Change in the Carrying Amount of Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
Goodwill [Roll Forward]
Balance, December 31, 2014	$ 825,038
Acquisitions	274,526
Foreign currency translation	(1,824)
Balance, September 30, 2015	$ 1,097,740