Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 624,330	$ 546,811
Short-term investments	157,657	394,346
Premium receivables	312,183	106,510
Deferred income taxes	28,253	24,720
Provider and other receivables	40,943	34,767
Prepaid expenses and other	58,265	58,606
Total current assets	1,221,631	1,165,760
Long-term investments	1,059,800	1,118,127
Investments on deposit for licensure	182,604	128,063
Property, equipment and software, net	121,939	110,602
Other long-term assets	44,580	18,300
Goodwill	316,747	260,496
Total assets	2,947,301	2,801,348
Current liabilities:
Claims payable	686,498	573,448
Unearned revenue	93,043	780
Accrued payroll and related liabilities	66,494	63,475
Contractual refunds payable	44,241	40,123
Accounts payable, accrued expenses and other	166,512	149,353
Current portion of long-term debt	0	256,995
Total current liabilities	1,056,788	1,084,174
Long-term debt	477,648	400,000
Deferred income taxes	23,101	19,447
Other long-term liabilities	11,663	13,208
Total liabilities	1,569,200	1,516,829
Stockholders' equity:
Common stock, $0.01 par value. Authorized 100,000,000 shares; outstanding 47,413,878 and 46,878,474 at June 30, 2012 and December 31, 2011, respectively	598	573
Additional paid-in capital	797,816	637,605
Accumulated other comprehensive income	13,946	11,942
Retained earnings	1,124,734	1,059,624
Stockholders' equity before treasury stock	1,937,094	1,709,744
Less treasury stock at cost (13,398,367 and 11,201,634 shares at June 30, 2012 and December 31, 2011, respectively)	(558,993)	(425,225)
Total stockholders' equity	1,378,101	1,284,519
Total liabilities and stockholders' equity	$ 2,947,301	$ 2,801,348