Receivables (Schedule Of Allowance For Doubtful Accounts) (Details) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Fiscal Year	$ 2,574	$ 2,016	$ 1,071
Charged to Operations	1,034	558	947
Recoveries (Deductions)	0	0	(2)
Balance at End of Fiscal Year	$ 3,608	$ 2,574	$ 2,016