Accrued Liabilities (Schedule Of Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accrued Liabilities [Abstract]
Accrued expenses	$ 65,835	$ 64,430
Accrued employee compensation and related expenses	59,080	102,944
Accrued taxes	26,452	29,389
Accrued customer incentives and refund obligations (Notes 2 and 3)	59,017	56,655
Total accrued liabilities	$ 210,384	$ 253,418