Income Taxes (Schedule Of Total Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Current taxes, Federal	$ (20,612)	$ 8,594	$ 15,845
Current taxes, State	(4)	784	146
Current taxes	(20,616)	9,378	15,991
Deferred taxes, Federal	(535,691)	68,360	87,839
Deferred taxes, State	(70,641)	8,925	12,893
Deferred taxes	(606,332)	77,285	100,732
Total provision	$ (626,948)	$ 86,663	$ 116,723