Segment Information - Revenue Classified by Major Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015		Sep. 30, 2016	Sep. 30, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 211,804	$ 207,478	[1]	$ 638,834	$ 672,612	[1]
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	199,878	197,973		606,168	641,366
United Kingdom Israel [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	11,118	8,715		30,150	28,019
CHINA
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 808	$ 790		$ 2,516	$ 3,227

[1] Amounts have been recast to reflect discontinued operations. See Note 3 for details.