Diamond Offshore Drilling (DODRW) 10-Q 30 Apr 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 24, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
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 Common Stock, Shares Outstanding	'	137,139,887

CONSOLIDATED_BALANCE_SHEETS_Un

CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$420,140	$347,011
Marketable securities	1,175,135	1,750,053
Accounts receivable, net of allowance for bad debts	416,177	469,355
Prepaid expenses and other current assets	146,510	143,997
Assets held for sale	7,694	7,694
Total current assets	2,165,656	2,718,110
Drilling and other property and equipment, net of accumulated depreciation	5,954,496	5,467,227
Other assets	207,835	206,097
Total assets	8,327,987	8,391,434
Current liabilities:	'	'
Accounts payable	92,924	94,151
Accrued liabilities	383,121	370,671
Taxes payable	28,442	30,806
Current portion of long-term debt	249,973	249,954
Total current liabilities	754,460	745,582
Long-term debt	2,244,262	2,244,189
Deferred tax liability	531,988	525,541
Other liabilities	219,186	238,864
Total liabilities	3,749,896	3,754,176
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; 143,952,248 shares issued and 137,170,137 shares outstanding at March 31, 2014; 143,952,248 shares issued and 139,035,448 shares outstanding at December 31, 2013)	1,440	1,440
Additional paid-in capital	1,990,137	1,988,720
Retained earnings	2,784,249	2,761,161
Accumulated other comprehensive gain (loss)	3,042	350
Treasury stock, at cost (6,782,111 and 4,916,800 shares of common stock at March 31, 2014 and December 31, 2013, respectively)	-200,777	-114,413
Total stockholders' equity	4,578,091	4,637,258
Total liabilities and stockholders' equity	$8,327,987	$8,391,434

CONSOLIDATED_BALANCE_SHEETS_Un1

CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
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	143,952,248	143,952,248
Common stock, shares outstanding	137,170,137	139,035,448
Treasury stock, shares	6,782,111	4,916,800

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues:	'	'
Contract drilling	$685,308	$699,973
Revenues related to reimbursable expenses	24,116	29,768
Total revenues	709,424	729,741
Operating expenses:	'	'
Contract drilling, excluding depreciation	369,790	375,094
Reimbursable expenses	23,666	29,289
Depreciation	107,011	96,821
General and administrative	22,827	16,815
Gain on disposition of assets	-147	-2,004
Total operating expenses	523,147	516,015
Operating income	186,277	213,726
Other income (expense):	'	'
Interest income	408	617
Interest expense	-18,155	-8,069
Foreign currency transaction gain (loss)	-1,178	159
Other, net	327	-254
Income before income tax expense	167,679	206,179
Income tax expense	-21,869	-30,190
Net income	$145,810	$175,989
Earnings per share, Basic and Diluted	$1.05	$1.27
Weighted-average shares outstanding:	'	'
Shares of common stock	138,469	139,032
Dilutive potential shares of common stock	4	49
Total weighted-average shares outstanding	138,473	139,081
Cash dividends declared per share of common stock	$0.88	$0.88

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Net income	$145,810	$175,989
Derivative financial instruments:	'	'
Unrealized holding gain	2,839	283
Reclassification adjustment for loss (gain) included in net income	-177	-1,451
Investments in marketable securities:	'	'
Unrealized holding (loss) gain	38	7
Reclassification adjustment for loss (gain) included in net income	-8	-83
Total other comprehensive gain (loss)	2,692	-1,244
Comprehensive income	$148,502	$174,745

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating activities:	'	'
Net income	$145,810	$175,989
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation	107,011	96,821
Gain on disposition of assets	-147	-2,004
Gain on foreign currency forward exchange contracts	-511	-2,435
Deferred tax provision	4,997	9,994
Accretion of discounts on marketable securities	-144	-326
Stock-based compensation expense	1,417	788
Deferred income, net	1,384	-23,085
Deferred expenses, net	-26,044	5,600
Long-term employee remuneration programs	2,048	2,209
Other assets, noncurrent	-173	-4,366
Other liabilities, noncurrent	155	-1,612
Proceeds from settlement of foreign currency forward exchange contracts designated as accounting hedges	511	2,435
Bank deposits denominated in nonconvertible currencies	5,016	'
Other	572	463
Changes in operating assets and liabilities:	'	'
Accounts receivable	53,178	13,760
Prepaid expenses and other current assets	2,961	14,039
Accounts payable and accrued liabilities	10,176	6,925
Taxes payable	-5,202	-19,089
Net cash provided by operating activities	303,015	276,106
Investing activities:	'	'
Capital expenditures (including rig construction)	-595,314	-183,719
Proceeds from disposition of assets, net of disposal costs	173	2,230
Proceeds from sale and maturities of marketable securities	2,175,021	725,014
Purchases of marketable securities	-1,599,914	-724,793
Net cash used in investing activities	-20,034	-181,268
Financing activities:	'	'
Payment of dividends	-122,655	-122,298
Purchase of treasury stock	-86,364	'
Other	-833	137
Net cash used in financing activities	-209,852	-122,161
Net change in cash and cash equivalents	73,129	-27,323
Cash and cash equivalents, beginning of period	347,011	335,432
Cash and cash equivalents, end of period	$420,140	$308,109

General_Information

General Information	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
General Information	'
	1. General Information
	The unaudited 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, 2013 (File No. 1-13926).
	As of April 24, 2014, Loews Corporation owned 51.1 % of the outstanding shares of our common stock.
	Interim Financial Information
	The accompanying unaudited 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 complete financial statements. The consolidated financial information has not been audited but, in the opinion of management, includes all adjustments (consisting only of normal recurring accruals) necessary for a fair presentation of the consolidated balance sheets, statements of operations, statements of comprehensive income 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.
	Reclassifications
	Certain amounts applicable to the prior periods have been reclassified to conform to the classifications currently followed. Such reclassifications do not affect earnings.
	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. We had bank deposits denominated in Egyptian pounds totaling $8.5 million and $14.3 million at March 31, 2014 and December 31, 2013, respectively. However, the local currency is not readily convertible into U.S. dollars or other currencies at this time. While we believe that a portion of these amounts will be used to fund local obligations in Egyptian pounds in the short term, we have reported $7.7 million and $12.7 million as “Other assets” in our Consolidated Balance Sheets at March 31, 2014 and December 31, 2013, respectively.
	The effect of exchange rate changes on cash balances held in foreign currencies was not material for each of the three-month periods ended March 31, 2014 and 2013.
	Marketable Securities
	We classify our investments in marketable securities as available for sale and they are stated at fair value in our Consolidated Balance Sheets. Accordingly, any unrealized gains and losses, net of taxes, are reported in our Consolidated Balance Sheets in “Accumulated other comprehensive gain (loss),” or AOCGL, until realized. The cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity and such adjustments are included in our Consolidated Statements of Operations in “Interest income.” The sale and purchase of securities are recorded on the date of the trade. The cost of debt securities sold is based on the specific identification method. Realized gains or losses, as well as any declines in value that are judged to be other than temporary, are reported in our Consolidated Statements of Operations in “Other income (expense) – Other, net.” See Note 5.
	Derivative Financial Instruments
	Our derivative financial instruments consist of foreign currency forward exchange, or FOREX, contracts which we may designate as cash flow hedges. In accordance with GAAP, each derivative contract is stated in the balance sheet at its fair value with gains and losses reflected in the income statement except that, to the extent the derivative qualifies for and is designated as an accounting hedge, the gains and losses are reflected in income in the same period as offsetting gains and losses on the qualifying hedged positions. Designated hedges are expected to be highly effective, and therefore, adjustments to record the carrying value of the effective portion of our derivative financial instruments to their fair value are recorded as a component of AOCGL in our Consolidated Balance Sheets. The effective portion of the cash flow hedge will remain in AOCGL until it is reclassified into earnings in the period or periods during which the hedged transaction affects earnings or it is determined that the hedged transaction will not occur. We report such realized gains and losses as a component of “Contract drilling, excluding depreciation” expense in our Consolidated Statements of Operations to offset the impact of foreign currency fluctuations in our expenditures in local foreign currencies in the countries in which we operate. See Note 11.
	Adjustments to record the carrying value of the ineffective portion of our derivative financial instruments to fair value and realized gains or losses upon settlement of derivative contracts not designated as cash flow hedges are reported as “Foreign currency transaction gain (loss)” in our Consolidated Statements of Operations. See Notes 6 and 7.
	Drilling and Other Property and Equipment
	We carry our drilling and other property and equipment at cost. Maintenance and routine repairs are charged to income currently while replacements and betterments, which 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. Historically, the amount of capital additions requiring significant judgments, assumptions or estimates has not been significant. During the three months ended March 31, 2014 and the year ended December 31, 2013, we capitalized $84.5 million and $302.0 million, respectively, in replacements and betterments of our drilling fleet, resulting from numerous projects ranging from $25,000 to $30 million per project.
	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 ready for its intended use. 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 included in our results of operations as “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 three to 30 years.
	Treasury Stock
	We account for the purchase of treasury stock using the cost method, which reports the cost of the shares acquired in “Treasury stock” as a deduction from stockholders’ equity in our Consolidated Balance Sheets. Depending on market conditions, we may, from time to time, purchase shares of our common stock in the open market or otherwise. During the three months ended March 31, 2014, we repurchased 1,865,311 shares of common stock at a cost of $86.4 million.
	Capitalized Interest
	We capitalize interest cost for qualifying construction and upgrade projects. See Note 8. A reconciliation of our total interest cost to “Interest expense” as reported in our Consolidated Statements of Operations is as follows:
		Three Months Ended
		March 31,
		2014			2013
	Total interest cost, including amortization of debt issuance costs	$	34,367		$	23,905
	Capitalized interest		(16,212	)		(15,836	)
	Total interest expense as reported	$	18,155		$	8,069
	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 cold stacking a rig or excess spending over budget on a newbuild, construction project or major rig upgrade. At both March 31, 2014 and December 31, 2013, we had four cold-stacked rigs, of which one was reported as an “Asset held for sale” in our Consolidated Balance Sheets. We did not record any impairment with respect to our cold-stacked rigs for the three-month periods ended March 31, 2014 and 2013.
	Foreign Currency
	Our functional currency is the U.S. dollar. Foreign currency transaction gains and losses are reported as “Foreign currency transaction gain (loss)” in our Consolidated Statements of Operations and include, when applicable, unrealized gains and losses to record the carrying value of our FOREX contracts not designated as accounting hedges, as well as realized gains and losses from the settlement of such contracts. For the three-month periods ended March 31, 2014 and 2013, we recognized net foreign currency transaction gains (losses) of $(1.2) million and $0.2 million, respectively. See Note 6.
	Revenue Recognition
	We recognize revenue from dayrate drilling contracts as services are performed. In connection with such drilling contracts, we may receive fees (on either a lump-sum or dayrate basis) for the mobilization of equipment. We earn these fees as services are performed over the initial term of the related drilling contracts. We defer mobilization fees received, as well as direct and incremental mobilization costs incurred, and amortize each on a straight-line basis, over the term of the related drilling contracts (which is the period we estimate to be benefited from the mobilization activity). Straight-line amortization of mobilization revenues and related costs over the term of the related drilling contracts (which generally range from two to 60 months) is consistent with the timing of net cash flows generated from the actual drilling services performed. Absent a contract, mobilization costs are recognized currently.
	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 lump-sum or dayrate basis). These fees are generally earned as services are performed over the initial term of the related drilling contracts. We defer contract preparation fees received as well as direct and incremental costs associated with the contract preparation activities and amortize each, on a straight-line basis, over the term of the related drilling contracts (which we estimate to be benefited from the contract preparation activity).
	From time to time, we may receive fees from our customers for capital improvements to our rigs (either lump-sum or dayrate). We defer such fees received in “Accrued liabilities” and “Other liabilities” in our Consolidated Balance Sheets and recognize these fees into income on a straight-line basis over the period of the related drilling contract. We capitalize the costs of such capital improvements and depreciate them over the estimated useful life of the improvement.
	We record reimbursements received for the purchase of supplies, equipment, personnel services and other services provided at the request of our customers in accordance with a contract or agreement, for the gross amount billed to the customer, as “Revenues related to reimbursable expenses” in our Consolidated Statements of Operations.

Supplemental_Financial_Informa

Supplemental Financial Information	3 Months Ended
	Mar. 31, 2014
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'
Supplemental Financial Information	'
	2. Supplemental Financial Information
	Consolidated Balance Sheets Information
	Accounts receivable, net of allowance for bad debts, consists of the following:
			March 31,			December 31,
			2014			2013
			(In thousands)
	Trade receivables		$	415,146		$	473,013
	Value added tax receivables			23,780			19,407
	Amounts held in escrow			4,321			3,066
	Related party receivables			451			587
	Other			116			622
				443,814			496,695
	Allowance for bad debts			(27,637	)		(27,340	)
	Total		$	416,177		$	469,355
	Prepaid expenses and other current assets consist of the following:
			March 31,			December 31,
			2014			2013
			(In thousands)
	Rig spare parts and supplies		$	54,265		$	52,439
	Deferred mobilization costs			30,199			20,274
	Prepaid insurance			5,884			12,503
	Deferred tax assets			10,222			10,221
	Prepaid taxes			34,202			42,058
	FOREX contracts			4,628			1,562
	Other			7,110			4,940
	Total		$	146,510		$	143,997
	Accrued liabilities consist of the following:
			March 31,			December 31,
			2014			2013
			(In thousands)
	Rig operating expenses		$	74,879		$	87,307
	Payroll and benefits			125,252			121,387
	Deferred revenue			31,043			26,975
	Accrued capital project/upgrade costs			85,266			86,274
	Interest payable			47,748			28,324
	Personal injury and other claims			8,411			9,687
	FOREX contracts			6			1,143
	Other			10,516			9,574
	Total		$	383,121		$	370,671
	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:
			Three Months Ended
			March 31,
			2014			2013
			(In thousands)
	Accrued but unpaid capital expenditures at period end		$	85,266		$	72,193
	Cash interest payments(1)			12,531			12,531
	Cash income taxes paid, net of refunds:
	U.S. federal			—			20,000
	Foreign			24,416			17,700
	State			(31	)		—
	(1)	Interest payments, net of amounts capitalized, were $8.1 million and $3.3 million for the three months ended March 31, 2014 and 2013, respectively.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation	'
	3. Stock-Based Compensation
	In March 2014, our Board of Directors adopted our Equity Incentive Compensation Plan, or Equity Plan, which amends and restates our Second Amended and Restated 2000 Stock Option Plan, or Stock Plan, and directed that the Equity Plan be submitted to our stockholders for approval at the 2014 annual stockholders meeting to be held on May 20, 2014. The Equity Plan is expected to be approved.
	The Equity Plan amends and restates the Stock Plan by, among other things:
		•	increasing the number of shares of our common stock available for issuance under the Equity Plan from 1,500,000 shares to 7,500,000 shares;
		•	increasing the annual limit on the number of shares of our common stock with respect to which awards may be granted to any single individual from 200,000 shares to 500,000 shares;
		•	providing performance goals upon which the awards under the Equity Plan may be conditioned; and
		•	providing for the grant of other stock-based awards (in addition to options and stock appreciation rights) that may be granted under the Equity Plan, including awards of restricted stock, restricted stock units, or RSUs, performance shares and units and other stock-based awards.
	In March 2014, we awarded 52,581 in targeted performance RSUs, with a volume weighted average price of our common stock preceding the grant date of $47.52 per share, to our Chief Executive Officer, or CEO, in connection with his commencement of service with us on March 3, 2014, subject to stockholder approval of the Equity Plan. RSUs are contractual rights to receive shares of our common stock in the future if the applicable vesting conditions are met. Targeted RSUs will become earned RSUs upon achievement of certain performance goals as set forth in the award certificate. Earned RSUs granted to our CEO will vest in one-third increments annually, over three years, commencing on the first anniversary of his hire date, with the first year being prorated for the portion of 2014 during which he was employed.
	Because the stock-based compensation awarded to our CEO is a fixed monetary amount at the date of grant (the target value of $3.0 million on a prorated basis) with variances based on actual achievement of a performance goal, the award is being recorded as a share-based liability. Compensation cost will be recognized over the requisite service period as specified in the award. In connection with the targeted RSUs granted in March 2014, we recognized $66,000 in compensation expense. As of March 31, 2014, the targeted performance goal, as set forth in the award certificate, had not been met, but its achievement was deemed probable.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	4. Earnings Per Share
	A reconciliation of the numerators and the denominators of our basic and diluted per-share computations follows:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands, except per share
		data)
	Net income – basic and diluted numerator	$	145,810	$	175,989
	Weighted average shares – basic (denominator):		138,469		139,032
	Effect of dilutive potential shares
	Stock options and stock appreciation rights		4		49
	Weighted average shares including conversions – diluted (denominator)		138,473		139,081
	Earnings per share:
	Basic	$	1.05	$	1.27
	Diluted	$	1.05	$	1.27
	The following table sets forth the share effects of stock options and the number of stock appreciation rights excluded from our computations of diluted earnings per share, or EPS, as the inclusion of such potentially dilutive shares would have been antidilutive for the periods presented:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands)
	Employee and director:
	Stock options		49		10
	Stock appreciation rights		1,461		805

Marketable_Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2014
Investments Debt And Equity Securities [Abstract]	'
Marketable Securities	'
	5. Marketable Securities
	We report our investments as current assets in our 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:
		March 31, 2014
		Amortized		Unrealized			Market
		Cost		Gain (Loss)			Value
		(In thousands)
	U.S. Treasury Bills and Notes (due within one year)	$	1,174,937	$	24		$	1,174,961
	Mortgage-backed securities		167		7			174
	Total	$	1,175,104	$	31		$	1,175,135
		31-Dec-13
		Amortized		Unrealized			Market
		Cost		Gain (Loss)			Value
		(In thousands)
	U.S. Treasury Bills and Notes (due within one year)	$	1,749,879	$	(22	)	$	1,749,857
	Mortgage-backed securities		188		8			196
	Total	$	1,750,067	$	(14	)	$	1,750,053
	Proceeds from maturities and sales of marketable securities and gross realized gains and losses are summarized as follows:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands)
	Proceeds from maturities	$	2,175,000	$	725,000
	Proceeds from sales		21		14
	Gross realized gains		—		—
	Gross realized losses		—		—

Derivative_Financial_Instrumen

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	6. Derivative Financial Instruments
	Foreign Currency Forward Exchange Contracts
	Our international operations expose us to foreign exchange risk associated with our costs payable in foreign currencies for employee compensation, foreign income tax payments and purchases from foreign suppliers. We may utilize FOREX contracts to manage our foreign exchange risk. Our FOREX contracts generally require us to net settle the spread between the contracted foreign currency exchange rate and the spot rate on the contract settlement date, which, for most of our contracts, is the average spot rate for the contract period.
	We enter into FOREX contracts when we believe market conditions are favorable to purchase contracts for future settlement with the expectation that such contracts, when settled, will reduce our exposure to foreign currency gains and losses on future foreign currency expenditures. The amount and duration of such contracts are based on our monthly forecast of expenditures in the significant currencies in which we do business and for which there is a financial market (i.e., Australian dollars, Brazilian reais, British pounds sterling, Mexican pesos and Norwegian kroner). These forward contracts are derivatives as defined by GAAP.
	During the three months ended March 31, 2014 and 2013, we settled FOREX contracts with aggregate notional values of approximately $64.6 million and $77.1 million, respectively, of which the entire aggregate amounts were designated as a cash flow accounting hedge. During the three-month periods ended March 31, 2014 and 2013, we did not enter into or settle any FOREX contracts that were not designated as accounting hedges.
	The following table presents the aggregate amount of gain recognized in our Consolidated Statements of Operations related to our FOREX contracts designated as accounting hedges for the three-month periods ended March 31, 2014 and 2013.
		Three Months Ended
		March 31,
	Location of Gain Recognized in Income	2014			2013
	Contract drilling expense	$	511		$	2,435
	As of March 31, 2014, we had FOREX contracts outstanding in the aggregate notional amount of $146.1 million, consisting of $11.6 million in Australian dollars, $71.5 million in Brazilian reais, $32.3 million in British pounds sterling, $24.3 million in Mexican pesos and $6.4 million in Norwegian kroner. These contracts generally settle monthly through December 2014. As of March 31, 2014, all outstanding derivative contracts had been designated as cash flow hedges. See Note 7.
	We have International Swap Dealers Association, or ISDA, contracts, which are standardized master legal arrangements that establish key terms and conditions, which govern certain derivative transactions. At March 31, 2014, all of our FOREX contracts were with two counterparties and were governed under such ISDA contracts. There are no requirements to post collateral under these contracts; however, they do contain credit-risk related contingent provisions including credit support provisions and the net settlement of amounts owed in the event of early terminations. Additionally, should our credit rating fall below a specified rating immediately following the merger of Diamond Offshore with another entity, the counterparty may require all outstanding derivatives under the ISDA contract to be settled immediately at current market value. Our ISDA arrangements also include master netting agreements to further manage counterparty credit risk associated with our FOREX contracts. We have elected not to offset the fair value amounts recorded for our FOREX contracts under these agreements in our Consolidated Balance Sheets as of March 31, 2014 and December 31, 2013; however, there would have been no significant difference in our Consolidated Balance Sheets if the estimated fair values were presented on a net basis for these periods.
	The following table presents the fair values of our derivative FOREX contracts designated as hedging instruments at March 31, 2014 and December 31, 2013.
	Balance Sheet Location	Fair Value						Balance Sheet		Fair Value
								Location
		March 31,			December 31,					March 31,			December 31,
		2014			2013					2014			2013
		(In thousands)								(In thousands)
	Prepaid expenses and other current assets	$	4,628		$	1,562			Accrued liabilities	$	(6	)	$	(1,143	)
	The following table presents the amounts recognized in our Consolidated Balance Sheets and Consolidated Statements of Operations related to our derivative financial instruments designated as cash flow hedges for the three-month periods ended March 31, 2014 and 2013, respectively.
		Three Months Ended
		March 31,
		2014			2013
		(In thousands)
	FOREX Contracts:
	Amount of gain (loss) recognized in AOCGL on derivative (effective portion)	$	4,368		$	435
	Location of gain (loss) reclassified from AOCGL into income (effective portion)		Contract			Contract
			drilling			drilling
			expense			expense
	Amount of gain (loss) reclassified from AOCGL into income (effective portion)	$	269		$	2,232
	Location of gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)		Foreign			Foreign
			currency			currency
			transaction			transaction
			gain (loss)			gain (loss)
	Amount of gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	$	(1	)	$	(2	)
	Treasury lock agreements:
	Amount of gain recognized in AOCGL on derivative (effective portion)		—			—
	Location of gain reclassified from AOCGL into income (effective portion)		Interest			—
			Expense
	Amount of gain reclassified from AOCGL into income (effective portion)	$	2		$	—
	As of March 31, 2014, the estimated amount of net unrealized gains associated with our FOREX contracts and treasury lock agreements that will be reclassified to earnings during the next twelve months was $4.6 million and $8,052, respectively. The net unrealized gains associated with these derivative financial instruments will be reclassified to contract drilling expense and interest expense, respectively. During the three-month periods ended March 31, 2014 and 2013, we did not reclassify any amounts from AOCGL due to the probability of an underlying forecasted transaction not occurring.

Financial_Instruments_and_Fair

Financial Instruments and Fair Value Disclosures	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Financial Instruments and Fair Value Disclosures	'
	7. Financial Instruments and Fair Value Disclosures
	Financial instruments which 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, including residential mortgage-backed securities. We generally place our excess cash investments in U.S. government-backed short-term money market instruments through several financial institutions. At times, such investments may be in excess of the insurable limit. We periodically evaluate the relative credit standing of these financial institutions as part of our investment strategy.
	Most of our investments in debt securities are U.S. government securities with minimal credit risk. However, we are exposed to market risk due to price volatility associated with interest rate fluctuations.
	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 and government-owned oil companies. At March 31, 2014 and December 31, 2013, our largest customer in Brazil, Petróleo Brasileiro S.A. (a Brazilian multinational energy company that is majority-owned by the Brazilian government), accounted for $109.7 million and $154.5 million, or 28% and 35%, respectively, of our total consolidated net trade accounts receivable balance.
	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. 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 1 assets include short-term investments such as money market funds, U.S. Treasury Bills and Treasury notes. Our Level 1 assets at March 31, 2014 consisted of cash held in money market funds of $386.9 million, time deposits of $20.1 million and investments in U.S. Treasury securities of $1,175.0 million. Our Level 1 assets at December 31, 2013 consisted of cash held in money market funds of $281.3 million, time deposits of $30.0 million and investments in U.S. Treasury securities of $1,749.9 million.
	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 2 assets and liabilities include residential mortgage-backed securities and over-the-counter FOREX contracts. Our residential mortgage-backed securities were valued using a model-derived valuation technique based on the quoted closing market prices received from a financial institution. Our FOREX contracts are valued based on quoted market prices, which are derived from observable inputs including current spot and forward rates, less the contract rate multiplied by the notional amount. The inputs used in our valuation are obtained from a Bloomberg curve analysis which uses par coupon swap rates to calculate implied forward rates so that projected floating rate cash flows can be calculated. The valuation techniques underlying the models are widely accepted in the financial services industry and do not involve significant judgment.
	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.
	Market conditions could cause an instrument to be reclassified among Levels 1, 2 and 3. Our policy regarding fair value measurements of financial instruments transferred into and out of levels is to reflect the transfers as having occurred at the beginning of the reporting period. There were no transfers between fair value levels during the three-month periods ended March 31, 2014 and 2013.
	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 did not record any impairment charges related to assets measured at fair value on a nonrecurring basis during the three-month periods ended March 31, 2014 and 2013.
	Assets and liabilities measured at fair value are summarized below:
			March 31, 2014
			Fair Value Measurements Using							Assets at
			Level 1		Level 2			Level 3		Fair Value
			(In thousands)
	Recurring fair value measurements:
	Assets:
	Short-term investments		$	1,581,954	$	—		$	—	$	1,581,954
	FOREX contracts			—		4,628			—		4,628
	Mortgage-backed securities			—		174			—		174
	Total assets		$	1,581,954	$	4,802		$	—	$	1,586,756
	Liabilities:
	FOREX contracts		$	—	$	(6	)	$	—	$	(6	)
			December 31, 2013
			Fair Value Measurements Using							Assets at
			Level 1		Level 2			Level 3		Fair Value
			(In thousands)
	Recurring fair value measurements:
	Assets:
	Short-term investments		$	2,061,154	$	—		$	—	$	2,061,154
	FOREX contracts			—		1,562			—		1,562
	Mortgage-backed securities			—		197			—		197
	Total assets		$	2,061,154	$	1,759		$	—	$	2,062,913
	Liabilities:
	FOREX contracts		$	—	$	(1,143	)	$	—	$	(1,143	)
	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.
	We consider our senior notes, including current maturities, to be Level 2 liabilities under the GAAP fair value hierarchy and, accordingly, the fair value of our senior notes was derived using a third-party pricing service at March 31, 2014 and December 31, 2013. 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.
			March 31, 2014					December 31, 2013
			Fair Value		Carrying Value			Fair Value		Carrying Value
			(In millions)
	5.15% Senior Notes due 2014		$	254.5	$	250		$	257.4	$	250
	4.875% Senior Notes due 2015			262.8		249.9			265.7		249.9
	5.875% Senior Notes due 2019			578.9		499.6			578.1		499.6
	3.45% Senior Notes due 2023			242.9		249			241.4		249
	5.70% Senior Notes due 2039			546.6		496.9			543.1		496.9
	4.875% Senior Notes due 2043			731.5		748.8			736.1		748.8
	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_an

Drilling and Other Property and Equipment	3 Months Ended
	Mar. 31, 2014
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:
		March 31,			December 31,
		2014			2013
		(In thousands)
	Drilling rigs and equipment	$	8,515,784		$	7,412,066
	Construction work-in-progress		1,156,923			1,668,211
	Land and buildings		65,798			65,627
	Office equipment and other		67,318			65,799
	Cost		9,805,823			9,211,703
	Less: accumulated depreciation		(3,851,327	)		(3,744,476	)
	Drilling and other property and equipment, net	$	5,954,496		$	5,467,227
	Construction work-in-progress, including capitalized interest, at March 31, 2014 and December 31, 2013 is summarized as follows:
		March 31,			December 31,
		2014			2013
		(In thousands)
	Ultra-deepwater drillships	$	655,277		$	868,908
	Ultra-deepwater semisubmersible:
	Ocean GreatWhite		199,294			195,578
	Deepwater semisubmersibles:
	Ocean Onyx		—			339,129
	Ocean Apex		302,352			264,596
	Total construction work-in-progress	$	1,156,923		$	1,668,211
	In January and February of 2014, the deepwater semisubmersible Ocean Onyx and the ultra-deepwater drillship Ocean BlackHawk, respectively, were placed in service and are no longer reported as construction work-in-progress at March 31, 2014.

Credit_Agreement

Credit Agreement	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Credit Agreement	'
	9. Credit Agreement
	We have a syndicated 5-Year Revolving Credit Agreement, or Credit Agreement, with Wells Fargo Bank, National Association, as administrative agent and swingline lender. Effective March 17, 2014, we entered into a commitment increase agreement and second amendment to the Credit Agreement, which, among other things, provided for a $250.0 million increase in the aggregate commitment under the revolving credit facility and an approximately six-month extension of the maturity date with all of the existing lenders. The Credit Agreement provides for a $1.0 billion senior unsecured revolving credit facility for general corporate purposes, maturing on March 17, 2019. The entire amount of the facility is available for revolving loans. Up to $250 million of the facility is available for the issuance of performance or other standby letters of credit and up to $100 million is available for swingline loans.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
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.
	Litigation. We are one of several unrelated defendants in lawsuits filed in 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 offshore 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 and we expect to receive complete defense and indemnity with respect to many of the lawsuits from Murphy Exploration & Production Company pursuant to the terms of our 1992 asset purchase agreement with them. We also believe that we are not liable for the damages asserted in the remaining lawsuits pursuant to the terms of our 1989 asset purchase agreement with Diamond M Corporation, and we filed a declaratory judgment action in Texas state court against NuStar Energy LP, or NuStar, the successor to Diamond M Corporation, seeking a judicial determination that we did not assume liability for these claims. We obtained summary judgment on our claims in the declaratory judgment action, but NuStar appealed the trial court’s decision, and the appellate court has remanded the case to trial. We are unable to estimate our potential exposure, if any, to these lawsuits at this time but do not believe that ultimate liability, if any, resulting from this litigation will have a material effect on our consolidated financial condition, results of operations and cash flows.
	Various other claims have been filed against us in the ordinary course of business. 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 and cash flows.
	We intend to defend these matters vigorously; however, we cannot predict with certainty the outcome or effect of any litigation matters specifically described above or any other pending litigation or claims. There can be no assurance as to the ultimate outcome of these lawsuits.
	NPI Arrangement. We received payments measured by a percentage net profits interest (of primarily 27%) under an overriding royalty interest in certain developmental oil-and-gas producing properties, or NPI, which we believe is a real property interest. Our drilling program related to the NPI was completed in 2011, and the balance of the amounts due to us under the NPI was received in 2013. However, the customer who conveyed the NPI to us filed a voluntary petition for reorganization under Chapter 11 of the Bankruptcy Code in August 2012. Certain parties (including the debtor) in the bankruptcy proceedings have questioned whether our NPI, and certain amounts we received under it since the filing of the bankruptcy, should be included in the debtor’s estate under the bankruptcy proceeding. We filed a declaratory judgment action in the bankruptcy court seeking a declaration that our NPI, and payments that we received from it since the filing of the bankruptcy, are not part of the bankruptcy estate. We expect that once discovery is concluded in the bankruptcy court, the federal district court will hold a trial to determine the nature of our NPI. We will vigorously defend our rights and pursue our interests in this matter.
	Personal Injury Claims. Under our current insurance policies that expire on May 1, 2014, our deductibles for marine liability insurance coverage, including personal injury claims, which primarily result from Jones Act liability in the Gulf of Mexico, are $10.0 million for the first occurrence, with no aggregate deductible, 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. We intend to increase our deductible for marine liability insurance coverage to $25.0 million for the first occurrence, with no aggregate deductible, effective with our policy renewals on May 1, 2014.
	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 March 31, 2014, our estimated liability for personal injury claims was $35.4 million, of which $8.2 million and $27.2 million were recorded in “Accrued liabilities” and “Other liabilities,” respectively, in our Consolidated Balance Sheets. At December 31, 2013, our estimated liability for personal injury claims was $35.5 million, of which $9.5 million and $26.0 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
	Ultra-Deepwater Floater Construction. The Ocean GreatWhite, a 10,000 foot dynamically positioned, harsh environment semisubmersible drilling rig, is under construction in South Korea at an estimated cost of $755 million, including shipyard costs, capital spares, commissioning and shipyard supervision. The contracted price to Hyundai Heavy Industries Co., Ltd., or Hyundai, totaling $628.5 million is payable in two installments, of which the first installment of $188.6 million has been paid. The final installment of $439.9 million is due upon delivery of the rig, which is expected to occur in the first quarter of 2016.
	Drillship Construction. At March 31, 2014, we had three ultra-deepwater drillships under construction at Hyundai in South Korea at an estimated aggregate cost of $1.9 billion, including shipyard costs, commissioning, capital spares and project management costs. The contracted price of each drillship is payable to Hyundai in two installments, with final payment due on delivery of each drillship. We have paid the first installment for each of our drillships currently under construction, aggregating $493.2 million. The Ocean BlackHornet, Ocean BlackRhino and Ocean BlackLion are expected to be delivered in the second quarter of 2014, third quarter of 2014 and first quarter of 2015, respectively, at which times approximately $390 million will be payable to Hyundai for each rig.
	Ocean Apex Construction. We are obligated under a vessel modification agreement with Jurong Shipyard Pte Ltd, or Jurong, for the construction of the Ocean Apex, a moored semisubmersible deepwater rig, which is expected to be delivered in the third quarter of 2014 at an aggregate cost of approximately $370.0 million, including shipyard costs, commissioning, capital spares and project management costs. The contracted price due to Jurong is payable in 12 installments based on the occurrence of certain events as detailed in the vessel modification agreement. We have paid the first eight installments, aggregating $87.8 million that has been paid to date. The remaining $47.3 million in aggregate milestone payments are payable to Jurong during 2014 as construction milestones are met.
	Ocean Patriot Enhancements. The rig’s North Sea enhancement project is ongoing and is expected to be completed in the second quarter of 2014 at an estimated cost of approximately $120.0 million, including shipyard costs, owner-furnished equipment and labor, commissioning and capital spares. We are financially obligated to Keppel FELS Limited, or Keppel Singapore, for $29.0 million of the total project cost, payable in seven installments based on the occurrence of certain events as detailed in the vessel modification agreement. We have paid the first four installments due to Keppel Singapore, aggregating $18.8 million. The remaining $10.2 million in aggregate milestone payments is payable during the remainder of 2014 as construction milestones are met.
	At March 31, 2014 and December 31, 2013, we had no other 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.
	Letters of Credit and Other. We were contingently liable as of March 31, 2014 in the amount of $65.1 million under certain performance, supersedeas and customs bonds and letters of credit. Agreements relating to approximately $60.5 million of performance, supersedeas and customs bonds can require collateral at any time. As of March 31, 2014, 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. On our behalf, banks have issued letters of credit securing certain of these bonds.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Gain (Loss)	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Accumulated Other Comprehensive Gain (Loss)	'
	11. Accumulated Other Comprehensive Gain (Loss)
	The components of our AOCGL and related changes thereto are as follows:
		Unrealized Gain (Loss) on
		Derivative			Marketable			Total
		Financial			Securities			AOCGL
		Instruments
		(In thousands)
	Balance at January 1, 2014	$	357		$	(7	)	$	350
	Change in other comprehensive gain (loss) before reclassifications, after tax of $(1,529) and $(16)		2,839			38			2,877
	Reclassification adjustments for items included in Net Income, after tax of $94 and $1		(177	)		(8	)		(185	)
	Balance at March 31, 2014	$	3,019		$	23		$	3,042
	The following table presents the line items in our Consolidated Statements of Operations affected by reclassification adjustments out of AOCGL.
	Major Category of AOCGL	Three Months Ended						Consolidated Statements of
		March 31,						Operations Line Items
		2014			2013
	(In thousands)
	Derivative Financial Instruments:
	Unrealized (gain) loss on FOREX contracts	$	(269	)	$	(2,232	)	Contract drilling, excluding depreciation
	Unrealized (gain) on Treasury Lock Agreements		(2	)		—		Interest expense
			94			781		Income tax expense
		$	(177	)	$	(1,451	)	Net of tax
	Marketable Securities:
	Unrealized (gain) loss on marketable securities	$	(9	)	$	(97	)	Other, net
			1			14		Income tax expense
		$	(8	)	$	(83	)	Net of tax

Segments_and_Geographic_Area_A

Segments and Geographic Area Analysis	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segments and Geographic Area Analysis	'
	12. 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.
	Revenues from contract drilling services by equipment type are listed below:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands)
	Floaters:
	Ultra-Deepwater	$	205,794	$	191,357
	Deepwater		146,559		164,420
	Mid-Water		285,979		305,221
	Total Floaters		638,332		660,998
	Jack-ups		46,976		38,975
	Total contract drilling revenues		685,308		699,973
	Revenues related to reimbursable expenses		24,116		29,768
	Total revenues	$	709,424	$	729,741
	Geographic Areas
	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 March 31, 2014, our actively-marketed drilling rigs were en route to or located offshore 11 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.
		Three Months Ended
		March 31,
		2014		2013
	United States	$	114,868	$	105,760
	International:
	South America		287,925		283,565
	Europe/Africa/Mediterranean		155,591		116,389
	Australia/Asia		95,764		172,706
	Mexico		55,276		51,321
	Total revenues	$	709,424	$	729,741

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	13. Income Taxes
	Our income tax expense is a function of the mix between our domestic and international pre-tax earnings or losses, as well as the mix of international tax jurisdictions in which we operate. Certain of our international rigs are owned and operated, directly or indirectly, by one of our wholly owned foreign subsidiaries. It is our intention to indefinitely reinvest future earnings of this subsidiary to finance foreign activities. Accordingly, we have not made a provision for U.S. income taxes on such earnings except to the extent that such earnings were immediately subject to U.S. income taxes.
	During 2013 we were under audit by the Egyptian tax authorities for the tax years 2006 through 2010. In December 2013, after receiving notification that the Egyptian government had concluded the income tax audit for the period 2006 to 2008 and proposed a $1.2 billion increase to taxable income, we accrued an additional $56.9 million of expense for uncertain tax positions in Egypt for all open years. During the first quarter of 2014, we settled certain disputes for the years 2006 through 2008 with the Egyptian tax authorities, which resulted in an aggregate $17.2 million reduction in tax expense, comprised of a $23.2 million reversal of uncertain tax positions, partially offset by $6.0 million in current income tax expense.

General_Information_Policies

General Information (Policies)	3 Months Ended
	Mar. 31, 2014
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.
Reclassifications	'
	Reclassifications
	Certain amounts applicable to the prior periods have been reclassified to conform to the classifications currently followed. Such reclassifications do not affect earnings.
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. We had bank deposits denominated in Egyptian pounds totaling $8.5 million and $14.3 million at March 31, 2014 and December 31, 2013, respectively. However, the local currency is not readily convertible into U.S. dollars or other currencies at this time. While we believe that a portion of these amounts will be used to fund local obligations in Egyptian pounds in the short term, we have reported $7.7 million and $12.7 million as “Other assets” in our Consolidated Balance Sheets at March 31, 2014 and December 31, 2013, respectively.
	The effect of exchange rate changes on cash balances held in foreign currencies was not material for each of the three-month periods ended March 31, 2014 and 2013.
Marketable Securities	'
	Marketable Securities
	We classify our investments in marketable securities as available for sale and they are stated at fair value in our Consolidated Balance Sheets. Accordingly, any unrealized gains and losses, net of taxes, are reported in our Consolidated Balance Sheets in “Accumulated other comprehensive gain (loss),” or AOCGL, until realized. The cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity and such adjustments are included in our Consolidated Statements of Operations in “Interest income.” The sale and purchase of securities are recorded on the date of the trade. The cost of debt securities sold is based on the specific identification method. Realized gains or losses, as well as any declines in value that are judged to be other than temporary, are reported in our Consolidated Statements of Operations in “Other income (expense) – Other, net.” See Note 5.
Derivative Financial Instruments	'
	Derivative Financial Instruments
	Our derivative financial instruments consist of foreign currency forward exchange, or FOREX, contracts which we may designate as cash flow hedges. In accordance with GAAP, each derivative contract is stated in the balance sheet at its fair value with gains and losses reflected in the income statement except that, to the extent the derivative qualifies for and is designated as an accounting hedge, the gains and losses are reflected in income in the same period as offsetting gains and losses on the qualifying hedged positions. Designated hedges are expected to be highly effective, and therefore, adjustments to record the carrying value of the effective portion of our derivative financial instruments to their fair value are recorded as a component of AOCGL in our Consolidated Balance Sheets. The effective portion of the cash flow hedge will remain in AOCGL until it is reclassified into earnings in the period or periods during which the hedged transaction affects earnings or it is determined that the hedged transaction will not occur. We report such realized gains and losses as a component of “Contract drilling, excluding depreciation” expense in our Consolidated Statements of Operations to offset the impact of foreign currency fluctuations in our expenditures in local foreign currencies in the countries in which we operate. See Note 11.
	Adjustments to record the carrying value of the ineffective portion of our derivative financial instruments to fair value and realized gains or losses upon settlement of derivative contracts not designated as cash flow hedges are reported as “Foreign currency transaction gain (loss)” in our Consolidated Statements of Operations. See Notes 6 and 7.
Drilling and Other Property and Equipment	'
	Drilling and Other Property and Equipment
	We carry our drilling and other property and equipment at cost. Maintenance and routine repairs are charged to income currently while replacements and betterments, which 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. Historically, the amount of capital additions requiring significant judgments, assumptions or estimates has not been significant. During the three months ended March 31, 2014 and the year ended December 31, 2013, we capitalized $84.5 million and $302.0 million, respectively, in replacements and betterments of our drilling fleet, resulting from numerous projects ranging from $25,000 to $30 million per project.
	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 ready for its intended use. 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 included in our results of operations as “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 three to 30 years.
Treasury Stock	'
	Treasury Stock
	We account for the purchase of treasury stock using the cost method, which reports the cost of the shares acquired in “Treasury stock” as a deduction from stockholders’ equity in our Consolidated Balance Sheets. Depending on market conditions, we may, from time to time, purchase shares of our common stock in the open market or otherwise. During the three months ended March 31, 2014, we repurchased 1,865,311 shares of common stock at a cost of $86.4 million.
Capitalized Interest	'
	Capitalized Interest
	We capitalize interest cost for qualifying construction and upgrade projects. See Note 8. A reconciliation of our total interest cost to “Interest expense” as reported in our Consolidated Statements of Operations is as follows:
		Three Months Ended
		March 31,
		2014			2013
	Total interest cost, including amortization of debt issuance costs	$	34,367		$	23,905
	Capitalized interest		(16,212	)		(15,836	)
	Total interest expense as reported	$	18,155		$	8,069
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 cold stacking a rig or excess spending over budget on a newbuild, construction project or major rig upgrade. At both March 31, 2014 and December 31, 2013, we had four cold-stacked rigs, of which one was reported as an “Asset held for sale” in our Consolidated Balance Sheets. We did not record any impairment with respect to our cold-stacked rigs for the three-month periods ended March 31, 2014 and 2013.
Foreign Currency	'
	Foreign Currency
	Our functional currency is the U.S. dollar. Foreign currency transaction gains and losses are reported as “Foreign currency transaction gain (loss)” in our Consolidated Statements of Operations and include, when applicable, unrealized gains and losses to record the carrying value of our FOREX contracts not designated as accounting hedges, as well as realized gains and losses from the settlement of such contracts. For the three-month periods ended March 31, 2014 and 2013, we recognized net foreign currency transaction gains (losses) of $(1.2) million and $0.2 million, respectively. See Note 6.
Revenue Recognition	'
	Revenue Recognition
	We recognize revenue from dayrate drilling contracts as services are performed. In connection with such drilling contracts, we may receive fees (on either a lump-sum or dayrate basis) for the mobilization of equipment. We earn these fees as services are performed over the initial term of the related drilling contracts. We defer mobilization fees received, as well as direct and incremental mobilization costs incurred, and amortize each on a straight-line basis, over the term of the related drilling contracts (which is the period we estimate to be benefited from the mobilization activity). Straight-line amortization of mobilization revenues and related costs over the term of the related drilling contracts (which generally range from two to 60 months) is consistent with the timing of net cash flows generated from the actual drilling services performed. Absent a contract, mobilization costs are recognized currently.
	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 lump-sum or dayrate basis). These fees are generally earned as services are performed over the initial term of the related drilling contracts. We defer contract preparation fees received as well as direct and incremental costs associated with the contract preparation activities and amortize each, on a straight-line basis, over the term of the related drilling contracts (which we estimate to be benefited from the contract preparation activity).
	From time to time, we may receive fees from our customers for capital improvements to our rigs (either lump-sum or dayrate). We defer such fees received in “Accrued liabilities” and “Other liabilities” in our Consolidated Balance Sheets and recognize these fees into income on a straight-line basis over the period of the related drilling contract. We capitalize the costs of such capital improvements and depreciate them over the estimated useful life of the improvement.
	We record reimbursements received for the purchase of supplies, equipment, personnel services and other services provided at the request of our customers in accordance with a contract or agreement, for the gross amount billed to the customer, as “Revenues related to reimbursable expenses” in our Consolidated Statements of Operations.

General_Information_Tables

General Information (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Reconciliation of Total Interest Cost to Interest Expense	'
	A reconciliation of our total interest cost to “Interest expense” as reported in our Consolidated Statements of Operations is as follows:
		Three Months Ended
		March 31,
		2014			2013
	Total interest cost, including amortization of debt issuance costs	$	34,367		$	23,905
	Capitalized interest		(16,212	)		(15,836	)
	Total interest expense as reported	$	18,155		$	8,069

Supplemental_Financial_Informa1

Supplemental Financial Information (Tables)	3 Months Ended
	Mar. 31, 2014
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:
			March 31,			December 31,
			2014			2013
			(In thousands)
	Trade receivables		$	415,146		$	473,013
	Value added tax receivables			23,780			19,407
	Amounts held in escrow			4,321			3,066
	Related party receivables			451			587
	Other			116			622
				443,814			496,695
	Allowance for bad debts			(27,637	)		(27,340	)
	Total		$	416,177		$	469,355
Prepaid Expenses and Other Current Assets	'
	Prepaid expenses and other current assets consist of the following:
			March 31,			December 31,
			2014			2013
			(In thousands)
	Rig spare parts and supplies		$	54,265		$	52,439
	Deferred mobilization costs			30,199			20,274
	Prepaid insurance			5,884			12,503
	Deferred tax assets			10,222			10,221
	Prepaid taxes			34,202			42,058
	FOREX contracts			4,628			1,562
	Other			7,110			4,940
	Total		$	146,510		$	143,997
Accrued Liabilities	'
	Accrued liabilities consist of the following:
			March 31,			December 31,
			2014			2013
			(In thousands)
	Rig operating expenses		$	74,879		$	87,307
	Payroll and benefits			125,252			121,387
	Deferred revenue			31,043			26,975
	Accrued capital project/upgrade costs			85,266			86,274
	Interest payable			47,748			28,324
	Personal injury and other claims			8,411			9,687
	FOREX contracts			6			1,143
	Other			10,516			9,574
	Total		$	383,121		$	370,671
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:
			Three Months Ended
			March 31,
			2014			2013
			(In thousands)
	Accrued but unpaid capital expenditures at period end		$	85,266		$	72,193
	Cash interest payments(1)			12,531			12,531
	Cash income taxes paid, net of refunds:
	U.S. federal			—			20,000
	Foreign			24,416			17,700
	State			(31	)		—
	(1)	Interest payments, net of amounts capitalized, were $8.1 million and $3.3 million for the three months ended March 31, 2014 and 2013, respectively.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Reconciliation of Numerators and Denominators of Basic and Diluted Per-Share Computations	'
	A reconciliation of the numerators and the denominators of our basic and diluted per-share computations follows:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands, except per share
		data)
	Net income – basic and diluted numerator	$	145,810	$	175,989
	Weighted average shares – basic (denominator):		138,469		139,032
	Effect of dilutive potential shares
	Stock options and stock appreciation rights		4		49
	Weighted average shares including conversions – diluted (denominator)		138,473		139,081
	Earnings per share:
	Basic	$	1.05	$	1.27
	Diluted	$	1.05	$	1.27
Securities Excluded from Computation of Diluted Earning Per Share	'
	The following table sets forth the share effects of stock options and the number of stock appreciation rights excluded from our computations of diluted earnings per share, or EPS, as the inclusion of such potentially dilutive shares would have been antidilutive for the periods presented:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands)
	Employee and director:
	Stock options		49		10
	Stock appreciation rights		1,461		805

Marketable_Securities_Tables

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2014
Investments Debt And Equity Securities [Abstract]	'
Investments in Marketable Securities as Available for Sale	'
	Our investments in marketable securities are classified as available for sale and are summarized as follows:
		March 31, 2014
		Amortized		Unrealized			Market
		Cost		Gain (Loss)			Value
		(In thousands)
	U.S. Treasury Bills and Notes (due within one year)	$	1,174,937	$	24		$	1,174,961
	Mortgage-backed securities		167		7			174
	Total	$	1,175,104	$	31		$	1,175,135
		31-Dec-13
		Amortized		Unrealized			Market
		Cost		Gain (Loss)			Value
		(In thousands)
	U.S. Treasury Bills and Notes (due within one year)	$	1,749,879	$	(22	)	$	1,749,857
	Mortgage-backed securities		188		8			196
	Total	$	1,750,067	$	(14	)	$	1,750,053
Summary of Proceeds from Sales and Maturities of Marketable Securities and Gross Realized Gains and Losses	'
	Proceeds from maturities and sales of marketable securities and gross realized gains and losses are summarized as follows:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands)
	Proceeds from maturities	$	2,175,000	$	725,000
	Proceeds from sales		21		14
	Gross realized gains		—		—
	Gross realized losses		—		—

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Amounts Recognized in Consolidated Statements of Operations Related to FOREX Contracts Designated as Accounting Hedges	'
	The following table presents the aggregate amount of gain recognized in our Consolidated Statements of Operations related to our FOREX contracts designated as accounting hedges for the three-month periods ended March 31, 2014 and 2013.
		Three Months Ended
		March 31,
	Location of Gain Recognized in Income	2014			2013
	Contract drilling expense	$	511		$	2,435
Fair Values of FOREX Contracts Designated as Hedging Instruments	'
	The following table presents the fair values of our derivative FOREX contracts designated as hedging instruments at March 31, 2014 and December 31, 2013.
	Balance Sheet Location	Fair Value						Balance Sheet		Fair Value
								Location
		March 31,			December 31,					March 31,			December 31,
		2014			2013					2014			2013
		(In thousands)								(In thousands)
	Prepaid expenses and other current assets	$	4,628		$	1,562			Accrued liabilities	$	(6	)	$	(1,143	)
Amounts Recognized in Consolidated Balance Sheets and Consolidated Statements of Operations Related to Derivative Financial Instruments Designated as Cash Flow Hedges	'
	The following table presents the amounts recognized in our Consolidated Balance Sheets and Consolidated Statements of Operations related to our derivative financial instruments designated as cash flow hedges for the three-month periods ended March 31, 2014 and 2013, respectively.
		Three Months Ended
		March 31,
		2014			2013
		(In thousands)
	FOREX Contracts:
	Amount of gain (loss) recognized in AOCGL on derivative (effective portion)	$	4,368		$	435
	Location of gain (loss) reclassified from AOCGL into income (effective portion)		Contract			Contract
			drilling			drilling
			expense			expense
	Amount of gain (loss) reclassified from AOCGL into income (effective portion)	$	269		$	2,232
	Location of gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)		Foreign			Foreign
			currency			currency
			transaction			transaction
			gain (loss)			gain (loss)
	Amount of gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	$	(1	)	$	(2	)
	Treasury lock agreements:
	Amount of gain recognized in AOCGL on derivative (effective portion)		—			—
	Location of gain reclassified from AOCGL into income (effective portion)		Interest			—
			Expense
	Amount of gain reclassified from AOCGL into income (effective portion)	$	2		$	—

Financial_Instruments_and_Fair1

Financial Instruments and Fair Value Disclosures (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Assets and Liabilities Measured at Fair Value on Recurring and Nonrecurring Basis	'
	Assets and liabilities measured at fair value are summarized below:
		March 31, 2014
		Fair Value Measurements Using							Assets at
		Level 1		Level 2			Level 3		Fair Value
		(In thousands)
	Recurring fair value measurements:
	Assets:
	Short-term investments	$	1,581,954	$	—		$	—	$	1,581,954
	FOREX contracts		—		4,628			—		4,628
	Mortgage-backed securities		—		174			—		174
	Total assets	$	1,581,954	$	4,802		$	—	$	1,586,756
	Liabilities:
	FOREX contracts	$	—	$	(6	)	$	—	$	(6	)
		December 31, 2013
		Fair Value Measurements Using							Assets at
		Level 1		Level 2			Level 3		Fair Value
		(In thousands)
	Recurring fair value measurements:
	Assets:
	Short-term investments	$	2,061,154	$	—		$	—	$	2,061,154
	FOREX contracts		—		1,562			—		1,562
	Mortgage-backed securities		—		197			—		197
	Total assets	$	2,061,154	$	1,759		$	—	$	2,062,913
	Liabilities:
	FOREX contracts	$	—	$	(1,143	)	$	—	$	(1,143	)
Fair Values and Related Carrying Values of Our Debt Instruments	'
	Fair values and related carrying values of our senior notes are shown below.
		March 31, 2014					December 31, 2013
		Fair Value		Carrying Value			Fair Value		Carrying Value
		(In millions)
	5.15% Senior Notes due 2014	$	254.5	$	250		$	257.4	$	250
	4.875% Senior Notes due 2015		262.8		249.9			265.7		249.9
	5.875% Senior Notes due 2019		578.9		499.6			578.1		499.6
	3.45% Senior Notes due 2023		242.9		249			241.4		249
	5.70% Senior Notes due 2039		546.6		496.9			543.1		496.9
	4.875% Senior Notes due 2043		731.5		748.8			736.1		748.8

Drilling_and_Other_Property_an1

Drilling and Other Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2014
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:
		March 31,			December 31,
		2014			2013
		(In thousands)
	Drilling rigs and equipment	$	8,515,784		$	7,412,066
	Construction work-in-progress		1,156,923			1,668,211
	Land and buildings		65,798			65,627
	Office equipment and other		67,318			65,799
	Cost		9,805,823			9,211,703
	Less: accumulated depreciation		(3,851,327	)		(3,744,476	)
	Drilling and other property and equipment, net	$	5,954,496		$	5,467,227
Summary of Construction Work-in-Progress, Including Capitalized Interest	'
	Construction work-in-progress, including capitalized interest, at March 31, 2014 and December 31, 2013 is summarized as follows:
		March 31,			December 31,
		2014			2013
		(In thousands)
	Ultra-deepwater drillships	$	655,277		$	868,908
	Ultra-deepwater semisubmersible:
	Ocean GreatWhite		199,294			195,578
	Deepwater semisubmersibles:
	Ocean Onyx		—			339,129
	Ocean Apex		302,352			264,596
	Total construction work-in-progress	$	1,156,923		$	1,668,211

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Gain (Loss) (Tables)	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Components of Accumulated Other Comprehensive Gain (Loss)	'
	The components of our AOCGL and related changes thereto are as follows:
		Unrealized Gain (Loss) on
		Derivative			Marketable			Total
		Financial			Securities			AOCGL
		Instruments
		(In thousands)
	Balance at January 1, 2014	$	357		$	(7	)	$	350
	Change in other comprehensive gain (loss) before reclassifications, after tax of $(1,529) and $(16)		2,839			38			2,877
	Reclassification adjustments for items included in Net Income, after tax of $94 and $1		(177	)		(8	)		(185	)
	Balance at March 31, 2014	$	3,019		$	23		$	3,042
Items in Consolidated Statements of Operations Affected by Reclassification Adjustments	'
	The following table presents the line items in our Consolidated Statements of Operations affected by reclassification adjustments out of AOCGL.
	Major Category of AOCGL	Three Months Ended						Consolidated Statements of
		March 31,						Operations Line Items
		2014			2013
	(In thousands)
	Derivative Financial Instruments:
	Unrealized (gain) loss on FOREX contracts	$	(269	)	$	(2,232	)	Contract drilling, excluding depreciation
	Unrealized (gain) on Treasury Lock Agreements		(2	)		—		Interest expense
			94			781		Income tax expense
		$	(177	)	$	(1,451	)	Net of tax
	Marketable Securities:
	Unrealized (gain) loss on marketable securities	$	(9	)	$	(97	)	Other, net
			1			14		Income tax expense
		$	(8	)	$	(83	)	Net of tax

Segments_and_Geographic_Area_A1

Segments and Geographic Area Analysis (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Revenues from Contract Drilling Services by Equipment Type	'
	Revenues from contract drilling services by equipment type are listed below:
		Three Months Ended
		March 31,
		2014		2013
		(In thousands)
	Floaters:
	Ultra-Deepwater	$	205,794	$	191,357
	Deepwater		146,559		164,420
	Mid-Water		285,979		305,221
	Total Floaters		638,332		660,998
	Jack-ups		46,976		38,975
	Total contract drilling revenues		685,308		699,973
	Revenues related to reimbursable expenses		24,116		29,768
	Total revenues	$	709,424	$	729,741
Revenues by Geographic Area Presented by Attributing Revenues to Individual Country	'
	Revenues by geographic area are presented by attributing revenues to the individual country or areas where the services were performed.
		Three Months Ended
		March 31,
		2014		2013
	United States	$	114,868	$	105,760
	International:
	South America		287,925		283,565
	Europe/Africa/Mediterranean		155,591		116,389
	Australia/Asia		95,764		172,706
	Mexico		55,276		51,321
	Total revenues	$	709,424	$	729,741

General_Information_Additional

General Information - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Apr. 24, 2014

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Egyptian Pounds [Member]

Egyptian Pounds [Member]

Subsequent Event [Member]

Other Assets [Member]

Other Assets [Member]

Cold-stacked rigs [Member]

Cold-stacked rigs [Member]

Minimum [Member]

Minimum [Member]

Maximum [Member]

Maximum [Member]

Egyptian Pounds [Member]

Egyptian Pounds [Member]

Rigs

Rigs

Property, Plant and Equipment [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding common stock owned by Loews Corporation

'

'

'

'

'

51.10%

'

'

'

'

'

'

'

'

Period considered to treat short-term, highly liquid investments as cash equivalents

'Three months or less

'

'

'

'

'

'

'

'

'

'

'

'

'

Bank deposits

'

'

'

$8,500,000

$14,300,000

'

$7,700,000

$12,700,000

'

'

'

'

'

'

Effect of exchange rate changes on cash balances held in foreign currencies

0

0

'

'

'

'

'

'

'

'

'

'

'

'

Amount capitalized for asset replacements and betterments

84,500,000

'

302,000,000

'

'

'

'

'

'

'

'

'

'

'

Rig and equipment project costs

'

'

'

'

'

'

'

'

'

'

25,000

25,000

30,000,000

30,000,000

Estimated useful life for drilling rigs and equipment

'

'

'

'

'

'

'

'

'

'

'3 years

'

'30 years

'

Repurchase of common stock, shares

1,865,311

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase of common stock, cost

86,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of cold stacked rigs

'

'

'

'

'

'

'

'

4

4

'

'

'

'

Number of cold stacked rigs held for sale

'

'

'

'

'

'

'

'

1

1

'

'

'

'

Gain (loss) on foreign currency transactions recognized in income

($1,200,000)

$200,000

'

'

'

'

'

'

'

'

'

'

'

'

Initial term of contracts minimum months

'2 months

'

'

'

'

'

'

'

'

'

'

'

'

'

Initial term of contracts maximum months

'60 months

'

'

'

'

'

'

'

'

'

'

'

'

'

General_Information_Reconcilia

General Information - Reconciliation of Total Interest Cost to Interest Expense (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Interest Costs Incurred [Abstract]	'	'
Total interest cost, including amortization of debt issuance costs	$34,367	$23,905
Capitalized interest	-16,212	-15,836
Total interest expense as reported	$18,155	$8,069

Supplemental_Financial_Informa2

Supplemental Financial Information - Accounts Receivable, Net of Allowance for Doubtful Accounts (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Receivables [Abstract]	'	'
Trade receivables	$415,146	$473,013
Value added tax receivables	23,780	19,407
Amounts held in escrow	4,321	3,066
Related party receivables	451	587
Other	116	622
Receivables Gross Current, Total	443,814	496,695
Allowance for bad debts	-27,637	-27,340
Total	$416,177	$469,355

Supplemental_Financial_Informa3

Supplemental Financial Information - Prepaid Expenses and Other Current Assets (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]	'	'
Rig spare parts and supplies	$54,265	$52,439
Deferred mobilization costs	30,199	20,274
Prepaid insurance	5,884	12,503
Deferred tax assets	10,222	10,221
Prepaid taxes	34,202	42,058
FOREX contracts	4,628	1,562
Other	7,110	4,940
Total	$146,510	$143,997

Supplemental_Financial_Informa4

Supplemental Financial Information - Accrued Liabilities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]	'	'
Rig operating expenses	$74,879	$87,307
Payroll and benefits	125,252	121,387
Deferred revenue	31,043	26,975
Accrued capital project/upgrade costs	85,266	86,274
Interest payable	47,748	28,324
Personal injury and other claims	8,411	9,687
FOREX contracts	6	1,143
Other	10,516	9,574
Total	$383,121	$370,671

Supplemental_Financial_Informa5

Supplemental Financial Information - Noncash Investing and Financing Activities (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements, Captions [Line Items]	'	'
Accrued but unpaid capital expenditures at period end	$85,266	$72,193
Cash interest payments	12,531	12,531
U.S federal [Member]	'	'
Cash income taxes paid, net of refunds:	'	'
Cash income taxes paid, net of refunds	'	20,000
Foreign [Member]	'	'
Cash income taxes paid, net of refunds:	'	'
Cash income taxes paid, net of refunds	24,416	17,700
State [Member]	'	'
Cash income taxes paid, net of refunds:	'	'
Cash income taxes paid, net of refunds	($31)	'

Supplemental_Financial_Informa6

Supplemental Financial Information - Noncash Investing and Financing Activities (Parenthetical) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Supplemental Cash Flow Information [Abstract]	'	'
Interest payments, net of amounts capitalized	$8.10	$3.30

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended			1 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014
			Equity Plan [Member]	Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Number of shares of common stock available for issuance	1,500,000	'	7,500,000	'
Annual limit on number of shares granted per individual	200,000	'	500,000	'
Targeted performance restricted stock units awarded	'	'	'	52,581
Weighted-average price of common stock grant date per share	'	'	'	$47.52
Restricted stock units, vesting period	'	'	'	'3 years
Target value of RSUs granted	'	'	'	$3,000,000
Stock-based compensation expense	$1,417,000	$788,000	'	$66,000

Earnings_Per_Share_Reconciliat

Earnings Per Share - Reconciliation of Numerators and Denominators of Basic and Diluted Per-Share Computations (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Net income - basic and diluted numerator	$145,810	$175,989
Weighted average shares - basic (denominator):	138,469	139,032
Effect of dilutive potential shares	'	'
Stock options and stock appreciation rights	4	49
Weighted average shares including conversions - diluted denominator)	138,473	139,081
Earnings per share:	'	'
Basic	$1.05	$1.27
Diluted	$1.05	$1.27

Earnings_Per_Share_Securities_

Earnings Per Share - Securities Excluded from Computation of Diluted Earning Per Share (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Stock options [Member]	'	'
Employee and director:	'	'
Securities excluded from computation of diluted earning per share	49	10
Stock appreciation rights [Member]	'	'
Employee and director:	'	'
Securities excluded from computation of diluted earning per share	1,461	805

Marketable_Securities_Investme

Marketable Securities - Investments in Marketable Securities as Available for Sale (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$1,175,104	$1,750,067
Unrealized Gain (Loss)	31	-14
Market Value	1,175,135	1,750,053
U.S. Treasury Bills and Notes (due within one year) [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	1,174,937	1,749,879
Unrealized Gain (Loss)	24	-22
Market Value	1,174,961	1,749,857
Mortgage-backed securities [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	167	188
Unrealized Gain (Loss)	7	8
Market Value	$174	$196

Marketable_Securities_Summary_

Marketable Securities - Summary of Proceeds from Sales and Maturities of Marketable Securities and Gross Realized Gains and Losses (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Investments Debt And Equity Securities [Abstract]	'	'
Proceeds from maturities	$2,175,000	$725,000
Proceeds from sales	21	14
Gross realized gains	'	'
Gross realized losses	'	'

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Additional Information (Detail)	3 Months Ended							3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2014
	USD ($)	USD ($)	AUD	BRL	GBP (£)	MXN	NOK	Reclassification out of Accumulated Other Comprehensive Income [Member]	Reclassification out of Accumulated Other Comprehensive Income [Member]	FOREX contracts [Member]	Treasury Lock Agreements [Member]
								USD ($)	USD ($)	USD ($)	USD ($)
										Counterparty
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Notional amount of foreign currency contracts settled	$64,600,000	$77,100,000	'	'	'	'	'	'	'	'	'
Derivative contracts outstanding in the aggregate notional amount	146,100,000	'	11,600,000	71,500,000	32,300,000	24,300,000	6,400,000	'	'	'	'
Number of counterparties to FOREX contracts	'	'	'	'	'	'	'	'	'	2	'
Net unrealized gains (losses) associated with derivative financial instruments to be reclassified to earnings	'	'	'	'	'	'	'	'	'	4,600,000	8,052
Amount reclassified from AOCGL due to the probability of a forecasted transaction not occurring	'	'	'	'	'	'	'	$0	$0	'	'

Derivative_Financial_Instrumen3

Derivative Financial Instruments - Amounts Recognized in Consolidated Statements of Operations Related to FOREX Contracts Designated as Accounting Hedges (Detail) (Contract drilling expense [Member], Designated as hedging instrument [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Contract drilling expense [Member] | Designated as hedging instrument [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of Gain Recognized in Income	$511	$2,435

Derivative_Financial_Instrumen4

Derivative Financial Instruments - Fair Values of Forex Contracts Designated as Hedging Instruments (Detail) (FOREX contracts [Member], USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accrued Liabilities [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative liabilities designated as hedging instruments, current	($6)	($1,143)
Prepaid expenses and other current assets [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Derivative assets designated as hedging instruments, current	$4,628	$1,562

Derivative_Financial_Instrumen5

Derivative Financial Instruments - Amounts Recognized in Consolidated Balance Sheets and Consolidated Statements of Operations Related to Derivative Financial Instruments Designated as Cash Flow Hedges (Detail) (Derivative designated as accounting hedges [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
FOREX contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of gain (loss) recognized in AOCGL on derivative (effective portion)	$4,368	$435
Treasury Lock Agreements [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of gain (loss) recognized in AOCGL on derivative (effective portion)	'	'
Contract drilling expense [Member] | FOREX contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of gain (loss) reclassified from AOCGL into income (effective portion)	269	2,232
Foreign currency transaction gain (loss) [Member] | FOREX contracts [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	-1	-2
Interest Expense [Member] | Treasury Lock Agreements [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Amount of gain (loss) reclassified from AOCGL into income (effective portion)	$2	'

Financial_Instruments_and_Fair2

Financial Instruments and Fair Value Disclosures - Additional Information (Detail) (USD $)	3 Months Ended									3 Months Ended	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013
				Level 1 [Member]	Level 1 [Member]	Level 1 [Member]	Level 1 [Member]	Level 1 [Member]	Level 1 [Member]	Accounts Receivable [Member]	Accounts Receivable [Member]
				Cash held in money market funds [Member]	Cash held in money market funds [Member]	Time deposits [Member]	Time deposits [Member]	U.S. Treasury securities [Member]	U.S. Treasury securities [Member]	Petroleo Brasileiro S.A. [Member]	Petroleo Brasileiro S.A. [Member]
										Credit Concentration Risk [Member]	Credit Concentration Risk [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Accounts receivable due from major customer	$416,177,000	'	$469,355,000	'	'	'	'	'	'	$109,700,000	$154,500,000
Percentage of accounts receivable due from major customer	'	'	'	'	'	'	'	'	'	28.00%	35.00%
Fair value of investments	'	'	'	386,900,000	281,300,000	20,100,000	30,000,000	1,175,000,000	1,749,900,000	'	'
Transfers between fair value levels	$0	$0	'	'	'	'	'	'	'	'	'
Measurement period for determining fair value of debt instruments	'10 days	'	'	'	'	'	'	'	'	'	'

Financial_Instruments_and_Fair3

Financial Instruments and Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring and Nonrecurring Basis (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:	'	'
FOREX contracts	$4,628	$1,562
Liabilities:	'	'
FOREX contracts	-6	-1,143
Fair Value Measurements, Recurring [Member]	'	'
Assets:	'	'
Short-term investments	1,581,954	2,061,154
FOREX contracts	4,628	1,562
Mortgage-backed securities	174	197
Total assets	1,586,756	2,062,913
Liabilities:	'	'
FOREX contracts	-6	-1,143
Fair Value Measurements, Recurring [Member] | Level 1 [Member]	'	'
Assets:	'	'
Short-term investments	1,581,954	2,061,154
FOREX contracts	'	'
Mortgage-backed securities	'	'
Total assets	1,581,954	2,061,154
Liabilities:	'	'
FOREX contracts	'	'
Fair Value Measurements, Recurring [Member] | Level 2 [Member]	'	'
Assets:	'	'
Short-term investments	'	'
FOREX contracts	4,628	1,562
Mortgage-backed securities	174	197
Total assets	4,802	1,759
Liabilities:	'	'
FOREX contracts	-6	-1,143
Fair Value Measurements, Recurring [Member] | Level 3 [Member]	'	'
Assets:	'	'
Short-term investments	'	'
FOREX contracts	'	'
Mortgage-backed securities	'	'
Total assets	'	'
Liabilities:	'	'
FOREX contracts	'	'

Financial_Instruments_and_Fair4

Financial Instruments and Fair Value Disclosures - Fair Value and Related Carrying Values of Our Debt Instruments (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
5.15% Senior Notes due 2014 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Carrying Value	$250	$250
Fair Value	254.5	257.4
4.875% Senior Notes due 2015 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Carrying Value	249.9	249.9
Fair Value	262.8	265.7
5.875% Senior Notes due 2019 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Carrying Value	499.6	499.6
Fair Value	578.9	578.1
3.45% Senior Notes due 2023 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Carrying Value	249	249
Fair Value	242.9	241.4
5.70% Senior Notes due 2039 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Carrying Value	496.9	496.9
Fair Value	546.6	543.1
4.875% Senior Notes due 2043 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Carrying Value	748.8	748.8
Fair Value	$731.50	$736.10

Financial_Instruments_and_Fair5

Financial Instruments and Fair Value Disclosures - Fair Value and Related Carrying Values of Our Debt Instruments (Parenthetical) (Detail)	Mar. 31, 2014	Dec. 31, 2013
5.15% Senior Notes due 2014 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Interest rate of senior notes	5.15%	5.15%
4.875% Senior Notes due 2015 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Interest rate of senior notes	4.88%	4.88%
5.875% Senior Notes due 2019 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Interest rate of senior notes	5.88%	5.88%
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%
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	4.88%	4.88%

Drilling_and_Other_Property_an2

Drilling and Other Property and Equipment - Summary of Cost and Accumulated Depreciation of Drilling and Other Property and Equipment (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	$9,805,823	$9,211,703
Less: accumulated depreciation	-3,851,327	-3,744,476
Drilling and other property and equipment, net	5,954,496	5,467,227
Drilling rigs and equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	8,515,784	7,412,066
Construction work-in-progress [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	1,156,923	1,668,211
Land and buildings [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	65,798	65,627
Office equipment and other [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property and equipment	$67,318	$65,799

Drilling_and_Other_Property_an3

Drilling and Other Property and Equipment - Summary of Construction Work-in-Progress, Including Capitalized Interest (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Rig(s) Under Construction	$1,156,923	$1,668,211
Ultra-deepwater drillships [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Rig(s) Under Construction	655,277	868,908
Ocean GreatWhite [Member] | Ultra-deepwater semisubmersible [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Rig(s) Under Construction	199,294	195,578
Ocean Onyx [Member] | Deepwater semisubmersibles [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Rig(s) Under Construction	'	339,129
Ocean Apex [Member] | Deepwater semisubmersibles [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Rig(s) Under Construction	$302,352	$264,596

Credit_Agreement_Additional_In

Credit Agreement - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Debt Instrument [Line Items]	'
Term of Credit agreement	'5 years
Maturity period of Credit agreement	17-Mar-19
Amount available for general purposes	$1,000,000,000
Letters of Credit [Member]	'
Debt Instrument [Line Items]	'
Amount available for general purposes	250,000,000
Swingline Loan Facility [Member]	'
Debt Instrument [Line Items]	'
Amount available for general purposes	$100,000,000

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Contingencies And Commitments [Line Items]	'	'
Net profits interest percent	27.00%	'
Deductible for marine liability coverage including personal injury claims, per first occurrence	$10	'
Range of deductible for liability coverage for personal injury claims, lower limit	5	'
Range of deductible for liability coverage for personal injury claims, upper limit	100	'
Other purchase obligations	0	0
Total Contingent Liabilities Under Letters of Credit and Bonds [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Contingent liability under letters of credit and other bonds	65.1	'
Collateralized Contingent Liabilities Under Letters of Credit and Bonds [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Contingent liability under letters of credit and other bonds	60.5	'
Hyundai Heavy Industries, Co., Ltd. [Member] | Ultra-Deepwater Floater Construction [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Water depth of rig	10,000	'
Cost of enhancement of project	755	'
Total number of installments due under each turnkey construction agreements	2	'
Cost of construction per shipyard agreement	628.5	'
Construction installments paid	188.6	'
Final installment for Ultra-Deep water Floater Construction	439.9	'
Hyundai Heavy Industries, Co., Ltd. [Member] | Ultra-deepwater drillships [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Cost of enhancement of project	1,900	'
Total number of installments due under each turnkey construction agreements	2	'
Construction installments paid	493.2	'
Number of ultra-deepwater drillships under construction	3	'
Hyundai Heavy Industries, Co., Ltd. [Member] | Ultra-deepwater drillships [Member] | Second Quarter of 2014 [Member] | Ocean BlackHornet [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Expected amount of second installments payable in next 12 months	390	'
Hyundai Heavy Industries, Co., Ltd. [Member] | Ultra-deepwater drillships [Member] | Third Quarter 2014 [Member] | Ocean BlackRhino [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Expected amount of second installments payable in next 12 months	390	'
Hyundai Heavy Industries, Co., Ltd. [Member] | Ultra-deepwater drillships [Member] | First Quarter 2015 [Member] | Ocean BlackLion [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Expected amount of second installments payable in next 12 months	390	'
Jurong Shipyard Pte Ltd [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Cost of enhancement of project	370	'
Construction installments paid	87.8	'
Number of installments due under each rig construction agreement	12	'
Number of installments paid	8	'
Construction agreement balance amount payable	47.3	'
Keppel FELS Limited [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Cost of enhancement of project	120	'
Cost of construction per shipyard agreement	29	'
Construction installments paid	18.8	'
Number of installments due under each rig construction agreement	7	'
Number of installments paid	4	'
Construction agreement balance amount payable	10.2	'
Effective May 1, 2014 [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Deductible for marine liability coverage including personal injury claims, per first occurrence	25	'
Personal Injury Claims [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Personal injury claims recorded	35.4	35.5
Personal Injury Claims [Member] | Accrued Liabilities [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Personal injury claims recorded	8.2	9.5
Personal Injury Claims [Member] | Other Liabilities [Member]	'	'
Contingencies And Commitments [Line Items]	'	'
Personal injury claims recorded	$27.20	$26

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Gain (Loss) - Components of Accumulated Other Comprehensive Gain (Loss) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Beginning balance	$350
Change in other comprehensive gain (loss) before reclassifications, after tax of $(1,529) and $(16)	2,877
Reclassification adjustments for items included in Net Income, after tax of $94 and $1	-185
Ending balance	3,042
Derivative Financial Instrument [Member]	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Beginning balance	357
Change in other comprehensive gain (loss) before reclassifications, after tax of $(1,529) and $(16)	2,839
Reclassification adjustments for items included in Net Income, after tax of $94 and $1	-177
Ending balance	3,019
Marketable Securities [Member]	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'
Beginning balance	-7
Change in other comprehensive gain (loss) before reclassifications, after tax of $(1,529) and $(16)	38
Reclassification adjustments for items included in Net Income, after tax of $94 and $1	-8
Ending balance	$23

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Gain (Loss) - Components of Accumulated Other Comprehensive Gain (Loss) (Parenthetical) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Equity [Abstract]	'
Change in other comprehensive gain (loss), tax	($1,529)
Change in other comprehensive gain (loss), tax	-16
Reclassification adjustments for items included in Net Income, tax	94
Reclassification adjustments for items included in Net Income, tax	$1

Accumulated_Other_Comprehensiv4

Accumulated Other Comprehensive Gain (Loss) - Items in Consolidated Statements of Operations Affected by Reclassification Adjustments (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Other, net	($327)	$254
Contract drilling, excluding depreciation	369,790	375,094
Interest expense	18,155	8,069
Income tax expense	21,869	30,190
Net of tax	-145,810	-175,989
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash Flow Hedges [Member]	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Income tax expense	94	781
Net of tax	-177	-1,451
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash Flow Hedges [Member] | FOREX contracts [Member]	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Contract drilling, excluding depreciation	-269	-2,232
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash Flow Hedges [Member] | Treasury Lock Agreements [Member]	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Interest expense	-2	'
Reclassification out of Accumulated Other Comprehensive Income [Member] | Marketable Securities [Member]	'	'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'	'
Other, net	-9	-97
Income tax expense	1	14
Net of tax	($8)	($83)

Segments_and_Geographic_Area_A2

Segments and Geographic Area Analysis - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014
	Segment
	Country
Segment Reporting [Abstract]	'
Number of reportable segments	1
Number of countries with rigs	11

Segments_and_Geographic_Area_A3

Segments and Geographic Area Analysis - Revenues from Contract Drilling Services by Equipment Type (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Contract drilling	$685,308	$699,973
Revenues related to reimbursable expenses	24,116	29,768
Total revenues	709,424	729,741
Ultra-deepwater semisubmersible [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Contract drilling	205,794	191,357
Deepwater [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Contract drilling	146,559	164,420
Mid-Water [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Contract drilling	285,979	305,221
Total Floaters [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Contract drilling	638,332	660,998
Jack-ups [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Contract drilling	$46,976	$38,975

Segments_and_Geographic_Area_A4

Segments and Geographic Area Analysis - Revenues by Geographic Area Presented by Attributing Revenues to Individual Country (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total revenues	$709,424	$729,741
United States [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total revenues	114,868	105,760
South America [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total revenues	287,925	283,565
Europe/Africa/Mediterranean [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total revenues	155,591	116,389
Australia/Asia [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total revenues	95,764	172,706
Mexico [Member]	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Total revenues	$55,276	$51,321

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014
			2006 through 2010 Tax Year [Member]	2006 through 2008 Tax Year [Member]
			Egypt [Member]	Egypt [Member]
Income Tax Contingency [Line Items]	'	'	'	'
Proposed increase to taxable income	'	'	$1,200,000,000	'
Accrued expense related to income tax examination	'	'	56,900,000	'
Current income tax expense due to settlement	'	'	'	6,000,000
Reversal of uncertain tax positions due to settlement	'	'	'	23,200,000
Income tax (expense) benefit	($21,869,000)	($30,190,000)	'	$17,200,000