Debt And Interest Expense (Components Of Interest Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Short-term Debt [Line Items]
Contractual interest on Convertible Debentures	$ 40,625	$ 40,625	$ 40,625
Interest Expense, Debt	60,938	54,667	34,688
Amortization of debt discount on the Convertible Debentures	11,094	10,218	9,412
Other interest expense	2,907	2,121	1,269
Total interest expense	$ 115,564	$ 107,631	$ 85,994