Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Operating activities
Consolidated net income	$ 75,033	$ 70,296
Adjustments to reconcile consolidated net income to net cash flows from operating activities:
Depreciation and amortization	31,616	31,712
Deferred income taxes	492	(1,559)
Stock-based compensation expense	11,594	11,443
Provision for bad debt	990	1,076
Equity in net income of unconsolidated entities	(1,541)	(1,397)
Excess tax benefits from stock-option exercises and vesting of restricted stock units	(5,007)	(7,621)
Other, net	342	1,607
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(6,569)	(403)
Other assets	(3,551)	1,996
Accounts payable and accrued liabilities	(4,316)	(5,275)
Accrued compensation	(20,851)	(3,242)
Income taxes- current	7,220	9,442
Deferred revenue	7,684	618
Deferred rent	291	(984)
Other liabilities	(1,111)	(1,393)
Cash provided by operating activities	92,316	106,316
Investing activities
Purchases of investments	(134,929)	(298,876)
Proceeds from maturities and sales of investments	216,350	222,599
Capital expenditures	(22,876)	(14,689)
Acquisitions, net of cash acquired	0	300
Purchases of equity and cost method investments	10,304	0
Other, net	(4)	875
Cash used for investing activities	48,237	(89,791)
Financing activities
Proceeds from stock-option exercises, net	2,760	6,630
Excess tax benefits from stock-option exercises and vesting of restricted stock units	5,007	7,621
Common shares repurchased	(183,698)	(28,526)
Dividends paid	(14,867)	(7,539)
Other, net	(18)	(363)
Cash provided by (used for) financing activities	(190,816)	(22,177)
Effect of exchange rate changes on cash and cash equivalents	2,007	(254)
Net increase (decrease) in cash and cash equivalents	(48,256)	(5,906)
Cash and cash equivalents-beginning of period	200,437	180,176
Cash and cash equivalents-end of period	152,181	174,270
Supplemental disclosure of cash flow information:
Cash paid for income taxes	33,163	28,437
Supplemental information of non-cash investing and financing activities:
Unrealized Gain (Loss) on Available For Sale Investments	$ 2,221	$ (2,598)