INCOME TAXES (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Current provision [Abstract]
Federal	$ 200,766,000		$ 199,986,000		$ 350,451,000
State	18,279,000		21,105,000		28,216,000
Deferred provision/(benefit) [Abstract]
Federal	62,643,000		86,483,000		(117,600,000)
State	15,784,000		7,422,000		(13,149,000)
Income tax expense	297,472,000		314,996,000		247,918,000
Effective Tax Rate Reconciliation [Abstract]
Statutory federal tax rate (in hundredths)	35.00%		35.00%		35.00%
State income taxes, net of federal benefit (in hundredths)	3.08%		2.64%		1.56%
Tax exempt investment income (in hundredths)	(1.35%)		(0.97%)		(1.34%)
Remuneration disallowed (in hundredths)	1.35%		0.51%		0.55%
Other (in hundredths)	(0.16%)		(0.47%)		0.34%
Effective tax rate (in hundredths)	37.92%		36.71%		36.11%
Deferred tax assets [Abstract]
Net operating loss carryforward	37,203,000		50,913,000
Deferred compensation	42,990,000		82,747,000
Deferred revenue	9,750,000		8,540,000
Medical liabilities	61,631,000		55,442,000
Accounts receivable	1,039,000		1,499,000
Other accrued liabilities	44,160,000		96,429,000
Unrealized capital losses	153,000		1,415,000
Other assets	12,361,000		14,435,000
Gross deferred tax assets	209,287,000		311,420,000
Less valuation allowance	(2,335,000)		(4,168,000)
Deferred tax asset	206,952,000		307,252,000
Deferred tax liabilities [Abstract]
Unrealized gain on securities	(41,746,000)		(36,226,000)
Other liabilities	(4,798,000)		(11,119,000)
Depreciation	(10,127,000)		(12,119,000)
Intangibles	(169,243,000)		(179,802,000)
Internally developed software	(30,553,000)		(28,744,000)
Tax liability of limited partnership investment	(5,332,000)		(11,719,000)
Gross deferred tax liabilities	(261,799,000)		(279,729,000)
Net deferred tax (liability) asset	(54,847,000)	[1]	27,523,000	[1]
Operating Loss Carryforwards [Line Items]
Deferred tax asset - current assets	132,500,000		181,800,000
Deferred tax asset - noncurrent assets (liabilities)	187,300,000		154,200,000
Operating loss carryforwards, valuation allowance	2,300,000		4,200,000
Unrecognized tax benefits that would impact effective tax rate	34,400,000		38,200,000
Accrued interest and penalties, net of related tax benefit, recognized in statement of financial position	9,300,000		10,400,000
Accrued interest and penalties, net of related tax benefit, recognized in the statement of operations	2,800,000		3,300,000		4,000,000
Unrecognized Tax Benefits [Roll Forward]
Gross unrecognized tax benefits - beginning balance	85,432,000		136,255,000		129,084,000
Gross increases to tax positions taken in the current period	53,308,000		46,949,000		100,426,000
Gross increases to tax positions taken in prior periods	3,568,000		2,985,000		7,128,000
Gross decreases to tax positions taken in prior periods	(49,413,000)		(92,390,000)		(94,712,000)
Decrease due to setlements with tax authorities	(1,722,000)		0		0
Decreases due to a lapse of statute of limitations	(3,674,000)		(8,367,000)		(5,671,000)
Gross unrecognized tax benefits - ending balance	87,499,000		85,432,000		136,255,000
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	93,500,000
State Taxes [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 224,700,000

[1] Includes $132.5 million and $181.8 million classified as other current assets at December 31, 2012 and 2011, respectively, and $187.3 million and $154.2 million classified as other long-term liabilities at December 31, 2012 and 2011, respectively.