Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Goodwill balance at January 1	$ 184,464	$ 184,505
Effect of foreign exchange	(52)	(41)
Additions as the result of acquisitions	60	0
Goodwill balance at December 31	$ 184,472	$ 184,464