Share-Based Compensation - Unrecognized Compensation Expense (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 62,244
Stock options
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 11,150
Average Expected Recognition Period - in Years	2 years 6 months 7 days
Restricted stock units
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 51,094
Average Expected Recognition Period - in Years	2 years 8 months 5 days