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, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, Fair Value	$ 52,737	$ 55,614
Present Value of Expected Payments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	7.30%	6.30%
Probability of meeting earnout	94.00%	96.00%
Present Value of Expected Payments [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	3.30%	3.30%
Probability of meeting earnout	75.00%	75.00%
Present Value of Expected Payments [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	9.20%	9.20%
Probability of meeting earnout	100.00%	100.00%