Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Revenue:
Premium revenue	$ 1,128,770		$ 976,685		$ 2,210,208		$ 1,941,905
Service revenue	36,888		21,054		73,562		21,054
Investment income	1,446		1,599		3,040		3,120
Total revenue	1,167,104		999,338		2,286,810		1,966,079
Expenses:
Medical care costs	949,359		839,613		1,862,891		1,662,429
Cost of service revenue	39,215		14,254		70,436		14,254
General and administrative expenses	96,921		78,079		191,357		156,959
Premium tax expenses	37,709		34,995		74,259		69,541
Depreciation and amortization	12,490		11,219		25,157		21,280
Total expenses	1,135,694		978,160		2,224,100		1,924,463
Operating income	31,410		21,178		62,710		41,616
Interest expense	3,683		4,099		7,286		7,456
Income before income taxes	27,727		17,079		55,424		34,160
Provision for income taxes	10,287		6,500		20,596		12,991
Net income	$ 17,440		$ 10,579		$ 34,828		$ 21,169
Net income per share (1):
Basic	$ 0.38	[1]	$ 0.27	[1]	$ 0.76	[1]	$ 0.55	[1]
Diluted	$ 0.38	[1]	$ 0.27	[1]	$ 0.75	[1]	$ 0.54	[1]
Weighted average shares outstanding (1):
Basic	45,897	[1]	38,611	[1]	45,743	[1]	38,541	[1]
Diluted	46,471	[1]	38,926	[1]	46,392	[1]	38,929	[1]

[1] All applicable share and per-share amounts reflect the retroactive effects of the three-for-two common stock split in the form of a stock dividend that was effective May 20, 2011.