Stockholders' Equity - Schedule of Stock Based Compensation Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 28,008	$ 24,479	$ 84,800	$ 72,211
Provision for income taxes	(8,472)	(8,272)	(26,852)	(24,581)
Total stock-based compensation, net of income taxes	19,536	16,207	57,948	47,630
Cost of revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	3,030	2,885	8,901	8,230
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	4,979	4,583	14,517	12,819
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	12,110	10,048	35,438	29,278
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 7,889	$ 6,963	$ 25,944	$ 21,884