Acquisition - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Aggregate business acquisition purchase price				$ 37,827
Revenue		$ 303,098	$ 262,774	238,733
Net loss		$ (96,037)	$ (74,806)	(76,016)
Xtrakter Limited [Member]
Business Acquisition [Line Items]
Aggregate business acquisition purchase price	$ 37,827
Revenue				18,400
Net loss				$ 900