Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill, Translation Adjustments	$ (15,011)	$ (21,411)
Goodwill, Acquired During Period	57,992
Goodwill, Period Increase (Decrease)		(955)
Goodwill [Roll Forward]
Beginning Balance	553,335	575,701
Ending Balance	596,316	$ 553,335
DVTEL [Member]
Goodwill [Line Items]
Goodwill, Acquired During Period	$ 57,992