Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues:
Premium	$ 2,219,238	$ 1,523,433	$ 3,980,043	$ 3,059,228
Investment income and other	7,955	4,001	15,346	8,121
Total revenues	2,227,193	1,527,434	3,995,389	3,067,349
Expenses:
Health benefits	1,929,098	1,281,760	3,430,251	2,538,722
Selling, general and administrative	171,412	122,289	319,365	238,748
Premium tax	51,818	40,439	95,207	80,887
Depreciation and amortization	12,290	9,332	23,190	18,422
Interest	10,651	4,170	22,716	8,349
Total expenses	2,175,269	1,457,990	3,890,729	2,885,128
Income before income taxes	51,924	69,444	104,660	182,221
Income tax expense	19,900	25,150	39,550	67,450
Net income	$ 32,024	$ 44,294	$ 65,110	$ 114,771
Net income per share:
Basic net income per share	$ 0.68	$ 0.91	$ 1.38	$ 2.37
Weighted average number of common shares outstanding	47,312,154	48,419,556	47,186,248	48,342,756
Diluted net income per share	$ 0.63	$ 0.83	$ 1.27	$ 2.18
Weighted average number of common shares and dilutive potential common shares outstanding	50,439,487	53,541,368	51,170,927	52,658,303