Reconciliation of Changes in Contingent Earn-Out Obligations (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Business Combinations [Abstract]
Beginning balance	$ 39,129
Contingent earn-out obligations associated with acquisitions	990
Remeasurement of fair value	(428)
Payments of contingent earn-out obligations	(5,556)
Ending balance	$ 34,135