Fair Value - Change in Fair Value for All Assets and Liabilities Using Unobservable Level 3 Inputs As Determined By Level 3 Inputs (Detail) - Fair Value Measurement at Reporting Date (Level 3) [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 23,500
Additions for contingent consideration		$ 23,900
Payment for contingent consideration	(1,182)
Change in fair value	482	(400)
Current portion	10,502
Long-term portion	12,298
Ending balance	$ 22,800	$ 23,500