Segment Information - Revenue Classified by Major Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 213,261	$ 214,956
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	203,663	203,469
Europe/Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	8,460	10,592
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,138	$ 895