Segment Information Revenues By Region (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
Revenues from External Customers [Line Items]
Total revenues	$ 510,095	$ 496,454	$ 489,353	$ 474,795	$ 523,526	$ 495,491	$ 482,175	$ 447,536	$ 1,970,697	$ 1,948,728	$ 2,178,178
United States and Canada [Member]
Revenues from External Customers [Line Items]
Total revenues									899,399	851,295	1,014,739
EMEA [Member]
Revenues from External Customers [Line Items]
Total revenues									848,502	858,026	878,615
Other Countries [Member]
Revenues from External Customers [Line Items]
Total revenues									$ 222,796	$ 239,407	$ 284,824