Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 116,052	$ 11,917
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Amortization and depreciation	22,722	24,066
Adjustment to loss on sale of business	0	(40,822)
Gain on sale of discontinued operation	(116,990)	0
Share-based compensation expense	23,413	21,345
Deferred income taxes	24,883	(14,400)
Excess tax benefit on share-based compensation	(6,059)	(1,279)
Net realized (gain) loss on investments	(29,661)	(32,320)
Other changes	6,832	11,679
Changes in assets and liabilities, net of effects of acquisitions and dispositions:
Premiums receivable and unearned premiums	(173,387)	305,568
Other current assets, receivables and noncurrent assets	(78,203)	(70,468)
Amounts receivable/payable under government contracts	3,218	26,453
Reserves for claims and other settlements	158,581	(68,987)
Accounts payable and other liabilities	47,765	50,445
Net cash provided by (used in) operating activities	(834)	223,197
CASH FLOWS FROM INVESTING ACTIVITIES:
Sales of investments	1,132,836	1,632,037
Maturities of investments	97,815	148,196
Purchases of investments	(1,283,227)	(1,742,649)
Purchases of property and equipment	(55,030)	(32,136)
Net cash received from sale of business	248,238	0
Purchase price adjustment on sale of Northeast Health Plans	0	82,101
Sales (purchases) of restricted investments and other	6,024	(9,647)
Net cash provided by investing activities	146,656	77,902
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options and employee stock purchases	16,589	12,309
Excess tax benefit on share-based compensation	6,059	1,279
Repurchases of common stock	(69,330)	(313,440)
Borrowings under financing arrangements	110,000	697,500
Repayment of borrowings under financing arrangements	(122,500)	(552,500)
Net increase in checks outstanding, net of deposits	34	(40,817)
Customer funds administered	(4,348)	(79,232)
Net cash (used in) provided by financing activities	(63,496)	(274,901)
Net increase (decrease) in cash and cash equivalents	82,326	26,198
Cash and cash equivalents, beginning of period	230,253	350,138
Cash and cash equivalents, end of period	312,579	376,336
SUPPLEMENTAL CASH FLOWS DISCLOSURE:
Interest paid	16,990	16,783
Income taxes paid	$ 5,058	$ 28,209