Segment Information - Revenue Classified by Major Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 238,928	$ 249,689	$ 484,489	$ 504,857
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	229,717	236,884	462,748	477,212
Europe Middle East [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	8,332	10,040
United Kingdom Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue			19,304	23,877
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 879	$ 2,765
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue			$ 2,437	$ 3,768