Share-Based Compensation (Details) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 6,946	$ 10,716	$ 10,525	$ 17,881
Share-based Compensation Expense Per Share, Basic	$ 0.09	$ 0.14	$ 0.14	$ 0.24
Share-based Compensation Expense Per Share, Diluted	$ 0.09	$ 0.14	$ 0.14	$ 0.24
Cost of Service [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	707	866	1,203	1,463
Selling and Marketing Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	261	1,831	308	2,937
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 5,978	$ 8,019	$ 9,014	$ 13,481