Long-Term Debt (Maturities Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2012
Debt Instrument [Line Items]
Less than one year	$ 28,144
One to two years	35,926
Two to three years	36,222
Three to four years	201,532
Four to five years	6,858
Over five years	263,610
Total debt	572,292	592,668
Current maturities	(28,144)	(20,376)
Long-term debt, less current maturities	544,148
Unamortized debt discount	(20,920)	(26,516)
Long-term debt	523,228	545,776
Term Loan Maturing June 2018 [Member]
Debt Instrument [Line Items]
Less than one year	22,500
One to two years	30,000
Two to three years	30,000
Three to four years	195,000
Total debt	277,500	292,500
Current maturities	(22,500)
Long-term debt, less current maturities	255,000
Long-term debt	255,000
Debt instrument, maturity date	June 2018
MARAD Debt [Member]
Debt Instrument [Line Items]
Less than one year	5,644
One to two years	5,926
Two to three years	6,222
Three to four years	6,532
Four to five years	6,858
Over five years	63,610
Total debt	94,792	100,168
Current maturities	(5,644)
Long-term debt, less current maturities	89,148
Long-term debt	89,148
Debt instrument, maturity date	February 2027
Convertible Senior Notes 2032 [Member]
Debt Instrument [Line Items]
Over five years	200,000
Total debt	200,000	200,000	200,000
Long-term debt, less current maturities	200,000
Unamortized debt discount	(20,920)	(26,500)	(35,400)
Long-term debt	$ 179,080
Debt instrument, maturity date	March 2032