Income Taxes (Schedule Of Changes In Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Total amounts of unrecognized tax benefits, beginning of period	$ 18,463	$ 7,204	$ 5,942
Gross increases in unrecognized tax benefits as a result of tax positions taken during a prior period	74	75	47
Gross increases in unrecognized tax benefits as a result of tax positions taken in the current period	4,681	12,657	1,569
Decreases in unrecognized tax benefits relating to settlements with taxing authorities	(713)	(1,326)
Decreases in unrecognized tax benefits as a result of a lapse of the applicable statutes of limitations	(1,088)	(147)	(354)
Total amounts of unrecognized tax benefits, end of period	$ 21,417	$ 18,463	$ 7,204