Long-Term Debt (Narrative) (Details) (USD $)	3 Months Ended	9 Months Ended					1 Months Ended	9 Months Ended			9 Months Ended										1 Months Ended	3 Months Ended		9 Months Ended				1 Months Ended	9 Months Ended			1 Months Ended	9 Months Ended						9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Aug. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Convertible Senior Notes 2032 [Member]	Sep. 30, 2012 Convertible Senior Notes 2032 [Member]		Mar. 06, 2012 Convertible Senior Notes 2032 [Member]	Sep. 30, 2012 Helix Term Loan [Member]		Feb. 21, 2012 Helix Term Loan [Member]	Sep. 30, 2011 Helix Term Loan [Member]	Jul. 31, 2006 Helix Term Loan [Member]	Sep. 30, 2012 Revolving Credit Facility [Member]	Mar. 31, 2012 Revolving Credit Facility [Member]	Dec. 31, 2011 Revolving Credit Facility [Member]	Jul. 31, 2006 Revolving Credit Facility [Member]	Sep. 30, 2012 Helix Revolving Loans [Member]	Mar. 31, 2012 Senior Unsecured Notes [Member]	Mar. 31, 2012 Senior Unsecured Notes [Member]	Sep. 30, 2011 Senior Unsecured Notes [Member]	Sep. 30, 2012 Senior Unsecured Notes [Member]	Dec. 31, 2011 Senior Unsecured Notes [Member]	Dec. 31, 2010 Senior Unsecured Notes [Member]	Dec. 31, 2007 Senior Unsecured Notes [Member]	Mar. 31, 2005 Convertible Senior Notes 2025 [Member]	Sep. 30, 2012 Convertible Senior Notes 2025 [Member]		Mar. 31, 2012 Convertible Senior Notes 2025 [Member]	Sep. 30, 2005 MARAD Debt [Member]	Sep. 30, 2012 MARAD Debt [Member]		Sep. 30, 2012 Letters Of Credit [Member]	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Minimum [Member] Helix Term Loan [Member]	Sep. 30, 2012 Minimum [Member] Helix Revolving Loans [Member]	Sep. 30, 2012 Maximum [Member] Helix Term Loan [Member]	Sep. 30, 2012 Maximum [Member] Helix Revolving Loans [Member]
Debt Instrument Convertible Conversion Premium Percentage										35.00%
Indebtedness Of Foreign Subsidiaries		$ 400,000,000			$ 200,000,000
Issuance Of Notes Percentage								100.00%
Convertible Senior Notes, shares of common stock								39.9752
Senior Unsecured Notes amount issued																											550,000,000
Unsecured letters of credit																44,300,000																			44,300,000
Long-term debt, noncurrent		1,159,958,000				1,147,444,000		167,076,000	[1]		361,165,000	[2]								100,000,000				274,960,000	475,000,000	550,000,000			156,589,000	[3]			100,168,000
Long-term debt, Carrying Value		1,207,243,000					200,000,000									100,000,000								274,960,000				300,000,000					105,288,000	[4]
Long-term debt								157,800,000
Debt instrument interest rate							3.25%																				9.50%	3.25%				4.93%
Stated maturity Year																																February 2027
Aggregate amount of debt payment		209,500,000		77,394,000																		213,500,000	77,400,000
Payment on senior notes																					200,000,000		75,000,000						145,100,000
Premium on debt extinguishment																						9,500,000	2,400,000						1,800,000
Accrued interest on notes		61,637,000		73,096,000																		4,000,000	800,000						1,100,000
Accelerated amortization of debt discount		7,253,000		6,693,000																		2,000,000	900,000						3,500,000
Loss on early extinguishment of debt	2,354,000	17,127,000		2,354,000																				11,500,000					5,600,000
Original borrowing capacity																600,000,000			300,000,000
Cash and cash equivalents plus available capacity under revolving credit facility																																				400,000,000
Spread on LIBOR																																	20.00%				2.25%	1.50%	3.50%	3.50%
Revolving credit facility, outstanding															835,000,000	100,000,000	100,000,000	0
Average interest rate											3.70%			3.60%		3.00%
Revolving credit facility available													100,000,000			455,700,000
Credit facility, annual amortization of principal balance													5,000,000
Debt interest, maturity date											Jul. 01, 2015																												Jul. 01, 2016
Interest rate swap		200,000,000				200,000,000
Debt instrument issued percentage																												100.00%
Effective interest rate								6.90%																					6.60%
Per share conversion price		$ 32.14						$ 25.02
Deferred financing costs, net		26,091,000				26,483,000
Amortization of deferred financing costs		4,990,000		7,197,000																									300,000
Repayment of revolving credit facility				109,400,000
Debt Instrument, Repurchase Amount																															142,200,000
Proceeds from Issuance of Debt							195,000,000
Debt percentage guaranteed																																	50.00%
Notional Amount of Interest Rate Cash Flow Hedge Derivatives		200,000,000				200,000,000
Closing price per share										$ 18.53
Debt Instrument, Unamortized Discount		$ 34,165,000	[5]				$ 35,400,000	$ 32,924,000	[1],[5]																				$ 1,241,000	[3],[5]

[1] Beginning in March 2018, the holders of these Convertible Senior Notes may require us to repurchase these notes or we may at our own option elect to repurchase notes. These notes will mature in March 2032.

[2] Amounts reflect both our Term Loan and Term Loan A.

[3] Beginning in December 2012, the holders of these Convertible Senior Notes may require us to repurchase these notes or we may at our own option elect to repurchase notes. These notes will mature in March 2025.

[4] The estimated fair value of all debt, other than the MARAD debt, was determined using Level 1 inputs using the market approach. The fair value of the MARAD debt was determined using a third party evaluation of the remaining average life and outstanding principal balance of the MARAD indebtedness as compared to other governmental obligations in the marketplace with similar terms. The fair value of the MARAD Debt was estimated using Level 2 fair value inputs using the market approach.

[5] The notes will increase to their principal amount through accretion of non-cash interest charges through December 2012 for the Convertible Senior Notes due 2025 and through March 2018 for the Convertible Senior Notes due 2032.