CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 582,771	$ 763,946
Short-term investments	272,113	230,007
Premium receivables	114,819	83,203
Deferred income taxes	28,008	28,063
Provider and other receivables	29,785	32,861
Prepaid expenses	39,929	13,538
Other current assets	14,319	7,083
Total current assets	1,081,744	1,158,701
Long-term investments	855,783	639,165
Investments on deposit for licensure	125,154	114,839
Property, equipment and software, net of accumulated depreciation of $189,830 and $174,683 at June 30, 2011 and December 31, 2010, respectively	99,315	96,967
Other long-term assets	13,109	13,220
Goodwill	260,496	260,496
Total assets	2,435,601	2,283,388
Current liabilities:
Claims payable	519,508	510,675
Unearned revenue	104,213	103,067
Accrued payroll and related liabilities	44,504	71,253
Contractual refunds payable	66,865	44,563
Accounts payable, accrued expenses and other	159,876	121,283
Current portion of long-term convertible debt	251,432	0
Total current liabilities	1,146,398	850,841
Long-term convertible debt	0	245,750
Deferred income taxes	10,506	7,393
Other long-term liabilities	13,161	13,767
Total liabilities	1,170,065	1,117,751
Stockholders' equity:
Common stock, $0.01 par value. Authorized 100,000,000 shares; outstanding 48,354,495 and 48,167,229 at June 30, 2011 and December 31, 2010, respectively	567	554
Additional paid-in capital	606,989	543,611
Accumulated other comprehensive income	5,982	627
Retained earnings	978,774	864,003
Stockholders' equity before treasury stock	1,592,312	1,408,795
Less treasury stock at cost (9,069,207 and 7,759,234 shares at June 30, 2011 and December 31, 2010, respectively)	(326,776)	(243,158)
Total stockholders' equity	1,265,536	1,165,637
Total liabilities and stockholders' equity	$ 2,435,601	$ 2,283,388