Share-Based Compensation Unrecognized Share-Based Compensation Expense (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 49,097
Stock option
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 11,194
Average Expected Recognition Period - in Years	2 years 3 months 19 days
Restricted stock units
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 37,903
Average Expected Recognition Period - in Years	2 years 6 months 11 days