Operating Segments and Related Information (Details 5) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 464,712	$ 405,228	$ 1,305,650	$ 1,187,429
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	250,755	229,350	696,612	647,938
Europe [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	91,529	71,949	265,842	240,656
Asia [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	56,416	42,639	170,061	133,877
Mid_East/Africa [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	26,437	41,889	86,826	98,231
Canada/Latin_America [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 39,575	$ 19,401	$ 86,309	$ 66,727