Goodwill and Intangible Assets - Schedule of Changes in Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Net balance at January 1	$ 252,520	$ 260,134
Additions	97,959	0
Currency translation	(10,141)	(7,614)
Net balance at December 31	$ 340,338	$ 252,520