CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 46,424	$ 40,745
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	3,365	4,180
Provision for doubtful debts / advances	107	564
Realized gains on sales of short term investments	(1,544)	(603)
Deferred income taxes	(1,413)	(715)
Compensation expense related to restricted stock	1,011	856
Changes in assets and liabilities:
Accounts receivable and revenue earned in excess of billings	(12,385)	(9,737)
Other Current assets	(12,022)	(13,084)
Accrued payroll and other liabilities	(558)	(4,713)
Deferred revenue	(2,110)	(3,976)
Net cash provided by operating activities	20,875	13,517
CASH FLOWS FROM INVESTING ACTIVITIES:
Property and equipment expenditures	(5,189)	(4,820)
Proceeds from sale of property and equipment	31	331
Purchase of mutual funds	(50,858)	(57,675)
Purchase of term deposits with banks	(106,207)	(76,414)
Proceeds from sales of mutual funds	82,445	58,067
Maturities of term deposits with banks	97,204	50,433
Net cash provided by (used in) investing activities	17,426	(30,078)
CASH FLOWS FROM FINANCING ACTIVITIES:
Dividends paid	0	(2,494)
Net cash used in financing activities	0	(2,494)
Effect of foreign currency exchange rate changes on cash	(1,727)	(1,724)
Change in cash and cash equivalents	36,574	(20,779)
Cash and cash equivalents, beginning of period	94,622	104,628
Cash and cash equivalents, end of period	131,196	83,849
Non cash investing and financing activities:
Cash dividends declared but unpaid	0	2,494
Cash paid for income taxes	12,299	7,977
Cash paid for interest	$ 218	$ 0