Share Based Compensation - Summary of Total Unrecognized Compensation Cost Related to Stock-Based Compensation (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 43,081
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	24,909
Weighted Average Period of Expense Recognition (in Years)	1 year 6 months 15 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost	$ 18,172
Weighted Average Period of Expense Recognition (in Years)	1 year 7 days