Accounting For Income Taxes (Schedule Of Components Of Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of Income Tax Expense (Benefit) [Line Items]
Current income tax expense (benefit)	$ (46,457)	$ 12,212	$ (67,059)
Deferred income tax expense	124,543	55,237	139,299
Total income tax expense	$ 78,086	$ 67,449	$ 72,240