Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Balance as of beginning of year	$ 131,014	$ 123,031
Goodwill from businesses acquired	293,390	17,010
Currency translation effect on foreign goodwill balances	(2,841)	(9,027)
Balance as of end of year	$ 421,563	$ 131,014