Stock-Based Compensation (Schedule of Stock Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	$ 61,305	$ 76,468	$ 58,797
Less: Income tax benefit	(21,212)	(26,566)	(22,633)
Provision for income taxes	(21,212)	(26,566)	(22,633)
Total stock-based compensation, net of taxes	40,093	49,902	36,164
Stock Based Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	13,533	15,154	17,636
Deferred Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	1,885	1,885	2,085
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	47,807	62,928	41,584
1999 ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	5,553	4,319	3,772
Capitalized Internal Use Software [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation	7,473	7,818	6,280
Cost of Revenue [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effect of stock-based compensation on income	2,360	2,806	2,195
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effect of stock-based compensation on income	11,125	14,539	10,967
Sales and Marketing Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effect of stock-based compensation on income	27,990	35,525	27,411
General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Effect of stock-based compensation on income	$ 19,830	$ 23,598	$ 18,224