Share-Based Compensation - Unrecognized Compensation Expense (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($)
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 49,386
Stock options
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 9,444
Average Expected Recognition Period - in Years	2 years 2 months 5 days
Restricted stock units
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 39,942
Average Expected Recognition Period - in Years	2 years 6 months