Segment Information - Revenue Classified by Major Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 230,360	$ 213,536	$ 238,928	$ 245,561	$ 254,928	$ 244,679	$ 249,689	$ 255,168	$ 928,385	$ 1,004,464	$ 1,019,714
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									883,805	955,361	978,249
Europe/Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									40,603	43,087	36,516
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue									$ 3,977	$ 6,016	$ 4,949