Segment Information (Schedule Of Revenue From Unaffiliated Customers By Product) (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]
Revenue	$ 187,438	$ 166,944	$ 151,512	$ 147,758	$ 154,817	$ 135,717	$ 120,787	$ 102,079	$ 653,652	$ 513,400	$ 353,633
Printers And Other Products [Member]
Segment Reporting Information [Line Items]
Revenue									283,339	227,627	126,798
Materials [Member]
Segment Reporting Information [Line Items]
Revenue									158,859	128,405	103,182
Services [Member]
Segment Reporting Information [Line Items]
Revenue									$ 211,454	$ 157,368	$ 123,653