Long-Term Debt (Narrative) (Details) (USD $)	12 Months Ended					1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended											1 Months Ended			1 Months Ended	3 Months Ended		12 Months Ended				1 Months Ended				12 Months Ended					12 Months Ended					12 Months Ended			12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010	Aug. 31, 2012	Mar. 31, 2012 Convertible Senior Notes 2032 [Member]	Dec. 31, 2012 Convertible Senior Notes 2032 [Member]		Mar. 06, 2012 Convertible Senior Notes 2032 [Member]	Feb. 28, 2013 Helix Term Loan [Member]	Dec. 31, 2012 Helix Term Loan [Member]		Feb. 19, 2013 Helix Term Loan [Member]	Feb. 21, 2012 Helix Term Loan [Member]	Dec. 31, 2011 Helix Term Loan [Member]	Jul. 31, 2006 Helix Term Loan [Member]	Feb. 19, 2013 Revolving Credit Facility [Member]	Dec. 31, 2012 Revolving Credit Facility [Member]		Mar. 31, 2012 Revolving Credit Facility [Member]	Jul. 31, 2006 Revolving Credit Facility [Member]	Feb. 28, 2013 Helix Revolving Loans [Member]	Dec. 31, 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]	Dec. 31, 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]	Feb. 28, 2013 Convertible Senior Notes 2025 [Member]	Dec. 31, 2012 Convertible Senior Notes 2025 [Member]		Mar. 31, 2005 Convertible Senior Notes 2025 [Member]	Dec. 31, 2012 Convertible Senior Notes 2025 [Member]		Mar. 31, 2012 Convertible Senior Notes 2025 [Member]	Dec. 31, 2011 Convertible Senior Notes 2025 [Member]		Dec. 31, 2012 MARAD Debt [Member]		Dec. 31, 2011 MARAD Debt [Member]		Sep. 30, 2005 MARAD Debt [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Minimum [Member] Helix Term Loan [Member]	Dec. 31, 2012 Minimum [Member] Helix Revolving Loans [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Maximum [Member] Helix Term Loan [Member]	Dec. 31, 2012 Maximum [Member] Helix Revolving Loans [Member]
Debt Instrument [Line Items]
Base Principal Amount							$ 1,000
Mandatory Prepayments Percentage											60.00%
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																		12,400,000
Long-term debt, less current maturities	1,002,621,000		1,147,444,000				168,312,000	[1]			359,181,000	[2]											100,000,000	[2]				274,960,000	475,000,000	550,000,000											100,168,000
Long-term debt, Carrying Value						200,000,000	200,000,000	[3]					73,300,000	100,000,000			78,100,000	100,000,000	[4]									274,960,000	474,960,000				3,487,000	[5]	300,000,000	3,487,000	[5]		300,000,000	[5]	105,288,000	[6]	110,166,000	[6]
Percentage Of Principal To Be Paid Due To Change Of Control																												101.00%
Debt instrument interest rate						3.25%																									9.50%				3.25%										4.93%
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																										4,000,000	800,000									1,100,000
Accelerated amortization of debt discount	9,729,000		8,973,000	8,409,000																																3,500,000
Loss on early extinguishment of debt	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																																									0.20%						2.25%	1.50%		3.50%	3.50%
Revolving credit facility, outstanding																835,000,000		100,000,000		100,000,000
Average interest rate											3.70%				3.80%			3.00%
Revolving credit facility available																		487,600,000
Term Loan, annual amortization of principal balance														5,000,000
Interest rate swap	200,000,000
Debt instrument issued percentage																																			100.00%
Effective interest rate							6.90%																													6.60%
Per share conversion price							$ 25.02																										$ 32.14			$ 32.14
Deferred financing costs, net	24,338,000		26,483,000
Amortization of deferred financing costs	9,086,000		8,910,000	7,703,000																						2,000,000	900,000									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	31,688,000	[7]	9,555,000			35,400,000	31,688,000	[1],[7]																															9,600,000
Expected life used to estimate fair value	6 years
Commitment fee percentage																																														2.00%			3.00%
Deferred financing costs	7,580,000		9,311,000	2,947,000
Repayments of debt	$ 12,569,000		$ 130,691,000	$ 4,326,000						$ 293,900,000												$ 24,500,000										$ 3,500,000	$ 154,300,000
Line of Credit Facility, Commitment Fee Percentage	0.50%

[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] Term Loan amounts reflect both our Term Loan A and Term Loan B. In February 2013, we repaid $293.9 million of our Term Loans and $24.5 million under our Revolving Credit Facility with the after-tax proceeds from the sale of ERT.

[3] Carrying value excludes the related unamortized debt discount of $31.7 million at December 31, 2012.

[4] In February 2013, we repaid $293.9 million of our Term Loans and $24.5 million under our Revolving Credit Facility with the after-tax proceeds from the sale of ERT.

[5] Carrying value excludes the related unamortized debt discount of $9.6 million at December 31, 2011.

[6] 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.

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