Segment Information (Schedule Of Intercompany Sales By Geographic Area) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total revenue	$ 164,570	$ 629,094	$ 687,660	$ 646,069
Intercompany Sales
Total revenue		188,519	203,904	175,898
Americas | Intercompany Sales
Total revenue		73,742	82,850	75,668
EMEA | Intercompany Sales
Total revenue		90,231	87,313	70,961
APAC | Intercompany Sales
Total revenue		24,546	33,741	29,269
Americas | Intercompany Sales
Total revenue		58,896	84,510	74,246
Americas | Americas | Operating Segments
Total revenue		1,764	2,342	2,169
Americas | EMEA | Operating Segments
Total revenue		40,704	59,206	51,689
Americas | APAC | Operating Segments
Total revenue		16,428	22,962	20,388
EMEA
Total revenue		240,403	237,462	220,357
EMEA | Intercompany Sales
Total revenue		119,209	111,159	94,752
EMEA | Americas | Operating Segments
Total revenue		66,832	75,875	70,709
EMEA | EMEA | Operating Segments
Total revenue		47,395	28,075	19,098
EMEA | APAC | Operating Segments
Total revenue		4,982	7,209	4,945
APAC
Total revenue		72,866	109,433	91,936
APAC | Intercompany Sales
Total revenue		10,414	8,235	6,900
APAC | Americas | Operating Segments
Total revenue		5,146	4,633	2,790
APAC | EMEA | Operating Segments
Total revenue		2,132	32	174
APAC | APAC | Operating Segments
Total revenue		$ 3,136	$ 3,570	$ 3,936