Segment Information - Revenue Classified by Major Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 213,536	$ 244,679	$ 698,025	$ 749,536
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	204,031	234,317	666,779	711,529
United Kingdom Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	8,715	9,106	28,019	32,983
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 790	$ 1,256	$ 3,227	$ 5,024