Stock Based Awards and Other Equity Instruments - Summary of Unrecognized Compensation Expense, Net of Estimated Forfeitures and the Weighted Average Period Remaining (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense (net of forfeitures), RSUs	$ 32,234
Weighted average period remaining (in years), RSUs	3 years 6 months 4 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense (net of forfeitures), Stock Options	$ 77,179
Weighted average period remaining (in years), Stock Options	2 years 10 months 21 days