Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning of Period	$ 18,065
Increases Related To Current Period Tax Positions	5,154
Increases Related To Prior Period Tax Positions	293
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(1,595)
Unrecognized Tax Benefits, Decreases Resulting From Payments for Prior Period Tax Positions	(120)
Unrecognized Tax Benefits, End of Period	$ 21,797