Income Taxes (Changes In Gross Liability For Unrecognized Tax Benefits Excluding Interest And Penalties) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning of period	$ 55,539	$ 73,100
Increase in unrecognized tax benefits for tax positions taken in a prior period	9,513	2,828
Decrease in unrecognized tax benefits for tax positions taken in a prior period	(3,749)	(21,061)
Increase in unrecognized tax benefits for tax positions taken in the current period	13,779	7,402
Statute lapses	0	(1,907)
Settlements with taxing authorities	(2,852)	(4,823)
Unrecognized tax benefits, end of period	$ 72,230	$ 55,539