Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance	$ 320,761	$ 335,402	$ 345,453
Business acquisitions	54,631		3,232
Foreign currency translation adjustments	(2,275)	(14,641)	(13,283)
Ending Balance	$ 373,117	$ 320,761	$ 335,402