Other Current and Long-Term Assets (Schedule Of Other Current Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Assets, Noncurrent [Abstract]
Customer acquisition costs	$ 42,906	$ 39,329
Prepaid expenses	35,966	31,992
Taxes receivable	24,051	20,516
Contract assets, net	20,361	17,659
Deferred sales commissions	5,510	5,202
Other assets	9,108	10,284
Other current assets	$ 137,902	$ 124,982