Long-Term Debt (Schedule of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified				12 Months Ended		12 Months Ended		12 Months Ended					12 Months Ended				12 Months Ended			12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2013 Term Loan [Member]	Dec. 31, 2012 Term Loan [Member]	Dec. 31, 2013 Revolving Credit Facility [Member]	Dec. 31, 2012 Revolving Credit Facility [Member]	Dec. 31, 2013 Term Loan Maturing June 2018 [Member]		Dec. 31, 2013 2025 Notes [Member]	Dec. 31, 2012 2025 Notes [Member]	Jan. 31, 2009 2025 Notes [Member]	Dec. 31, 2013 2032 Notes [Member]		Dec. 31, 2012 2032 Notes [Member]	Mar. 31, 2012 2032 Notes [Member]	Dec. 31, 2013 Senior Unsecured Notes [Member]	Dec. 31, 2012 Senior Unsecured Notes [Member]	Dec. 31, 2011 Senior Unsecured Notes [Member]	Dec. 31, 2013 MARAD Debt [Member]	Dec. 31, 2012 MARAD Debt [Member]
Debt Instrument [Line Items]
Total debt	$ 566,152		$ 1,019,228		$ 367,181		$ 100,000	$ 292,500			$ 3,487		$ 200,000		$ 200,000			$ 274,960		$ 100,168	$ 105,288
Current maturities	(20,376)		(16,607)
Long-term debt, less current maturities	545,776		1,002,621					277,500	[1]				173,484	[2]				275,000	475,000	94,792
Unamortized debt discount	$ (26,516)	[3]	$ (31,688)									$ (60,200)	$ (26,516)	[2],[3]		$ (35,400)
Maturity date				July 2015		July 2015		June 2018		December 2025			March 2032				January 2016			February 2027

[1] The amount reflects the borrowings made in July 2013 (see Credit Agreement discussion above).

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

[3] The 2032 Notes will increase to their principal amount through accretion of non-cash interest charges through March 2018.