Stockholders' Equity Schedule of Stock Based Compensation Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 24,479	$ 22,635	$ 72,211	$ 69,180
Provision for income taxes	(8,272)	(9,242)	(24,581)	(27,114)
Total stock-based compensation, net of taxes	16,207	13,393	47,630	42,066
Cost of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	2,885	2,834	8,230	8,604
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	4,583	4,427	12,819	13,258
Sales and Marketing Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	10,048	8,746	29,278	25,671
General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 6,963	$ 6,628	$ 21,884	$ 21,647