Other Current and Long-Term Assets (Schedule Of Other Long-term Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Other Assets, Noncurrent [Abstract]
Customer acquisition costs	$ 108,947	$ 104,369
Contract assets, net	114,668	91,681
Deferred income taxes	24,861	31,549
Deferred sales commissions	12,695	11,719
Investment in long-term product supply arrangements	9,790	12,065
Taxes receivable	2,450	6,329
Other assets	43,733	31,883
Other long-term assets	$ 317,144	$ 289,595