Long-Term Debt (Maturities Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified					6 Months Ended
	Jun. 30, 2014		Dec. 31, 2013	Jun. 30, 2014 Term Loan Maturing June 2018 [Member]	Jun. 30, 2014 MARAD Debt [Member]	Jun. 30, 2014 Convertible Senior Notes 2032 [Member]		Mar. 31, 2012 Convertible Senior Notes 2032 [Member]
Debt Instrument [Line Items]
Less than one year	$ 20,508			$ 15,000	$ 5,508
One to two years	35,783			30,000	5,783
Two to three years	36,072			30,000	6,072
Three to four years	36,375			30,000	6,375
Four to five years	186,693			180,000	6,693
Over five years	267,082				67,082	200,000	[1]
Total debt	582,513			285,000	97,513	200,000	[1]	200,000
Current maturities	(20,508)		(20,376)	(15,000)	(5,508)
Long-term debt, less current maturities	562,005			270,000	92,005	200,000	[1]
Unamortized debt discount	(23,751)	[2]				(23,751)	[1],[2]	(35,400)
Long-term debt	$ 538,254		$ 545,776	$ 270,000	$ 92,005	$ 176,249	[1]
Debt instrument, maturity date					February 2027	March 2032

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

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