Income Taxes (Components Of Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal, Current (expense) benefit	$ 123,933	$ (74,283)	$ (99,127)
State, Current (expense) benefit	(10,522)	(2,069)	(1,088)
Foreign, including foreign withholding tax, Current (expense) benefit	(29,152)	(31,385)	(76,199)
Current (expense) benefit	(84,259)	107,737	176,414
Federal, Deferred (expense) benefit	(4,348)	(30,462)	16,448
State, Deferred (expense) benefit	(17,388)	(22,899)	(42,624)
Foreign, Deferred (expense) benefit	2,121	14,621	55,563
Deferred (expense) benefit	19,615	38,740	(29,387)
Income tax (expense) benefit	$ (64,644)	$ 146,477	$ 147,027