Goodwill and Intangible Assets - Summary of Carrying Value of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Balance - beginning of the period	$ 315,920	$ 148,879
Acquisitions	5,945	167,041
Balance - end of the period	$ 321,865	$ 315,920