Other Current and Long-Term Assets (Schedule Of Other Long-term Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Other Assets, Noncurrent [Abstract]
Customer acquisition costs	$ 98,463	$ 98,117
Contract assets, net	69,196	66,226
Taxes receivable	14,960	14,960
Investment in long-term product supply arrangements	13,785	13,657
Deferred sales commissions	10,672	10,442
Deferred income taxes	7,172	8,100
Other assets	34,717	28,690
Other long-term assets	$ 248,965	$ 240,192