Income Taxes (Schedule Of Income Before Income Tax Expense (Benefit) And Equity In Earnings Of 50% Or Less Owned Companies) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Income Before Income Tax Expense (Benefit) and Equity in Earnings of 50% or Less Owned Companies	$ (262,248)	$ (30,798)	$ 163,235
United States [Member]
Income Tax Contingency [Line Items]
Income Before Income Tax Expense (Benefit) and Equity in Earnings of 50% or Less Owned Companies	(242,375)	(25,441)	160,782
Foreign [Member]
Income Tax Contingency [Line Items]
Income Before Income Tax Expense (Benefit) and Equity in Earnings of 50% or Less Owned Companies	(29,200)	(2,896)	(5,409)
Eliminations And Other [Member]
Income Tax Contingency [Line Items]
Income Before Income Tax Expense (Benefit) and Equity in Earnings of 50% or Less Owned Companies	$ 9,327	$ (2,461)	$ 7,862