Share-Based Compensation - Unrecognized Compensation Expense (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($)
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 69,581
Stock options
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 12,710
Average Expected Recognition Period - in Years	2 years 8 months 9 days
Restricted stock units
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 56,871
Average Expected Recognition Period - in Years	2 years 10 months 2 days