Restatement of Previously Issued Financial Statements Cash Flow Restatement (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
NET INCOME	$ 26,355
Stock-based compensation	8,716	12,161
Deferred income taxes	9,603
Accounts receivable	18,927
Prepaid expenses and other assets	(1,967)
Accounts payable	488
Accrued expenses and other liabilities	3,329
Deferred revenue	5,640
Net cash provided by operating activities	118,154
Net cash used in provided by investing activities	(2,507)
Scenario, Previously Reported [Member]
NET INCOME		72,450
Stock-based compensation		13,073
Deferred income taxes		14,652
Accounts receivable		(17,674)
Prepaid expenses and other assets		(12,772)
Accounts payable		(13,817)
Accrued expenses and other liabilities		9,749
Deferred revenue		20,935
Net cash provided by operating activities		132,620
Payment of direct costs related to acquisitions		(2,579)
Net cash used in provided by investing activities		(12,446)
Scenario, Adjustment [Member]
NET INCOME		6,663
Stock-based compensation		(912)
Deferred income taxes		3,914
Accounts receivable		878
Prepaid expenses and other assets		9,798
Accounts payable		(1,140)
Accrued expenses and other liabilities		(9,090)
Deferred revenue		(12,690)
Net cash provided by operating activities		(2,579)
Payment of direct costs related to acquisitions		2,579
Net cash used in provided by investing activities		2,579
As Restated [Member]
NET INCOME		79,113	[1]
Stock-based compensation		12,161	[1]
Deferred income taxes		18,566	[1]
Accounts receivable		(16,796)	[1]
Prepaid expenses and other assets		(2,974)	[1]
Accounts payable		(14,957)	[1]
Accrued expenses and other liabilities		659	[1]
Deferred revenue		8,245	[1]
Net cash provided by operating activities		130,041	[1]
Payment of direct costs related to acquisitions		0
Net cash used in provided by investing activities		$ (9,867)	[1]

[1] (1) As restated - See Note 14 “Restatement of Previously Issued Financial Statements” of Notes to Condensed Consolidated Financial Statements.See notes to Condensed Consolidated Financial Statements.