5 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
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		137,694,313
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 Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 147,509	$ 154,073
Marketable securities	149,945	299,849
Accounts receivable, net of allowance for bad debts	163,086	168,620
Prepaid expenses and other current assets	130,124	163,396
Total current assets	590,664	785,938
Drilling and other property and equipment, net of accumulated depreciation	5,163,696	5,184,222
Other assets	222,876	65,534
Total assets	5,977,236	6,035,694
Current liabilities:
Accounts payable	60,533	43,933
Accrued liabilities	192,194	172,228
Taxes payable	16,722	20,685
Total current liabilities	269,449	236,846
Long-term debt	1,974,816	1,973,922
Deferred tax liability	74,281	104,380
Other liabilities	259,793	135,893
Total liabilities	2,578,339	2,451,041
Commitments and contingencies (Note 9)
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; 144,764,125 shares issued and 137,690,627 shares outstanding at June 30, 2019; 144,383,662 shares issued and 137,438,353 shares outstanding at December 31, 2018)	1,448	1,444
Additional paid-in capital	2,021,095	2,018,143
Retained earnings	1,582,099	1,769,415
Accumulated other comprehensive (loss) gain	(6)	21
Treasury stock, at cost (7,073,498 and 6,945,309 shares of common stock at June 30, 2019 and December 31, 2018, respectively)	(205,739)	(204,370)
Total stockholders’ equity	3,398,897	3,584,653
Total liabilities and stockholders’ equity	$ 5,977,236	$ 6,035,694

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Paranthetical) - $ / shares	Jun. 30, 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	144,764,125	144,383,662
Common stock, shares outstanding	137,690,627	137,438,353
Treasury stock, shares	7,073,498	6,945,309

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Total revenues	$ 216,706	$ 268,861	$ 450,248	$ 564,371
Operating expenses:
Depreciation	88,253	81,825	175,151	163,650
General and administrative	15,294	18,236	32,605	36,749
Impairment of assets		27,225		27,225
Restructuring and separation costs		1,265		4,276
Gain on disposition of assets	(9,436)	(50)	(5,149)	(560)
Total operating expenses	328,206	321,236	610,874	616,234
Operating loss	(111,500)	(52,375)	(160,626)	(51,863)
Other income (expense):
Interest income	1,933	2,001	4,346	3,638
Interest expense, net of amounts capitalized	(31,159)	(29,585)	(61,084)	(57,903)
Foreign currency transaction (loss) gain	(721)	411	(1,806)	858
Other, net	105	262	438	842
Loss before income tax benefit	(141,342)	(79,286)	(218,732)	(104,428)
Income tax benefit	27,354	10,012	31,416	54,475
Net loss	$ (113,988)	$ (69,274)	$ (187,316)	$ (49,953)
Loss per share, Basic and Diluted	$ (0.83)	$ (0.50)	$ (1.36)	$ (0.36)
Weighted-average shares outstanding:
Shares of common stock	137,691	137,429	137,607	137,362
Total weighted-average shares outstanding	137,691	137,429	137,607	137,362
Contract Drilling [Member]
Revenues:
Total revenues	$ 207,273	$ 265,353	$ 433,970	$ 553,279
Operating expenses:
Contract drilling, excluding depreciation	224,782	189,321	392,210	374,010
Reimbursable Expenses [Member]
Revenues:
Total revenues	9,433	3,508	16,278	11,092
Operating expenses:
Contract drilling, excluding depreciation	$ 9,313	$ 3,414	$ 16,057	$ 10,884

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (113,988)	$ (69,274)	$ (187,316)	$ (49,953)
Derivative financial instruments:
Reclassification adjustment for gain included in net loss	(2)	(1)	(3)	(3)
Investments in marketable securities:
Unrealized holding gain	9	31	23	31
Reclassification adjustment for gain included in net loss	(15)		(47)
Total other comprehensive (loss) gain	(8)	30	(27)	28
Comprehensive loss	$ (113,996)	$ (69,244)	$ (187,343)	$ (49,925)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - 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, 2017	$ 3,774,261	$ 1,441	$ 2,011,397	$ 1,964,497	$ (5)	$ (203,069)
Beginning 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	(49,953)			(49,953)
Anti-dilution adjustment/ payments	3			3
Stock options exercised, shares		3,773
Stock-based compensation, net of tax	1,203	$ 3	2,465			$ (1,265)
Stock-based compensation, net of tax, shares		284,941				85,580
Net gain/ (loss) on investments	31				31
Net loss on derivative financial instruments	(3)				(3)
Ending Balance at Jun. 30, 2018	3,710,730	$ 1,444	2,013,862	1,899,735	23	$ (204,334)
Ending Balance, shares at Jun. 30, 2018		144,374,006				6,943,090
Beginning Balance at Mar. 31, 2018	3,779,632	$ 1,442	2,012,993	1,969,006	(7)	$ (203,802)
Beginning Balance, shares at Mar. 31, 2018		144,249,563				6,906,592
Net loss	(69,274)			(69,274)
Anti-dilution adjustment/ payments	3			3
Stock options exercised, shares		3,773
Stock-based compensation, net of tax	339	$ 2	869			$ (532)
Stock-based compensation, net of tax, shares		120,670				36,498
Net gain/ (loss) on investments	31				31
Net loss on derivative financial instruments	(1)				(1)
Ending Balance at Jun. 30, 2018	3,710,730	$ 1,444	2,013,862	1,899,735	23	$ (204,334)
Ending Balance, shares at Jun. 30, 2018		144,374,006				6,943,090
Beginning Balance at Dec. 31, 2018	3,584,653	$ 1,444	2,018,143	1,769,415	21	$ (204,370)
Beginning Balance, shares at Dec. 31, 2018		144,383,662				6,945,309
Net loss	(187,316)			(187,316)
Stock-based compensation, net of tax	1,587	$ 4	2,952			$ (1,369)
Stock-based compensation, net of tax, shares		380,463				128,189
Net gain/ (loss) on investments	(24)				(24)
Net loss on derivative financial instruments	(3)				(3)
Ending Balance at Jun. 30, 2019	3,398,897	$ 1,448	2,021,095	1,582,099	(6)	$ (205,739)
Ending Balance, shares at Jun. 30, 2019		144,764,125				7,073,498
Beginning Balance at Mar. 31, 2019	3,511,876	$ 1,446	2,019,555	1,696,087	2	$ (205,214)
Beginning Balance, shares at Mar. 31, 2019		144,606,992				7,026,789
Net loss	(113,988)			(113,988)
Stock-based compensation, net of tax	1,017	$ 2	1,540			$ (525)
Stock-based compensation, net of tax, shares		157,133				46,709
Net gain/ (loss) on investments	(6)				(6)
Net loss on derivative financial instruments	(2)				(2)
Ending Balance at Jun. 30, 2019	$ 3,398,897	$ 1,448	$ 2,021,095	$ 1,582,099	$ (6)	$ (205,739)
Ending Balance, shares at Jun. 30, 2019		144,764,125				7,073,498

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities:
Net loss	$ (187,316)	$ (49,953)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation	175,151	163,650
Loss on impairment of assets		27,225
Gain on disposition of assets	(5,149)	(560)
Deferred tax provision	(31,125)	(61,160)
Stock-based compensation expense	2,956	2,468
Contract liabilities, net	14,017	(3,255)
Contract assets, net	(566)	(956)
Deferred contract costs, net	26,879	24,703
Other assets, noncurrent	(118)	742
Other liabilities, noncurrent	3	(3,849)
Other	(1,300)	2,577
Changes in operating assets and liabilities:
Accounts receivable	5,534	53,451
Prepaid expenses and other current assets	(2,002)	28
Accounts payable and accrued liabilities	9,961	(21,466)
Taxes payable	(9,608)	(2,878)
Net cash (used in) provided by operating activities	(2,683)	130,767
Investing activities:
Capital expenditures	(172,335)	(90,432)
Proceeds from maturities of marketable securities	2,025,000	300,000
Purchase of marketable securities	(1,872,107)	(573,837)
Proceeds from disposition of assets, net of disposal costs	15,573	1,723
Net cash used in investing activities	(3,869)	(362,546)
Financing activities:
Other	(12)	(90)
Net cash used in financing activities	(12)	(90)
Net change in cash and cash equivalents	(6,564)	(231,869)
Cash and cash equivalents, beginning of period	154,073	376,037
Cash and cash equivalents, end of period	$ 147,509	$ 144,168

General Information

General Information	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
General Information	1. General Information The unaudited condensed consolidated financial statements of Diamond Offshore Drilling, Inc. and subsidiaries, which we refer to as “Diamond Offshore,” “we,” “us” or “our,” should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2018 (File No. 1-13926). As of July 26, 2019, Loews Corporation owned approximately 53% of the outstanding shares of our common stock. Interim Financial Information The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the U.S., or GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission. Accordingly, pursuant to such rules and regulations, they do not include all disclosures required by GAAP for annual financial statements. The condensed consolidated financial information has not been audited but, in the opinion of management, includes all adjustments (consisting of normal recurring adjustments) necessary for a fair presentation of Diamond Offshore’s condensed consolidated balance sheets, statements of operations, statements of comprehensive income or loss, statements of stockholders’ equity and statements of cash flows at the dates and for the periods indicated. Results of operations for interim periods are not necessarily indicative of results of operations for the respective full years. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with 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. Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, No. 2016-02, 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 unaudited Condensed Consolidated Statements of Stockholders’ Equity. See Note 10. 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 . 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

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jun. 30, 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 drilling contracts include (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. 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. Dayrate and other revenue for activities that correspond to a distinct time increment within the contract term are recognized in the period in which the services are performed. 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 is allocated across the single performance obligation and recognized ratably in proportion to the actual services performed 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). Such consideration may include mobilization, demobilization, contract preparation and capital modification revenue that is stipulated in our drilling contracts. Contract Balances The following table provides information about receivables, contract assets and contract liabilities from our contracts with customers (in thousands): June 30, December 31, 2019 2018 Trade receivables $ 153,638 $ 160,463 Current contract assets (1) 7,398 6,832 Noncurrent contract assets (1) 2,107 2,107 Current contract liabilities (deferred revenue) (1) (9,521 ) (2,803 ) Noncurrent contract liabilities (deferred revenue) (1) (25,023 ) (17,723 ) (1) Significant changes in the contract assets and the contract liabilities balances during the period are as follows (in thousands): Net Contract Balances Contract assets at January 1, 2019 $ 8,939 Contract liabilities at January 1, 2019 (20,526 ) Net balance at January 1, 2019 (11,587 ) Decrease due to amortization of revenue included in the beginning contract liability balance 3,681 Increase due to cash received, excluding amounts recognized as revenue during the period (17,698 ) Increase due to revenue recognized during the period but contingent on future performance 2,535 Decrease due to transfer to receivables during the period (926 ) Adjustments (1,044 ) Net balance at June 30, 2019 $ (25,039 ) Contract assets at June 30, 2019 $ 9,505 Contract liabilities at June 30, 2019 (34,544 ) Transaction Price Allocated to Remaining Performance Obligations The following table reflects the specified types of revenue expected to be recognized in the future related to unsatisfied performance obligations as of June 30, 2019 (in thousands): For the Years Ending December 31, 2019 (1) 2020 2021 2022 Total Mobilization and contract preparation revenue $ 3,071 $ 571 $ 632 $ 124 $ 4,398 Capital modification revenue 3,364 4,937 229 — 8,530 Blended rate revenue — 16,933 5,542 — 22,475 Total $ 6,435 $ 22,441 $ 6,403 $ 124 $ 35,403 (1) The revenue included above consists of expected fixed mobilization and upgrade revenue for both wholly and partially unsatisfied performance obligations as well as expected variable mobilization 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 June 30, 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.

Impairment of Assets

Impairment of Assets	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment of Assets	3. Impairment of Assets 2019 Evaluation. During the second quarter of 2019, we evaluated three of our drilling rigs with indicators of impairment. Based on our assumptions and analysis at that time, we determined that the undiscounted probability-weighted cash flow for each rig was in excess of its respective carrying value. As a result, we concluded that no impairment of these rigs had occurred at June 30, 2019. As of June 30, 2019, there were ten rigs in our drilling fleet not previously written down to scrap, for which there were no current indicators that their carrying amounts may not be recoverable and, thus, were not evaluated for impairment. If market fundamentals in the offshore oil and gas industry deteriorate further or a projected market recovery is further delayed, we may be required to recognize additional impairment losses in future periods. 2018 Impairment. During the second quarter of 2018, we recorded an impairment loss of $27.2 million to recognize a reduction in fair value of the , a jack-up rig that was marketed for sale at that time. We estimated the fair value of the impaired jack-up 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. The was sold in July 2018.

Supplemental Financial Informat

Supplemental Financial Information	6 Months Ended
	Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Supplemental Financial Information	4. Supplemental Financial Information Condensed Accounts receivable, net of allowance for bad debts, consist of the following (in thousands): June 30, December 31, 2019 2018 Trade receivables $ 153,638 $ 160,463 Value added tax receivables 14,314 13,237 Related party receivables 133 174 Other 460 205 168,545 174,079 Allowance for bad debts (5,459 ) (5,459 ) Total $ 163,086 $ 168,620 Prepaid expenses and other current assets consist of the following (in thousands): June 30, December 31, 2019 2018 Deferred contract costs $ 45,736 $ 70,021 Prepaid taxes 45,621 54,412 Rig spare parts and supplies 17,873 20,256 Current contract assets 7,398 6,832 Prepaid insurance 4,490 2,742 Other 9,006 9,133 Total $ 130,124 $ 163,396 Accrued liabilities consist of the following (in thousands): June 30, December 31, 2019 2018 Payroll and benefits $ 43,340 $ 47,564 Rig operating expenses 39,980 42,323 Accrued capital project/upgrade costs 32,916 37,379 Interest payable 28,234 28,234 Current operating lease liability 19,697 — Personal injury and other claims 5,408 5,544 Deferred revenue 9,521 2,803 Shorebase and administrative costs 5,190 6,217 Other 7,908 2,164 Total $ 192,194 $ 172,228 We adopted ASU 2016-02 effective January 1, 2019, which required us to recognize a right of use asset and a lease liability on the balance sheet for most leases. See Note 10. Condensed Consolidated Statements of Cash Flows Information Noncash investing activities excluded from the unaudited Condensed Consolidated Statements of Cash Flows and other supplemental cash flow information is as follows (in thousands): Six Months Ended June 30, 2019 2018 Accrued but unpaid capital expenditures at period end $ 32,916 $ 12,714 Common stock withheld for payroll tax obligations (1) 1,369 1,265 Cash interest payments 56,531 56,531 Cash income taxes paid, net of (refunds): Foreign 10,025 4,035 State (15 ) 2 (1) Represents the cost of 128,189 shares and 85,580 shares of common stock withheld to satisfy payroll tax obligations incurred as a result of the vesting of restricted stock units in the six-month periods ended June 30, 2019 and 2018, respectively. These costs are presented as a deduction from stockholders’ equity in “Treasury stock” in our unaudited Condensed Consolidated Balance Sheets at June 30, 2019 and 2018, respectively.

Loss Per Share

Loss Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Loss Per Share	5. Loss Per Share We present basic and diluted net income (loss) per share on our Condensed Consolidated Statements of Operations. Basic net income (loss) per share excludes dilution and is computed by dividing net income (loss) by the weighted-average number of common shares outstanding for the period. Diluted net income (loss) 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. The following table sets forth the share effects of stock-based awards excluded from the computations of diluted loss per share (in thousands). Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Employee and director: Stock appreciation rights 994 1,144 1,008 1,207 Restricted stock units 1,273 1,194 1,151 1,133

Marketable Securities

Marketable Securities	6 Months Ended
	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Marketable Securities	6. Marketable Securities We report our investments as current assets in our unaudited Condensed Consolidated Balance Sheets in “Marketable securities,” representing the investment of cash available for current operations. See Note 7. Our investments in marketable securities are classified as available for sale and are summarized as follows (in thousands): June 30, 2019 Amortized Cost Unrealized Gain Market Value U.S. Treasury bills (due within one year) $ 149,935 $ 10 $ 149,945 December 31, 2018 Amortized Cost Unrealized Gain Market Value U.S. Treasury bills (due within one year) $ 299,813 $ 36 $ 299,849

Financial Instruments and Fair

Financial Instruments and Fair Value Disclosures	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Disclosures	7. Financial Instruments and Fair Value Disclosures 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 has consisted primarily of major and independent oil and gas companies and government-owned oil companies. Based on our current customer base and the geographic areas in which we operate, we do not believe that we have any significant concentrations of credit risk at June 30, 2019. 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 customer. Based on that analysis, we may require that the customer present a letter of credit, prepay or provide other credit enhancements. We record a provision for bad debts on a case-by-case basis when facts and circumstances indicate that a customer receivable may not be collectible and, historically, 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 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. Certain of our assets and liabilities are required to be measured at fair value on a recurring basis in accordance with GAAP. Assets measured at fair value are summarized below (in thousands). June 30, 2019 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value U.S. Treasury bills $ 149,945 $ — $ — $ 149,945 Money market funds 134,319 — — 134,319 Total short-term investments $ 284,264 $ — $ — $ 284,264 Year ended December 31, 2018 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value U.S. Treasury bills $ 299,849 $ — $ — $ 299,849 Money market funds 135,822 — — 135,822 Total short-term investments $ 435,671 $ — $ — $ 435,671 We had no Level 2 or Level 3 assets or liabilities as of June 30, 2019 or December 31, 2018 that were required to be valued at fair value on a recurring basis. 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 unaudited Condensed 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. 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 June 30, 2019 and December 31, 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 are shown below (in millions). June 30, 2019 December 31, 2018 Fair Value Carrying Value Fair Value Carrying Value 3.45% Senior Notes due 2023 $ 210.0 $ 249.5 $ 185.0 $ 249.5 7.875% Senior Notes due 2025 475.0 497.1 415.0 496.8 5.70% Senior Notes due 2039 335.0 497.3 305.0 497.2 4.875% Senior Notes due 2043 465.0 748.9 416.3 748.9 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	6 Months Ended
	Jun. 30, 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): June 30, December 31, 2019 2018 Drilling rigs and equipment $ 8,228,429 $ 8,210,824 Land and buildings 63,795 63,757 Office equipment and other 91,887 91,819 Cost 8,384,111 8,366,400 Less: accumulated depreciation (3,220,415 ) (3,182,178 ) Drilling and other property and equipment, net $ 5,163,696 $ 5,184,222 In April 2019, we sold the Ocean Guardian

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. 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 reasonably estimated, we record a liability for the amount of the reasonably 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 consolidated financial condition, results of operations or cash flows. 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. Additionally, tax authorities in Brazil have issued tax assessments on intercompany revenue between our subsidiaries doing business in Brazil that, if upheld by the Brazilian courts, could result in additional taxes, interest and penalties for which the fully assessed amounts would be material to our financial statements. 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 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 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 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 June 30, 2019 our estimated liability for personal injury claims was $25.2 million, of which $4.9 million and $20.3 million were recorded in “Accrued liabilities” and “Other liabilities,” respectively, in our unaudited Condensed 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 and volume of personal injuries claimed; • 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. Letters of Credit and Other. We were contingently liable as of June 30, 2019 in the amount of $41.7 million under certain customs, performance, tax and VAT bonds and letters of credit. Agreements relating to approximately $33.2 million of tax and customs bonds can require collateral at any time. As of June 30, 2019, we had not been required to make any collateral deposits with respect to these agreements. The remaining agreements cannot require collateral except in events of default. Banks have issued letters of credit on our behalf, securing certain of these bonds.

Leases and Lease Commitments

Leases and Lease Commitments	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases and Lease Commitments	10. 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 General Electric Company, or GE, pursuant to the 2016 sale of certain blowout preventers and related well control equipment, or Well Control Equipment, on our drillships and corresponding agreements to lease back that equipment under ten-year operating leases for approximately $26 million per year in the aggregate with renewal options for two successive five-year periods. At the time of the transactions with GE, the carrying value of the Well Control Equipment exceeded the aggregate proceeds received from the sale, resulting in the recognition 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 unaudited Condensed Consolidated Balance Sheets and continue to be amortized over the remaining terms of the leases. In connection with the sale and leaseback transactions, we also entered into a ten-year service agreement with a subsidiary of Baker Hughes, a GE company, or BHGE, another GE affiliate, pertaining to the Well Control Equipment. Such services include management of maintenance, certification and reliability with respect to such equipment. In applying 2016-02, we utilize an exemption for short-term leases whereby we do 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. 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 three and six months ended June 30, 2019 was $9.5 million and $18.9 million, respectively, of which $0.8 million and $2.1 million, respectively, related to short-term leases. Total operating lease expense for the three and six months ended June 30, 2018 was $7.4 million and $15.0 million, respectively. Supplemental information related to leases is as follows (in thousands, except weighted-average data): Six Months Ended June 30, 2019 Operating cash flows used for operating leases $ 20,659 Right-of-use assets obtained in exchange for lease liabilities 16,300 Weighted-average remaining lease term 7.0 years Weighted-average discount rate 8.63 % 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 Maturities of lease liabilities as of June 30, 2019 are as follows (in thousands): 2019 (excluding six months ended June 30, 2019) $ 17,079 2020 30,597 2021 28,702 2022 28,252 2023 28,236 2024 28,315 Thereafter 46,448 Total lease payments 207,629 Less: interest (52,990 ) Total lease liability $ 154,639 Amounts recognized in unaudited Condensed Consolidated Balance Sheets: Accrued liabilities $ 19,697 Other liabilities 134,942 Total operating lease liability $ 154,639 Operating lease assets, including prepaid rent balances related to the GE transaction, totaling $171.0 million are included in “Other assets” in our unaudited Condensed Consolidated Balance Sheets as of June 30, 2019. As of June 30, 2019, we had an additional operating lease for mooring equipment to be used on a rig that has not yet commenced. The agreement, which is expected to commence in September 2019, provides for fixed lease payments of approximately $12 million in the aggregate to be paid over a lease term of 9.5 years.

Segments and Geographic Area An

Segments and Geographic Area Analysis	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segments and Geographic Area Analysis	11. 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. 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 June 30, 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 and, unless otherwise noted, reflect earnings attributable to our floater rigs (drillships and semisubmersibles). The following tables provide information about disaggregated revenue by primary geographical market (in thousands): Three Months Ended June 30, 2019 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 117,423 $ 1,603 $ 119,026 South America 29,139 (23 ) 29,116 Europe 39,413 2,930 42,343 Australia 21,298 4,923 26,221 Total $ 207,273 $ 9,433 $ 216,706 Six Months Ended June 30, 2019 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 256,055 $ 3,551 $ 259,606 South America 82,423 6 82,429 Europe 64,022 4,836 68,858 Australia 31,470 7,885 39,355 Total $ 433,970 $ 16,278 $ 450,248 Three Months Ended June 30, 2018 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States (1) $ 162,202 $ 1,172 $ 163,374 South America 26,288 - 26,288 Europe 18,738 1,742 20,480 Australia/Asia 58,125 594 58,719 Total $ 265,353 $ 3,508 $ 268,861 (1) Includes $3.6 million in loss-of-hire insurance proceeds received in 2018 related to early contract terminations in prior years for two jack-up rigs that previously worked in Mexico. Six Months Ended June 30, 2018 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States (1) $ 326,641 $ 3,309 $ 329,950 South America 80,556 1 80,557 Europe 30,130 3,120 33,250 Australia/Asia 115,952 4,662 120,614 Total $ 553,279 $ 11,092 $ 564,371 (1) Includes $8.4 million in loss-of-hire insurance proceeds received in 2018 related to early contract terminations in prior years for two jack-up rigs that previously worked in Mexico.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes In June 2019, the Internal Revenue Service 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. 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.

General Information (Policies)

General Information (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
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 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.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, No. 2016-02, 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 unaudited Condensed Consolidated Statements of Stockholders’ Equity. See Note 10. 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 .
Accounting Pronouncements Not Yet Adopted	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

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jun. 30, 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): June 30, December 31, 2019 2018 Trade receivables $ 153,638 $ 160,463 Current contract assets (1) 7,398 6,832 Noncurrent contract assets (1) 2,107 2,107 Current contract liabilities (deferred revenue) (1) (9,521 ) (2,803 ) Noncurrent contract liabilities (deferred revenue) (1) (25,023 ) (17,723 ) (1)
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 Contract assets at January 1, 2019 $ 8,939 Contract liabilities at January 1, 2019 (20,526 ) Net balance at January 1, 2019 (11,587 ) Decrease due to amortization of revenue included in the beginning contract liability balance 3,681 Increase due to cash received, excluding amounts recognized as revenue during the period (17,698 ) Increase due to revenue recognized during the period but contingent on future performance 2,535 Decrease due to transfer to receivables during the period (926 ) Adjustments (1,044 ) Net balance at June 30, 2019 $ (25,039 ) Contract assets at June 30, 2019 $ 9,505 Contract liabilities at June 30, 2019 (34,544 )
Summary of Specified Types Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations	The following table reflects the specified types of revenue expected to be recognized in the future related to unsatisfied performance obligations as of June 30, 2019 (in thousands): For the Years Ending December 31, 2019 (1) 2020 2021 2022 Total Mobilization and contract preparation revenue $ 3,071 $ 571 $ 632 $ 124 $ 4,398 Capital modification revenue 3,364 4,937 229 — 8,530 Blended rate revenue — 16,933 5,542 — 22,475 Total $ 6,435 $ 22,441 $ 6,403 $ 124 $ 35,403 (1)

Supplemental Financial Inform_2

Supplemental Financial Information (Tables)	6 Months Ended
	Jun. 30, 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, consist of the following (in thousands): June 30, December 31, 2019 2018 Trade receivables $ 153,638 $ 160,463 Value added tax receivables 14,314 13,237 Related party receivables 133 174 Other 460 205 168,545 174,079 Allowance for bad debts (5,459 ) (5,459 ) Total $ 163,086 $ 168,620
Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): June 30, December 31, 2019 2018 Deferred contract costs $ 45,736 $ 70,021 Prepaid taxes 45,621 54,412 Rig spare parts and supplies 17,873 20,256 Current contract assets 7,398 6,832 Prepaid insurance 4,490 2,742 Other 9,006 9,133 Total $ 130,124 $ 163,396
Accrued Liabilities	Accrued liabilities consist of the following (in thousands): June 30, December 31, 2019 2018 Payroll and benefits $ 43,340 $ 47,564 Rig operating expenses 39,980 42,323 Accrued capital project/upgrade costs 32,916 37,379 Interest payable 28,234 28,234 Current operating lease liability 19,697 — Personal injury and other claims 5,408 5,544 Deferred revenue 9,521 2,803 Shorebase and administrative costs 5,190 6,217 Other 7,908 2,164 Total $ 192,194 $ 172,228
Noncash Investing and Financing Activities	Noncash investing activities excluded from the unaudited Condensed Consolidated Statements of Cash Flows and other supplemental cash flow information is as follows (in thousands): Six Months Ended June 30, 2019 2018 Accrued but unpaid capital expenditures at period end $ 32,916 $ 12,714 Common stock withheld for payroll tax obligations (1) 1,369 1,265 Cash interest payments 56,531 56,531 Cash income taxes paid, net of (refunds): Foreign 10,025 4,035 State (15 ) 2 (1) Represents the cost of 128,189 shares and 85,580 shares of common stock withheld to satisfy payroll tax obligations incurred as a result of the vesting of restricted stock units in the six-month periods ended June 30, 2019 and 2018, respectively. These costs are presented as a deduction from stockholders’ equity in “Treasury stock” in our unaudited Condensed Consolidated Balance Sheets at June 30, 2019 and 2018, respectively.

Loss Per Share (Tables)

Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Securities Excluded from Computation of Diluted Loss Per Share	The following table sets forth the share effects of stock-based awards excluded from the computations of diluted loss per share (in thousands). Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Employee and director: Stock appreciation rights 994 1,144 1,008 1,207 Restricted stock units 1,273 1,194 1,151 1,133

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Schedule of Marketable Securities	Our investments in marketable securities are classified as available for sale and are summarized as follows (in thousands): June 30, 2019 Amortized Cost Unrealized Gain Market Value U.S. Treasury bills (due within one year) $ 149,935 $ 10 $ 149,945 December 31, 2018 Amortized Cost Unrealized Gain Market Value U.S. Treasury bills (due within one year) $ 299,813 $ 36 $ 299,849

Financial Instruments and Fai_2

Financial Instruments and Fair Value Disclosures (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring Basis	Certain of our assets and liabilities are required to be measured at fair value on a recurring basis in accordance with GAAP. Assets measured at fair value are summarized below (in thousands). June 30, 2019 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value U.S. Treasury bills $ 149,945 $ — $ — $ 149,945 Money market funds 134,319 — — 134,319 Total short-term investments $ 284,264 $ — $ — $ 284,264 Year ended December 31, 2018 Fair Value Measurements Using Level 1 Level 2 Level 3 Assets at Fair Value U.S. Treasury bills $ 299,849 $ — $ — $ 299,849 Money market funds 135,822 — — 135,822 Total short-term investments $ 435,671 $ — $ — $ 435,671
Fair Values and Related Carrying Values of Our Debt Instruments	Fair values and related carrying values of our senior notes are shown below (in millions). June 30, 2019 December 31, 2018 Fair Value Carrying Value Fair Value Carrying Value 3.45% Senior Notes due 2023 $ 210.0 $ 249.5 $ 185.0 $ 249.5 7.875% Senior Notes due 2025 475.0 497.1 415.0 496.8 5.70% Senior Notes due 2039 335.0 497.3 305.0 497.2 4.875% Senior Notes due 2043 465.0 748.9 416.3 748.9

Drilling and Other Property a_2

Drilling and Other Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 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): June 30, December 31, 2019 2018 Drilling rigs and equipment $ 8,228,429 $ 8,210,824 Land and buildings 63,795 63,757 Office equipment and other 91,887 91,819 Cost 8,384,111 8,366,400 Less: accumulated depreciation (3,220,415 ) (3,182,178 ) Drilling and other property and equipment, net $ 5,163,696 $ 5,184,222

Leases and Lease Commitments (T

Leases and Lease Commitments (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Supplemental Information Related to Leases	Supplemental information related to leases is as follows (in thousands, except weighted-average data): Six Months Ended June 30, 2019 Operating cash flows used for operating leases $ 20,659 Right-of-use assets obtained in exchange for lease liabilities 16,300 Weighted-average remaining lease term 7.0 years Weighted-average discount rate 8.63 %
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 June 30, 2019 are as follows (in thousands): 2019 (excluding six months ended June 30, 2019) $ 17,079 2020 30,597 2021 28,702 2022 28,252 2023 28,236 2024 28,315 Thereafter 46,448 Total lease payments 207,629 Less: interest (52,990 ) Total lease liability $ 154,639 Amounts recognized in unaudited Condensed Consolidated Balance Sheets: Accrued liabilities $ 19,697 Other liabilities 134,942 Total operating lease liability $ 154,639

Segments and Geographic Area _2

Segments and Geographic Area Analysis (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Summary of Information about Disaggregated Revenue by Primary Geographical Market	The following tables provide information about disaggregated revenue by primary geographical market (in thousands): Three Months Ended June 30, 2019 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 117,423 $ 1,603 $ 119,026 South America 29,139 (23 ) 29,116 Europe 39,413 2,930 42,343 Australia 21,298 4,923 26,221 Total $ 207,273 $ 9,433 $ 216,706 Six Months Ended June 30, 2019 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States $ 256,055 $ 3,551 $ 259,606 South America 82,423 6 82,429 Europe 64,022 4,836 68,858 Australia 31,470 7,885 39,355 Total $ 433,970 $ 16,278 $ 450,248 Three Months Ended June 30, 2018 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States (1) $ 162,202 $ 1,172 $ 163,374 South America 26,288 - 26,288 Europe 18,738 1,742 20,480 Australia/Asia 58,125 594 58,719 Total $ 265,353 $ 3,508 $ 268,861 (1) Includes $3.6 million in loss-of-hire insurance proceeds received in 2018 related to early contract terminations in prior years for two jack-up rigs that previously worked in Mexico. Six Months Ended June 30, 2018 Total Contract Drilling Revenues Revenues Related to Reimbursable Expenses Total United States (1) $ 326,641 $ 3,309 $ 329,950 South America 80,556 1 80,557 Europe 30,130 3,120 33,250 Australia/Asia 115,952 4,662 120,614 Total $ 553,279 $ 11,092 $ 564,371 (1) Includes $8.4 million in loss-of-hire insurance proceeds received in 2018 related to early contract terminations in prior years for two jack-up rigs that previously worked in Mexico.

General Information - Additiona

General Information - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 26, 2019	Jun. 30, 2019	Jan. 01, 2019
Property Plant And Equipment [Line Items]
Operating lease assets		$ 171,000
Operating lease liabilities		$ 154,639
ASU 2016-02 [Member]
Property Plant And Equipment [Line Items]
Operating lease assets			$ 146,800
Operating lease liabilities			$ 146,800
Subsequent Event [Member]
Property Plant And Equipment [Line Items]
Outstanding common stock owned by loews corporation	53.00%

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019
Minimum [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Initial term of contract	2 months
Maximum [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [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	Jun. 30, 2019	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Trade receivables	$ 153,638	$ 160,463
Current contract assets	7,398	6,832
Noncurrent contract assets	2,107	2,107
Current contract liabilities (deferred revenue)	(9,521)	(2,803)
Noncurrent contract liabilities (deferred revenue)	$ (25,023)	$ (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) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Revenue From Contract With Customer [Abstract]
Contract assets at January 1, 2019	$ 8,939
Contract liabilities at January 1, 2019	(20,526)
Net balance at January 1, 2019	(11,587)
Decrease due to amortization of revenue included in the beginning contract liability balance	3,681
Increase due to cash received, excluding amounts recognized as revenue during the period	(17,698)
Increase due to revenue recognized during the period but contingent on future performance	2,535
Decrease due to transfer to receivables during the period	(926)
Adjustments	(1,044)
Net balance at June 30, 2019	(25,039)
Contract assets at June 30, 2019	9,505
Contract liabilities at June 30, 2019	$ (34,544)

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Summary of Specified Types of Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 35,403
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-07-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	6 months
Revenue remaining performance obligation	$ 6,435
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	$ 22,441
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	$ 6,403
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	4,398
Mobilization and Contract Preparation Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-07-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	3,071
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	571
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	632
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	8,530
Capital Modification Revenue [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-07-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	3,364
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	4,937
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	229
Blended Rate Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	22,475
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	16,933
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	$ 5,542

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Summary of Specified Types of Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations (Detail 1) $ in Thousands	Jun. 30, 2019USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 35,403
Mobilization and Contract Preparation Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	4,398
Capital Modification Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	8,530
Blended Rate Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 22,475

Revenue from Contracts with C_8

Revenue from Contracts with Customers - Summary of Specified Types of Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations (Detail) (Parenthetical)	Jun. 30, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-07-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	6 months
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, 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, 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

Impairment of Assets - Addition

Impairment of Assets - Additional Information (Detail)	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)Rig	Jun. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Schedule Of Asset Impairment Charges [Line Items]
Loss on impairment of assets		$ 27,225,000	$ 27,225,000
Number of rigs not evaluated for impairment | Rig	10
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 jack-up 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.

Supplemental Financial Inform_3

Supplemental Financial Information - Accounts Receivable, Net of Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Receivables [Abstract]
Trade receivables	$ 153,638	$ 160,463
Value added tax receivables	14,314	13,237
Related party receivables	133	174
Other	460	205
Receivables Gross Current, Total	168,545	174,079
Allowance for bad debts	(5,459)	(5,459)
Total	$ 163,086	$ 168,620

Supplemental Financial Inform_4

Supplemental Financial Information - Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Deferred contract costs	$ 45,736	$ 70,021
Prepaid taxes	45,621	54,412
Rig spare parts and supplies	17,873	20,256
Current contract assets	7,398	6,832
Prepaid insurance	4,490	2,742
Other	9,006	9,133
Total	$ 130,124	$ 163,396

Supplemental Financial Inform_5

Supplemental Financial Information - Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Payroll and benefits	$ 43,340	$ 47,564
Rig operating expenses	39,980	42,323
Accrued capital project/upgrade costs	32,916	37,379
Interest payable	28,234	28,234
Current operating lease liability	19,697
Personal injury and other claims	5,408	5,544
Deferred revenue	9,521	2,803
Shorebase and administrative costs	5,190	6,217
Other	7,908	2,164
Total	$ 192,194	$ 172,228

Supplemental Financial Inform_6

Supplemental Financial Information - Noncash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Accrued but unpaid capital expenditures at period end	$ 32,916	$ 12,714
Common stock withheld for payroll tax obligations	1,369	1,265
Cash interest payments	56,531	56,531
Foreign [Member]
Cash income taxes paid, net of (refunds):
Cash income taxes paid, net of refunds	10,025	4,035
State [Member]
Cash income taxes paid, net of (refunds):
Cash income taxes paid, net of refunds	$ (15)	$ 2

Supplemental Financial Inform_7

Supplemental Financial Information - Noncash Investing and Financing Activities (Parenthetical) (Detail) - shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Restricted Stock [Member]
Condensed Financial Statements, Captions [Line Items]
Number of shares of common stock withheld	128,189	85,580

Loss Per Share - Securities Exc

Loss Per Share - Securities Excluded from Computations of Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restricted Stock Units [Member]
Employee and director:
Securities excluded from computation of diluted loss per share	1,273	1,194	1,151	1,133
Stock Appreciation Rights [Member]
Employee and director:
Securities excluded from computation of diluted loss per share	994	1,144	1,008	1,207

Marketable Securities - Schedul

Marketable Securities - Schedule of Marketable Securities (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Marketable Securities [Line Items]
Market Value	$ 149,945	$ 299,849
U.S. Treasury Bills (due within one year) [Member]
Marketable Securities [Line Items]
Amortized Cost	149,935	299,813
Unrealized Gain	10	36
Market Value	$ 149,945	$ 299,849

Financial Instruments and Fai_3

Financial Instruments and Fair Value Disclosures - Assets Measured at Fair Value on Recurring Basis (Detail) - Fair Value Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	$ 284,264	$ 435,671
U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	149,945	299,849
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	284,264	435,671
Level 1 [Member] | U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	149,945	299,849
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	134,319	135,822
Money Market Funds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total short-term investments	$ 134,319	$ 135,822

Financial Instruments and Fai_4

Financial Instruments and Fair Value Disclosures - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Measurement period for determining fair value of debt instruments	10 days

Financial Instruments and Fai_5

Financial Instruments and Fair Value Disclosures - Fair Value and Related Carrying Values of Our Debt Instruments (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
3.45% Senior Notes due 2023 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	$ 210	$ 185
Carrying Value	249.5	249.5
7.875% Senior Notes due 2025 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value	475	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	335	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	465	416.3
Carrying Value	$ 748.9	$ 748.9

Financial Instruments and Fai_6

Financial Instruments and Fair Value Disclosures - Fair Value and Related Carrying Values of Our Debt Instruments (Parenthetical) (Detail)	Jun. 30, 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	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment	$ 8,384,111	$ 8,366,400
Less accumulated depreciation	(3,220,415)	(3,182,178)
Drilling and other property and equipment, net	5,163,696	5,184,222
Drilling Rigs and Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment	8,228,429	8,210,824
Land and Buildings [Member]
Property Plant And Equipment [Line Items]
Property and equipment	63,795	63,757
Office Equipment and Other [Member]
Property Plant And Equipment [Line Items]
Property and equipment	$ 91,887	$ 91,819

Drilling and Other Property a_4

Drilling and Other Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Property Plant And Equipment [Line Items]
Gain (loss) on disposition of assets		$ 9,436	$ 50	$ 5,149	$ 560
Semisubmersible Rig [Member]
Property Plant And Equipment [Line Items]
Gain (loss) on disposition of assets	$ 14,300
Other Property and Equipment [Member]
Property Plant And Equipment [Line Items]
Gain (loss) on disposition of assets				$ (9,200)

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Contingencies And Commitments [Line Items]
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
Total Contingent Liabilities Under Letters of Credit and Bonds [Member]
Contingencies And Commitments [Line Items]
Contingent liability under letters of credit and other bonds	41,700,000
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	33,200,000
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	25,200,000	$ 27,900,000
Personal Injury Claims [Member] | Accrued Liabilities [Member]
Contingencies And Commitments [Line Items]
Personal injury claims recorded	4,900,000	5,200,000
Personal Injury Claims [Member] | Other Liabilities [Member]
Contingencies And Commitments [Line Items]
Personal injury claims recorded	$ 20,300,000	$ 22,700,000

Leases and Leases Commitments -

Leases and Leases Commitments - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jan. 01, 2019
Lessee Lease Description [Line Items]
Options to extend the leases	5 years		5 years
Operating cash flows used for operating leases			$ 20,659
Total operating lease expense	$ 9,500	$ 7,400	18,900	$ 15,000
Short-term leases expense	800		2,100
Operating lease assets	$ 171,000		$ 171,000
Operating Lease Right Of Use Asset Statement Of Financial Position Extensible List	us-gaap:OtherAssetsMember		us-gaap:OtherAssetsMember
Mooring Equipment [Member]
Lessee Lease Description [Line Items]
Operating lease payments, lease not yet commenced			$ 12,000
Lease term of lease expected to commence in September 2019	9 years 6 months		9 years 6 months
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		10 years
Options to extend the leases	5 years		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.
Sale leaseback transaction service period			ten-year
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		1 month
Maximum [Member]
Lessee Lease Description [Line Items]
Operating lease term	10 years		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	6 Months Ended
	Jun. 30, 2019USD ($)
Leases [Abstract]
Operating cash flows used for operating leases	$ 20,659
Right-of-use assets obtained in exchange for lease liabilities	$ 16,300
Weighted-average remaining lease term	7 years
Weighted-average discount rate	8.63%

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	Jun. 30, 2019USD ($)
Leases [Abstract]
2019 (excluding six months ended June 30, 2019)	$ 17,079
2020	30,597
2021	28,702
2022	28,252
2023	28,236
2024	28,315
Thereafter	46,448
Total lease payments	207,629
Less: interest	(52,990)
Operating lease liabilities	154,639
Amounts recognized in unaudited Condensed Consolidated Balance Sheets:
Accrued liabilities	$ 19,697
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesMember
Other liabilities	$ 134,942
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesMember
Total operating lease liability	$ 154,639

Segments and Geographic Area _3

Segments and Geographic Area Analysis - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019SegmentCountry
Segment Reporting [Abstract]
Number of reportable segments | Segment	1
Number of countries with rigs | Country	3

Segments and Geographic Area _4

Segments and Geographic Area Analysis - Summary of Information about Disaggregated Revenue by Primary Geographical Market (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Total revenues	$ 216,706	$ 268,861	$ 450,248	$ 564,371
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	207,273	265,353	433,970	553,279
Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	9,433	3,508	16,278	11,092
United States [Member]
Segment Reporting Information [Line Items]
Total revenues	119,026	163,374	259,606	329,950
United States [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	117,423	162,202	256,055	326,641
United States [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	1,603	1,172	3,551	3,309
South America [Member]
Segment Reporting Information [Line Items]
Total revenues	29,116	26,288	82,429	80,557
South America [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	29,139	26,288	82,423	80,556
South America [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	(23)		6	1
Europe [Member]
Segment Reporting Information [Line Items]
Total revenues	42,343	20,480	68,858	33,250
Europe [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	39,413	18,738	64,022	30,130
Europe [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	2,930	1,742	4,836	3,120
Australia [Member]
Segment Reporting Information [Line Items]
Total revenues	26,221		39,355
Australia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	21,298		31,470
Australia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 4,923		$ 7,885
Australia/Asia [Member]
Segment Reporting Information [Line Items]
Total revenues		58,719		120,614
Australia/Asia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues		58,125		115,952
Australia/Asia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues		$ 594		$ 4,662

Segments and Geographic Area _5

Segments and Geographic Area Analysis - Summary of Information about Disaggregated Revenue by Primary Geographical Market (Parenthetical) (Detail) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018USD ($)Rig	Jun. 30, 2018USD ($)Rig
United States [Member] | Jack-up Rigs [Member]
Segment Reporting Information [Line Items]
Proceeds from loss-of-hire insurance related to early contract terminations | $	$ 3.6	$ 8.4
MEXICO
Segment Reporting Information [Line Items]
Number of Jackup Rigs | Rig	2	2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) $ in Millions	3 Months Ended
	Jun. 30, 2019USD ($)
Income Tax Disclosure [Abstract]
Net tax benefit related to tax law change	$ 14.2