Operating Segments and Related Information (Details 5) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 402,729	$ 392,975	$ 782,201	$ 737,492
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	224,300	204,900	418,600	371,400
Canada/Latin_America
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	18,085	19,972	47,327	36,399
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	84,297	95,869	168,707	189,124
Mid_East/Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	28,629	26,009	56,341	52,576
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 47,413	$ 46,179	$ 91,237	$ 87,992