CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 131,196	$ 94,622
Short term investments	306,823	326,653
Accounts receivable, net of allowance for doubtful accounts of $ 2,161 and $ 2,168 at March 31,2013 and December 31,2012, respectively	84,450	86,004
Revenue earned in excess of billings	25,576	11,875
Deferred income taxes and other current assets	60,840	51,736
Total current assets	608,885	570,890
Property and equipment	209,477	204,151
Less accumulated depreciation and amortization	87,972	85,033
Property and equipment, net	121,505	119,118
Goodwill	906	906
Non current term deposits with banks	14	14
Deferred income taxes and other non current assets	35,163	34,908
TOTAL ASSETS	766,473	725,836
Current liabilities:
Accounts payable	12,599	11,306
Accrued payroll and related costs	41,520	49,889
Income taxes payable	11,785	8,873
Accrued liabilities	20,794	23,644
Deferred revenue	2,708	4,694
Loans and borrowings	50,021	50,029
Total current liabilities	139,427	148,435
Other non current liabilities	12,387	11,731
TOTAL LIABILITIES	151,814	160,166
SHAREHOLDERS' EQUITY
Total shareholders' equity	614,659	565,670
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 766,473	$ 725,836