Long-Term Obligations (Debt And Equity Components Recognized For Convertible Debentures) (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010	Oct. 31, 2007
Series A [Member]
Debt Instrument [Line Items]
Principal amount of convertible debentures	$ 275,000,000	$ 275,000,000	$ 275,000,000
Convertible debt, principal amount	275,000,000	275,000,000	275,000,000
Unamortized discount	(9,059,000)	(19,273,000)
Net carrying amount	265,941,000	255,727,000
Additional paid-in capital	29,065,000	29,065,000
Series B [Member]
Debt Instrument [Line Items]
Principal amount of convertible debentures	275,000,000	275,000,000	275,000,000
Convertible debt, principal amount	275,000,000	275,000,000	275,000,000
Unamortized discount	(31,332,000)	(40,953,000)
Net carrying amount	243,668,000	234,047,000
Additional paid-in capital	$ 41,238,000	$ 41,238,000