Accounting For Income Taxes (Schedule Of Components Of Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Current income tax expense (benefit)	$ 17,490	$ 13,101	$ (46,457)
Deferred income tax expense	8,570	69,657	124,543
Total income tax expense	$ 26,060	$ 82,758	$ 78,086