Segment and Geographic Information - Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Product sales	$ 709,438	$ 691,496	$ 654,599
Service sales	218,016	200,242	171,827
Total sales	927,454	891,738	826,426
U.S. and Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Product sales	167,876	200,778	179,126
Service sales	92,759	90,942	78,118
Total sales	260,635	291,720	257,244
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Product sales	205,857	185,598	206,994
Service sales	64,803	59,124	54,319
Total sales	270,660	244,722	261,313
Asia Pacific Region and Rest of World [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Product sales	335,705	305,120	268,479
Service sales	60,454	50,176	39,390
Total sales	$ 396,159	$ 355,296	$ 307,869