Fair Value Measurements - Changes in Level 3 Financial Assets and Liabilities Measured on Recurring Basis (Detail) - Accounts Payable and Accrued Expenses [Member] - Contingent Consideration [Member] - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance, Contingent Consideration	$ 4,374	$ 1,452
Revaluations included in earnings	139	5,886
Ending Balance, Contingent Consideration	$ 4,513	$ 7,338