Segment Information (Schedule Of Income Or Loss From Operations By Geographic Area) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Income (loss) from operations	$ 4,228	$ 8,208	$ 4,362	$ 9,517	$ 17,976	$ 28,570	$ 16,796	$ 17,519	$ 26,315	$ 80,861	$ 60,571
Subtotal [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									27,398	82,393	60,991
Inter-Segment Elimination [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									(1,083)	(1,532)	(420)
Americas [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									(24,663)	43,743	37,743
Germany [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									2,749	302	1,305
Other EMEA [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									9,181	7,849	5,415
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									$ 40,131	$ 30,499	$ 16,528