Income Taxes (Schedule Of Components Of Income And Loss From Continuing Operations Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
Domestic	$ (260,117)	$ (81,443)	$ (448,575)
Foreign	(35,159)	(936)	(21,831)
Loss from continuing operations before income taxes	$ (295,276)	$ (82,379)	$ (470,406)