Debt And Interest Expense (Carrying Amounts Of Liability And Equity Components) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Mar. 27, 2015	Dec. 31, 2014	Apr. 16, 2013	Aug. 15, 2007
Debt Disclosure [Abstract]
Debt Instrument, Unamortized Discount (Premium), Net	$ 686,221		$ 686,221
deferred tax on debenture discount	(267,225)		(267,225)
Carrying amount of equity component (net of issuance costs of $14,449)	418,996		418,996
Principal amount of debt	1,250,000	$ 500,000	1,250,000	$ 750,000	$ 1,250,000
Unamortized discount of liability component	(635,378)		(645,565)
Unamortized Debt Issuance Expense	(10,422)		(10,570)
Carrying amount of liability component	604,200		593,865
Contingent interest derivative	30,126		26,755
Convertible Debt	$ 634,326		$ 620,620