Long-Term Debt (Narrative) (Details) (USD $)	6 Months Ended				1 Months Ended	6 Months Ended			6 Months Ended										1 Months Ended	3 Months Ended	6 Months Ended			1 Months Ended	6 Months Ended			1 Months Ended	6 Months Ended					6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011	Dec. 31, 2011	Mar. 31, 2012 Convertible Senior Notes 2032 [Member]	Jun. 30, 2012 Convertible Senior Notes 2032 [Member]		Mar. 06, 2012 Convertible Senior Notes 2032 [Member]	Jun. 30, 2012 Helix Term Loan [Member]		Feb. 21, 2012 Helix Term Loan [Member]	Jun. 30, 2011 Helix Term Loan [Member]	Jul. 31, 2006 Helix Term Loan [Member]	Jun. 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]	Jun. 30, 2012 Helix Revolving Loans [Member]	Mar. 31, 2012 Senior Unsecured Notes [Member]	Mar. 31, 2012 Senior Unsecured Notes [Member]	Jun. 30, 2012 Senior Unsecured Notes [Member]	Dec. 31, 2011 Senior Unsecured Notes [Member]	Dec. 31, 2007 Senior Unsecured Notes [Member]	Mar. 31, 2005 Convertible Senior Notes 2025 [Member]	Jun. 30, 2012 Convertible Senior Notes 2025 [Member]		Mar. 31, 2012 Convertible Senior Notes 2025 [Member]	Sep. 30, 2005 MARAD Debt [Member]	Jun. 30, 2012 MARAD Debt [Member]		Jun. 30, 2012 Letters Of Credit [Member]	Jun. 30, 2012 Minimum [Member] Helix Term Loan [Member]	Jun. 30, 2012 Minimum [Member] Helix Revolving Loans [Member]	Jun. 30, 2012 Maximum [Member] Helix Term Loan [Member]	Jun. 30, 2012 Maximum [Member] Helix Revolving Loans [Member]
Debt Instrument Convertible Conversion Premium Percentage								35.00%
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														46,300,000																	46,300,000
Long-term debt, noncurrent	1,167,908,000			1,147,444,000		165,840,000	[1]		369,000,000	[2]								100,000,000			274,960,000	475,000,000			155,348,000	[3]			102,760,000
Long-term debt, Carrying Value	1,217,547,000				200,000,000									100,000,000							274,960,000			300,000,000					107,757,000	[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																			213,500,000
Payment on senior notes																			200,000,000						145,100,000
Premium on debt extinguishment																				9,500,000					1,800,000
Accrued interest on notes	39,259,000		40,220,000																	4,000,000					1,100,000
Accelerated amortization of debt discount	4,776,000		4,414,000																	2,000,000					3,500,000
Loss on early extinguishment of debt	17,127,000																				11,500,000				5,600,000
Original borrowing capacity														600,000,000			300,000,000
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									3.80%			3.20%		3.00%
Revolving credit facility available											100,000,000			453,700,000
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
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	26,528,000			26,483,000
Amortization of deferred financing costs	3,292,000		4,777,000																						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
Closing price per share								$ 18.53
Debt Instrument, Unamortized Discount	$ 36,642,000	[5]			$ 35,400,000	$ 34,160,000	[1],[5]																		$ 2,482,000	[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 the 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 March 2018 for the Convertible Senior Notes due 2032.