CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 536,009	$ 617,686
Short-term investments	111,844	111,359
Accounts receivable	355,272	331,815
Unbilled services	162,396	141,707
Inventory	52,429	48,257
Deferred income taxes	54,211	51,543
Prepaid expenses and other current assets	233,574	201,621
Total Current Assets	1,505,735	1,503,988
Property and equipment, net	875,977	913,612
Goodwill	118,581	109,820
Other assets	38,351	29,168
Total Assets	2,538,644	2,556,588
Current Liabilities:
Accounts payable	83,048	59,713
Accrued payroll and benefits	123,122	170,806
Accrued expenses and other current liabilities	111,889	153,808
Unearned revenue	202,560	240,398
Short-term debt	40,000	0
Income taxes payable	20,572	7,952
Total Current Liabilities	581,191	632,677
Long-term debt	250,000	250,000
Deferred income taxes	13,402	32,035
Other liabilities	78,378	76,630
Total Liabilities	922,971	991,342
Commitments and Contingent Liabilities
Stockholders' Equity:
Preferred Stock - Par value $1.00 per share; 10,000,000 shares authorized; no shares issued and outstanding at June 30, 2014 and December 31, 2013	0	0
Common Stock - Par value $0.01 per share; 140,000,000 shares authorized; 82,396,835 and 80,935,089 shares issued and outstanding, including those held in treasury, at June 30, 2014 and December 31, 2013, respectively	824	809
Paid-in capital	943,652	859,535
Retained earnings	1,847,586	1,779,833
Accumulated other comprehensive income	37,708	25,746
Treasury stock at cost (25,877,192 and 24,595,756 shares at June 30, 2014 and December 31, 2013, respectively)	(1,214,097)	(1,100,677)
Total Stockholders' Equity	1,615,673	1,565,246
Total Liabilities and Stockholders' Equity	$ 2,538,644	$ 2,556,588