Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net income	$ 2,601	$ 3,371
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15,751	12,429
Compensation expense associated with stock-based payments	6,083	7,413
Impairment losses on intangible assets	3,365
Unrealized foreign currency gains, net	(3,429)	(3,346)
Deferred income taxes	406	(221)
Excess tax benefit related to stock-based compensation	(266)	(1,481)
Other non-cash adjustments, net	301	567
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	65,929	61,594
Prepaid expenses and other current assets	(2,500)	3,044
Other assets	(132)	1,744
Accounts payable	2,280	786
Accrued compensation	(6,883)	(10,722)
Other accrued expenses	(385)	1,998
Income taxes payable	(7,682)	(692)
Deferred revenue	(20,614)	(4,792)
Other liabilities	(2,577)	(2,048)
Net cash provided by operating activities	52,248	69,644
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(7,566)	(70,724)
Purchases of property and equipment	(8,129)	(4,427)
Change in restricted cash	937	(11,331)
Purchases of cost method investments	(2,106)	(20,203)
Purchases of investment securities	(6,007)	(4,067)
Sales and maturities of investment securities	5,477	29,061
Contributions on equity method investment	(1,926)
Change in notes receivable	(90)	(350)
Net cash used in investing activities	(19,410)	(82,041)
Cash flows from financing activities:
Proceeds from loans payable	561
Repayment of loans payable	(20,148)	(103)
Repurchase of common stock		(84,359)
Repayment of capital lease obligations	(131)	(25)
Cash paid for line of credit fees		(500)
Proceeds from the exercise of stock options	14,751	20,248
Excess tax benefit related to stock-based compensation	266	1,481
Net cash used in financing activities	(4,701)	(63,258)
Effect of exchange rate changes on cash and cash equivalents	(296)	4,537
Net increase (decrease) in cash and cash equivalents	27,841	(71,118)
Cash and cash equivalents, beginning of period	192,165	356,533
Cash and cash equivalents, end of period	220,006	285,415
Supplemental disclosures of consolidated cash flow information:
Cash paid for interest	911	782
Cash paid for income taxes	$ 8,742	$ 721

Name:	us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits are not generally reported as cash and cash equivalents. Includes cash and cash equivalents associated with the entity's continuing operations. Excludes cash and cash equivalents associated with the disposal group (and discontinued operation).