Other Current and Long-Term Assets (Schedule Of Other Long-term Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Assets, Noncurrent [Abstract]
Customer acquisition costs	$ 103,075	$ 98,117
Contract assets, net	80,936	66,226
Investment in long-term product supply arrangements	12,599	13,657
Deferred sales commissions	10,993	10,442
Deferred income taxes	8,198	8,100
Taxes receivable	6,329	14,960
Other assets	32,672	28,690
Other long-term assets	$ 254,802	$ 240,192