Segment Reporting (Schedule Of Net Long-Lived Assets By Principal Geographic Areas) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	$ 303,587	$ 281,214
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	267,951	248,494
Americas [Member] | United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	262,475	245,511
Americas [Member] | Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	3,206	869
Americas [Member] | Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	2,270	2,114
Europe, The Middle East And Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	30,135	29,041
Europe, The Middle East And Africa [Member] | United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	14,366	12,959
Europe, The Middle East And Africa [Member] | Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	4,836	5,733
Europe, The Middle East And Africa [Member] | France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	3,172	3,127
Europe, The Middle East And Africa [Member] | Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	3,456	2,956
Europe, The Middle East And Africa [Member] | Switzerland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	2,631	3,076
Europe, The Middle East And Africa [Member] | Other Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	1,674	1,190
Asia Pacific Region [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	5,501	3,679
Asia Pacific Region [Member] | Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	2,204	690
Asia Pacific Region [Member] | Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	1,789	1,801
Asia Pacific Region [Member] | Other Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Assets	$ 1,508	$ 1,188