Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 786,084	$ 546,811
Short-term investments	174,028	394,346
Premium receivables	220,900	106,510
Deferred income taxes	36,926	24,720
Provider and other receivables	48,694	34,767
Prepaid expenses	18,540	37,851
Other current assets	17,852	20,755
Total current assets	1,303,024	1,165,760
Long-term investments	1,131,911	1,118,127
Investments on deposit for licensure	188,140	128,063
Property, equipment and software, net	129,671	110,602
Other long-term assets	42,859	18,300
Goodwill	316,747	260,496
Total assets	3,112,352	2,801,348
Current liabilities:
Claims payable	770,417	573,448
Unearned revenue	145,601	780
Accrued payroll and related liabilities	66,158	63,475
Contractual refunds payable	30,921	40,123
Accounts payable, accrued expenses and other	153,848	149,353
Current portion of long-term debt	0	256,995
Total current liabilities	1,166,945	1,084,174
Long-term debt	477,558	400,000
Deferred income taxes	28,527	19,447
Other long-term liabilities	12,377	13,208
Total liabilities	1,685,407	1,516,829
Stockholders' equity:
Common stock, $0.01 par value. Authorized 100,000,000 shares; outstanding 49,204,828 and 46,878,474 at September 30, 2012 and December 31, 2011, respectively	599	573
Additional paid-in capital	655,284	637,605
Accumulated other comprehensive income	19,811	11,942
Retained earnings	1,156,466	1,059,624
Stockholders' equity before treasury stock	1,832,160	1,709,744
Less treasury stock at cost (11,704,135 and 11,201,634 shares at September 30, 2012 and December 31, 2011, respectively)	(405,215)	(425,225)
Total stockholders' equity	1,426,945	1,284,519
Total liabilities and stockholders' equity	$ 3,112,352	$ 2,801,348