Long-Term Debt (Maturities Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified					9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013	Sep. 30, 2014 Term Loan Maturing June 2018 [Member]	Sep. 30, 2014 MARAD Debt [Member]	Sep. 30, 2014 Convertible Senior Notes 2032 [Member]		Mar. 31, 2012 Convertible Senior Notes 2032 [Member]
Debt Instrument [Line Items]
Less than one year	$ 24,394			$ 18,750	$ 5,644
One to two years	35,926			30,000	5,926
Two to three years	36,222			30,000	6,222
Three to four years	36,532			30,000	6,532
Four to five years	179,358			172,500	6,858
Over five years	263,610				63,610	200,000	[1]
Total debt	576,042			281,250	94,792	200,000	[1]	200,000
Current maturities	(24,394)		(20,376)	(18,750)	(5,644)
Long-term debt, less current maturities	551,648			262,500	89,148	200,000	[1]
Unamortized debt discount	(22,367)	[2]				(22,367)	[1],[2]	(35,400)
Long-term debt	$ 529,281		$ 545,776	$ 262,500	$ 89,148	$ 177,633	[1]
Debt instrument, maturity date					February 2027	March 2032

[1] Beginning in March 2018, the holders of our 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] Our Convertible Senior Notes due 2032 will increase to their face amount through accretion of non-cash interest charges through March 2018.