Other Current and Noncurrent Assets (Schedule Of Other Noncurrent Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Current and Noncurrent Assets [Abstract]
Investment in long-term product supply arrangements	$ 9,949	$ 10,978
Customer acquisition costs, net	64,670	50,309
Deferred income taxes	7,698	5,707
Other assets	36,299	36,321
Total other long-term assets	$ 118,616	$ 103,315