Share-Based Compensation Unrecognized Share-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 45,352
Stock option
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	14,978
Average Expected Recognition Period - in Years	2 years 6 months 4 days
Restricted stock units
Unrecognized Share Based Compensation Expense [Line Items]
Unrecognized Expense	$ 30,374
Average Expected Recognition Period - in Years	2 years 6 months 15 days