Long-Term Debt (Maturities Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012	Sep. 30, 2013 Term Loan Maturing June 2018 [Member]		Sep. 30, 2013 MARAD Debt [Member]	Sep. 30, 2013 Convertible Senior Notes 2032 [Member]		Mar. 31, 2012 Convertible Senior Notes 2032 [Member]
Debt Instrument [Line Items]
Less than one year	$ 20,376			$ 15,000	[1]	$ 5,376
One to two years	24,394			18,750	[1]	5,644
Two to three years	35,926			30,000	[1]	5,926
Three to four years	36,222			30,000	[1]	6,222
Four to five years	209,032			202,500	[1]	6,532
Over five years	270,468					70,468	200,000	[2]
Total debt	596,418			296,250	[1]	100,168	200,000	[2]
Current maturities	(20,376)		(16,607)	(15,000)	[1]	(5,376)
Long-term debt, less current maturities	576,042			281,250	[1]	94,792	200,000	[2]
Unamortized debt discount	(27,838)	[3]					(27,838)	[2],[3]	(35,400)
Long-term debt	$ 548,204		$ 1,002,621	$ 281,250	[1]	$ 94,792	$ 172,162	[2]

[1] Amount reflects the borrowings made in July 2013 (see “Credit Agreement” below).

[2] 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 notes. These notes will mature in March 2032.

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