Other Current and Long-Term Assets (Schedule Of Other Current Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Other Assets, Noncurrent [Abstract]
Customer acquisition costs	$ 41,569	$ 39,329
Prepaid expenses	31,795	31,992
Contract assets, net	18,860	17,659
Taxes receivable	15,769	20,516
Deferred sales commissions	5,321	5,202
Other assets	11,308	10,284
Other current assets	$ 124,622	$ 124,982