Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 78,896	$ 83,830
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	12,783	10,815
Bad debt provisions	28	34
Realized gains on sales of short term investments	(1,901)	(849)
Deferred income taxes	(4,490)	(6,058)
Compensation expense related to restricted stock	1,949	1,301
Adjustment related to the uncertain tax positions and other tax credits	(1,470)	(500)
Changes in assets and liabilities:
Accounts receivable and revenue earned in excess of billings	(32,651)	(36,118)
Other assets	(8,878)	24,043
Accrued payroll and other liabilities	30,021	13,598
Deferred revenue	(1,997)	1,718
Net cash provided by operating activities	72,290	91,814
CASH FLOWS FROM INVESTING ACTIVITIES:
Property and equipment expenditures	(37,445)	(13,541)
Purchase of mutual funds	(182,576)	(230,761)
Purchase of term deposits with banks	(91,077)	(110,261)
Proceeds from sales of mutual funds	181,027	236,649
Maturities of term deposits with banks	72,323	32,455
Net cash used in investing activities	(57,748)	(85,459)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common stock	2	831
Dividends paid	(7,495)	(7,458)
Net cash used in financing activities	(7,493)	(6,627)
Effect of foreign currency exchange rate changes on cash	3,618	(555)
Change in cash and cash equivalents	10,667	(827)
Cash and cash equivalents, beginning of period	78,505	87,822
Cash and cash equivalents, end of period	89,172	86,995
Non cash investing and financing activities:
Cash dividends declared but unpaid	2,494	2,489
Cash paid for income taxes	$ 9,266	$ 12,015