Organization And Accounting Policies (Rollforward Analysis Of The Allowance Against Accounts Receivable Balance) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Organization And Accounting Policies [Abstract]
Balance at beginning of year	$ (7,033)	$ (5,211)
Recovery (charge) to costs and expenses	56	(98)
Foreign currency loss	(187)	(90)
Balance at end of period	$ (7,164)	$ (5,399)