Fair Value of Financial Assets and Liabilities - Quantitative Information about Level 3 Fair Value Measurements (Detail) - Accounts Payable Accrued and Other Liabilities [Member] - Contingent Consideration [Member] - Level 3 [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, Fair Value	$ 64,337	$ 65,043	$ 63,514	$ 56,299
Present Value of Expected Payments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	5.50%	5.60%