Summary Of Significant Accounting Policies (Value Of Long Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, carrying value	$ 572,292	$ 592,668
Long-term debt, Fair Value	598,293	645,687
Unamortized debt discount	20,920	26,516
Term Loan Maturing June 2018 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, carrying value	277,500	292,500
Long-term debt, Fair Value	270,563	293,963
Convertible Senior Notes 2032 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, carrying value	200,000	200,000	200,000
Long-term debt, Fair Value	222,900	242,250
Unamortized debt discount	20,920	26,500	35,400
MARAD Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, carrying value	94,792	100,168
Long-term debt, Fair Value	$ 104,830	$ 109,474